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Probiotics in fridge

Designing Probiotic Clinical Trials: What Placebo Should I Use?

By Daniel J. Merenstein, MD, Professor, Department of Family Medicine and Director of Research Programs, Georgetown University Medical Center, Washington DC

Specifying a placebo is one of the most important decisions for a clinical trialist. The first trial I led was a study giving Benadryl to kids to see if it helped them sleep. We spent hours working with our pharmacist on the placebo to make sure it had the same sweet cherry taste of the active drug, Benadryl. We didn’t want parents to be able to determine whether they were randomized to Benadryl or the placebo by comparing the study product to what they had at home. Do study subjects really do this? Yes. Early in my career I was helping an orthopedist who was putting pain pumps directly into a patient’s ankle post-surgery in order to see if it would decrease oral narcotic usage. One of our first patients pulled his pump out, tasted the medicine and called us late at night complaining he was in the saline (placebo) group.

When undertaking a study on probiotics, and specifically probiotic yogurts, we can debate for weeks about the best placebo. Our intervention is yogurt fortified with an additional probiotic. Therefore, our intervention yogurt contains both the starter lactic acid bacteria and the probiotic. So assuming we want both groups to get nutritionally equivalent yogurt that can be blinded our placebo options could be as follows. Note that in recent years, we have become more cognizant that dead microbes may not be biologically inactive.

Placebo Microbiological content of Placebo Research question addressed
Yogurt Live starter cultures, no probiotic What is the contribution of probiotics to any health benefit?
Acidified yogurt No live or dead microbes What is the contribution of live probiotic + live starter cultures to any health benefit?
Heat treated yogurt No live microbes, dead starter microbes Beyond any contribution of dead starter cultures, what is the contribution of live probiotic + live starter cultures to the health benefit?
Heat treated probiotic yogurt No live microbes, dead starter + dead probiotic microbes Beyond any contribution of dead probiotics + dead starter cultures, what is the contribution of live probiotic + live starter cultures to the health benefit?
Probiotic yogurt using a different probiotic Live starter cultures, live probiotic different from the probiotic in the intervention What is the contribution of the intervention probiotic to any health benefit compared to the control probiotic?

 

We chose regular yogurt (the first option above) and now about eight papers later, I would say that about 50% of reviewers question our choice.

There are many reasons the placebo needs to be well considered, including the specific research question under consideration. But an important one is clinical equipoise, “a state of genuine uncertainty on the part of the clinical investigator regarding the comparative therapeutic merits of each arm in a trial”, as defined Freedman 1987. Thus, for example in a study of a new hypertension drug, one cannot use a placebo that has no chance of lowering a patient’s blood pressure as a comparator as that is ethically indefensible. Instead, a well proven hypertension drug will be studied versus the new experimental drug.

For most of my career the goal in my studies was to pick a placebo that was as inactive as possible that still smelled, looked and tasted like my active intervention. However, the times are changing. When I started working there were fewer than 200 randomized controlled clinical probiotic trials retrievable from PubMed; today the number is over 2,300. Well that means we have gone beyond merely recognizing the value of probiotics in different indications, to detailed comparisons of different probiotic and non-probiotic interventions, so one has to consider how inactive their placebo is for probiotic intervention trials.

In 2020 the American Gastrointestinal Association came out with recommendations and guidelines after they conducted a thorough review of probiotic evidence. (See ISAPP blog ISAPP take-home points from American Gastroenterological Association guidelines on probiotic use for gastrointestinal disorders.) For three indications, they recommended using select probiotics over no or other probiotics, in populations of preterm low birthweight infants, patients receiving antibiotics, and patients with pouchitis. So what does this mean for trials evaluating one of these indications? It means that the placebo should be an active control, a probiotic versus probiotic trial.

Today if I’m asked what placebo should be used, my first question is what indication are you studying? If you are studying infant colic or preterm low birthweight infants, I think you need an active control, such as another probiotic. (Colleagues and I suggested this for probiotic studies on necrotizing enterocolitis in 2013.) If you are studying anxiety, then an inert placebo makes the most sense since insufficient evidence exists for any probiotic for this endpoint as yet. In the case of antibiotic associated diarrhea, it will be a much longer discussion as the data are not clear, but it would be reasonable for an IRB to argue that your placebo should be another probiotic. It is not ethical to deny a placebo group an effective intervention if one is available.

So in the last 15 years of my career the answer to what placebo should I use has greatly changed. As probiotic research has advanced, so has the evidence base for usage. As we proceed with research we now need to consider conducting our clinical trials differently. This is just another example of how probiotic evidence has matured over a relatively short period of time.

Five things scientists should know about the future of probiotics and prebiotics

By Marla Cunningham​, Metagenics Global R&D Innovation Manager and 2021 ISAPP Industry Advisory Committee representative

As anyone connected with probiotics and prebiotics knows – there’s a lot happening in this space.

After a well-attended discussion group at the 2019 ISAPP Annual Meeting in Antwerp, a collaboration of 16 industry and academic scientists came together to produce a broad overview of current and emerging trends that were covered in this discussion. Just released online by Trends in Microbiology, the open access paper identifies some top trends across multiple spheres of influence on the future of probiotics and prebiotics.

  1. Discovery: Prebiotics and probiotics are emerging from unexpected sources – naturally occurring as well as synthesised or engineered. Food, human and animal microbiome-derived probiotics feature heavily in probiotic development through top-down microbiome data-driven approaches as well as physiological target-driven screening approaches. Prebiotic sources have expanded beyond traditional plant sources to include food waste streams, animal gut-derived glycans and mammalian milk as well as increasingly sophisticated synthesis techniques, involving sonication, high pressure, acid, enzyme and oxidation treatments. A growing understanding of the implications of carbohydrate structure on microbial metabolism is driving the emergence of designer prebiotics, as specific substrates for microbes of interest or the production of target metabolites, such as polyphenol-derived bioactives.
  2. Evaluation: Calls for integrated systems biology -omic approaches to the evaluation of probiotic and prebiotics effects continue to increase, utilising whole genome and metabolite approaches, with a focus on better understanding of mode of action as well as differential host and microbial responses that serve to improve host health.
  3. Product development: Quality assurance techniques continue to undergo evolution as the challenges of divergent product formats and increasingly complex formulations necessitate innovation in the field. There is a focus on techniques beyond cell culture enumeration for probiotic product verification as well as on the identification of functional markers of probiotic and prebiotic activity, which can be applied in complex food matrices.
  4. Regulation: Recent regulatory challenges with claim approval are understood to have driven corresponding evolution in clinical science and an increased focus on mechanistic elucidation. However, the converse is also occurring, with the development of novel probiotic species, therapeutics for disease treatment and increasingly microbiome-driven modes of action having implications for regulatory frameworks. This ‘give and take’ between science and regulatory requirements will likely accelerate into the future as the field continues to evolve.
  5. Implementation: Interest continues to grow in precision and personalised approaches to nutrition and healthcare, especially in the field of microbiome-related interventions where there is significant appreciation of host-to-host variability. The identification of putative microbial signatures of health and disease continues to fuel the development of health-associated microbes as candidate probiotics and as targets for novel prebiotic substrates. Further, a focus beyond microbial composition and into microbial function is driving interest in interventions which can correct metabolomic profiles, such as probiotics with specific enzyme activity to boost synthesis or catabolism of key microbial metabolites in vivo, including purine and monoamine compounds.

These and other trends create a rich and evolving landscape for scientists within the field and provide the promise of a bright future for prebiotics and probiotics.

Read the full paper here

Reference:

Cunningham, M., Azcarate-Peril, M. A., Barnard, A., Benoit, V., Grimaldi, R., Guyonnet, D., Holscher, H. D., Hunter, K., Manurung, S., Obis, D., Petrova, M. I., Steinert, R. E., Swanson, K. S., van Sinderen, D., Vulevic, J., & Gibson, G. R. (2021). Shaping the Future of Probiotics and Prebiotics. Trends in microbiology, S0966-842X(21)00005-6. Advance online publication. https://doi.org/10.1016/j.tim.2021.01.003

 

 

 

Video Presentation: Behind the scenes of the consensus panel discussion on the definition of fermented foods

Numerous misunderstandings and questions exist around the concept of fermented foods. For example:

  • If a food does not contain live microorganisms, can it still be a fermented food?
  • Should the live microbes in fermented foods be called probiotics?
  • Do fermentation microbes colonize the human gut?

The first step in answering these questions is for scientists to come to agreement on what constitutes a fermented food. A new global definition of fermented foods was recently published by 13 interdisciplinary scientists from various fields—microbiology, food science and technology, immunology, and family medicine. In their paper in Nature Reviews Gastroenterology & Hepatology, fermented foods are defined as: “foods and beverages made through desired microbial growth and enzymatic conversions of food components”.

The panel discussion and the definition of fermented foods are covered in this video presentation by the paper’s first author Prof. Maria Marco, from the Department of Food Science and Technology at the University of California, Davis. This presentation was originally given at the virtual ISAPP 2020 annual meeting.

The new definition is intended to provide a clearer conceptual understanding of fermented foods for the public and industry, with the authors expecting that in the years ahead, scientists will undertake more hypothesis-driven research to determine the extent that various fermented foods improve human health and precisely how this occurs. More studies that address fermented foods in promoting health will be useful for establishing the importance of fermented foods in dietary guidelines.

The panel acknowledged that regulations on fermented foods from country to country are mainly concerned with food safety — and that, when properly made, fermented foods and their associated microorganisms have a long history of safe use.

 

ISAPP ha estado trabajando en colaboración con la Sociedad de Enterocolitis Necrotizante

La Asociación Científica Internacional para Probióticos y Prebióticos (ISAPP, por sus siglas en inglés), ha estado trabajando en colaboración con la Sociedad de Enterocolitis Necrotizante (NEC Society) en el desarrollo de una infografía sobre el rol de los probióticos en la prevención de la Enterocolitis Necrotizante (ECN).

La ECN es una enfermedad intestinal que puede poner en peligro la vida principalmente en bebés prematuros. Esta enfermedad produce un proceso inflamatorio que puede provocar daños en el tejido intestinal e incluso la muerte.

La leche materna de la madre del bebé es la forma más importante de ayudar a disminuir el riesgo de ECN. La leche pasteurizada de madres donantes es la segunda mejor opción. Adicionalmente, suministrar probióticos a bebés prematuros, junto con la leche materna, puede reducir el riesgo de ECN.

Los probióticos son microorganismos vivos que, cuando se administran en cantidades adecuadas, confieren un beneficio para la salud del huésped.

Los padres con hijos con riesgo de desarrollar ECN pueden consultar a los responsables de la Unidad de Cuidados Intensivos, sobre la posibilidad de utilizar probióticos para contribuir a prevenir el desarrollo de ECN.

ISAPP ha preparado una infografía en español con mayor información sobre este tema, la cual se puede encontrar aquí.

Can fermented or probiotic foods with added sugars be part of a healthy diet?

By Dr. Chris Cifelli, Vice President of Nutrition Research, National Dairy Council, Rosemont IL, USA

What about added sugar in fermented or probiotic foods? I am almost always asked this question whenever I give a nutrition presentation, no matter the audience. It’s not a surprising question as people care about what they eat and, often, are looking for ways to reduce their intake of sugar. Yet, if someone wants to add fermented or probiotic foods such as yogurt, kefir or kombucha to their diet, they often find the products available to them contain sugar as an added ingredient.

Should these products be part of you and your family’s healthy eating plan even if they have added sugar? The simple answer – yes, they likely can still fit into a healthy eating plan.

According to the U.S. Food and Drug Administration, ‘added sugars’ are defined as sugars that are either added during the processing of foods or are packaged separately as sugars (e.g. the bag of sugar you buy to make your treats). Added sugars in the diet have received attention because of their link to obesity and chronic disease risk. The World Health Organization, American Heart Association, Dietary Guidelines for America, and American Diabetes Association all recommend reducing added sugar intake to improve overall health. While data from the US National Health and Nutrition Examination Survey (NHANES) has shown that consumption of added sugar decreased from the 2007-2010 to the 2013-2017 surveys, the most recent Dietary Guidelines Advisory Committee report noted that the mean usual consumption of added sugars was still 13% of daily energy in 2015-16, which exceeds recommendations of 10%.

Including fermented foods in one’s diet may be important for overall health. The recent ISAPP consensus paper on fermented foods indicated that fermented foods, especially the live microbes contained in them, could benefit health in numerous ways, such as by beneficially modulating the gut microbiota or the immune system. Similarly, foods with added probiotics may confer health benefits ranging from impacting digestive health to metabolic parameters, depending on the probiotic contained in the product. Our understanding of the gut microbiota continues to evolve, but one thing is for certain: it is important for health. This provides a compelling reason to find ways to include these foods in healthy eating patterns.

So, back to the question at hand. Should you reduce or eliminate fermented foods and foods with probiotics from your diet if they have added sugars? Just like a “spoonful of sugar helps the medicine go down,” a little added sugar to improve the palatability of nutrient-dense foods is okay. Indeed, government and health organizations all agree that people can eat some sugar within the daily recommendations (which is 10% of total daily calories), especially in foods like yogurt or whole-grain cereals, or other healthy foods. And, there is no scientific evidence to show that the sugar in these products reduces the health benefits associated with eating foods like yogurt or probiotics. Human studies assessing health benefits of probiotic foods typically use products with added sugar, yet health effects are still observed.

The next time you are out shopping you can choose your favorite fermented or probiotic-containing food guilt free, as long as you’re watching your overall daily intake of sugar. But, if are you are still concerned, then choose plain varieties to control your own level of sweetness or you could opt for a probiotic supplement to avoid the sugar. Whether you go with the sweetened or unsweetened version of your favorite fermented food, you’ll not only get the benefit of the live microbes in these products but also the nutritional benefit that comes with foods like yogurt.

 

Creating a scientific definition of ‘fermented foods’

By Prof. Maria Marco, Department of Food Science and Technology, University of California Davis, USA

A panel of scientific experts was recently convened by ISAPP to discuss the state of knowledge on fermented foods. While there was much agreement on the underlying microbiological processes and health-related properties of those foods and beverages, our conversation on definitions led to sustained debate. So what exactly is a fermented food?

The word “ferment” originates from fervere, which in Latin means to boil. According to the Merriam-Webster dictionary, the verb ferment is defined as “to undergo fermentation or to be in a state of agitation or intense activity”. Fermentation is defined as both a chemical change with effervescence and as an enzymatically controlled anaerobic breakdown of energy-rich compounds (such as a carbohydrate to carbon dioxide and alcohol or to an organic acid). In biochemistry, fermentation is understood as an ATP-generating process in which organic compounds act as both electron donors and acceptors. In industry, fermentation means the intentional use of bacteria and eukaryotic cells to make useful products such as drugs or antibiotics. As you can see, there are clearly many meanings implied in “ferment” and “fermentation”. We add onto this by defining how those words apply to foods.

As our ISAPP panel began to deliberate the definition of fermented foods, it quickly became clear how difficult reaching consensus can be! Even though many panel members shared similar academic backgrounds and scientific expertise, finding agreement on the definition required several rounds of debate and some consuming of fermented foods and beverages along the way. Finally, we defined fermented foods and beverages as being “foods made through desired microbial growth and enzymatic conversions of food components” (see the published consensus paper here).

Find ISAPP’s infographic on fermented foods here.

This definition is very specific by requiring microbial growth and enzymatic processes for the making of those foods. Activity of the endogenous enzymes from the food components or enzymes added to the food is not enough for a food to be regarded as fermented. Similarly, foods made by only adding vinegar or “pickling” should not be called fermented. The definition acknowledges the essential roles of microorganisms for making fermented foods but does not require their presence or viability at the time of consumption.

On the other hand, our definition does not restrict fermented foods to only those foods and beverages made using microorganisms using metabolic pathways implicit in the strict biochemical definition. Yogurt and kimchi made using lactic acid bacteria relying on fermentative energy metabolism are included as much as koji and vinegar, foods made using fermentation processes that employ fungi and bacteria that perform aerobic respiratory metabolism.

Each word in a definition needs to be carefully calibrated. The best example of this in our definition of fermented foods is the word “desired”. Unlike a food that is spoiled as a result of microbial growth and enzymatic activity, food fermentations generate wanted attributes. Other words such as “intentional”, “desirable”, or “controlled” may also be used to describe this meaning. However, those words also have caveats that not all fermented foods are made “intentionally”, at least in the way that they were first prepared thousands of years ago. Qualities of fermented foods may be “desirable’ in some cultures but not others. While some fermentations are “controlled”, others are spontaneous, requiring little human input.

The process of discussing the definition with a group of scientific experts was enlightening because it required us to deconstruct our individual assumptions of the term in order to reach agreement on descriptions and meaning. With a definition in hand, we can use a shared language to study fermented foods and to communicate on the significance of these foods and beverages in our diets. There will also certainly be more “fermenting” of these concepts to improve our knowledge on the production and health impacting properties of fermented foods for years to come.

Find the ISAPP press release on this paper here.

Read about another ISAPP-led publication on fermented foods here.

Learn more in a webinar on the science of fermented foods here.

‘Probiotic’ on food labels in Europe: Spain adopts a pioneering initiative

By Silvia Bañares, PhD in commercial law, attorney Barcelona Bar Association, Spain; and Miguel Gueimonde, Departamento de Microbiología y Bioquímica de Productos Lácteos, IPLA-CSIC, Villaviciosa, Asturias, Spain. 

The word ‘probiotic’ has been absent from food products in most countries in Europe for years. Authorities there concluded that the word is an implied health claim, which is a reasonable position based on the probiotic definition: live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. The argument proceeds: since there are no health claims approved for probiotics by the European Union, the word is not allowed on food labels. However, the logic fails since in 2010 ESFA actually did approve a health claim for probiotics – although they didn’t use the term ‘probiotic’. This claim was for yogurt cultures improving lactose digestion. But nonetheless, restrictions on using the word ‘probiotic’ have endured.

Recently, akin to positions taken by Italy (here and here) and ostensibly the Czech Republic (as stated here), Spanish authorities have determined that the term ‘probiotic’ may be used.

In October 2020 the Spanish Health Authority (AESAN) delivered a new decision related to the use of the term “probiotic” in foodstuffs. According to it:

“until  a uniform criterion is generated on the part of the Member States of the European Union, it is considered that it could be accepted that the term probiotic/s  on the label of foodstuffs, both of national manufacturing as well as from other countries of the European Union. In all cases, these products must meet the safety requirements. However, it should be noted that the use of this term cannot be accompanied by any health claim, unless expressly authorized under the Regulation of the European Union  -Regulation EC 1924/2006[1], [2]

This new decision completely differs from the previous one (February 2020), which forbade the use of “probiotic/s” term in food products. Surprisingly, both documents are extremely similar in their reasoning.

However, the new Guidance contains some points that might be relevant for the future:

  • First, there is a clear statement related to the EU Commission Guidance of 2007 [3]; such Guidance had always been invoked as the rationale in order to forbid the term probiotic in foodstuffs, since according to it, the reference to “probiotic/s implies a health benefit”[4]. But the AESAN communication points out for first time that such Guidance is not binding since it has no legal force.
  • Secondly it recognizes the lack of harmonization at the EU level regarding the “probiotic” term:

 “From the discussions that have been held within the European Commission’s group of experts on nutritional and health claims, it is found that there are different interpretations by State Members regarding the use of the term “probiotic”, which, in turn, implies a non-harmonized situation in the European Union market”[5].

  • Third, there is a clear reference to mutual recognition principle; that is to say, any product legally marketed and sold in any EU country might be, in its turn, marketed in any other European Union Member State. For instance, any foodstuff labelled as “probiotic” in Italy might be legally sold in Spain as far as it fulfils the aforementioned criterion in its country of origin. The AESAN communication recognized such fact, pointing out that:

“In this sense, infant formulas and follow-on formulas are marketed which, as a voluntary added ingredient, contain different live microorganisms. The presence of these live microorganisms is indicated on the product label in the ingredient list. In the field of food supplements, it has been found that there are a large number of food supplements on the market, which include the term “probiotic/s”. These products come from different EU countries, where they are allowed to be marketed under this name and, therefore, they could not be prevented from being marketed in Spain, in application of the “principle of mutual recognition” established in the European Union Treaty”[6].

This statement is clearly aligned with Regulation EU 2019/515 [7] (related to mutual recognition principle) and a recent Commission Regulation (Implementing Regulation 2020/1668), which develops the previous one [8]. According to these dispositions, any competent authority suspending market access should notify the legitimate public interest grounds for such suspension. Therefore, Spain would find quite difficult to reject a foodstuff labelled as “probiotic” in another EU country when it is legally sold as such. Hence, it can be said that Spain has adopted a pioneering initiative that maybe could be followed by other EU Member States.

Italy and the Czech Republic have allowed use of the term ‘probiotic’ on foods – perhaps simply because they considered it to be the right thing to do – but they did not make the convincing legal argument made by Spanish authorities. The rationale presented by Spain could likely be easily adopted by other EU countries as well. Perhaps the Spanish initiative will motivate the EU Commission and EFSA to reach a consensus about this word.

Two decades ago, with a rapidly growing list of probiotic-containing products reaching the market worldwide, there was increasing concern by consumers about how to distinguish among the different probiotic strains available and how to know which products have evidence for different health benefits. This, together with the interest of scientist and industry for clear rules and fair competence, prompted the EU Commission to regulate the area and the Regulation EC n° 1924/2006 on nutrition and health claims made on foods was developed. In its preamble this Regulation states, “to ensure a high level of protection for consumers and to facilitate their choice, products put on the market must be safe and adequately labelled” and recognises that  “general principles applicable to all claims made on foods should be established in order to ensure a high level of consumer protection, give the consumer the necessary information to make choices in full knowledge of the facts, as well as creating equal conditions of competition for the food”.  Therefore, consumer protection and facilitating informed purchase choices was in the forefront of the Regulation, in an attempt to satisfy the concerns and demands that consumers had leveraged.

Subsequent interpretation of the Regulation EC n° 1924/2006 led to the conclusion that the term “probiotic” was a health claim and, as a consequence, should not be used in product labelling. Different countries, such as Italy or the Czech Republic, reacted to this by developing national regulations allowing the probiotic food labelling. Now Spain, on the basis of mutual recognition principle, accepts its use as well.

However, this new situation makes relevant again the challenges that consumers had identified two decades ago:  how to differentiate among the different available probiotic products and make an informed, purposeful purchase. This unsolved issue should now be addressed. In this context, we advocate for the development of easy-to-use guidelines targeted to regular consumers, not to clinicians or scientists, to provide consumers with the necessary tools to make their choice.

Related article: Spanish agency approves use of term ‘probiotic’ on food and supplements

References:

[1] https://www.aesan.gob.es/AECOSAN/web/seguridad_alimentaria/subdetalle/probioticos.htm

[2] Translation by the authors

[3] https://ec.europa.eu/food/sites/food/files/safety/docs/labelling_nutrition_claim_reg-2006-124_guidance_en.pdf

[4] Guidance on the implementation of Regulation n° 1924/2006 on nutrition and health claims made on foods conclusions of the Standing Committee on the Food Chain and Animal Health /14/12/2007

[5] Translation by the authors

[6] Translation by the authors

[7] Commission Implementing Regulation (EU) 2020/1668 of 10 November 2020 specifying the details and functionalities of the information and communication system to be used for the purposes of Regulation (EU) 2019/515 of the European Parliament and of the Council on the mutual recognition of goods lawfully marketed in another Member State.

[8] Regulation (EU) 2019/515 of the European Parliament and of the Council of 19 march 2019 on the mutual recognition of goods lawfully marketed in another Member State and repealing regulation (EC) nº 764/2008

ISAPP collaborates with NEC Society to help parents understand the role of probiotics in reducing the risk of necrotizing enterocolitis

By Dr. Mary Ellen Sanders, PhD, ISAPP Executive Science Officer

To date, over 50 clinical trials on probiotics and necrotizing enterocolitis have been published. Medical organizations have considered the trials completed to date and have provided guidance (ESPHGAN) and recommendations (American Gastroenterological Association) for implementing probiotics in clinical practice.

As important as the science on this issue are the perspectives from parents of babies who have suffered from NEC or are at risk of developing the disease. Such parents consistently point to the need for credible and balanced educational materials about this condition. Recently, ISAPP has been fortunate to work with the NEC Society to develop materials that will help inform parents.

See the new ISAPP infographic Probiotics and Necrotizing Enterocolitis: What Parents Should Know.

Disponible también en español. Информация также доступна на русском языке.

Also, a recent ISAPP blog Probiotics to Prevent Necrotizing Enterocolitis: Moving to Evidence-Based Use by Dr. Ravi Patel MD, a neonatologist on the NEC Society’s Scientific Advisory Council, summarizes the state of the science supporting this use, including both controlled efficacy trials and post-implementation surveys.

The NEC Society is a nonprofit organization – the only US group dedicated to NEC – with the stated mission of “building a world without necrotizing enterocolitis (NEC) through research, advocacy, and education.” They advocate for families affected by NEC by bringing together critical stakeholders to improve understanding, prevention, and treatment for NEC. Jennifer Canvasser founded the NEC Society in 2014 after her son, Micah, died from complications of NEC just before his first birthday. Micah was born at 27-week’s gestation, placing him at increased risk of NEC. Despite Micah’s risk factors and his parents asking the care team to consider offering Micah probiotics, he was not treated with probiotics. Although it is impossible to know if probiotics could have changed Micah’s course, his parents feel that more could have been done to better protect Micah from the devastation of NEC. Micah’s photo is featured in the new infographic co-created by ISAPP and the NEC Society.

“It is vital for healthcare providers to support NICU parents in understanding the protective and risk factors associated with NEC,” Canvasser shared. “Parents are the most important members of their baby’s care team. For parents to effectively engage and contribute, they need to be supported in accessing and understanding important information related to their child’s health. This new resource on probiotics and NEC will help to ensure that NICU parents are informed and feel encouraged to ask questions so they can best advocate for their child.”

The NEC Society intends to use the new infographic as a resource available to NICU parents and providers. It will be downloadable from the websites of both the NEC Society and ISAPP, and it will be shared via both social media platforms. Once in-person events are possible again, print versions will be made available. ISAPP will also work with the NEC Society’s Scientific Advisory Council to explore how we can further disseminate this resource to NICUs.

Read more about the efforts of the NEC Society here:

Head of the Herd: Jennifer Canvasser, Founder and Director, Necrotizing Enterocolitis (NEC) Society

Family Reflections: harnessing the power of families to improve NEC outcomes

10 Things All Parents of NICU Babies Need to Know

9 Things You Need to Know About Necrotizing Enterocolitis

New ISAPP-led paper calls for investigation of evidence for links between live dietary microbes and health

The past two decades have brought a massive increase in knowledge about the human gut microbiota and its links to human health through diet. And although many people perceive that regular consumption of safe, live microbes will benefit their health, the scientific evidence to date has not been sufficiently developed to justify adding a daily recommended intake of live microbes to food guides for different populations.

Recently, a group of seven scientists, including six ISAPP board members, published their perspective about the value of establishing the link between live dietary microbes and health. They conclude that although the scientific community has a long way to go to build the evidence base, efforts to do this are worthwhile.

The collaboration on this review was rooted in an ISAPP expert discussion group held at the 2019 annual meeting in Antwerp, Belgium. During the discussion, various experts presented evidence from their fields—addressing the potential health benefits of live microbes in general, rather than the narrow group of microbial strains that qualify as probiotics.

Below, the authors of this new review answer questions about their efforts to quantify the relationship between greater consumption of live microbes and human health.

Why is it interesting to look at the potential importance of live microbes in nutrition?

Prof. Joanne Slavin, PhD, RD, University of Minnesota

Current recommendations for fiber intake are based on protection against cardiovascular disease—so can we do something similar for live microbes? We know that intake of live microbes is thought to be health promoting, but actual recommended intakes for live microbes are missing.  Bringing together a talented group of microbiologists, epidemiologists, nutritionists, and food policy experts moves this agenda forward.

Humans need proper nutrition to survive, and a lack of certain nutrients creates a ‘deficiency state’. Is this the case for live microbes?

Dr. Mary Ellen Sanders, PhD, ISAPP Executive Science Officer

I don’t think we’ll find that live microbes are essential in the same way that vitamins and minerals lead to deficiency diseases. After all, gnotobiotic animal colonies are viable. But I believe there is enough evidence to suggest that consumption of live microbes will promote health. Exactly how and to what extent remains to be established.

Why think about intake of ‘live microbes’ in general, rather than intake of probiotic & fermented foods specifically?

Prof. Maria Marco, PhD, University of California Davis

We are constantly exposed to microorganisms in our foods and beverages, in the air, and on the things we touch. While much of our attention has been on the microbes that can cause harm, most of our microbial exposures may not affect us at all or, quite the opposite, be beneficial for maintaining and improving health. Research on probiotic intake as a whole supports this possibility. However, probiotic-containing foods and dietary supplements are only a part of our dietary connection with live microbes. Non-pasteurized fermented foods (such as kimchi and yogurts) can contain large numbers of non-harmful bacteria (>10^7 cells/g). Fruits and vegetables are also sources of living microbes when eaten raw.  Although those raw foods they may contain lower numbers of microbes, they may be more frequently eaten and consumed in larger quantities. Therefore, our proposal is that we take a holistic view of our diets when weighing the potential significance of live microbe intake on health and well-being.

What are dietary sources of live microbes? And do we get microbes in foods besides fermented & probiotic foods?

Prof. Bob Hutkins, PhD, University of Nebraska Lincoln

For tens of thousands of years, humans consumed large amounts of microbes nearly every time they ate food or drank liquids. Milk, for example, would have been unheated and held at ambient temperature with minimal sanitation and exposed to all sorts of microbial environments.  Thus, a cup of this milk could easily have contained millions of bacteria. Other foods like fruits and vegetables that were also exposed to natural conditions could have also contained similar levels of microbes. Even water would have contributed high numbers of live microbes.

Thanks to advances in food processing, hygiene, and sanitation, the contemporary western diet generally contains low levels of microbes. Consider how many foods we eat that are canned, pasteurized, or cooked – those foods will contain few, in any live microbes. Fresh produce can serve as a source of live microbes, but washing, and certainly cooking, will reduce those levels.

For sure, the most reliable sources of dietary microbes are fermented foods and beverages. Even if a fresh lettuce salad were to contribute a million bacteria, a single teaspoon of yogurt could contain 100 times more live bacteria. Other popular fermented foods like kefir, kimchi, kombucha, and miso, can contain a large and relatively diverse assortment of live microbes. Other fermented foods, such as cheese and sausage, are also potential sources, but the levels will depend on manufacturing and aging conditions. Many fermented, as well as non-fermented foods are also supplemented with probiotics, often at very high levels.

What’s the evidence that a greater intake of live microbes may lead to health benefits?

Prof. Dan Merenstein, MD, Georgetown University

Studies have shown that fermented foods are linked to a reduced risk of cardiovascular disease, reduced risk of weight gain, reduced risk of type 2 diabetes, healthier metabolic profiles (blood lipids, blood glucose, blood pressure and insulin resistance), and altered immune responses. This link is generally from associative studies on certain fermented foods. Many randomized controlled trials on specific live microbes (probiotics and probiotic fermented foods) showing health benefits have been conducted, but randomized controlled trials on traditional fermented foods (such as kimchi, sauerkraut, kombucha) are rare. Further, no studies have aimed to assess the specific contribution of safe, live microbes in diets as a whole on health outcomes.

Why is it difficult to interpret past data on people’s intake of live microbes and their health?

Prof. Colin Hill, PhD, University College Cork

It would be wonderful if there were a simple equation linking the past intake of microbes in the diet and the health status of an individual (# MICROBES x FOOD TYPE = HEALTH). In reality, this is a very complex challenge. Microbes are the most diverse biological entities on earth, our consumption of microbes has not been deliberately recorded and can only be estimated, and even the concept of health has defied precise definitions for centuries. To further confuse the situation microbes meet the host in the gastrointestinal tract, the site of our enormously complex mucosal immune system and equally complex microbiome.  But the complexity of the problem should not prevent us from looking for prima facie evidence as to whether or not such a relationship is likely to exist.

Databases of dietary information have data on people’s intake of live microbes, but what are the limitations of our available datasets?

Prof. Dan Tancredi, PhD, University of California Davis

Surveys often rely on food frequency questionnaires or diaries to determine consumption of specific foods. These are notoriously prone to recall error and/or other types of measurement error. So, even just measuring consumption of foods is difficult. For researchers seeking to quantify survey respondents’ consumption of live microbes, these challenges become further aggravated because the respondents would not typically know the microbial content in the foods they consumed. Instead, we would have to have them tell us the types and amounts of the foods they ate, and then we would need to translate that into approximate microbial counts—but even within a particular food, the microbial content can vary, depending on how it was processed, stored, and/or prepared prior to consumption.

See ISAPP’s press release on this paper here.

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.

 

Locally produced probiotic yogurt for better nutrition and health in Uganda

By Prof. Seppo Salminen, Director of Functional Foods Forum, University of Turku, Turku, Finland

Can locally produced probiotic yogurt be a way to increase the health and wealth of people in resource-poor areas of Uganda? Recently Dr. Nieke Westerik, a researcher from the Netherlands, partnered with a local Ugandan team to explore a yogurt production and distribution program similar to one that had previously proved successful in low-income areas of Argentina.

Since 2008, “Yogurito Social Program” has been operating in Argentina and now some 350,000 schoolchildren in less developed provinces enjoy the benefits of daily probiotic yogurt developed locally. Dr. Westerik (Free University of Amsterdam and Yoba 4 Life Foundation), with support from former ISAPP board member Prof. Gregor Reid, has now helped adapt the program to local needs in Uganda, making use of a well-known probiotic (Lacticaseibacillus rhamnosus GG) plus a yogurt starter (produced by the Yoba 4 Life Foundation) for production of the yogurt. The probiotic’s health effects have been demonstrated in human intervention studies.

The team worked on technical training and quality control of the locally produced yogurt, developing a production protocol suitable for Ugandan small-scale manufacture of probiotic fermented foods. Dr. Westerik’s team then conducted two clinical studies that demonstrated that the consumption of this probiotic product improved natural defenses and prevented respiratory infections (e.g. the common cold) and intestinal infections, which are the infectious conditions of greatest relevance in childhood in Uganda.

Yogurt is a new tool for individuals in developing areas of Uganda to achieve better health through diet, with potentially significant social and economic implications. Both the Ugandan and Argentinian experiences illustrate the power of microbes to positively impact the lives of women, men, and children. Given the positive results from these two different contexts, such activities could be replicated in other geographical areas—with either dairy, vegetable, or grain fermentations used locally with defined, well-studied starter cultures.

Further reading:

Julio Villena, Susana Salva, Martha Núñez, Josefina Corzo, René Tolaba, Julio Faedda, Graciela Font and Susana Alvarez. Probiotics for Everyone! The Novel Immunobiotic Lactobacillus rhamnosus CRL1505 and the Beginning of Social Probiotic Programs in Argentina. International Journal of Biotechnology for Wellness Industries, 2012, 1, 189-198.

Westerik N. 2020. Locally produce probiotic yoghurt for better nutrition and increased incomes in Uganda. PhD thesis, Free University of Amsterdam, The Netherlands.

Reid G, Kort R, Alvarez S, Bourdet- Sicard R, Benoit V, Cunningham M,  Saulnier DM, van Hylckama  Vlieg JET, Verstraelen H, Sybesma W.  Expanding the reach of probiotics through social enterprises. Beneficial Microbes, 9 (5): 707-715.

YOGURITO –the Argentinian social program with a special yogurt

 

 

 

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.

 

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.

ISAPP Conference Session

New Probiotic and Prebiotic Society Among Ibero-American Countries

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

On February 8, 2019, within the framework of the X Workshop of the Spanish Society for Microbiota, Probiotics and Prebiotics (SEMiPyP), the Ibero-American Society for Microbiota, Probiotics and Prebiotics (SIAMPyP) was established, with the aim of enhancing communication among researchers and clinicians from Spain, Portugal, Mexico and several South American countries.

SIAMPyP will build on 10 years of collaboration among experts from both sides of the Atlantic, who have come together as SEMiPyP with a common interest in the potential of the microbiome in human health and disease, in promoting and disseminating scientific discovery, in rigor of scientific evidence, and facilitating future research to the benefit of Ibero-America and the globe.

Currently, the plan is for SIAMPyP to convene biennial meetings, the first being planned for March 2021 (dependent on the state of the pandemic) in Madrid and subsequently in 2023 in Mexico City.  Academic sessions of basic and clinical science will be presented in this context, taking advantage of common languages (Spanish and Portuguese) to establish synergies in Latin American countries and the Iberian Peninsula.

The SIAMPyP has fostered connections with other international academic and scientific societies with knowledge in microbiota, probiotics and prebiotics in the pediatric, gastroenterology and neurogastroenterology fields of various Spanish and Portuguese speaking countries, as well as with ISAPP. Likewise, it has the support of research-oriented pharmaceutical and food industries that seek to modulate the microbiota to benefit human health in various clinical settings with probiotics, prebiotics and postbiotics.

The current board of directors of SIAMPYP is chaired and represented by doctors from both continents, including the well-known scientists Dr. Francisco Guarner (former ISAPP board member, from Spain), Dr. Guiilermo Alvarez-Calatayud (Spain), Dr. Luis Peña (Spain), as well as Dr. Aldo Maruy (Peru), Dr. Christian Boggio (Argentina) and Dr. Ana Teresa Abreu (Mexico), in addition to members and consultants who support and strengthen it, divided by region, with Latin America being a region with several countries.

SIAMPyP welcomes scientific partners from all Ibero-American countries, at no cost. See www.siampyp.org for further information.

Hear from ISAPP board members in webinar covering probiotic and prebiotic mechanisms of action

This webinar is now complete — see the recorded version here.

New probiotic and prebiotic trials are published all the time – but when they show a health benefit, what do we know about the basic science behind it?

To provide insight into this topic, ISAPP has partnered with the International Life Sciences Institute (ILSI) Europe on a free webinar titled Understanding Prebiotic and Probiotic Mechanisms that Drive Health Benefits. This webinar helps scientists, members of the public, and media take a deep dive into what we know about the mechanisms of action of probiotics and prebiotics.

The live webinar is scheduled for Thursday, September 17, 2020 from 3 – 4:15pm Central European Time.

Short, 10-minute perspectives will be provided by the following top experts:

  • Prof. Sarah Lebeer, University of Antwerp, Belgium
  • Prof. Colin Hill, University College Cork, Ireland
  • Prof. Karen Scott, University of Aberdeen, UK
  • Prof. Koen Venema NUTRIM School of Nutrition and Translational Research in Metabolism, Venlo, The Netherlands

The presentations will be followed by a 35-minute live Q&A session, enabling participants to probe deeper into the science behind mechanisms of probiotics and prebiotics.

ILSI Europe is a non-profit organization that aims to improve public health and well-being from a science-based approach.

To learn more about probiotic mechanisms of action in advance of the webinar, see ISAPP’s blog post here.

¿Cómo permanecen vivos los probióticos hasta el momento de ser consumidos?

Por Gabriel Vinderola, Dr. en Química, Investigador Principal del Consejo Nacional de Investigaciones Científicos y Técnicas (CONICET) en el Instituto de Lactología Industrial (INLAIN, CONICET-UNL) y Profesor Asociado de la Facultad de Ingeniería Química de la Universidad Nacional del Litoral.

Como docente-investigador, la mayor parte del tiempo se comparte con personas del ambito académico y científico. Pero a través de las actividades de divulgación, tengo también la posibilidad de interactuar con personas que no tienen formación en ciencias, pero que tienen curiosidad por el mundo científico. Una pregunta que me hacen a menudo es: “¿Es posible que los probióticos sigan vivos cuando están deshidratados y en una cápsula?” La respuesta es sí. Permítanme proporcionar algo de información básica sobre los probióticos y explicar mi respuesta.

La idea de consumir microbios vivos para promover la salud no es nueva. En 1907, Élie Metchnikoff, discípulo de Louis Pasteur, el padre de la microbiología, asoció el consumo de leches fermentadas que contenían lactobacilos vivos, con una vida prolongada y saludable en campesinos búlgaros (see here). Esta idea fue retomada más tarde por el concepto de probióticos: microorganismos vivos que, cuando se administran en cantidades adecuadas, confieren un beneficio para la salud del huésped (Hill et al. 2014). Son cuatro criterios sencillos y pragmáticos los permiten concluir si determinadas cepas de microorganismos reúnen las condiciones para ser consideradas probióticos. Los probióticos deben: i) estar correctamente identificados (género, especie, cepa); ii) ser seguros para el uso previsto; iii) estar respaldados por al menos un ensayo clínico en humanos que demuestre su eficacia; y iv) estar vivos en el producto, y en cantidades suficientes para ser eficaces, durante todo el período de conservación (Binda et al. 2020). Estar viables en el momento del consumo es una de las características clave de los probióticos.

La vida es la condición que distingue a los animales y las plantas de la materia inorgánica. La vida implica actividad metabólica y la capacidad de crecer y reproducirse. Para que la vida sea posible, deben darse ciertas condiciones ambientales, las cuales difieren para los distintos organismos. Para los microorganismos en general, la disponibilidad de agua y nutrientes, la temperatura adecuado y la ausencia de inhibidores de crecimiento (como la acidez o los antibióticos) son condiciones esenciales para su desarrollo. Sin embargo, es posible manipular ciertas condiciones para lograr un estado en el que el crecimiento puede ponerse en “stand-by”, pero el microorganismo seguirá vivo. Nosotros los humanos no podemos imaginarnos en una condición “en modo de espera”, en la que estemos vivos aún sin ninguna actividad metabólica, pero para los microbios esto sí es posible. Los probióticos pueden estar en alimentos (ciertos yogures, jugos de fruta, barras de cereales) o en suplementos alimenticios (cápsulas, píldoras, sachets) en un estado de “hibernación”, caracterizado por la ausencia de crecimiento, de reproducción, en espera a que se den las condiciones adecuadas para retomar la actividad metabólica. Esto último ocurre cuando los probióticos llegan al intestino, donde encuentran la temperatura adecuada, los nutrientes necesarios, la ausencia de inhibidores y el agua necesaria para retomar su actividad metabólica. Por lo tanto, en el caso de los microorganismos, hay una disociación de la vida y la actividad metabólica. Incluso sin tener ninguna actividad metabólica, pueden seguir vivos, pero en un estado de latencia.

Al abrir un suplemento alimenticio que contenga probióticos, probablemente encontraremos un polvo seco blanco. Así es como los microorganismos pueden estar en un estado de latencia, debido a un proceso tecnológico llamado liofilización. La liofilización es un proceso de dos etapas en el que las células primero se congelan rápidamente a temperaturas muy bajas (de -40 a -70°C, o menos, utilizando nitrógeno líquido, por ejemplo). Luego, el agua congelada se elimina mediante un proceso de evaporación a baja presión y baja temperatura, llamado sublimación. Este proceso elimina la mayor parte del agua de las células, dejando a los microorganismos en un estado de inactividad o latencia. La actividad de agua es la forma en que los científicos miden la disponibilidad de agua para los probióticos. Esta medida tecnológica oscila entre 0 (sin disponibilidad de agua) y 1 (con total disponibilidad agua). Una actividad de agua cercana a 0 impide el crecimiento. En los suplementos dietarios, la liofilización deja la actividad de agua en un valor menor a 0,2, lo que asegura que no se produzca actividad metabólica durante la vida útil del producto.

Células de un probiótico constituido por bifidobacterias liofilizadas (indicadas por un círculo rojo). Esta es una imagen de microscopía electrónica de barrido amplificada 10.000 veces. Las células están incrustadas en una matriz de polidextrosa deshidratada, sin agua.

Así es que sí, los probióticos en los suplementos alimenticios están vivos, a su manera. Este es el caso también de los probióticos incluidos en ciertos alimentos como barras de cereales. En el caso de alimentos con actividades de agua más cercanas a 1, como los yogures, las leches fermentadas, los quesos o los jugos de fruta que contienen probióticos, el factor que limita la actividad metabólica es la baja temperatura a la que se conservan estos productos, combinada en ciertos casos (como los yogures y jugos de fruta) con el bajo pH (o alta acidez) de estos productos. La combinación de baja temperatura y acidez es eficaz para mantener a las células probióticas en un estado de latencia, lo que impide la actividad metabólica que pueda provocar estrés celular y muerte a lo largo de la vida útil del producto. Sin embargo, aunque se controlen estrictamente los factores que impiden la actividad metabólica durante la conservación, puede producirse cierta pérdida de viabilidad celular durante la vida útil de los probióticos en los productos que los contienen. En este caso, se agregan cantidades adicionales de probióticos para que la concentración de células viables necesaria para proporcionar un efecto benéfico sea la adecuada hasta el final de la vida útil del producto.

En los alimentos y suplementos probióticos, el número de células viables se expresa comúnmente como un número de unidades formadoras de colonias, abreviado “UFC”. Como los probióticos están presentes en altas concentraciones, el número de células viables suele alcanzar los miles de millones dentro de una cápsula o en una porción de yogur. Para poder contar un número tan grande de células, los microbiólogos deben hacer diluciones sucesivas del producto probiótico. Luego, pondrán una pequeña gota de las mayores diluciones en la superficie de una placa de Petri que contiene un medio de cultivo en el que crecerán los probióticos. Cada célula probiótica (o grupo de células) es una unidad formadora de colonias, que crecerá en su lugar y formará una colonia visible que puede ser observada a simple vista, y contada.

Placa de medio de cultivo que contiene colonias de una bacteria probiótica. Las células depositadas en la superficie del medio de cultivo se duplicaron varias veces hasta formar una cantidad visible de células: una colonia.

En síntesis, los probióticos están presentes en los alimentos y suplementos como cultivos vivos, pero en un estado de vida diferente al de los organismos superiores. Durante la vida útil de los probióticos, la actividad metabólica se detiene mediante la liofilización (en el caso de suplementos alimenticios) o mediante una combinación de baja temperatura y acidez (en el caso de yogures y jugos de fruta con probióticos, por ejemplo). El crecimiento activo de los probióticos suceso otra vez cuando estos microorganismos entran en el intestino y encuentran las condiciones adecuadas de nutrientes, temperatura, acidez y agua para estar activos y producir sus efectos benéficos sobre la salud.

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.

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.

 

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