Update on harmonized guidelines for probiotics being developed by the Codex Alimentarius

By Prof. Gabriel Vinderola, PhD,  Associate Professor of Microbiology at the Faculty of Chemical Engineering from the National University of Litoral and Principal Researcher from CONICET at Dairy Products Institute (CONICET-UNL), Santa Fe, Argentina

In December 2017, at the 39th session of the Codex Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU) in Berlin, members of the Committee agreed to include in the agenda a discussion of harmonized guidelines on probiotics for use in foods and food supplements. Argentina supported this initiative and proposed itself to lead the work, building a guideline based on the present Argentinian framework on probiotics.

The first draft of the document was presented in 2018. Some countries supported the work to develop harmonized guidelines with a definition and minimum requirements for characterization, quality, and labeling, while other countries did not support the initiative, arguing that there was no perceived need to start this new work, it was not a priority for the Committee at that moment, and the document should be revised to provide more clarity on the need to start work on this topic.

Early in 2019, Argentina convened a panel of local experts to contribute to the discussion of the paper based on the issues raised in the first round of revision. I participated in that panel.

In November 2019, at the 41th meeting of the CCNFSDU, an updated version of the paper was presented. This revision clarified that the goal of the work was to produce a regulatory framework for the use of probiotics in food and food supplements. This objective is in line with the purpose of the Codex Alimentarius to guarantee safe and quality food and to ensure equity in international food trade.

In the course of the debate, some delegations favored the topic, stressing the value of regulatory harmonization within the Codex. They pointed out that framework could be based on the existing probiotic definition and guidelines of FAO and WHO, providing clear guidance and principles focused on the use of probiotics as ingredients. Delegations that opposed the new work noted that the Codex had already adopted principles and guidelines of a similar (horizontal) nature on issues such as labeling, claims, contaminants, safety and hygiene covering all foods, including food supplements, and that probiotic-specific regulations were not needed. FAO and WHO had also conducted work in this area.

After the debate, the Committee considered that the document presented needed further clarification, especially with regard to the scope and the issues raised in the discussion. Finally, it was agreed that Argentina and Malaysia would revise the document to be presented at the next plenary meeting of the Committee (42th meeting), to be held in November 2020. It was agreed that in order to assess the need to work on this topic, the new proposal should include a justification for additional probiotic-specific criteria in accordance with the mechanism for assigning Committee priorities.

Due to the COVID-19 pandemic, the 42th meeting has been postponed until November 2021, and a deadline of March 2021 was set for submitting the revised paper to the CCNFSDU.

The information reported in this post was kindly provided by Andrea Moser, Argentinian representative at the Codex Committee on Nutrition and Foods For Special Dietary Uses.

 

Probiotics to Prevent Necrotizing Enterocolitis: Moving to Evidence-Based Use

By Ravi Mangal Patel, MD, Msc, Associate Professor of Pediatrics, Emory University School of Medicine and Children’s Healthcare of Atlanta. rmpatel@nullemory.edu Twitter: @ravimpatelmd

Necrotizing enterocolitis (NEC) is one of the most lethal neonatal diseases, yet most people have never heard about it. The disease primarily affects preterm infants and is characterized by the development of intestinal inflammation. Clinically, the disease often manifests with an infant developing feeding intolerance or abnormal abdominal exam findings. The diagnosis is confirmed by abdominal x-ray or ultrasound. One of the key diagnostic radiographic findings is pneumatosis, which is air in the lumen of the bowel caused by gas-producing bacteria.

Dr Ravi Mangal Patel

NEC accounts for 1 out of every 10 deaths in US neonatal intensive care units. Among extremely preterm infants (those born at 22-28 weeks’ gestation) in the US, NEC is the most common single cause of death between 2 weeks and 2 months of age. Many infants with NEC undergo surgery to remove diseased bowel and those who recover and survive are at risk for long-term neurodevelopmental impairment and short bowel syndrome.

Decades of research into NEC have identified several key risk factors, including formula feeding, inconsistent feeding, abnormal intestinal oxygenation and [gut microbiota] dysbiosis. Studies have shown that dysbiosis, or abnormal intestinal colonization, is an important antecedent risk factor for the development of NEC. These studies have found that infants who develop NEC have an increase or bloom in the relative abundance of proteobacteria, compared to those who do not develop NEC. These proteobacteria, which contain a lipopolysaccharide coating, may lead to inflammation through their interaction with Toll-like receptor 4.

Given the role of dysbiosis in NEC, efforts to intervene by provision of probiotics to prevent NEC is a rational and extensively studied intervention, with over 63 randomized trials enrolling ~15,000 infants to date. The aforementioned meta-analysis, along with several others (Table 1), show probiotic supplementation results in large magnitude reductions in the risks of NEC and death and more modest reductions in the risks of late-onset sepsis. However, there is more limited data on extremely preterm infants and the quality or certainty of evidence for probiotics for the prevention of NEC was low in a recent Cochrane review.

 

Source: https://doi.org/10.1053/j.sempedsurg.2017.11.008

In the United States, an increasing number of centers have begun to routinely provide probiotics, with the greatest increase in use beginning in 2015. Observational studies evaluating routine probiotic use show benefits that are similar in magnitude to those from randomized trials, supporting the external validity of the results from the trials. This includes a large recent evaluation of probiotic use in the United States. Around the world, probiotic use is highly variable, from 100% of NICUs in New Zealand, 68% of NICUs in Germany, to 12% in the UK, 21% in Canada and 14% in the United States. Some of the variability in clinical use may be related to the uncertainty regarding the quality of commercially available probiotic products and need for clarity regarding strain-specificity of effects. There are many considerations both for and against routine use of probiotics to prevent NEC (Table 2). Current probiotic dietary supplements do not undergo FDA’s premarket review and approval requirements for safety and effectiveness or have to meet manufacturing and testing standards for drugs, and the potential risks were highlighted by a case of an infant death from a contaminated supplement. There is currently no FDA-approved live biotherapeutic product to prevent NEC.

Source: doi: 10.1016/j.earlhumdev.2019.05.009

Recent recommendations and guidance from ESPHGAN and the AGA also demonstrate that some medical organizations recognize the strength of the data in support of probiotic use to prevent NEC. It has been over two decades since the first study demonstrating the benefit of probiotic supplementation to prevent NEC in preterm infants. Now, more than ever, the evidence continues to accumulate regarding the beneficial effects of probiotic use in preterm infants as a compelling strategy to reduce the risks of both NEC and death. Therefore, considering the balance of potential risks and benefits including data from both randomized trials and routine implementation studies, my opinion is that the cumulative evidence to date supports routine probiotic use to prevent NEC and death in preterm infants.

As important is considering the parent voice regarding probiotic use. The NEC Society is a non-profit focused on NEC that has worked to incorporate the voice of the patient-family in clinical decisions.

Disclosures: Dr. Patel serves on the data-safety monitoring board of the Connection Study, which is a trial examining the use of an investigational probiotic to decrease the risk of NEC.

For further information, see this seminar by Dr. Patel: Practical Consideration for Probiotics in the NICU

Opportunity for research grants to help understand evidence linking live dietary microbes and health

For thousands of years, cultures across the globe have been consuming fermented foods, many of which contain diverse and numerous live microbes. Yet scientists are still puzzling over whether a greater intake of live microbes results in measurably better health. As part of long-term efforts to understand evidence for the health benefits of live dietary microbes and identify research gaps, ILSI North America is presenting a grant opportunity for researchers to help assess current scientific evidence for these links.

Researchers are invited to submit grant proposals, which should include the research approach along with anticipated challenges, resources, timeline, and key deliverables. The ILSI North America Gut Microbiome Committee also requests the inclusion of a suggested publication plan for the work. Budgets in the range of $100-150K will be considered. The deadline to submit the proposal is October 30, 2020 at 11:59PM EST. See here for more details.

ISAPP is supporting long-term efforts in this topic area. Its latest effort is the publication of a review paper (in press) on the links between dietary live microbes and health, called Should there be a recommended daily intake of microbes? The paper is authored by ISAPP board members Prof. Maria Marco, Prof. Colin Hill, Prof. Bob Hutkins, Prof. Dan Tancredi, Prof. Dan Merenstein, and Dr. Mary Ellen Sanders along with well-known nutrition researcher, Prof. Joanne Slavin.

ILSI North America is a non-profit scientific organization whose mission is to advance food safety and nutrition science for the benefit of public health. The organization engages academic, government, and industry experts by conducting­ research projects, workshops, seminars, and publications.

 

Current status of research on probiotic and prebiotic mechanisms of action

By Mary Ellen Sanders, PhD, ISAPP Executive Science Officer

Human intervention studies in the fields of probiotics and prebiotics assess the health effects of these ingredients, whether it’s improving specific symptoms or preventing the occurrence of a health condition. Yet scientists in the field recognize the importance of learning the ‘chain of events’ by which probiotics and prebiotics are able to confer health benefits. Such mechanistic insights allow better probiotic selection and development of therapeutic approaches, as well as more precise dosing.

Mechanisms of action for probiotics and prebiotics are complex and often difficult to pinpoint, especially since any given health benefit may derive from multiple co-functioning mechanisms. However, scientists have made incremental gains in understanding these mechanisms. This scientific progress was covered in a recent webinar co-presented by ISAPP and ILSI-Europe, titled Understanding Prebiotic and Probiotic Mechanisms that Drive Health Benefits. Speakers for the webinar were:

  • Sarah Lebeer, University of Antwerp, Belgium
  • Colin Hill, University College Cork, Ireland
  • Karen Scott, University of Aberdeen, UK
  • Koen Venema, Maastricht University – campus Venlo, The Netherlands

The webinar was held live on September 17, 2020. Of the 499 webinar registrants, 357 attended the webinar live from 57 countries, from Australia to the US. ISAPP and ILSI-Europe hope the webinar will serve as a resource for people who want a rapid overview about mechanisms of action.

Watch the full webinar here, and read further for a summary of key points from these experts.

Prebiotic benefits and mechanisms of action

Prebiotics are defined as substrates that are “selectively utilized by host microorganisms conferring a health benefit”. ‘Utilization’ in the gut may involve crossfeeding, which means products produced by the first microbes degrading the prebiotic can then be used by different members of the host microbiota – so it may take a series of complex steps to get to a final health outcome. However, selective utilization and health benefit are always required for a substance to meet the definition of a prebiotic.

The health benefit of a prebiotic can be local (in the gut) or systemic. Locally, prebiotics can act via fecal bulking, as they are typically types of fiber. In addition, they can produce short-chain fatty acids (SCFAs), which reduce gut pH and thereby can discourage pathogenic and toxigenic activity of gut microbes, increase calcium ion absorption and provide energy for gut epithelial cells.

Systemic functions of prebiotic metabolism include them being used as substrates for microbes that produce or interact with host cells to produce molecules with neurochemical, metabolic or immune activity. Further, SCFAs can end up in the blood and can reach the liver, muscles and the brain. The SCFAs interact with specific host receptors and can lead to the release of satiety hormones or interact with receptors in the liver, adipose tissue and muscle tissue, leading to reduced inflammation. Prebiotics can also interact directly with immune cells.

Probiotic health effects and mechanisms of action

Health and disease are the end results of complex interactions on a molecular scale within a human or animal host.  Host molecules also interact with microbial molecules, including those molecules introduced with or produced by probiotics. Designing studies to discover probiotic mechanisms in human research is extremely challenging because both host and probiotic are very complex systems that most probably engage with one another on multiple levels. Probiotic molecules can have direct effects and downstream effects, and we are aware of only a few cases where a health effect can be tied to one specific probiotic molecule.

Probiotics can interact directly with the host, but also can act indirectly by influencing the microbiome. There may be many different mechanisms by which a given probiotic interacts with the host.

It is interesting to note that probiotics use some of the same types of mechanisms (pili, small molecule production, etc.) that are used by pathogens, microbes that have a detrimental effect on the host.  But these shared mechanisms are usually connected to surviving or colonising strategies, not those that cause damage to the host.

L. rhamnosus GG is a well-researched model probiotic, for which many mechanisms have been identified, including pili, immune modulators and lactic acid production, some mechanisms shared with other probiotic strains and species. Other studies have identified mechanisms for novel types of probiotics. For example, in mice and humans taking a strain of Akkermansia, heat killed cells had the same or even better effect on markers of metabolic health, which implies that the molecules (perhaps proteins in the bacteria, unaffected by heat treatment) are mediating the effect in this case.

See here to watch the webinar in full.

 

 

Citizen scientists step up for a research project on women’s health

By Prof. Sarah Lebeer, Research Professor in Microbiology and Molecular Biology, Department of Bioscience Engineering, University of Antwerp, Belgium

Lactobacilli are a very important group of bacteria that live on the human body and in many other environments on Earth. They have been linked to human health for more than 100 years already, but mainly in the context of digestive health and dairy-based fermented foods. Knowledge about other habitats and applications of lactobacilli is lagging behind, and surprisingly, we know little about where lactobacilli come from in the life of an individual or even in the evolution of humans. Studying the genetic capabilities of lactobacilli and their interactions with the host will give us a clearer picture of how these bacteria help us stay healthy.

This knowledge gap inspired me to apply for a European Research Council (ERC) grant. Last year I was awarded with this prestigious grant, which provides funding to explore novel aspects about the ecology and evolutionary history of lactobacilli.

Lactobacilli are dominant colonizers of the human vagina, where they play a key role in women’s health. Among the lactobacilli, I consider the vaginal lactobacilli as ‘mother lactobacilli’. As you might have noticed from our recent reclassification of the Lactobacillus genus complex, the vaginal type strains Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii and Lactobacillus iners all belong to the Lactobacillus genus strictu sensu, because they are closely related to the first Lactobacillus species ever described: Lactobacillus delbrueckii subsp. bulgaricus, originating from yogurt. So, the study of vaginal lactobacilli could also be seen as a study on the basics of the genus Lactobacillus and what makes this group so important for human health.

At present, it is not well understood why lactobacilli dominate the human vagina under healthy conditions. Interestingly, this appears to be the case only in humans and not in other mammals. We speculate that it is because lactobacilli have beneficial functions and, when transmitted from mother to infant in early life, have a peculiar capacity to inhibit dangerous pathogens for our offspring, including group B streptococci, Enterobacteriaceae, fungi and various viruses. Lactobacilli also have interesting immune modulatory capacities. A rather unique feature in humans is the menstrual cycle and the estrogen-stimulated production of glycogen being a major sugar source for the lactobacilli in the vagina, resulting in high production of lactic acid, an excellent antimicrobial molecule against numerous pathogens. But the short answer is that we have no really clear answer to these fundamental questions of human biology.

Because the ERC funding allows us to be a bit more aspirational than in our usual research endeavors, we decided to address some of these questions by engaging women as citizen scientists. So we launched an ambitious citizen science project on vaginal lactobacilli and women’s health, named the Isala Project (see www.isala.be — it’s only in Dutch, but easily translatable with Google Translate 😊). The project is named after Isala Van Diest (1842-1916), the very first female physician in Belgium.

Our initial ambition was to ask 200 healthy women at different points in their menstrual cycle to provide vaginal swabs for microbiome sequencing and culture of lactobacilli. Our plan was to launch the call for volunteers on International Women’s Day (March 8, 2020), but COVID-19 made us revise our plans. We postponed our call until March 24, realizing that most women were at home during the lockdown. We assumed that since the national news was dominated by the SARS-CoV-2 virus, it was going to be difficult to reach out with traditional news channels. However, within two weeks, more than 5500 women registered for Isala on our website and we even had to restrict sign-ups!

We thought many women would still drop out if they found out they had to fill in an extensive questionnaire with intimate and lifestyle-related questions, but this was not the case. Almost 4700 women filled out the extensive questionnaire, demonstrating strong enthusiasm, commitment, and engagement. We decided to send a self-sampling kit to all the women who had filled in the entire questionnaire and supplied their postal address. Over the summer, we sent 4100 self-sampling kits, and of these, 80% of the women have already sent back their swabs to us. Our lab members are overjoyed with the citizen science enthusiasm!

Even though managing the logistics of the postal packages was a huge administrative challenge, we managed to keep everything straight. Thanks to an amazing team of dedicated and super-organized PhD students, lab techs, postdocs, master students, clinicians, bio-informaticians, statisticians, and communication partners, we can now say that we are around halfway through the project. We have been able to process all swabs that arrived to DNA extracts (for microbiome sequencing) and glycerol stocks (for the lactobacilli biobank and metabolomics later). Within the next months, these samples will be run on our MiSeq for 16S rRNA amplicon sequencing; the functional, genetic, and metabolomic characterization will of course take much more time. Making vaginal microbiome profiles for all these citizen scientists by next spring is now our priority, as we want to send all participants a personal update by then.

With this project, we are also changing up the traditional publication timeline: we are communicating about the process while not having all the results yet. We will inform the participants about their microbiome profiles before we submit or publish the related peer-reviewed manuscripts. This is because we want to actively communicate with our participants, opening discussions on the topic — and empowering women, without delay, to think about their vaginal health. We even have suggested conversation starters on our website and in the sampling boxes.

Time will tell whether these efforts will pay off for women’s health! Citizen Science can sometimes be surprising, but so far, we are very happy with the contact we’ve made with our committed and enthusiastic participants. We even have a hashtag, ‘#LetsSwab for the future’. I highly encourage my fellow scientists to consider organizing citizen science projects on topics related to the human microbiome, probiotics and prebiotics, because it is a unique way to get inspired and to do research on a large scale.

 

Precision approaches to microbiota modulation: Using specific fiber structures to direct the gut microbial ecosystem for better health

By now, hundreds of scientific articles show the differences in gut microbiota composition and function between states of health and disease, leading to the idea that gut microbiota modulation is a promising way to achieve better health. But in practice, changing the complex community of microbes in the gut has proved challenging—the gut microbiota of the average adult is remarkably stable.

When it comes to diet, non-digestible carbohydrates are the main way to provide nutritional support to microbial populations and to modulate these communities, either in composition or in function. Can these dietary fibers be used to modulate the gut microbiota in a precise manner, with the aim of inducing certain health effects?

Prof. Jens Walter of APC Microbiome Ireland addressed this topic in a plenary lecture at the ISAPP 2020 annual meeting, titled: Precision microbiome modulation through discrete chemical carbohydrate structures.

Walter sees the gut microbiota as an complex ecological community of interacting microbes that is remarkably stable in healthy adults (albeit with a high degree of inter-individual variation). In order to precisely modulate gut microbiomes through diet, scientists must consider the ecological principles that shape these communities and determine how they function.

In the lecture, Walter introduced a perspective for using discrete fiber substrates to precisely modulate gut microbiota – a framework first articulated in a 2014 paper by Hamaker and Tuncil. According to this framework, gut microbiomes can be precisely manipulated, whether to achieve a certain microbiota composition or the production of health-relevant metabolites, through the use of specific fiber structures that are aligned with microbes that have the ability to utilize them. Walter explains some of the main challenges of the framework, which relate to the vast inter-individual differences in the gut microbes that are present, and their response to fiber; and discovering the exact dose of a fiber required for reliable changes in a person’s gut microbiota.

At the core of the presentation is a study by the Walter Lab that systematically tested the framework through a human dose-response trial using resistant starches with slight differences in their chemical structure. The findings of the study, which were published this year, illustrate how this ecological concept can be successfully applied. This shows the colonic microbiota can be successfully shaped in a desired manner with discrete dietary fiber structures.

See Prof. Walter’s presentation in full here.

New publication co-authored by ISAPP board members gives an overview of probiotics, prebiotics, synbiotics, and postbiotics in infant formula

For meeting the nutritional needs of infants and supporting early development, human milk is the ideal food—and this is reflected in breastfeeding guidelines around the world, including the World Health Organization’s recommendation that babies receive human milk exclusively for the first six months of life and that breastfeeding be continued, along with complementary foods, up to two years of age or beyond. In certain cases, however, breastfeeding is challenging or may not even be an option. Then, parents rely on alternatives for feeding their infants.

A group of scientists, including three ISAPP board members, recently co-authored an article in the journal Nutrients entitled Infant Formula Supplemented with Biotics: Current Knowledge and Future Perspectives. In the review, they aimed to highlight the new technologies and ingredients that are allowing infant formula to better approximate the composition of human milk. They focused on four types of ingredients: probiotics, prebiotics, synbiotics, and postbiotics.

Co-author Gabriel Vinderola, Associate Professor of Microbiology at the Faculty of Chemical Engineering from the National University of Litoral and Principal Researcher from CONICET at Dairy Products Institute (CONICET-UNL) in Santa Fe, Argentina says, “Modern technologies have allowed the production of specific microbes, subtrates selectively used by the host microbes, and even non-viable microbes and their metabolites and cell fragments—for which scientific evidence is available on their effects on infant health, when administered in adequate amounts. Thus, this current set of gut modulators can be delivered by infant formula when breastfeeding is limited or when it is not an option.”

The authors say a well-functioning gut microbiota is essential for the overall health and proper development of the infant, and components of human milk support the development of this microbiota. They list important human milk components and the novel ingredients that aim to mimic the functions of these components in infant formulas:

  • Human milk oligosaccharides (HMOs)

HMOs are specialized complex carbohydrates found in human milk, which are digested in the infant colon and serve as substrates for beneficial microbes, mainly bifidobacteria, residing there. In recent years, prebiotic mixtures of oligosaccharides (e.g. short-chain GOS and long-chain FOS) have been added to infant formula to recapitulate the effects of HMOs. But now that it’s possible to produce several types of HMOs synthetically, some infant formulas are enriched with purified HMOs: 2’-fucosyllactose (2’FL) or lacto-N-neotetraose (LNnT). Even 3′-galactosyllactose (3′-GL) can be naturally produced by a fermentation process in certain infant formulas.

  • Human milk microbiota

Human milk has a complex microbiota, which is an important source of beneficial bacteria to the infant. Studies support the notion that the human milk microbiota delivers bioactive components that support the development of the infant’s immune system. Probiotic strains are sometimes added to infant formula in order to substitute for important members of the milk microbiota.

  • Bacterial metabolites

Human milk also contains metabolic byproducts of bacteria called “metabolites” in addition to the bacteria themselves. These components have not been fully studied to date, but bacterial metabolites such as butyrate and other short-chain fatty acids may have important health effects for the overall development of the infant. A future area of nutritional research is likely to be the addition of ‘postbiotics’ — non-viable cells, their metabolites and cell components that, when administered in adequate amounts, promote health and well-being — to infant formulas. (ISAPP convened a scientific consensus panel on the definition of postbiotics, with publication of this definition expected by the end of 2020.)

 

The precise short- and long-term health benefits of adding the above ingredients to infant formula are still under study. One pediatric society (the ESPGHAN Committee on Nutrition) examined the data in 2011 and at that time did not recommend the routine use of infant formulas with added probiotic and/or prebiotic components until further trials were conducted. A systematic review concluded that evidence for the health benefits of fermented infant formula (compared with standard infant formula) are unclear, although improvements in infant gastrointestinal symptoms cannot be ruled out. Although infant formulas are undoubtedly improving, review co-author Hania Szajewska, MD, Professor of Paediatrics at The Medical University of Warsaw, Poland, says, “Matching human milk is challenging. Any alternative should not only match human milk composition, but should also match breastfeeding performance, including how it affects infant growth rate and other functions, such as the immune response.”

 

Can the microbiota help protect against viral infections? Summary of an ISAPP discussion group

By Drs. Karen Scott, University of Aberdeen, and Sarah Lebeer, University of Antwerp

As part of the ISAPP virtual annual meeting 2020, around 85 members of the ISAPP community joined us in a Zoom discussion forum to discuss the topic: “Do our resident microbes help protect against viral infections?” A scientific perspective on this topic is especially important during the COVID-19 pandemic, when many members of the general public are wondering about actions (if any) they can take to protect themselves before a SARS-CoV-2 vaccine becomes widely available.

We introduced the topic and were joined by several invited experts, who also gave short presentations:

  • Joel Dore (INRAE France)
  • Tine Licht (Technical University of Denmark)
  • Mary O’Connell-Motherway (APC Microbiome, Cork)

The ensuing conversation, open to all participants, was wide-ranging, starting with the gut microbiota and expanding to include the microbiota at other body sites, and the effects of the gut microbiota around the body gut via transport of metabolites. Here are some of the main take-home messages from this discussion.

Components of the microbiota (bacteria, fungi, archaea, viruses and others) at a body site interact with each other. Although scientists often study one component of the (gut) microbiota at a time, members of the microbiota from different kingdoms interact with each other in ways that can be positive or negative for the host. In particular, specific activities of bacteria can be widespread, frequent or rare among members of the microbiota – and it is often the rare activities that have important impacts on the course of a disease: e.g. specific antimicrobial agents produced by some bacteria prevent Salmonella infections in pigs and cure mastitis in cows.

Mechanistic work shows bacteria in the microbiota can prevent, eliminate or promote viral infections. Studies have shown some microbes can prevent attachment of viruses to cell surfaces by offering alternative receptors. In contrast, virus particles can utilise other bacterial cells to “mask” them and facilitate entry into host cells. Other bacteria can stimulate the immune system to promote elimination of a viral infection, while under specific circumstances this same immune activation may promote viral infection. When it comes to the microbiota of the respiratory tract, studies have shown its bacterial members play a crucial defensive role. Probiotics that are already shown to be effective against other viral upper respiratory tract infections may have promise for COVID-19 (either for preventing infection or enhancing recovery), and currently studies are underway to investigate these.

Probiotics or prebiotics could be useful adjuncts to vaccination, but they are not likely to become a reality for COVID-19. Scientists are perennially interested in the topic of vaccine efficacy, and some probiotics have been shown to increase efficacy for widely available vaccines in certain populations. But in the current pandemic, developing a safe and effective vaccine (or vaccines) is the primary concern. Testing the possibility of probiotic or prebiotic combination therapies would be secondary, since the necessary testing would take longer in order to evaluate the adjuvant potential of different probiotic strains. Because the expression of cell surface molecules that can mediate adjuvant activity is strain-dependent, screening and selecting the best strains would probably take too long to become a reality for COVID-19. Certainly, participants agreed that introduction of a safe, effective vaccine was the priority, without any delays to test out ‘extras’.

A scientific rationale exists for maintaining gut microbiota diversity in order to reduce the development of diseases which, as “underlying health conditions”, may result in more severe COVID-19 outcomes. It is clear that individuals with certain underlying health conditions—related to the central nervous system and gastrointestinal system, and to metabolic and immunological dysfunction—tend to experience a more severe disease, with worse outcomes, following SARS-CoV-2 infection. Many of these conditions are also associated with a gut microbiota that is different from that of healthy controls. Research consistently shows that individuals with metabolic disease, for example, have a less diverse, lower ‘richness’ microbiota, which is often linked to increased intestinal permeability, higher gut inflammation and more oxidative stress throughout the body. This increased oxidative stress then exacerbates the microbial dysbiosis, causing more inflammation and increased intestinal permeability – creating a vicious cycle effect. This cycle is linked with obesity and metabolic disorders. In healthy individuals who are at risk of developing such conditions, the diversity of the existing resident microbiota may be increased by the application of prebiotics or synbiotics, included within a healthy, diverse, high-fibre diet. These approaches may improve bacterial fermentation in the large intestine, resulting in increased production of important bacterial metabolites that help regulate host metabolism, including short-chain fatty acids.

Until a SARS-CoV-2 vaccine is available, supporting a diverse and complex gut microbiota through diet may contribute to maintaining health in at-risk populations. Despite the intense worldwide scientific efforts and collaborations, it is unlikely that an effective vaccine against COVID-19 will be widely available soon. In the meantime, we have to protect ourselves and our local ‘at-risk’ populations as best we can. We are learning more and more about the mechanisms of dietary fibre’s health effects, in which gut bacteria play a major role. Evidence suggests that keeping our gut microbiota as complex and diverse as possible by consuming a high-fibre diet (supplemented by fermented foods, probiotics and prebiotics) might help mitigate susceptibility to infections in general.

New synbiotic definition lays the groundwork for continued scientific progress

By Karen Scott, Mary Ellen Sanders, Kelly Swanson, Glenn Gibson, and Bob Hutkins

When Glenn Gibson and Marcel Roberfroid first introduced the prebiotic concept in 1995, they also conceived that prebiotics could be combined with probiotics to form synbiotics. In 2011, Gibson and Kolida described additional criteria for defining synbiotics and proposed that synbiotics could have either complementary or synergistic activities.

In the past decade, nearly 200 clinical studies on synbiotics have been reported in the literature. Nonetheless, the term itself has been open to interpretation, and the existing definition – a probiotic plus a prebiotic – was inadequate to account for the synbiotic formulations described in the literature or available in the marketplace.

To provide clarity on the definition and lay the groundwork for progress in the years ahead, scientists working on probiotics, prebiotics, and gut health came together in an expert panel. The outcome of this panel, the ISAPP consensus definition and scope of the word synbiotic, has now been published in Nature Reviews Gastroenterology & Hepatology.

A diverse panel of experts

The panel of experts who met to discuss the definition of synbiotics in May, 2019, consisted of eleven interdisciplinary scientists in the fields of microbiology and microbial ecology, gastrointestinal physiology, immunology, food science, nutritional biochemistry, and host metabolism. The panel’s range of experience was important in order to ensure the definition made sense from different scientific perspectives. The panel met under the auspices of ISAPP and was led by Prof. Kelly Swanson.

An inclusive definition

Initially, it seemed logical that synbiotic could be defined as a combination of a probiotic and a prebiotic, with each component needing to meet the criteria for either probiotic or prebiotic according to the previous scientific consensus definitions (Hill, 2014; Gibson, 2017). However, as the group discussed different scenarios and combinations, it became clear that this narrow characterization of a synbiotic could place undue emphasis on the individual components of a synbiotic rather than the combination of these components. For example, the original definition would not include a combination of inulin (a prebiotic) with live microorganisms that did not have probiotic status, even if live microbes in the host selectively utilized inulin and the combination was shown to confer a health benefit.

The definition of synbiotic agreed upon by the panel is: “A mixture, comprising live microorganisms and substrate(s) selectively utilized by host microorganisms, that confers a health benefit on the host.”

The panel discussed exactly which microorganisms must be targeted by the substrate in a synbiotic and decided that the targeted ‘host microorganisms’ can include either autochthonous microbes (those already present in the host) or allochthonous microbes (those that are co-administered).

Further, the panel defined two distinct types of synbiotics: complementary and synergistic. In a ‘synergistic synbiotic’, the substrate is designed to be selectively utilized by the co-administered microorganism(s)—and do not necessarily have to be individual probiotics or prebiotics, as long as the synbiotic itself is health promoting. In a ‘complementary synbiotic’, an established probiotic is combined with an established prebiotic designed to target autochthonous microorganisms— therefore each component of a complementary synbiotic must meet the minimum criteria for a probiotic or a prebiotic.

The definition is purposefully inclusive, so a synbiotic could be established for different hosts, e.g. humans, companion animals, or agricultural animals. Even subsets of these hosts (those of a certain age or living situation) could be targeted by synbiotic products. Moreover, products may be called synbiotics if they target areas of the host’s body outside of the gut (e.g. the skin).

Implications for study design

According to the new definition, different types of studies must be designed for synergistic synbiotics versus complementary synbiotics. For the former, a single study must demonstrate both selective utilization of the substrate and a health benefit. For complementary synbiotics, however, it is only necessary to show a health benefit of the combined ingredients; it is not necessary to show selective utilization of the prebiotic substrate, since selective utilization should have already been established.

The panel remained open to different scientifically valid approaches to demonstrate selective utilization of the substrate. Further, the nature of the ‘health benefit’ was not prescribed, but to the extent biomarkers or symptoms are used, they must be validated.

Continuing scientific progress

The field of synbiotics is evolving – some studies exist to show human health benefits deriving from synbiotic ingredients. While the studies on individual components (probiotics and prebiotics separately) may guide those in the field, there is the possibility that we will find novel uses and applications for synbiotics in the years ahead.

Causality is an important issue that scientists will need to address in this field. The definition of synbiotics rests on an important concept originally advanced in the definition of prebiotics: evidence of health benefit plus selective utilization of the substrate by microbes must be demonstrated. More investigations of causal links between these two things will have to be explored; this is closely connected with ongoing work to uncover probiotic and prebiotic mechanisms of action.

This definition is a first step—and it is fully expected that the field will evolve in the years ahead as more data are generated on the benefits of synbiotics for human and animal hosts.

Find the ISAPP press release on this publication here.

See here for a previous ISAPP blog post on the synbiotic definition.

See below for ISAPP’s new infographic explaining the concept of synbiotics.

How do probiotics stay alive until they are consumed?

By Prof. Gabriel Vinderola PhD,  Associate Professor of Microbiology at the Faculty of Chemical Engineering from the National University of Litoral and Principal Researcher from CONICET at Dairy Products Institute (CONICET-UNL), Santa Fe, Argentina

See the Spanish version of this blog post here.

As a professor, most of my days are spent with people from the academic and scientific world. But through some outreach activities, I am also fortunate to interact with many people who are not scientists by training, but have curious, scientific minds. One question I am often asked is, “Is it really possible for probiotics to still be alive when they are dried and in a capsule?” The answer is yes. Let me provide some basic background on probiotics and explain my response.

The idea of consuming live microbes to promote health is not new. Back in 1907, Élie Metchnikoff, a disciple of Louis Pasteur, the father of microbiology, associated the intake of fermented milks containing live lactobacilli, with a prolonged and healthy life in Bulgarian peasants (see here). This idea was later captured by the concept of probiotics: live microorganisms that, when administered in adequate amounts, confer a health benefit on the host (Hill et al. 2014). Four simple and pragmatic criteria allow one to conclude if specific strains of microorganisms qualify as a probiotic for use in foods and dietary supplements. Probiotic strains must be (i) sufficiently characterized; (ii) safe for the intended use; (iii) supported by at least one human clinical trial showing they are effective; and (iv) alive in the product at an efficacious dose throughout shelf life (Binda et al. 2020). Being alive at the moment of consumption is one of the key characteristics of probiotics.

Life is the condition that distinguishes animals and plants from inorganic matter. Life includes the capacity for growth, for reproduction and for metabolic activity. In order to sustain life, certain environmental conditions must be met, but these differ for different organisms. For microbes, the availability of water and nutrients, adequate temperature and pH (acidity), and the absence of growth inhibitors are essential conditions. However, it is possible to manipulate certain conditions to bring about a state where growth may be put in “stand-by mode”, yet the microbe remains alive. We cannot imagine ourselves in a condition where life is preserved even without any metabolic activity, but for microbes it is possible. Probiotics can be in foods (yoghurts, fermented milks, fruit juices, cereal bars) or in food supplements (capsules, compressed pills) in a “hibernation” state, characterized by no growth, no reproduction and no metabolic activity, waiting for the proper conditions to come back to full metabolic life. This occurs when the microbes reach the gut, which has proper temperature, nutrient availability, lack of inhibitors, adequate acidity and water. Thus, in case of microbes, there is an uncoupling of life and metabolic activity. Even without having any metabolic activity, they can still be alive, but in a dormant state.

Open a food supplement containing probiotics and you will probably find a white dry powder. This is what the microbes may look like in their dormant state, due to a technological process called freeze-drying or lyophilization. Freeze-drying is a two-stage process where cells are first quickly frozen at very low temperatures (-40 to -70°C, or less, using liquid nitrogen for example). Then, frozen water is removed by a gentle process of evaporation at low pressure and temperature, called sublimation. This process removes most of the water from around and inside the cells, leaving the microbes in a dormant state. Water activity is scientists’ way of measuring water availability for the microbes. This technological measure ranges from 0 (no water) to 1 (pure water). A water activity close to 0 impairs growth. In food supplements, freeze-drying leaves water activities less to 0.2, ensuring that no metabolic activity will take place during the shelf life of the product.

Bifidobacteria cells (circled in red) freeze-dried in a probiotic powder. This is a scanning electron microscopy image amplified 10,000 times. Cells are embedded in dry polydextrose.

So yes, probiotics in food supplements are alive in their own way. This is the case also for probiotics included in certain foods such as cereal bars. In case of food products with water activities closer to 1, such as yogurts, fermented milks, cheeses or fruit juices containing probiotics, the factor that limits metabolic activity is the low temperature at which these products are stored, combined in certain cases (yogurts, fermented milks, fruit juices) with the low pH (or high acidity) of these products. The combination of low temperature and acidity is effective in maintaining probiotic cells in a dormant state, impairing any metabolic activity that may lead to cell stress and cell death along the shelf life of the product. Yet, even while tightly controlling factors that impair metabolic activity, some cell death may occur during the shelf life of probiotics in the products that deliver them. In this case, responsible manufacturers are sure to add extra probiotic cells so that the necessary amount of viable cells needed to deliver a health effect are present through the end of the shelf life of the product.

In both probiotic foods and food supplements, the number of viable cells is commonly expressed as a certain number of colony forming units, or by the abbreviation “CFU”. As probiotics are present in high concentrations, the number of viable cells often reaches into the billions within a capsule or in a serving of yogurt. To be able to count such enormous numbers of cells, microbiologists must make serial dilutions of the probiotic product. Then, they will put a small drop of a dilution on the surface of a Petri dish containing a culture medium on which probiotics will grow. Each probiotic cell (or clump of cells) will grow in place and form a visible colony that can be observed to the naked eye, and counted.

Agar plate containing colonies of a probiotic bacteria. Cells deposited on the surface of the agar plate duplicated several times until forming a visible amount of cells: a colony.

In brief, live probiotics are present in food and supplements, but in a state of life different to that of higher organisms where metabolic activity is taking place at all times. During shelf life, the metabolic activity of probiotics is stopped by freeze-drying them (food supplements) or by a combination of low temperature and acidity (yogurts and fruit juices, for example). Active growth returns when these microbes enter out gut and find the proper conditions of nutrients, temperature, acidity and water to be active and deliver their health effects.

EFSA’s QPS committee issues latest updates

By Bruno Pot, PhD, Vrije Universiteit Brussel and Mary Ellen Sanders, PhD, Executive Science Officer, ISAPP

On July 2nd, the European Food Safety Authority (EFSA) published the 12th update of the qualified presumption of safety (QPS) list, a list of safe biological agents, recommended for intentional addition to food or feed, covering notifications from October 2019-March 2020. It was good news to all stakeholders to see that EFSA discussed the recent taxonomic changes within the genus Lactobacillus (see ISAPP blog here) as well as addressed some microbes being considered as potential, novel probiotics.

What is QPS?

In 2005 EFSA established a generic approach to the safety assessment of microorganisms used in food and feed, prepared by a working group of the former Scientific Committee on Animal Nutrition, the Scientific Committee on Food and the Scientific Committee on Plants of the European Commission. This group introduced the concept of “Qualified Presumption of Safety” (QPS), which described the general safety profile of selected microorganisms. The QPS process was mainly developed to provide a generic pre‐evaluation procedure harmonized across the EU to support safety risk assessments of biological agents performed by EFSA’s scientific panels and units. A QPS assessment is performed by EFSA following a market authorisation request of a regulated product requiring a safety assessment. Importantly, in the QPS concept, a safety assessment of a defined taxonomic unit is performed independently of the legal framework under which the application is made in the course of an authorisation process.

QPS status is granted to a taxonomic unit (most commonly a species), based on reasonable evidence. A microorganism must meet the following four criteria:

1.       Its taxonomic identity must be well defined.

2.       The available body of knowledge must be sufficient to establish its safety.

3.       The lack of pathogenic properties must be established and substantiated (safety).

4.       Its intended use must be clearly described.

Any safety issues, noted as ‘qualifications’, that are identified for a species assessed under QPS must be addressed at the strain or product level. Microorganisms that are not well defined, for which some safety concerns are identified or for which it is not possible to conclude whether they pose a safety concern to humans, animals or the environment, are not considered suitable for QPS status and must undergo a full safety assessment. One generic qualification for all QPS bacterial taxonomic units is the need to establish the absence of acquired genes conferring resistance to clinically relevant antimicrobials (EFSA, 2008).

If an assessment concludes that a species does not raise safety concerns, it is granted “QPS status”. Once EFSA grants a microorganism QPS status, it is included on the “QPS list” and no microorganism belonging to that group needs to undergo a full safety assessment in the European Union.

The QPS list is re‐evaluated every 6 months by the EFSA Panel on Biological Hazards based on three “Terms of Reference” (ToR)*. This evaluation is based on an extensive literature survey covering the four criteria mentioned above.

What happened to the genus Lactobacillus?

In April 2020, based on a polyphasic approach involving whole genome sequencing of more than 260 species of the former genus Lactobacillus, the genus was reclassified into 25 genera including the emended genus Lactobacillus, which includes host-adapted organisms that have been referred to as the L. delbrueckii group, the earlier described genus Paralactobacillus as well as 23 novel genera, named Acetilactobacillus, Agrilactobacillus, Amylolactobacillus, Apilactobacillus, Bombilactobacillus, Companilactobacillus, Dellaglioa, Fructilactobacillus, Furfurilactobacillus, Holzapfelia, Lacticaseibacillus, Lactiplantibacillus, Lapidilactobacillus, Latilactobacillus, Lentilactobacillus, Levilactobacillus, Ligilactobacillus, Limosilactobacillus, Liquorilactobacillus, Loigolactobacilus, Paucilactobacillus, Schleiferilactobacillus, and Secundilactobacillus. Read more in the original paper here or on the ISAPP blog here).

These name changes could have considerable economic, scientific and regulatory consequences, as discussed during an expert workshop organised by the Lactic Acid Bacteria Industrial Platform (LABIP). One of the points discussed during this workshop was the possible implication of the name change on the QPS list in Europe and the FDA’s GRAS list in the USA.

What did EFSA do?

In a 42-page document, which can be found here, amongst others, the species of the former genus Lactobacillus that were already listed on the QPS list, have been formally renamed at the genus level. The species names remained the same, as the taxonomic revision from April 2020 only affected the genus name. As a result, the genus names of 37 former Lactobacillus species on the QPS were updated, and now span 13 different genera. Table 1 delineates these nomenclature updates.

Table 1: Taxonomic revision of the 37 species formerly of the Lactobacillus genus present on the QPS list (published here).

Earlier denomination                                                      Updated denomination
Lactobacillus acidophilus                     Lactobacillus acidophilus
Lactobacillus alimentarius Companilactobacillus alimentarius
Lactobacillus amylolyticus Lactobacillus amylolyticus
Lactobacillus amylovorus Lactobacillus amylovorous
Lactobacillus animalis Ligilactobacillus animalis
Lactobacillus aviarius Ligilactobacillus aviarius
Lactobacillus brevis Levilactobacillus brevis
Lactobacillus buchneri Lentilactobacillus buchneri
Lactobacillus casei Lacticaseibacillus casei
Lactobacillus collinoides Secundilactobacillus collinoides
Lactobacillus coryniformis Loigolactobacillus coryniformis
Lactobacillus crispatus Lactobacillus crispatus
Lactobacillus curvatus Latilactobacillus curvatus
Lactobacillus delbrueckii Lactobacillus delbrueckii
Lactobacillus dextrinicus Lapidilactobacillus dextrinicus
Lactobacillus diolivorans Lentilactobacillus dioliovorans
Lactobacillus farciminis Companilactobacillus farciminis
Lactobacillus fermentum Limosilactobacillus fermentum
Lactobacillus gallinarum Lactobacillus gallinarum
Lactobacillus gasseri Lactobacillus gasseri
Lactobacillus helveticus Lactobacillus helveticus
Lactobacillus hilgardii Lentilactobacillus hilgardii
Lactobacillus johnsonii Lactobacillus johnsonii
Lactobacillus kefiranofaciens Lactobacillus kefiranofaciens
Lactobacillus kefiri Lentilactobacillus kefiri
Lactobacillus mucosae Limosilactobacillus mucosae
Lactobacillus panis Limosilactobacillus panis
Lactobacillus paracasei Lacticaseibacillus paracasei
Lactobacillus paraplantarum Lactiplantibacillus paraplantarum
Lactobacillus pentosus Lactiplantibacillus pentosus
Lactobacillus plantarum Lactiplantibacillus plantarum
Lactobacillus pontis Limosilactobacillus pontis
Lactobacillus reuteri Limosilactobacillus reuteri
Lactobacillus rhamnosus Lacticaseibacillus rhamnosus
Lactobacillus sakei Latilactobacillus sakei
Lactobacillus salivarius Ligilactobacillus salivarius
Lactobacillus sanfranciscensis Fructilactobacillus sanfranciscensis

EFSA further specifies that “To maintain continuity within the QPS list, all the strains belonging to a previous designed Lactobacillus species will be transferred to the new species. Both the previous and new names will be retained”. (Emphasis added.)

Impact of the QPS update on the probiotic field

The probiotic field can also take note of this current update for its review of two ‘next generation’ probiotic species evaluated for possible QPS status, Akkermansia muciniphila and Clostridium butyricumAkkermansia muciniphila has been actively researched as a probiotic to help manage metabolic syndrome (Depommier et al. 2019). A probiotic preparation containing both Akkermansia muciniphila and Clostridium butyricum has been studied in a randomized controlled trial for postprandial glucose control in subjects with type 2 diabetes (Perraudeau et al 2020). The committee’s decisions:

  • Akkermansia muciniphila is not recommended for QPS status due to safety concerns;
  • Clostridium butyricum is not recommended for QPS status because some strains contain pathogenicity factors; this species is excluded for further QPS evaluation.

The publication of the next scientific opinion updating the QPS list is planned for December 2020, based on the 6-month assessments carried out by the BIOHAZ Panel.

Conclusion

Due to its scientific rigor and continuous updates, the EFSA QPS efforts provide useful perspective for the global scientific community on safety of candidate microbes for use in foods. Their embrace of the new taxonomic status of lactobacilli signals to other stakeholders that it is time to start the process of doing the same. Further, their assessment of species being proposed and studies as ‘next generation’ probiotics is an important reminder that a microbe’s status as a human commensal is not a guarantee of its safety for use in foods.

 

*QPS Terms of Reference (ToR) (quoted from here):

ToR 1: Keep updated the list of biological agents being notified in the context of a technical dossier to EFSA Units such as Feed, Pesticides, Food Ingredients and Packaging (FIP) and Nutrition, for intentional use directly or as sources of food and feed additives, food enzymes and plant protection products for safety assessment.

ToR 2: Review taxonomic units previously recommended for the QPS list and their qualifications when new information has become available. The latter is based on a review of the updated literature aiming at verifying if any new safety concern has arisen that could require the removal of the taxonomic unit from the list, and to verify if the qualifications still efficiently exclude safety concerns.

ToR 3: (Re)assess the suitability of new taxonomic units notified to EFSA for their inclusion in the QPS list. These microbiological agents are notified to EFSA and requested by the Feed Unit, the FIP Unit, the Nutrition Unit or by the Pesticides Unit.

 

New publication addresses the question: Which bacteria truly qualify as probiotics?

Although the international scientific consensus definition of probiotics, published in 2014, is well known—”live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”—the word is often used incorrectly in practice.

A recent article published in Frontiers in Microbiology builds on this definition and describes four criteria for accurate use of the word ‘probiotic’. Eight scientists co-authored the paper, including two ISAPP board members. The project was initiated by industry scientists affiliated with IPA Europe.

The authors explain why it’s important for scientists and companies to be sure the four identified criteria apply before using the term ‘probiotic’. Given the many misuses of the term that are evident today, however, consumers need to scrutinize ‘probiotic’ products to be sure they are legitimate.

Read the ISAPP press release on this publication here.

See an infographic summary of this publication here.

 

 

GG + BB-12 don’t reduce antibiotic use in an elderly, institutionalized population

By Mary Ellen Sanders, PhD, ISAPP Executive Science Officer

Close to two years ago, a team convened by ISAPP conducted a meta-analysis showing that probiotics may reduce number of antibiotic prescriptions, with evidence primarily in children (ISAPP-initiated systematic review and meta-analysis shows the association of probiotic consumption with reduced antibiotic prescriptions). A recent study suggests that this outcome likely does not extend to elderly care home residents.

A newly published randomized, placebo-controlled trial tested a combination product comprising two well-studied probiotic strains, Lacticaseibacillus (formerly known as Lactobacillus) rhamnosus GG and Bifidobacterium animalis subsp lactis BB-12, administered at ~1.5 × 1010 per day to institutionalized residents 65 years of age or older to test if this treatment reduced antibiotic administration. The study showed no reduction in antibiotic use compared to the control. Further, the probiotic was not associated with improvement in secondary endpoints, which included many that probiotics are hypothesized to mitigate, including incidence of common infections, duration of infections, C. difficile infection, antibiotic associated diarrhea, hospitalizations, or presence of antibiotic resistant microbes in fecal samples.

Other endpoints suggested that the probiotic group fared worse than the placebo group. Statistically significant differences were found between the probiotic and placebo groups for antibiotics administered for lower respiratory tract infections and well-being scores at 3 months.

This was a well-controlled, comprehensively reported study.  Some factors to consider in interpreting these results:  The population was elderly (mean age = 85.3 years) and infirmed (66% lacked capacity to consent and 63 of 310 randomized subjects died prior to conclusion of the study). Stool culture at 3 months showed L. rhamnosus present in 84% of intervention group compared to 37% of placebo group, although the groups were matched for this factor at baseline. This suggests some cross-contamination between the placebo and intervention groups may have occurred. As the authors state, exposure of the placebo group to the probiotic “would dilute any between-group differences in outcomes.” A higher number of C. diff positive subjects were assigned to the probiotic group than the placebo group (7.2% vs 0%, respectively).

Overall, this study provides evidence that L. rhamnosus GG + B. lactis BB-12 are not effective prophylactically in a population of elderly care home residents.

 

Bulgarian yogurt: An old tradition, alive and well

By Mariya Petrova, PhD, Microbiome insights and Probiotics Consultancy, Karlovo, Bulgaria

Family and family traditions are very important to me. Some of you may have seen my previous blog post on fermented food and my father’s tradition of making fermented cabbage and vegetables every autumn. Of course, this is not limited to my family – in Bulgaria, it is our culture and our country’s tradition. But despite the fact that I wrote about fermented vegetables first, Bulgarians are much more proud of another fermented product – yogurt.

I still remember waking up every morning when I was a kid and having a healthy homemade yogurt to start the day. I still do when I am back at home, because my father continues to make yogurt at home. Here, I’ll take you on a new adventure and tell you all about Bulgarian yogurt, an old tradition still alive in every home.

Élie Metchnikoff and his work are well familiar to anyone involved in probiotic research. In short, Metchnikoff observed in 1907 that Bulgarian peasants lived longer lives and he attributed this to their daily consumption of yogurt.

Thanks to Metchnikoff, research on Bulgaria and Bulgarian yogurt was put on the map because of our healthy way of living and eating fermented foods. You may know this part of the story. Still, few actually know that Metchnikoff was intrigued by the work of the Bulgarian researcher Stamen Grigorov a few years earlier. In fact, it was because of Stamen Grigorov’s work that we now know ‘who’ (i.e. which microbes) live in our yogurt and how essential those tiny bacteria are. In 1905 Stamen Grigorov actually discovered and isolated for the first time Lactobacillus bulgaricus (now known as Lactobacillus delbrueckii subsp. bulgaricus) from homemade yogurt. That’s why we are so proud of Bulgarian yogurt. Not only do we love to eat it, but the probiotic research was partially initiated in our country, and an entire Lactobacillus species is named after our country. There is even a small museum dedicated to Bulgarian yogurt and to the work of Stamen Grigorov, located in the house where he was born. In the museum, if you are visiting Bulgaria, you can learn how to make yogurt at home and a bit more about the history of Grigorov’s discoveries.

We are so proud of our yogurt that many Bulgarians will tell you that ancient Bulgarian tribes were the ones who discovered yogurt by accident. Since Bulgarian tribes were nomadic, they carried the milk in animal skins, which created an environment for bacteria to grow and produce yogurt. This is indeed the way people learned to make yogurt, but it most likely happened in many places independently. Of course, I know many countries make yogurt but I remain proud of all the discoveries that happened in my country (I am saying this because at times I have been judged when I tried to say how important we find the yogurt in Bulgaria and how proud we are).

Yogurt is a tradition in Bulgaria. I don’t know a Bulgarian who does not eat yogurt on a daily basis, up to a few pots per day. And I am not talking about those sweet yogurt products that are made by adding jam or vanilla. I am talking about real, natural yogurt, slightly sourer than most of the products that can be found in the Western world. We add yogurt to almost everything, it is just the perfect addition. It is even the basis of a traditional Bulgarian cold summer soup called “tarator,” made of yogurt, water, cucumber, garlic, and dill. We also make a salad with it called “snezhanka”, and it contains yogurt, cucumbers, garlic, and walnuts. (Recipes can be found below if you want to try something new during the lockdown.) In fact, I am so “addicted” to our yogurt that in every country I go to, the first thing I have do is to find a good yogurt. It took me years to find a good one in Belgium when I lived there (even though one product was labelled ‘Bulgarian yogurt’, it was not the same for sure). In Canada, it was somehow easier. After trying a few different products, it was even faster to find something that I like in the Netherlands, but they have many kinds of milk products. Yet none of them are truly comparable with what you can find in Bulgarian shops. Even the smallest shops have at least 3 to 4 different types because we have a lot of yogurt factories. Every product is different, it has a unique taste and can be made of different kinds of milk.

But honestly, nothing is the same as the homemade yogurt. Many people still make yogurt at home, including my father. I don’t quite remember a time when there was no homemade yogurt on the table at home. It was initially my grandmother making the yogurt and the white Bulgarian cheese (it is nothing to do with Feta but that’s the closest way to explain what it is). So it was somehow logical that my father started making yogurt as well. He knows the technique from his grandmother and grew up with fresh homemade yogurt. My grandparents had a lot of cows, sheep, and goats, so we always had plenty of milk to ferment. Making yogurt at home is so very simple that more and more young people dare to do it. In fact, making yogurt is so easy, I wonder why I am not doing it myself during the lockdown.

How to make it, you may ask?

So you need fresh milk, which my family in Bulgaria currently gets from a local farm. The milk is carefully boiled, and while it is still warm, transferred to a preferable container where you want to make the yogurt. We use old yogurt jars that were very popular before. For some time, my father also used Tupperware, so you can choose anything that you find handy. Before transferring the milk, my father also separates the cream from the milk in a separate jar and uses it to make homemade butter by constantly shaking the jar for around 10 minutes (it is an intensive workout, I tried it a few times!). The biggest problem these days is having a good starter culture so you can begin the milk fermentation. As a starter culture, most of the people, including my father, use a spoon or two of the previous batch of yogurt. So my father never finishes all the yogurt; he always makes sure that there are some leftovers so he can start a new fermentation. He usually adds one tablespoon of the old yogurt to 500 ml warm milk (around 45 C). Of course if the milk is too hot, the bacteria present in the starter culture will die, and nothing will happen. There is also the case that the milk is too cold, and then it will most likely still ferment, but it will have a strange consistency, something between milk and yogurt. If my father is out of old yogurt to start a new fermentation, he usually buys his favorite yogurt from the shop and uses this as starter. Once the jars are filled, he packs blankets all around them to keep the environment warm so the fermentation will begin. From here, you need around 4h to 5h to have a nice homemade yogurt. Simple and straightforward. The next morning you can have a great family breakfast, remembering the old traditions, talking about old memories, passing on the torch to the new generation, and enjoying a healthy start to the day.

The next time you have yogurt, I hope you enjoy it and remember the Bulgarian traditions!

 

Tarator soup recipe:

What you need: 1 cucumber, 250 -300 g yogurt, 1-2 cloves crushed garlic, salt, oil, water, fresh chopped dill. (Most of the ingredients depend on your taste so feel free to add more or less of certain ingredients. Some people also add parsley and walnuts, but it is up to your taste.)

How to make it: Peel and cut the cucumbers into cubes and put them in a preferred bowl; add the crushed garlic, and the minced dill. Beat the yogurt until it turns to liquid and mix it with the rest of the ingredients. Add salt and oil to taste. Add water to make the soup as liquid as you like. Put into the refrigerator to cool it. You can also make it with cold yogurt and cold water. It is perfect for the hot summer days.

Snezhanka (which means “Snow White” in Bulgarian) salad recipe:

What you need: 1 cucumber, 500 g yogurt, 1-2 cloves crushed garlic, 2-3 spoons ground walnuts, salt, oil, fresh chopped dill. (Again, it depends on your taste, if you like more cucumber or yogurt just add more.)

How to make it: First strain the yogurt for a couple of hours, so that all unnecessary water is drained away. Peel and cut the cucumbers into cubes and put them in the bowl. Add the strained yogurt. Add the fresh dill, salt and oil to taste. Sprinkle the walnuts on top of the salad. Perfect for all seasons. If you don’t have a fresh cucumber, you can also use pickles — the final result is also very delicious.

Early career researchers discuss the future of probiotics and prebiotics in the first ISAPP-SFA paper

By Irina Spacova, ISAPP-SFA 2019 President and postdoctoral fellow at the University of Antwerp, Belgium

Early career scientists play a vital and dynamic role in research, especially in environments supporting their enthusiasm and drive for innovation. ISAPP has long been promoting young researchers through its Students and Fellows Association (ISAPP-SFA), which is a student-led branch of ISAPP established in 2009. The SFA was championed and guided from its inception through June 2020 by Prof. Gregor Reid. Together with ISAPP, the organization encourages diversity and participation through free memberships and ISAPP meeting travel grants open to all students and fellows working in research institutions. Currently, ISAPP-SFA includes 450 members from 50 countries in Asia, Africa, North and South America, Europe, and Australia.

The 2019 ISAPP meeting in Antwerp, Belgium was a milestone for ISAPP-SFA participation with 48 early career attendees from 19 countries. Facilitated by discussion clubs and poster sessions, the Antwerp meeting created an exceptional ‘melting pot’ of ideas. It was clear that young researchers had a lot to say, and the lingering idea of creating the first ISAPP-SFA paper finally took shape during the ISAPP 2019 dinner cruise of the Antwerp Harbor.

Less than a year later, the paper “Future of probiotics and prebiotics and the implications for early career researchers” was accepted in Frontiers in Microbiology, just in time for the 2020 ISAPP meeting. This initiative was driven by the ISAPP-SFA 2019 executive committee members Irina Spacova, Hemraj Dodiya, Anna-Ursula Happel, Conall Strain, Dieter Vandenheuvel, and Xuedan Wang. The core of the paper reflects what we as early career researchers believe are the biggest opportunities and challenges in advancing probiotic and prebiotic science, and summarizes a wide array of promising in vitro, in vivo and in silico tools. We emphasize the important goal of using probiotics and prebiotics to ameliorate global issues, and give examples of current initiatives in developing countries, such as Westernheadseast.ca and Yoba4Life.org. Our advice for early career researchers is to form inter-connected teams and implement the diverse toolsets to further advance the probiotics and prebiotics field.

We had a lot of fun with this paper, but also several challenges. It was not trivial to produce a concise paper with many opinions, techniques and references that would be useful to both young and established researchers. This intercontinental endeavor between young scientists working in Belgium, Japan, Ireland, South Africa, USA, and UK required a lot of early-morning and late-night meetings. Many interactions and discussions were necessary to deliver a novel perspective to add to the many excellent reviews on probiotics and prebiotics already published. Accessibility of the publication was a decisive factor, and one of the reasons why we chose to publish open access in Frontiers in Microbiology. Of course, this publication would not be possible without ISAPP, and we are especially grateful for the input and encouragement from Gregor Reid and Mary Ellen Sanders.

60 Minutes’ 13 minutes on probiotics

By Mary Ellen Sanders, PhD, ISAPP Executive Science Officer 

On June 28, 60 Minutes aired a 13-minute segment about probiotics titled, “Do Probiotics Actually Do Anything?” Unfortunately the media segment did not provide listeners with a nuanced perspective.

‘Probiotics’ were treated as if they were one entity, ignoring the best approach to addressing the topic of what probiotics do: evaluate the evidence for specific strains, doses and endpoints, and then make a conclusion based on the totality of the evidence. They would have found that many experts agree that actionable evidence exists for certain probiotics to prevent antibiotic associated diarrhea (here, here), prevent upper respiratory tract infections (here), prevent morbidity and mortality associated with necrotizing enterocolitis (here,), treat colic (here), and treat acute pediatric gastroenteritis (here). (For an overall view of evidence, see here.)

Importantly, not all retail probiotics have evidence (at least evidence that is readily retrievable, see here and here). But that does not mean that none do.

The 60 Minutes segment also highlighted questions about probiotic safety. No intervention is without risk, and no one claims as much for probiotics. Prof. Dan Merenstein, MD, just one clinical investigator of probiotics, has collected over 20,000 pediatric clinical patient days’ worth of safety data over the past eight years of clinical investigation, with no indication of safety concerns. In fact, participants in the placebo group generally have more adverse events than in the probiotic groups. But importantly, the safety standard for probiotics was mischaracterized by 60 Minutes. According to Dr. James Heimbach, a food safety expert (not interviewed in the segment) who has conducted 41 GRAS determinations on probiotics, over 25 of them notified to the FDA, he objects to the statement that GRAS is a lower safety bar than a drug. He clarifies:

“The safety standard that applies to food additives and GRAS substances, “reasonable certainty of no harm,” is a far higher standard than that applying to drugs. Drugs are judged against a risk/benefit standard, which can potentially allow quite dangerous drugs on the market provided they offer a significant benefit. The safety standard for drugs also applies only to prescribed doses for specific individuals over prescribed durations. The food-additive/GRAS substance standard, on the other hand, requires safety at any biologically plausible level of intake, for any person (child, adult, elderly; pregnant; etc.), over a lifetime. And it is a risk-only standard—no potential benefit is allowed to override the “reasonable certainty of no harm” standard. Additionally, in the case of GRAS substances (which includes most probiotics), the evidence of safety must be published in the peer-reviewed scientific literature and be widely accepted by the scientific community as well as by government regulators.”

Finally, the story implied that benefits people claim for themselves when using probiotics are due to a placebo effect. This ignores the many properly controlled studies directly comparing the effects of specific probiotics to placebos. A positive trial on probiotics, such as observed in this recent trial on irritable bowel syndrome symptoms (here) and in most trials included in Cochrane meta-analyses on prevention of C. difficile-associated diarrhea (here), means that positive effects were observed beyond any placebo effect. The placebo effect is real, equally applicable to probiotics and drugs, but as with all clinically evaluated substances, properly controlled trials control for this effect.

The probiotic field has come a long way over the past 20 years with regard to number and quality of clinical trials. In that time, well-done systematic reviews of the evidence have found benefits for specific probiotics for specific conditions, while also finding a lack of evidence for beneficial effects in other contexts. There are of course well-conducted clinical trials that have failed to demonstrate benefit (here, here, here). This should not be equated to mean that probiotics do not do anything.

Many challenges remain for improving the quality of the evidence across the wide range of different strains, doses, endpoints and populations. More clinical research needs to be conducted in a manner that minimizes bias and is reported according to established standards. Confidence in the quality of commercial products could be improved by industry adopting third party verification (here), and the quality of products targeting compromised populations need to be fit for purpose (here). Companies should stop using the term ‘probiotic’ on products that have no evidence warranting that description. We need to understand much better how a person’s individual situation, such as diet, microbiome, use of medications and fitness, impact the ability of a probiotic to promote health. Much remains to be learned in this evolving and exciting field. As Dr. Merenstein says, “The key question is not, ‘Do probiotics actually do anything?’, as that is easily answered ‘yes’ when you look at robust placebo-controlled trials of specific probiotics. Better questions are ‘Which probiotics do anything, and for what?’”

Further reading:

Misleading press about probiotics: ISAPP responses

ISAPP take-home points from American Gastroenterological Association guidelines on probiotic use for gastrointestinal disorders

New publication gives a rundown on probiotics for primary care physicians

Safety and efficacy of probiotics: Perspectives on JAMA viewpoint

Are prebiotics good for dogs and cats? An animal gut health expert explains

By Kelly S. Swanson, PhD, The Kraft Heinz Company Endowed Professor in Human Nutrition, University of Illinois at Urbana-Champaign, USA

Pet dogs and cats are cherished companions. In developed countries, many households with pets treat them like family members. Similarly to humans, a high level of nutrition and veterinary care promotes health and longevity. As people become more aware of what they feed themselves and their human family, they make the same considerations for their canine and feline companions. Pet food trends have closely followed those of the human food industry over the last couple decades, with high-quality natural and organic foods gaining popularity.

One way pet food companies have enhanced their products is by incorporating functional ingredients into their formulas. Functional ingredients provide benefits beyond that of their nutrient content. One of the most popular target areas for functional ingredients is pet gastrointestinal health, with structure/function claims of “supporting digestive health”, or something similar, being quite common. Loose stools, constipation, and various gastrointestinal disorders and diseases such as inflammatory bowel diseases and irritable bowel syndrome are common in pets. The task of “poop scooping” after the dog in the park or cleaning out the cat’s litterbox provides owners with an opportunity for daily assessment of stool quality and serves as a reminder of how important diet is to gut health.

Benefits of prebiotics for pets

Many ingredients, including dietary fibers, prebiotics, probiotics, synbiotics, postbiotics, and other immunomodulators may provide gastrointestinal benefits to pets, but today we will focus on prebiotics. The most recent ISAPP expert consensus panel on prebiotics clarified that the prebiotic concept not only applies to humans, but also to companion and production animals (Gibson). Dogs and cats evolved as Carnivora, mainly consuming high-protein, high-fat diets that were low in fiber, and their short, simple gastrointestinal tracts have a limited capacity to ferment non-digestible substances. Nonetheless, they possess an active microbiota population, primarily in the colon, that may be manipulated by diet to impact health.

Most prebiotic research in pets has focused on the gastrointestinal tract. Prebiotic administration has been shown to reduce the incidence or severity of infections (Apanavicius; Gouveia), improve stool consistency (Kanakupt), and beneficially shift fecal microbiota and metabolite profiles (Propst). A few have reported the benefits that prebiotics may have on metabolic health, demonstrating improved glucose metabolism and insulin sensitivity in pets consuming prebiotics (Respondek; Verbrugghe). Since we’re looking at foods rather than at medicines that address disease, the majority of research has been conducted in healthy animals so evidence of health improvements in diseased pets is sparse.

Types of pet-friendly prebiotics

Although a few studies have tested galactooligosaccharides (GOS), mannanoligosaccharides, and other potential prebiotics, by far the most common prebiotics studied and present in pet foods are the non-digestible fructans. Natural sources, such as chicory, or isolates and extracts that have a high purity, including short-chain fructooligosaccharides (FOS), oligofructose, and inulin, are all present in pet foods.

Which pets benefit most?

Similar to dietary fiber, the need for prebiotic inclusion is dependent upon diet type and formulation. Animals consuming plant-based diets that are rich in natural fibers and non-digestible oligosaccharides likely do not require additional fermentable substrate in the formula. Dogs and cats fed high-protein, meat-based diets, however, typically have greater fecal odor, a higher colonic pH, and higher density of potential pathogens due to a high rate of protein fermentation. In those diets, prebiotic inclusion may help animals normalize their gut microbiota abundance and metabolism.

Prebiotics may be fed to all pets, but will likely provide the greatest benefits to geriatrics, animals who are or have received antibiotics, those under high stress conditions, or those with certain gastrointestinal disorders. The low caloric density of prebiotics and the metabolic benefits that come from their fermentation will be most beneficial to pets with obesity and diabetes. As for all functional ingredients, dosage is important. When comparing dogs and cats, dogs usually can tolerate a higher dosage than cats. In regard to dog size, small dogs can typically tolerate a higher dosage (per unit body weight) than large dogs, which are more susceptible to loose stools. In most commercial pet foods, prebiotic inclusion levels are <0.5% of the formula to limit side effects.

Further research on prebiotic substances

Using the powerful tools that are now available to study gut microbiota and host physiology, future research can hopefully determine what microbes are most important to the health of dogs and cats and identify mechanisms by which prebiotics provide health benefits to pets. Further testing, which may include plant-based ingredients, yeast-based products, and milk oligosaccharide mimics, will hopefully identify other prebiotic substances and continue to expand our knowledge in the field.

 

Kelly Swanson joined the ISAPP board of directors in June, 2020, providing valuable expertise in animal gut health and overall health. Swanson also chaired the 2019 ISAPP-led international consensus panel on the definition of synbiotics.

 

 

 

ISAPP take-home points from American Gastroenterological Association guidelines on probiotic use for gastrointestinal disorders

By ISAPP Board of Directors

June 15, 2020

The recent American Gastroenterological Association (AGA) Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders provided the AGA’s assessment of evidence.

Considering these AGA recommendations for probiotics to prevent necrotizing enterocolitis (NEC) and C. difficile infection, all hospital formularies should stock at least one appropriately tested probiotic. Further, all physicians should consider recommending appropriately tested probiotics for their patients for whom they prescribe antibiotics.

Here are ISAPP’s other key take-home points:

  1. AGA conditionally recommends certain probiotics for 3 of 8 disease uses that they assessed*.
  2. For preterm infants, AGA conditionally recommends 13 different probiotic preparations to prevent NEC. Considering that probiotics are currently used in only 14% of US neonatal intensive care units, this is a very significant recommendation.
  3. For adults and children on antibiotics, AGA conditionally recommends certain probiotics to prevent C. difficile infection. However, AGA did not examine evidence for probiotics for managing diarrheal side effects of antibiotics, a well-studied endpoint for probiotics for which they make no recommendation.
  4. Seven of the recommended probiotics or probiotic combinations for prevention of NEC and three recommended for prevention of C. difficile infection do not specify strains, even though the AGA guidelines paper states, “Within species, different strains can have widely different activities and biologic effects.” This lack of strain specificity in the recommendations will likely lead to confusion for implementation of these recommendations.
  5. AGA did not recommend probiotics for children or adults with irritable bowel syndrome (IBS) for two endpoints, global response (overall symptoms) and abdominal pain severity. However, this should not be interpreted as a lack of evidence for ‘digestive’ symptoms, considering the exclusion criteria imposed.
    • The technical report states that 22 studies in IBS subjects were excluded from analysis, representing a potentially important gap in available evidence. Studies were excluded when no extractable data were reported and the corresponding author failed to provide data after two attempts of being contacted. Examples of excluded studies are here, here, here, and here, and this study was published after AGA’s December 2018 literature search cutoff. These studies could have been included by estimating effect sizes of interest using standard meta-analytical methods for the types of effect sizes that were reported in those excluded studies. However, because of the level of evidence AGA required, the overall conclusion may not have been different if such studies had been included.
    • Only studies on subjects diagnosed with IBS that reported on global response or abdominal pain severity were included, excluding studies on other clinically meaningful endpoints. Many studies on endpoints such as occasional diarrhea, occasional constipation, gut transit time, or individual digestive symptoms outside the context of IBS such as gas, bloating, or distension have been conducted (for example, here, here). Such benefits can be meaningful and very helpful to people afflicted with such symptoms that severely impact quality of life.
  6. AGA recommended against the use of probiotics for acute pediatric diarrhea. Although the technical report considered evidence from over 50 trials (for comparison, the European Society for Paediatric Gastroenterology, Hepatology and Nutrition working group on probiotics identified over 150 randomized, controlled trials for its document), AGA ultimately opted to base its recommendation on only trials conducted in North America, all null. Differences in rotavirus vaccination rates and time of initiation of probiotic therapy may have accounted for null results in two trials. (See rhamnosus GG for treatment of acute pediatric diarrhea: the totality of current evidence and Late initiation of probiotic therapy for acute pediatric gastroenteritis may account for null results for more on this topic.) Although AGA is an American organization, its recommendations carry weight globally, so it is unfortunate that AGA did not word its recommendation in the Summary of recommendations (Table 3) as applying only to North America.
  7. Doses were not stipulated in the recommendations.
  8. Probiotics have been studied for endpoints far beyond the eight endpoints considered by AGA (see here for a review of other evidence), including benefits for generally healthy people.
  9. AGA guidelines are not solely based on the balance between the benefits and harms of the interventions, but considered patients’ values and preferences, resource use (i.e. cost), health equity, acceptability, and feasibility (the Evidence to Decision Framework). As such, AGA’s recommendations differ in significant ways from other societies’ evidence-based recommendations, including the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN), World Gastroenterology Organisation, European Crohn’s and Colitis Organization, and European Society for Primary Care Gastroenterology.

ISAPP agrees with AGA that additional human efficacy trials are needed, all human trials on probiotics should be conducted in a manner that will minimize bias, and study results should be made available to the scientific community for assessment, irrespective of outcome. Yet ISAPP also agrees with Purna Kashyap MD, a co-author of AGA’s technical report upon which their recommendations were based, who in an unrelated article states, “Diet plays a very significant role in the health of our microbiome – the food we eat provides nutrient to support both the growth and diversity of our microbiota. A diverse diet rich in prebiotic and probiotic foods is optimal.” The AGA recommendations do not address such uses of probiotics, and the negative headlines that resulted from the AGA’s press release on these guidelines may discourage probiotic use where it may be beneficial.

AGA’s recommendations sometimes lack clarity for clinicians regarding which specific strains are recommended.  Further, considering the limited scope of this review and the positive recommendations for three indications for probiotic use, ISAPP considers that conclusions such as “Probiotics don’t do much for most people’s gut health despite the hype” (CNN, June 9) leave the impression that the findings of the AGA review were broader and more negative than the data support.

 

*AGA evaluated the evidence by the GRADE criteria for use of probiotics on the following GI diseases:

  1. In symptomatic adults with confirmed Clostridioides difficile infection, should probiotics be used as part of the treatment regimen?
  2. In adults and children receiving antibiotic therapy for any indication except C. difficile infection, should probiotics be used to prevent C. difficile-associated diarrhea?
  3. In adults and children with Crohn’s disease, should probiotics be used for induction or maintenance of remission?
  4. In adults and children with ulcerative colitis, should probiotics be used for induction or maintenance of remission?
  5. In adults and children with ileal pouch-anal anastomosis for chronic ulcerative colitis, should probiotics be used for prevention or maintenance of remission of pouchitis?
  6. In symptomatic children and adults with irritable bowel syndrome, should probiotics be used to improve global response or abdominal pain severity?
  7. In children with acute infectious gastroenteritis, should probiotics be used to reduce the duration or severity of diarrhea?
  8. In preterm, low birthweight newborns, should probiotics be used to prevent necrotizing enterocolitis, sepsis, and all-cause mortality?

 

Related articles

https://www.nutraingredients-usa.com/Article/2020/06/12/AGA-issues-guidelines-for-probiotics-for-sick-at-risk-populations

What makes a synbiotic? ISAPP provides a sneak peek at the forthcoming international scientific consensus definition

By Kristina Campbell, science and medical writer

The word ‘synbiotic’ is found on the labels of many different products, from supplements to chocolate bars, and it has generally been understood to be a combination of a probiotic and a prebiotic. But what happens when scientists want to test whether these combination products really deliver any health benefits? Can these products be tailored to have specific effects on the body or on the human gut microbiota? Agreeing on a clear definition of synbiotics is needed to provide focus for scientific research in this area, to facilitate the design of studies, and to allow for progress wherein their health effects are uncovered.

The scientific definition of synbiotic was the central topic of the international scientific panel brought together by ISAPP in May 2019 in Antwerp, Belgium. Members of the panel, eleven of the top academic experts in the field of probiotics and prebiotics, gathered to clarify a scientifically valid approach for use of the word ‘synbiotic’, and to communicate this by position paper. The outcome of this consensus panel is currently in press at Nature Reviews Gastroenterology & Hepatology.

Kelly Swanson, Professor in the Department of Animal Sciences and Division of Nutritional Sciences at University of Illinois at Urbana-Champaign, chaired the panel and led the paper’s publication. Swanson has been studying gastrointestinal health in both humans, companion animals (dogs and cats) and rodent models for the past 20 years—and having followed the rapid advances in the field of probiotics and prebiotics during those two decades, he knew the task of creating a synbiotic definition would not be easy.

He says, “The field is highly complicated, so an interdisciplinary panel was essential. The main areas of expertise included microbiology and microbial ecology; gastrointestinal physiology; immunology; food science; nutritional biochemistry and host metabolism.”

A timely discussion

According to Swanson, an increase in research interest, built on a foundation of recent scientific and technical gains, made this the right time to come to consensus on a synbiotic definition. He says, “Over the past decade, technological advances have allowed scientists to study the gut microbiome at a molecular level. In addition to characterizing the composition of the gut microbes, researchers are learning more about their biological activity and how they may impact host health.”

Furthermore, clarity about the definition was urgently needed because of the rapidly growing synbiotics market. Consumers seem to be more aware of synbiotics than ever, but they face a bewildering array of product offerings labeled as ‘synbiotic’ without a clear understanding of what that term entails and with no framework for establishing scientific efficacy. Swanson says, “As the field has moved forward and the sales of probiotics and prebiotics have increased, there has been more interest in combining substances to enhance efficacy. Some of these combinations may function as synbiotics, but it is not guaranteed. Rather than randomly combining substances together, there should be scientific rationale supporting their use.”

Clarifying the concept

One of the first questions the panel members had to tackle was whether to stick to the idea of a synbiotic as ‘probiotic plus prebiotic’, thus leaning heavily on the ISAPP-led international consensus definitions of probiotics and prebiotics published in 2014 and 2017, respectively. But the panel members decided this narrow scope would ultimately limit innovation in the synbiotic category.

Swanson explains, “While many synbiotics may be composed of an established prebiotic and established probiotic, the panel did not want to restrict scientific advances in the synbiotic category by requiring use of components already established on their own.”

As a result, he says, previously untested live microbes and potential prebiotic substances could be considered a synbiotic if the combination showed efficacy, and if the health benefit came from administering both the live microbe and the substrate it utilized—that is, the microbe together with its ‘food’.

Another conclusion from the panel is that probiotics (with known health benefits) and prebiotics (with known health benefits) cannot be called synbiotics unless they have been tested together. “There should be a rationale supporting the combination used, and then testing of the combination to confirm its efficacy,” says Swanson.

The panel suggests a synbiotic may be composed of either of the following, as long as efficacy is demonstrated for the combination:

  • Established probiotic + established prebiotic (each component meeting the efficacy and mechanistic criteria for each)
  • Previously untested live microbe + a substrate that is selectively utilized by the co-administered live microbe

Further details, including two different ‘categories’ of synbiotics, will be provided in the published paper.

In addition to the definition, the publication will cover the history of synbiotic-type products, how these products can be characterized, levels of evidence that currently exist versus levels of evidence desired, points about safety documentation and reporting, and relevant characteristics of the target hosts.

A remaining challenge—not just for the expert group, but also across the field—is the difficulty of establishing causal links between substances’ effects on the gut microbiota (e.g. ‘selective utilization’ of a substrate) and health outcomes.

While the publication of the synbiotic definition will be an important milestone, Swanson anticipates further discussion in the years ahead. “As more is learned, I expect the criteria for assessing synbiotic efficacy will continue to change,” he says.

An update on the scientific consensus definition of synbiotic was presented to ISAPP members at the 2020 virtual meeting in June.

 

New publication gives a rundown on probiotics for primary care physicians

With an increasing number of patients becoming aware of the human microbiome and its role in health, primary care physicians are faced with questions about probiotics as a possible strategy for maintaining health. Patients may see conflicting messages in the news and on product labels – so how can they know which probiotic benefits are scientifically proven?

A new publication in the Journal of Family Practice provides a quick update on evidence for the use of probiotics in different indications, so primary care physicians can equip themselves to provide evidence-based recommendations and to answer patients’ most commonly asked questions about probiotics.

Written by ISAPP board members Daniel J. Merenstein, MD and Mary Ellen Sanders, PhD, along with Daniel J. Tancredi, PhD, the article provides practical advice in the form of practice recommendations, along with comments about safety data from numerous clinical trials.

As Dr. Merenstein stated, “We wrote this article for working clinicians. They are interested in the science but are busy and want a straightforward evidence-based resource. We are hopeful this will be a go-to resource during the busy clinic day.”

Verbatim from the article are the following practice recommendations:

  • Consider specific probiotics to prevent antibiotic-associated diarrhea, reduce crying time in colicky infants, and improve therapeutic effectiveness of antibiotics for bacterial vaginosis.
  • Consider specific probiotics to reduce the risk for Clostridioides (formerly Clostridium) difficile  infections, to treat acute  pediatric diarrhea, and to manage symptoms of constipation.
  • Check a product’s label to ensure that it includes the probiotic’s genus, species, and strains; the dose delivered in colony-forming units through the end of shelf life; and expected benefits.

The full text can be accessed by logging into Medscape.

How some probiotic scientists are working to address COVID-19

By ISAPP board of directors

With the global spread of COVID-19, the scientific community has experienced an unusual interruption. Across every field, many laboratories are temporarily shuttered and research programs of all sizes are on hiatus. Principal investigators around the world are doing their part to keep their students and local communities safe, and many are donating lab safety equipment to medical first responders who urgently need it.

In this global circumstance of research being put on hold, it is enlightening to consider what some scientists in the fields of probiotics, prebiotics, and fermented foods are working on—or proposing—in the context of understanding ways to combat viral threats. These individuals are rising to the scientific challenge of finding effective ways to prevent or treat viral infections, which may directly or indirectly contribute to progress against SARS-CoV-2.

Here, ISAPP shares words from some of these scientists—and how they have connected the dots from probiotics to coronavirus-related work with potential medical relevance.

Prof. Sarah Lebeer, University of Antwerp, Belgium: Relevance of the airway microbiome profile to COVID-19 respiratory infection and using certain lactobacilli to enhance delivery or efficacy of vaccines

Could the microbes in our upper and lower airways play a role in how we respond to the virus? Significant individual differences exist in the microbes that are prevalent and dominant in our airways. Lactobacilli are found in the respiratory tract, especially in the nasopharynx. They might originate there from the oral cavity via the oronasopharynx, but we have found some strains that seem to be more adapted to the respiratory environment, for example by expressing catalase enzymes to withstand oxidative stress. Currently we have a Cell Reports paper in press that shows certain lactobacilli are more prevalent in the upper respiratory tract of healthy people compared to those with chronic rhinosinusitis. Further investigation of one strain found in healthy people showed it inhibited growth and virulence of several upper respiratory tract pathogens. Our work on other viruses shows that certain lactobacilli can even block the attachment of viral particles to human cells. This raises the possibility that lactobacilli could be supplemented through a local spray to help improve defenses against the inhaled virus. Based on these data, we are initiating an exploratory study with clinicians and virologists on whether specific strains of lactobacilli in the nasopharynx and oropharynx could have potential to reduce viral activity via a multifactorial mode of action, including barrier-enhancing and anti-inflammatory effects, and reduce the risk of secondary bacterial infections in COVID-19.

Another line of exploratory research from our lab pertains to the delivery or efficacy of SARS-CoV-2 vaccines. Currently, many groups are rapidly developing vaccines, which predominantly use the viral spike S protein or its receptor-binding domain as antigen to induce protective immunity. We are exploring the potential of specific strains of lactobacilli with immunostimulatory effects as adjuvants for intranasal SARS-CoV-2 vaccination, or the potential of a genetically engineered antigen-producing organism for vaccine delivery.

At this year’s virtual ISAPP annual meeting, Dr. Karen Scott and I will also be leading an ISAPP discussion group called “How your gut microbiota can help protect against viral infections”. We will discuss previous work that has shown bacteria can have anti-viral effects. For many years, our colleagues, Profs. Hania Szajewska and Seppo Salminen, have studied a different virus, namely rotavirus, that causes acute diarrhea in children, and have found that Lactobacillus rhamnosus GG (new taxonomy Lacticaseibacillus rhamnosus GG) binds rotavirus and disables it, thereby blocking viral infection/multiplication. This may explain why this probiotic reduces the incidence and duration of acute diarrhea in children. Similar findings have been reported for specific probiotics and prebiotics and prevention of upper respiratory tract infections.

Prof. Rodolphe Barrangou, North Carolina State University, USA: Engineering probiotic lactobacilli for vaccine development

Between NC State University and Colorado State University (CSU) there is a historical collaborative effort aiming at engineering probiotics to develop novel vaccines. The intersection of probiotics and antivirals is the focus here with expressing antigens on the cell surface of probiotics to develop oral vaccines. The CSU infectious diseases center is very much fully operational and focused on COVID-19 now, and we recently received a research exception to open our lab for two individuals assigned to this NIH-funded project, and pivot our rotavirus efforts here to coronavirus. We are actively engineering Lactobacillus acidophilus probiotics expressing COVID-19 proteins to be tested as potential vaccines at CSU in the near future, as progress dictates.

Prof. Colin Hill, University College Cork, Ireland: The microbiome as a predictor of COVID-19 outcomes

We have recently proposed a project to examine oral and faecal microbiomes to identify correlations/associations between COVID-19 disease severity and individual microbiome profiles. If funded, we propose to analyse bacterial and viral components of the microbiome from three body sites (nasopharyngeal swabs, saliva, and faeces) in 200 donors and mine the data for biomarkers of disease risk and clinical severity. We will use machine learning to identify microbiome signatures in patients who contract the virus and remain asymptomatic, those who develop a mild infection, or those who have an acute infection requiring admission to an intensive care unit and intubation. This will enable microbiome-based risk stratification of subjects testing positive, and appropriate clinical management and early intervention, and prioritization of subjects for receiving an eventual vaccine.

Dr. Dinesh Saralaya, Bradford Institute for Health Research, UK: A live biotherapeutic product for targeted immunomodulation in COVID-19 infection

The COVID-19 pandemic presents an unprecedented challenge to our healthcare systems and we desperately require the rapid development of new therapies to ease the burden on our intensive care units. As well as its appropriate mechanism of action (targeted immunomodulation rather than broad immunosuppression), the highly favourable safety profile of MRx-4DP0004 makes it a particularly attractive candidate for COVID-19 patients, and may potentially allow us to prevent or delay their progression to requiring ventilation and intensive care.

The trial is a Phase II randomised, double-blind, placebo-controlled trial to evaluate the efficacy and safety of oral Live Biotherapeutic MRx-4DP0004 in addition to standard supportive care for hospitalised COVID-19 patients. Up to 90 subjects will be randomised 2:1 to receive either MRx-4DP0004 or placebo (two capsules, twice daily) for 14 days. The primary endpoint is change in mean clinical status score as measured by the WHO’s 9-point Ordinal Scale for Clinical Improvement, while secondary endpoints include a suite of additional measures of clinical efficacy such as need for and duration of ventilation, time to discharge, mortality, as well as safety and tolerability. The size and design of the trial are intended to generate a meaningful signal of clinical benefit as rapidly as possible.

Drs. Paul Wischmeyer and Anthony Sung, Duke University School of Medicine, USA: Probiotics for prevention or treatment of COVID-19 infection

We are planning several randomized clinical trials of probiotics in COVID-19 prevention and treatment. These trials are based on multiple randomized clinical trials and meta-analyses that have shown that prophylaxis with probiotics may reduce upper and lower respiratory tract infections, sepsis, and ventilator associated pneumonia by 30-50%. These benefits may be mediated by the beneficial effects of probiotics on the immune system. The Wischmeyer laboratory and others have shown that probiotics, such as Lactobacillus rhamnosus GG, can improve intestinal/lung barrier and homeostasis, increase regulatory T cells, improve anti-viral defense, and decrease pro-inflammatory cytokines in respiratory and systemic infections. These clinical and immunomodulatory benefits are especially relevant to individuals who have developed, or are at risk of developing, COVID-19. COVID-19 has been characterized by severe lower respiratory tract illness, and patients may manifest an excessive inflammatory response similar to cytokine release syndrome, which has been associated with increased complications and mortality. We hypothesize that probiotics will directly reduce COVID-19 infection risk and severity of disease/symptoms. Thus, we are proposing a range of trials, the first of which will be:

A Randomized, Double-Blind, Placebo-Controlled Trial of the PRObiotics To Eliminate COVID-19 Transmission in Exposed Household Contacts (PROTECT-EHC). Objective: Prevent infection and progression of illness in household contacts/caregivers of known COVID-19 patients exposed to COVID-19 (who have a >20-fold increased risk of infection). We will conduct a multicenter, randomized, double blind, phase 2 trial of the probiotic Lactobacillus rhamnosus GG vs. placebo to decrease infections and improve outcomes. This trial will include weekly collection of microbiome samples from multiple locations (i.e. fecal, oral). This trial will utilize a commercial probiotic, delivering 20 billion CFU of Lactobacillus rhamnosus GG, and placebo.

We are currently developing protocols to study prevention and treatment of COVID-19 in a range of other at-risk populations including: 1) Healthcare providers; 2) Hospitalized patients; 3) Nursing home and skilled nursing facilities workers. We are seeking additional funding and potential collaborators/trial sites for this work, and encourage interested funders and collaborators to reach out for further information or to join the effort at: Paul.Wischmeyer@nullduke.edu and also encourage you to follow our progress and our other probiotic/microbiome work on Twitter: @paul_wischmeyer

Prof. Gregor Reid, University of Western Ontario, Canada: Documenting anti-viral mechanisms of certain probiotic strains

While our institute is now studying the cytokine storm in COVID-19 patients, the closure of my lab has meant I have turned to surveying the literature: Prof. Glenn Gibson and I have a paper published in Frontiers in Public Health stating a case for probiotics and prebiotics to help ‘flatten the curve’ and keep patients from progressing to severe illness. There is good evidence that certain orally administered probiotic strains can reduce the incidence and severity of viral respiratory tract infections. Mechanistically this appears to be, in part, through modulation of inflammatory responses similar to those causing severe illness in COVID-2 patients, and antiviral activity — which has not been shown against SARS-Co-V2 but has been documented against common respiratory viruses, including influenza, rhinovirus and respiratory syncytial virus. Improving gut barrier integrity and affecting the gut-lung axis may also be part of these probiotics’ mechanism of action. At a time when drugs are being tried with little or no anti-COVID-19 data, probiotic strains documented for anti-viral, immunomodulatory and respiratory activities should be considered for clinical trials to be part of the armamentarium to reduce the burden and severity of this pandemic.

Rapid, collaborative effort

As the world waits in ‘lockdown’ mode, continued scientific progress for coronavirus prevention or treatment is critically important. ISAPP salutes all probiotic and prebiotic scientists who are stepping up to pursue unique solutions. Addressing the important research questions described above will require a rapid collaborative effort, from obtaining ethical approval and involving medical staff to collecting the samples, to recruiting participants as well as experts to process and analyze samples. All of this has to be done in record time – but from our experience of this scientific community, it’s definitely up to the challenge.

ISAPP provides guidance on use of probiotics and prebiotics in time of COVID-19

By ISAPP board of directors

Summary: No probiotics or prebiotics have been shown to prevent or treat COVID-19 or inhibit the growth of SARSCoV-2. We recommend placebo-controlled trials be conducted, which have been undertaken by some research groups. If being used in clinical practice in advance of such evidence, we recommend a registry be organized to collect data on interventions and outcomes.  

Many people active in the probiotic and prebiotic fields have been approached regarding their recommendations for using these interventions in an attempt to prevent or treat COVID-19. Here, the ISAPP board of directors provides some basic facts on this topic.

What is known. Some human trials have shown that specific probiotics can reduce the incidence and duration of common upper respiratory tract infections, especially in children (Hao et al. 2015; Luoto et al. 2014), but also with some evidence for adults (King et al. 2014) and nursing home residents (Van Puyenbroeck et al. 2012; Wang et al. 2018). However, not all evidence is of high quality and more trials are needed to confirm these findings, as well as determine the optimal strain(s), dosing regimens, time and duration of intervention. Further, we do not know how relevant these studies are for COVID-19, as the outcomes are for probiotic impact on upper respiratory tract infections, whereas COVID-19 is also a lower respiratory tract infection and inflammatory disease.

There is less information on the use of prebiotics for addressing respiratory issues than there is for probiotics, as they are used mainly to improve gut health. However, there is evidence supporting the use of galactans and fructans in infant formulae to reduce upper respiratory infections (Shahramian et al. 2018; Arslanoglu et al. 2008). A meta-analysis of synbiotics also showed promise in repressing respiratory infections (Chan et al. 2020).

Mechanistic underpinnings. Is there scientific evidence to suggest that probiotics or prebiotics could impact SARS-CoV-2? Data are very limited. Some laboratory studies have suggested that certain probiotics have anti-viral effects including against other forms of coronavirus (Chai et al. 2013). Other studies indicate the potential to interfere with the main host receptor of the SARS-CoV-2 virus, the angiotensin converting enzyme 2 (ACE2). For example, during milk fermentation, some lactobacilli have been shown to release peptides with high affinity for ACE (Li et al. 2019). Recently, Paenibacillus bacteria were shown to naturally produce carboxypeptidases homologous to ACE2 in structure and function (Minato et al. 2020). In mice, intranasal inoculation of Limosilactobacillus reuteri (formerly Lactobacillus reuteri) F275 (ATCC 23272) has been shown to have protective effects against lethal infection from a pneumonia virus of mice (PVM) (Garcia-Crespo et al. 2013). These data point towards immunomodulatory effects involving rapid, transient neutrophil recruitment in association with proinflammatory mediators but not Th1 cytokines. A recent study demonstrated that TLR4 signaling was crucial for the effects of preventive intranasal treatment with probiotic Lacticaseibacillus rhamnosus (formerly Lactobacillus rhamnosus) GG in a neonatal mouse model of influenza infection (Kumova et al., 2019). Whether these or other immunomodulatory effects, following local or oral administration, could be relevant to SARS-CoV-2 infections in humans is at present not known.

Our immune systems have evolved to respond to continual exposure to live microbes. Belkaid and Hand (2016) state: “The microbiota plays a fundamental role on the induction, training, and function of the host immune system. In return, the immune system has largely evolved as a means to maintain the symbiotic relationship of the host with these highly diverse and evolving microbes.” This suggests a mechanism whereby exposure to dietary microbes, including probiotics, could positively impact immune function (Sugimura et al. 2015; Jespersen et al. 2015).

The role of the gut in COVID-19. Many COVID-19 patients present with gastrointestinal symptoms and also suffer from sepsis that may originate in the gut. This could be an important element in the development and outcome of the disease. Though results from studies vary, it is evident that gastrointestinal symptoms, loss of taste, and diarrhea, in particular, can be features of the infection and may occur in the absence of overt respiratory symptoms. There is a suggestion that gastrointestinal symptoms are associated with a more severe disease course. Angiotensin converting enzyme 2 and virus nucleocapsid protein have been detected in gastrointestinal epithelial cells, and infectious virus particles have been isolated from feces. In some patients, viral RNA may be detectable in feces when nasopharyngeal samples are negative. The significance of these findings in terms of disease transmission is unknown but, in theory, do provide an opportunity for microbiome-modulating interventions that may have anti-viral effects (Cheung et al. 2020; Tian et al. 2020; Han et al. 2020).

A preprint (not peer reviewed) has recently been released, titled ‘Gut microbiota may underlie the predisposition of healthy individuals to COVID-19’ (Gao et al. 2020) suggesting that this could be an interesting research direction and worthy of further discussion. A review of China National Health Commission and National Administration of Traditional Chinese Medicine guidelines also suggested probiotic use, although more work on specific strains is needed (Mak et al. 2020).

Are probiotics or prebiotics safe? Currently marketed probiotics and prebiotics are available primarily as foods and food/dietary supplements, not as drugs to treat or prevent disease. Assuming they are manufactured in a manner consistent with applicable regulations, they should be safe for the generally healthy population and can be consumed during this time.

Baud et al. (in press) presented a case for probiotics and prebiotics to be part of the management of COVID-19. Although not fully aligned with ISAPP’s official position, readers may find the points made and references cited of interest.

Conclusion. We reiterate, currently no probiotics or prebiotics have been shown to prevent or treat COVID-19 or inhibit the growth of SARSCoV-2.

 

Connecting with the ISAPP community: Continuing to advance the science of probiotics and prebiotics

By Mary Ellen Sanders PhD, executive science officer, ISAPP

On behalf of the ISAPP board of directors, I am reaching out to the ISAPP community to say we hope you are doing well and taking all the necessary steps in your local communities to remain healthy. At present, the global ISAPP community is physically distant but digitally close, and it is important for us to remain connected and strong.

ISAPP’s activities are as important as ever during this time of increased attention to health, and ISAPP is continuing to uphold its commitment to (1) stewardship, (2) advancing the science, and (3) working with stakeholders. Although our annual meeting, which some of you may have initially planned to attend, has been cancelled, other ISAPP activities are continuing or expanding as follows:

 

  • Building on an important topic for our annual meeting, ISAPP is working to develop a strategic approach to communicating the science on probiotics, prebiotics, fermented foods, synbiotics, and postbiotics.
  • The ISAPP board of directors is pleased that our founding board members, Profs. Gregor Reid and Glenn Gibson, have agreed to remain on the board until the 2021 meeting, in particular to help with long-range planning. New academic board members will also be elected, thereby expanding the board. Working together, we will bring fresh insights, strategies and global reach.
  • The board is considering how best to approach our cancelled meeting. In lieu of re-scheduling this year’s in-person meeting, we are planning to have virtual content covering some of the originally scheduled topics. Some discussion group topics will be carried over to the 2021 meeting, while others will be addressed virtually. We will communicate further on this soon.
  • Our newsletter will continue on a monthly basis.
  • Blog postings, which are aimed at either consumers or scientists, remain timely and popular – with new contributions posted on average every 2-3 weeks. Authored by board members and other experts in the field, these blogs provide a forum for opinions and observations on current issues and controversies as well as insights on global fermented foods, critical regulatory actions, and other relevant topics.
  • ISAPP filed comments on March 17 with the American Gastroenterological Association in response to their draft recommendations for probiotic use in GI conditions.
  • Spearheaded by former ISAPP IAC representative to the board, Dr. Roberta Grimaldi, ISAPP has subtitled several of the most popular ISAPP videos in different languages, including Dutch, French, Spanish, Russian, Japanese, Italian and Indonesian. The first of these should be posted by end of April.
  • The ISAPP-Students and Fellows Association has launched a blog program to provide perspectives by young scientists on issues of importance to the probiotic and prebiotic fields. They have also submitted a manuscript to Frontiers in Microbiology discussing a toolkit needed for their future in science: “Future of probiotics and prebiotics: an early career researchers’ perspective”.
  • Three consensus panels have been conducted since May of 2019. A manuscript arising from the synbiotics panel, chaired by Prof. Kelly Swanson, is in press with Nature Reviews Gastroenterology and Hepatology. The paper summarizing the consensus panel on fermented foods, chaired by Profs. Robert Hutkins and Maria Marco, is almost ready for submission to Nature Reviews Gastroenterology and Hepatology. A manuscript from the consensus panel on postbiotics, chaired by Prof. Seppo Salminen, is currently being written. All three papers are expected to provide clarity to the field with regard to definition of terms, current evidence for health benefits, and impact on stakeholders.
  • In addition to the three consensus panel papers in progress, several different ISAPP endeavors are at different stages of publication:
    • ISAPP vice president, Prof. Dan Merenstein, and executive science officer, Dr. Mary Ellen Sanders, worked with biostatistician and frequent ISAPP contributor, Prof. Dan Tancredi, to summarize evidence for clinical endpoints for probiotics, to be published in the Journal of Family Physicians. This paper, titled “Probiotics as a Tx resource in primary care”. The paper is currently in press.
    • Several ISAPP board members and other participants in a 2019 meeting discussion group recently submitted to Current Developments in Nutrition a paper titled “Dietary Recommendation on Adequate Intake of Live Microbes: A Path Forward”.
    • Marla Cunningham, the current IAC representative to the ISAPP board, has led an effort to compile results from the IAC Learning Forum from the 2019 ISAPP meeting on the topic of matrix effects impacting probiotic and prebiotic functionality. Manuscript in preparation.
    • Colin Hill and I represented ISAPP on a paper under review at Nutrients initiated by IPA-Europe titled “Criteria to qualify microorganisms as ‘probiotic’ in foods and dietary supplements”. This paper consolidates and fleshes out minimum criteria for use of the term ‘probiotic’ published by different groups, including the 2002 FAO/WHO working group, the 2014 ISAPP consensus paper on probiotics, and the 2018 ISAPP discussion group on global harmonization.
    • Glenn Gibson and Marla Cunningham are coordinating a paper titled “The future of probiotics and prebiotics in human health” as an output from their 2019 discussion group.

See here for all published ISAPP papers.

ISAPP board members, 2019 annual meeting

Messages about probiotics and COVID-19

With many conflicting and confusing health messages circulating during this global pandemic, including some criticisms of our field as well as some unsupported claims made by certain individuals and companies, ISAPP will remain an important touchstone for scientifically accurate information. Focusing on health effects is key to demonstrating probiotic and prebiotic efficacy, and we acknowledge that human studies are the ultimate measure of efficacy, but also, elucidating mechanisms of action help us understand how these interventions interface with the immune system and other mediators of health.  Currently, there is some evidence that certain probiotics/prebiotics can reduce the risk of viral infections (discussed in other blog posts here and here), but it is important to remember that they have not been studied specifically for COVID-19 prevention or treatment. This must be acknowledged when communicating with the wider community.

We greatly appreciate the continued support of our IAC members. The ISAPP Board, colleagues, and SFA will continue to chart a course forward in preparation for life after the pandemic. Our intent is to emerge from these experiences more connected and purposeful than ever. We welcome suggestions on how collectively we can endure and strengthen the science and communications that remain foundations of our field.

 

 

 

Safety and efficacy of probiotics: Perspectives on JAMA viewpoint

By Mary Ellen Sanders PhD, executive science officer, ISAPP,  and Daniel Merenstein MD, Department of Family Medicine, Georgetown University School of Medicine

The Journal of the American Medical Association (JAMA) recently published a short viewpoint that called into question the safety and efficacy of probiotics. After careful review, we concluded that some opinions expressed were not consistent with available data. We share our perspectives here.

Claim 1: The paucity of high-quality data supporting the value of probiotics.

The authors speak to the “paucity” and “lack” of data supporting probiotic use. They criticize probiotic meta-analyses in general, even though there are many well-done ones, which describe clear PICOS, assess the quality of studies included, and assess publication bias. Many conclude that there is evidence that certain probiotics may be beneficial for several clinical endpoints. In the case of treatment of colic, an individual participant data meta-analysis was conducted on a single strain, and concluded “L reuteri DSM17938 is effective and can be recommended for breastfed infants with colic” (Sung et al. 2018). For necrotizing enterocolitis (NEC), a change in practice is recommended by a Cochrane meta-analysis (AlFaleh et al. 2018), which is consistent with draft American Gastroenterological Association (AGA) recommendations posted last month. In some cases, conclusions are qualified as being based on low quality data, which is also the case with many standard-of-care medical interventions. Other benefits supported for certain probiotics by evidence are shown in Table 1 of Sanders et al. 2018. But an evidence-based review of available data would not support a general statement that “data are lacking.”

Instead, we think a discussion of what evidence is actionable is reasonable to have. For this discussion, different people or groups can reasonably set the bar at different levels for what constitutes actionable evidence. But several medical organizations, including the European Society for Paediatric Gastroenterology, Hepatology and Nutrition, World Gastroenterology Organisation, American College of Gastroenterology, AGA (proposed, for antibiotic-associated diarrhea, NEC and pouchitis), European Crohn’s and Colitis Organization, and European Society for Primary Care Gastroenterology have actionable recommendations for probiotic use for one or more indications. For those indications, any individual physician may judge that the available evidence as not convincing to him or her, but many qualified healthcare experts did find the evidence convincing and have made recommendations accordingly. We recognize that the JAMA viewpoint was limited in the number of words and references allowed, but to impugn an entire field, the authors are obliged to explain why their views differ so much from established organizations.

The authors also criticize the inclusion of small, single-center trials in probiotic meta-analyses. They state such studies have less oversight, are more susceptible to misconduct and are at greater risk of bias than larger, multicenter trials, and thereby skew conclusions of meta-analyses in favor of probiotics. They state, without evidence, that small trials are more likely to show large effects and are more likely to be published. They advocate for meta-analyses that only include multi-center trials, thereby ignoring much available evidence on the basis of unsubstantiated preferences. There are a number of reasons why some trials are multi-center, but improved quality or closer monitoring are not among them (see here, here and here). Multicenter trials may be necessary to study a rare medical endpoint, a condition with an expected small effect size but significant health implications, or to accelerate the time course for a study. In fact, an analysis of 81 meta-analyses of RCTs in 2012 concluded:

“Our results do not support prior findings of larger effects in SC (single-center) than MC (multi-center) trials addressing binary outcomes but show a very similar small increase in effect in SC than MC trials addressing continuous outcomes. Authors of systematic reviews would be wise to include all trials irrespective of SC vs. MC design and address SC vs. MC status as a possible explanation of heterogeneity (and consider sensitivity analyses).” [Emphasis ours]

 

In our experience, the size of a study does not inevitably minimize risk of bias. We have directly witnessed private physicians enroll for large multi-site trials without such oversight or professionalism. As the great David Sackett said in his paper from 20 years ago, “The more detailed the entry form and eligibility criteria for ‘somebody else’s’ RCT, the greater the risk the criteria will be ignored, misunderstood or misapplied by distracted clinicians who regard them as further intrusions into an overfull call schedule.” Further, due to often being underpowered, taken alone smaller studies are less, not more, likely to generate positive findings than larger trials. But when they are included in a meta-analysis, these studies contribute to the total body of evidence. We have personally worked on many single-center randomized controlled trials on probiotics. These often have monitors from the U.S. Food and Drug Administration and/or the National Institutes of Health, they are all registered with both primary and secondary outcomes listed, they utilize a data safety monitoring board, they undergo true allocation concealment, and otherwise are conducted to minimize risk of bias. To criticize probiotic studies for being single-center vs multicenter seems unjustified and baseless.

It is quite true that many of the studies conducted on probiotics were done 15 or more years ago, and the quality standards do not meet what we expect today. We wholeheartedly agree but would ask the authors to review studies conducted on drugs 15 years ago, and they will see the same issues. So we agree that more trials using modern quality standards are needed in the field of probiotics, as is the case for any interventions with a long history of being studied.

Claim 2: Potentially biased reviews of probiotic efficacy

In trying to explain why physicians might recommend probiotics, the authors speculate that some professional societies and some journals may be insufficiently critical in reviewing probiotic studies due to financial conflicts of interest. We have no doubt that there is bias in the scientific realm, which is not just limited to financial conflicts of interest, but question if there is any evidence that this occurs any more or less frequently with probiotics compared to any other realm of science. To leverage this accusation at the probiotic field specifically implies it is especially egregious, but no data supporting this accusation were provided. Also there is no face validity for this accusation. There is much more money to be made by pharmaceuticals and medical interventions than probiotic supplements and yogurts.

Claim 3: Complex framework in which probiotics are regulated and sold

The regulatory framework for probiotics can be difficult to navigate and is not always in the best interest of stakeholders, but we don’t think it’s reasonable to criticize the probiotic field for this situation. In the USA, probiotic products are bound by law that was enacted by Congress and the rules/guidance developed by the FDA for allowable product claims, levels of required regulatory oversight, and lack of requirements for premarket approval. It is fair to criticize Congress and the FDA for these circumstances surrounding the category of dietary supplements, but doing this in the context of an article on probiotics unfairly maligns probiotics.

Drugs vs dietary supplements. Most probiotics are sold as foods or dietary supplements. Since probiotics were first described as fermenting microbes in soured milk, this makes historical sense. Companies and consumers do not view these products as drugs, and in most cases they are not used as drugs. Outside a regulatory mindset, it makes perfect sense for foods to be useful for promoting health and managing symptoms, and this is what has driven 30 years of research and marketing of probiotics. Forcing all probiotics into a drug rubric would deprive consumers of access, would greatly increase their cost, and would preclude responsible food/supplement manufacturers from producing them. Drugs are drugs primarily to protect the safety of the patient. All drugs are assessed with a risk/benefit balance, and in some cases, the risk is significant. In the case of probiotics, we agree with the authors that most probiotics are likely safe for the general population. We see no reasonable justification to advocate that these products must all be researched and sold as drugs.

Probiotic product quality.The authors seem to prefer the drug model for probiotics based on a perceived need for improved product quality and oversight. Yet all foods and dietary supplements in the USA are required by law to be manufactured under good manufacturing practices. This includes most every product bought at the grocery store and served for dinner as well as probiotic foods and supplements. Further, companies are required to label their products in a truthful and not misleading fashion, including representations of contents and claims. Companies that fail to meet these standards are in violation of the law. Yes, there are products – of all types – that fall short of these requirements. The many responsible probiotic manufacturers and probiotic scientists decry such occurrences. However, these cases do not define the probiotic field any more than medical errors define physicians. It is not fair to impugn the entire probiotic industry based on the ‘bad apples’ that participate in it. A 2017 ESPGHAN review cites surveys of probiotic products from different regions globally, most of which report examples of probiotic products falling short in some quality attribute. Such surveys highlight quality problems, but due to sampling and methodological approaches, their results do not provide a reliable estimate of the extent of problem among commercial probiotic products. Many probiotic products are produced responsibly and are subjected to third party quality audits. The absence of such third party documentation is not evidence of poor quality, but we agree that it serves to improve consumer and healthcare provider confidence (see Jackson et al. 2019), and if more fully adopted, would weed out irresponsible probiotic manufacturers.

Oversight of probiotic research. The authors state, “If a manufacturer claims that any product, including a probiotic, cures, mitigates, treats, or prevents disease, the product is classified as a drug, thereby triggering a costly Investigational New Drug (IND) application process.” However, they seem to conflate the regulatory approach to product claims and the regulatory oversight of biologic drug research. In the case of product claims, if a product claims to cure, treat, prevent or mitigate disease, it is by definition a drug. If it has not undergone appropriate drug approval process, it is an illegally marketed drug and is subject to FDA action, including recall. Probiotics not destined for sale as drugs should not have to be researched under a drug rubric. This does NOT mean that such studies will de facto be substandard studies. We all understand the importance of conducting and reporting trials according to well-established guidelines. Studies on foods and supplements can and should follow those same principles.

Claim 4: Possible concerns about probiotic safety

Medical professionals balance potential harm with potential benefit for any intervention they recommend. Regarding safety of probiotics, the authors acknowledge that most probiotics are likely safe, but we would qualify that statement with “for their intended uses.” The use of probiotics in critically ill patient populations needs to be done with caution, proper oversight and a justification that the potential benefit will outweigh risk. The authors cite two examples to support their concern about probiotic safety, both in critically ill patient populations. One was a retrospective study looking at bacteremia in critically ill children (see the report here and responses to the report here and here). The second was a RCT that reported higher mortality in patients with pancreatitis (see the report here, with additional perspectives on interpreting safety outcomes here and here). We are not aware of any probiotics that are marketed for such uses, and if they were, they would be marketed as drugs, requiring drug-level safety and efficacy evidence. These studies are not an indictment of safety of probiotic foods and supplements, which in most cases are intended for the generally healthy population.

The authors further state that studies identifying adverse events from probiotics are the “tip of the iceberg” – creating an image of a huge number of unreported adverse incidents poised to be revealed. We have personally studied the most widely used Bifidobacterium strain, and in well over 30,000 pediatric patient days have not seen any serious adverse events and no more adverse events than placebo. The article cited by the authors states that our trials adequately reported harm. Obviously, no intervention is harmless, and no one claims as much for probiotics. It is true that older probiotic studies can rightly be criticized for not rigorously collecting and reporting data on adverse events (Hempel et al. 2011). However, a reasonable assessment of all available data, including data from well-conducted clinical trials, including trials in vulnerable populations, history of safe use, FDA notified assessments for GRAS use of certain probiotic strains, European Food Safety Authority QPS list, and others support that commonly used probiotics have a strong safety record for use in the general public.

Transferable antibiotic resistance. Regarding the risk that probiotics may transfer antibiotic resistance genes, this is a hypothetical concern – there is no documented case of this. Further, one pillar of probiotic safety assessments is that strains with antibiotic resistance genes flanked by mobile genetic elements are excluded from commercialization. As stated by Ouwehand et al. 2016, “Probiotics are specifically selected to not contribute to the spread of antibiotic resistance and not carry transferable antibiotic resistance.” The current approach to probiotic safety is that complete, well annotated genome sequences are available for commercial strains. This information is typically included in GRAS notices submitted to the FDA, and all the major probiotic suppliers require this level of safety assessment. This is the expected standard by the European Food Safety Authority as well, a standard that we enthusiastically and unreservedly endorse. Transferable antibiotic resistance is not a lurking threat of probiotics use, but is a well-considered issue adequately addressed by responsible probiotic manufacturers.

Conclusion

We believe that this JAMA viewpoint misrepresents the totality of data on probiotics and can potentially do harm by dissuading use of probiotics in an evidence-based manner. Important points have been raised by the authors, especially with regard to the use of probiotics in vulnerable populations, but this does not characterize most of probiotic use. We agree, as we expect the majority of scientists working on probiotics would, that additional, well controlled human studies are needed. That was why we were pleased to see the authors’ studies assessing the impact of L. rhamnosus R0011 and L. helveticus R0052 or L. rhamnosus GG on acute pediatric gastroenteritis, even though the results of both studies were null (see blog post regarding these studies here and here). But as we await additional trials, we have a responsibility to consider available evidence. The authors raise many good points that the entire medical field could learn from, but there are clear indications for probiotics and they should continue to be used for these indications, likely benefitting many while harming few.

Acknowledgements

MES and DM are grateful for the critical review of this perspective by probiotic safety expert Dr. James Heimbach, biostatistician Dr. Daniel Tancredi, and gastroenterologist and probiotic expert Dr. Eamonn Quigley.

 

 

 

New names for important probiotic Lactobacillus species

By Mary Ellen Sanders, PhD, and Sarah Lebeer, PhD

The genus Lactobacillus was listed as the fifth most important category of living organism to have influenced the planet throughout its evolutionary history in a 2009 book, What on Earth Evolved?. From their central role in food fermentations around the globe to their ability to benefit health in their human and animal hosts, species of Lactobacillus have great importance in our lives.

But for the past several decades there’s been a problem brewing with this genus. Using the research tools available at the time, researchers through history who discovered new bacteria grouped many diverse species under the “umbrella” of the genus Lactobacillus. Since the naming of the first Lactobacillus species, Lactobacillus delbrueckii, in 1901, microbial taxonomists assigned over 250 species to this genus.

These species were a diverse group, and when DNA analysis tools became more sophisticated, many were found to be only loosely related. A consensus grew among scientific experts that, given the genetic makeup of these bacteria, the current Lactobacillus genus was too diverse and did not conform to nomenclature conventions. Moreover, it was important to split the genus into functionally relevant groups that shared certain physiological, metabolic properties and lifestyles in order to facilitate functional and ecological studies on bacteria from this genus.

To tackle this problem, 15 scientists (see below) from 12 different institutions and 7 different countries came together, applying whole genome analysis to analyze each Lactobacillus species. Their proposal, which was accepted for publication in the official journal of record for bacterial names, is that the species once contained within the Lactobacillus genus should now spread over 25 genera, including 23 novel genera (see paper link here).

Based on this polyphasic approach, the authors reclassified the genus Lactobacillus into 25 genera including the emended genus Lactobacillus, which includes host-adapted organisms that have been referred to as the L. delbrueckii group; Paralactobacillus; as well as 23 novel genera: Acetilactobacillus, Agrilactobacillus, Amylolactobacillus, Apilactobacillus, Bombilactobacillus, Companilactobacillus, Dellaglioa, Fructilactobacillus, Furfurilactobacillus, Holzapfelia, Lacticaseibacillus, Lactiplantibacillus, Lapidilactobacillus, Latilactobacillus, Lentilactobacillus, Levilactobacillus, Ligilactobacillus, Limosilactobacillus, Liquorilactobacillus, Loigolactobacilus, Paucilactobacillus, Schleiferilactobacillus, and Secundilactobacillus.

While genus names have changed in some cases, the parts of the names that indicate species were not changed. See the table below for some examples of how names of important probiotic lactobacilli have changed. Note that all new genera proposed for this group begin with the letter “L”. Thus, the ‘L.’ genus abbreviation may still be used.

Because of the importance of this genus and the implications of the name change for both science and industry, the researchers involved in this project have developed a web-based tool that makes it very easy to determine the new names of all Lactobacillus species.

Scientifically, one exciting outcome of these new taxonomic groupings is that species that are more closely related, and therefore are more likely to share physiological traits, are grouped into the same genus. This may facilitate our understanding of common mechanisms that may mediate health benefits, as described in an ISAPP consensus paper and a publication entitled “Shared mechanisms among probiotic taxa: implications for general probiotic claims”.

To date, bacteria in the group Bifidobacterium have not changed, but nomenclature changes are expected soon for this genus, too.

The Lactobacillus taxonomy changes are summarized in this ISAPP infographic for scientists and in this ISAPP infographic for consumers.

Names of important Lactobacillus probiotic species

The following chart lists the new names for some prominent Lactobacillus probiotic species. (Note: All new genera proposed for this group begin with the letter “L”, so abbreviated genus/species – such as L. rhamnosus – remain unchanged.)

 

Current name New name
Lactobacillus casei Lacticaseibacillus casei
Lactobacillus paracasei Lacticaseibacillus paracasei
Lactobacillus rhamnosus Lacticaseibacillus rhamnosus
Lactobacillus plantarum Lactiplantibacillus plantarum
Lactobacillus brevis Levilactobacillus brevis
Lactobacillus salivarius Ligilactobacillus salivarius
Lactobacillus fermentum Limosilactobacillus fermentum
Lactobacillus reuteri Limosilactobacillus reuteri
Lactobacillus acidophilus Unchanged
Lactobacillus delbrueckii subsp. bulgaricus

(aka Lactobacillus bulgaricus)

Unchanged
Lactobacillus crispatus Unchanged
Lactobacillus gasseri Unchanged
Lactobacillus johnsonii Unchanged
Lactobacillus helveticus Unchanged

Authors

  • Jinshui Zheng, Huazhong Agricultural University, State Key Laboratory of Agricultural Microbiology, Hubei Key Laboratory of Agricultural Bioinformatics, Wuhan, Hubei, P.R. China.
  • Stijn Wittouck, Research Group Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
  • Elisa Salvetti, Dept. of Biotechnology, University of Verona, Verona, Italy
  • Charles M.A.P. Franz, Max Rubner-Institut, Department of Microbiology and Biotechnology, Kiel, Germany
  • Hugh M.B. Harris, School of Microbiology & APC Microbiome Ireland, University College Cork, Co. Cork, Ireland
  • Paola Mattarelli, University of Bologna, Dept. of Agricultural and Food Sciences, Bologna, Italy
  • Paul W. O’Toole, School of Microbiology & APC Microbiome Ireland, University College Cork, Co. Cork, Ireland
  • Bruno Pot, Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Vrije Universiteit Brussel, Brussels, Belgium
  • Peter Vandamme, Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
  • Jens Walter, Department of Agricultural, Food & Nutritional Science, University of Alberta, Edmonton, Canada; Department of Biological Sciences, University of Alberta, Edmonton, Canada
  • Koichi Watanabe, National Taiwan University, Dept. of Animal Science and Technology, Taipei, Taiwan R.O.C.; Food Industry Research and Development Institute, Bioresource Collection and Research Center, Hsinchu, Taiwan R.O.C.
  • Sander Wuyts, Research Group Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
  • Giovanna E. Felis, Dept. of Biotechnology, University of Verona, Verona, Italy
  • Michael G. Gänzle, Department of Agricultural, Food & Nutritional Science, University of Alberta, Edmonton, Canada; Hubei University of Technology, College of Bioengineering and Food Science, Wuhan, Hubei, P.R. China.
  • Sarah Lebeer, Research Group Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium.

See ISAPP’s press release on the Lactobacillus name changes here.