Is probiotic colonization essential?

By Prof. Maria Marco, PhD, Department of Food Science & Technology, University of California, Davis

It is increasingly appreciated by consumers, physicians, and researchers alike that the human digestive tract is colonized by trillions of bacteria and many of those bacterial colonists have important roles in promoting human health. Because of this association between the gut microbiota and health, it seems appropriate to suggest that probiotics consumed in foods, beverages, or dietary supplements should also colonize the human digestive tract. But do probiotics really colonize? What is meant by the term “colonization” in the first place? If probiotics don’t colonize, does that mean that they are ineffective? In that case, should we be searching for new probiotic strains that have colonization potential?

My answer to the first question is no – probiotics generally do not colonize the digestive tract or other sites on the human body. Before leaping to conclusions on what this means for probiotic efficacy, “colonization” as defined here means the permanent, or at least long-term (weeks, months, or years) establishment at a specific body site. Colonization can also result in engraftment with consequential changes to the gut microbiota composition and function. For colonization to occur, the probiotic should multiply and form a stably replicating population. This outcome is distinct from a more transient, short-term (a few days to a week or so) persistence of a probiotic. For transient probiotics, it has been shown in numerous ways that they are metabolically active in the intestine and might even grow and divide. However, they are not expected to replicate to high numbers or displace members of the native gut microbiota.

Although some studies have shown that digestive tracts of infants can be colonized by probiotics (weeks to months), the intestinal persistence times of probiotic strains in children and adults is generally much shorter, lasting only few days. This difference is likely due to the resident gut microbiota that develops during infancy and tends to remain relatively stable throughout adulthood. Even with perturbations caused by antibiotics or foodborne illness, the gut microbiome tends to be resilient to the long-term establishment of exogenous bacterial strains. In instances where probiotic colonization or long-term persistence was found, colonization potential has been attributed more permissive gut microbiomes specific to certain individuals. In either case, for colonization to occur, any introduced probiotic has to overcome the significant ecological constraints inherent to existing, stable ecosystems.

Photo by http://benvandenbroecke.be/ Copyright, ISAPP 2019.

This leads to the next question: Can probiotics confer health benefits even if they do not colonize? My answer is definitely yes! Human studies on probiotics with positive outcomes have not relied on intestinal colonization by those microbes to cause an effect. Instead of colonizing, probiotics can alter the digestive tract in other ways such as by producing metabolites that modulate the activity of the gut microbiota or stimulate the intestinal epithelium directly. These effects could happen even on short-time scales, ranging from minutes to hours.

Should we be searching for new probiotic strains that have greater colonization potential? By extension of what we know about the resident human gut microbiota, it is increasingly attractive to identify bacteria that colonize the human digestive tract in the same way. In some situations, colonization might be preferred or even essential to impacting health, such as by engrafting a microbe that performs critical metabolic functions in the gut (e.g. break down complex carbohydrates). However, colonization also comes with risks of unintended consequences and the loss of ability to control the dose, frequency, and duration of exposure to that particular microbe.

Just as most pharmaceutical drugs have a transient impact on the human body, why should we expect more from probiotics? Many medications need to be taken life-long in order manage chronic conditions. Single or even repeated doses of any medication are similarly not expected to cure disease. Therefore, we should not assume a priori that any observed variations in probiotic efficacy are due to a lack of colonization. To the contrary, the consumption of probiotics could be sufficient for a ripple effect in the intestine, subtly altering the responses of the gut microbiome and intestinal epithelium in ways that are amplified throughout the body. Instead of aiming for engraftment directly or hand-wringing due to a lack of colonization, understanding the precise molecular interactions and cause/effect consequences of probiotic introduction will lead to a path that ultimately determines whether colonization is needed or just a distraction.

Prebiotics do better than low FODMAPs diet

By Francisco Guarner MD PhD, Consultant of Gastroenterology, Digestive System Research Unit, University Hospital Vall d’Hebron, Barcelona, Spain

Bloating and visible abdominal distention after meals is a frequent complaint of people suffering from irritable bowel syndrome, but even generally healthy people sometimes have these complaints. These symptoms are thought to be due to fermentation of food that escapes our digestive processes. Some sugars and oligosaccharides end up at the far end of our small bowel and cecum, where they become food for our resident microbes.

To manage this problem, medical organizations recommend antibiotics to suppress the microbial growth in our small intestine (known as small intestinal bacterial overgrowth or SIBO) or avoidance of foods that contain fermentable oligosaccharides, disaccharides, monosaccharides and polyols, called a low “FODMAP” diet. These approaches are generally successful in reducing symptoms, but do not provide permanent relief: symptoms typically return after the strategies are stopped.

Even worse, both approaches are known to disrupt the entire gut microbial ecosystem (not only at small bowel and cecum). Whereas a healthy microbial gut ecosystem has many different types of bacteria, antibiotics deplete them.  The low FODMAP diet deprives beneficial bacteria (such as Faecalibacterium, Roseburia, Bifidobacterium, Akkermansia, Lactobacillus and others) of the food they like to eat, and these species wane (see here).

Prof. Glenn Gibson, a founding father of prebiotic and synbiotic science, suggested that increasing ingestion of certain prebiotics could increase levels of bifidobacteria. These bifidobacteria in turn could prevent excessive gas production since they are not able to produce gas when fermenting sugars.  (Instead, bifidobacteria product short chain fatty acids, mainly lactate, which are subsequently converted to butyrate by other healthy types of bacteria, such as Faecalibacterium and Roseburia.)

Prof. Gibson’s hypothesis was tested in pilot studies where volunteers ingested a prebiotic known as galacto-oligosaccharide (Brand name: Bimuno). Healthy subjects were given 2.8 g/day of Bimuno for 3 weeks. At first, they had more gas: significantly higher number of daily anal gas evacuations than they had before taking the prebiotic (see here). The volume of gas evacuated after a test meal was also higher. However, after 3 weeks of taking the prebiotic, daily evacuations and volume of gas evacuated after the test meal returned to baseline. The microbe populations also started to recover. The relative abundance of healthy butyrate producers in fecal samples increased and correlated inversely with the volume of gas evacuated. This suggested that the prebiotic induced an adaptation of microbial metabolism, resulting in less gas.

Then researchers launched a second study, also in healthy volunteers, to look at how the metabolic activity of the microbiota changed after taking this prebiotic. They showed that adaptation to this prebiotic involves a shift in microbiota metabolism toward low-gas producing pathways (see here).

A third controlled study (randomized, parallel, double-blind), this time in patients with functional gastrointestinal disorders with flatulence, compared the effects of the prebiotic supplement (2.8 g/d Bimuno) plus a placebo diet (mediterranean-type diet) to a placebo supplement plus a diet low in FODMAPs. The study subjects were divided between these 2 diets, which they consumed for 4 weeks (see here). Both groups had statistically significant reductions in symptom scores during the 4-week intervention. Once subjects stopped taking the prebiotic, they still showed improved symptoms for 2 additional weeks (at this point, the study was completed). However, for subjects on the low-FODMAP diet, once the diet was stopped, symptoms reappeared. Very interestingly, these 2 diets had opposite effects on fecal microbiota composition. Bifidobacterium increased in the prebiotic group and decreased in the low-FODMAP group, whereas Bilophila wadsworthia (a sulfide producing species) decreased in the prebiotic group and increased in the low-FODMAP group.

The bottom line conclusion is that a diet including intermittent prebiotic administration might be an alternative to the low FODMAP diets that are currently recommended for people with functional gut symptoms, such as bloating and abdominal distention. Since low FOD MAP diets are low in fiber, the prebiotic option may provide a healthier dietary option.

 

  1. Halmos EP, Christophersen CT, Bird AR, Shepherd SJ, Gibson PR, Muir JG. Diets that differ in their FODMAP content alter the colonic luminal microenvironment. Gut. 2015;64(1):93–100.
  2. Mego M, Manichanh C, Accarino A, Campos D, Pozuelo M, Varela E, et al. Metabolic adaptation of colonic microbiota to galactooligosaccharides: a proof-of-concept-study. Aliment Pharmacol Ther. 2017;45(5):670–80.
  3. Mego M, Accarino A, Tzortzis G, Vulevic J, Gibson G, Guarner F, et al. Colonic gas homeostasis: Mechanisms of adaptation following HOST-G904 galactooligosaccharide use in humans. Neurogastroenterol Motil. 2017;29(9):e13080.
  4. Huaman J-W, Mego M, Manichanh C, Cañellas N, Cañueto D, Segurola H, et al. Effects of Prebiotics vs a Diet Low in FODMAPs in Patients With Functional Gut Disorders. Gastroenterology. 2018;155(4):1004-7.

 

Additional reading:

Halmos EP, Christophersen CT, Bird AR, Shepherd SJ, Gibson PR, Muir JG. Diets that differ in their FODMAP content alter the colonic luminal microenvironment. Gut. 2015;64(1):93–100.

Mego M, Manichanh C, Accarino A, Campos D, Pozuelo M, Varela E, et al. Metabolic adaptation of colonic microbiota to galactooligosaccharides: a proof-of-concept-study. Aliment Pharmacol Ther. 2017;45(5):670–80.

Mego M, Accarino A, Tzortzis G, Vulevic J, Gibson G, Guarner F, et al. Colonic gas homeostasis: Mechanisms of adaptation following HOST-G904 galactooligosaccharide use in humans. Neurogastroenterol Motil. 2017;29(9):e13080.

Huaman J-W, Mego M, Manichanh C, Cañellas N, Cañueto D, Segurola H, et al. Effects of Prebiotics vs a Diet Low in FODMAPs in Patients With Functional Gut Disorders. Gastroenterology. 2018;155(4):1004-7.

Halmos EP, Gibson PR. Controversies and reality of the FODMAP diet for patients with irritable bowel syndrome. J Gastroenterol Hepatol. 2019 Jul;34(7):1134-1142. doi: 10.1111/jgh.14650. Epub 2019 Apr 4.

 

 

The threat of disease – Ignore science at your peril

By Dr. Karen Scott, University of Aberdeen

We live in an age when life expectancy has increased and many diseases that used to be fatal are curable. Much of this is the result of years of efforts by dedicated scientists, painstakingly working out the causes of diseases, and then the best way to treat or prevent them. Yet the high profile of social media can boost the profile of results from poorly conducted studies, sometimes even beyond the publicity received by the original seminal results. Responsible scientists are partly to blame for this. We are a cagey bunch, frequently suffixing stories about our wonderful successes with caveats, maybes and the recurring refrain “more research is needed”. Those spreading sensationalist publicity have no such qualms.

Take vaccination for diseases caused by viruses. In 1796, Dr Edward Jenner realised that milk parlour girls did not seem to get small pox and theorised that they were protected from the devastating disease due to their continual exposure to the less dangerous cow pox virus. He proceeded to prove his theory by inoculating many people with cow pox, and then exposing them to the small pox virus. Although the experiment would nowadays perhaps be considered unethical, it worked and people infected with cow pox did not get small pox. This heralded the start of vaccination, a huge medical advance that has since protected millions of people from contracting polio, measles, mumps, rabies, tuberculosis and many more devastating diseases. In the 19th Century, Louis Pasteur advanced the method, using inactivated viruses as the inoculation. Vaccination has been so successful that small pox was ‘officially’ eradicated globally in 1979, and the polio vaccine, which was developed in 1955, has led to the virtual world-wide elimination of polio.

But more and more people people are declining to vaccinate their children. The very success of the vaccination scheme may be why it is now in danger. People have forgotten the devastating consequences and lasting effects of these diseases. In the western world it is now unusual to see people crippled by the effects of childhood polio. What about measles? Prior to vaccination, measles was a highly contagious disease, spreading through water droplets in air when an infected person sneezed. Forty percent of those with measles develop complications including pneumonia (which is often the case of measles-related deaths), deafness, blindness and encephalitis (brain swelling), which can even cause brain damage. If the patient survives, the effects of such complications can last for life. Yes – measles, a disease fully preventable by vaccination, kills. I was struck by a recent story about Roald Dahl, whose daughter sadly died after contracting measles when she was seven (see here). In 1986 Roald Dahl wrote an open letter describing his experience, encouraging people to vaccinate their children. The post was illustrated with a picture of a ward full of children suffering from polio, all confined in iron lungs as their breathing had been so badly affected due to paralysis of their chest muscles. No one can want to return to that.

Another contributor to reduced vaccination rates are reports that vaccinations cause more harm than good. Such reports are sustained in part by non-science-based social media claims. Even when original scientific reports are discredited, many parents continue to decide not to vaccinate their children.

How will these “anti-vaccination” parents/carers feel, sitting at the bedside of their critically ill child trying to make sense of the doctor’s explanation that even if their child pulls through, they will never be able to see again? Or explaining to their grown up child that he will never be able to father children due to an almost forgotten childhood disease? All because Mum and/or Dad paid more attention to a campaign on social media with no scientific basis, than to medical advice supported by decades of evidence? Yes, there are instances of people becoming ill with the diseases themselves, or suffering rare side effects of vaccination, but these are rare and pale in comparison to the morbidity and mortality prevented by vaccinations. After all, these same people do not stop driving their car to work when they hear that someone else had an accident doing so. The huge decline in epidemics of viral diseases following the introduction of vaccination programmes speaks to their effectiveness. The vaccine for measles was introduced in 1968 and is estimated to have prevented 20 million cases of measles and 4,500 deaths. In fact the vaccination programme was so successful that it led to the UK being declared ‘measles free’ in 2017.

 

 

 

 

 

 

 

Source – Public Health England; University of Oxford Vaccine Knowledge Project

Yet countries that we travel to on holiday still have measles outbreaks so it is still crucial to get children vaccinated. Even in the US and UK, the large increase in non-vaccinated children means that measles outbreaks (starting with people catching the disease abroad) are becoming more common – evidenced by the second graph above. An alarming statistic is that there are more cases of measles in 2018 than there were in 1998.

Increased numbers of unvaccinated people pose a threat to society at large. Herd immunity can protect a small number of unvaccinated individuals. Indeed, some individuals cannot be effectively vaccinated, including very young infants or when there is a problem with their immune system. But when the number of unvaccinated people rises, these viruses can ‘find’ susceptible hosts and take root once again in the population. This puts our most vulnerable society members at risk. The decision to not immunize is not a victimless decision. We need to maintain vaccination programmes on a global scale, to maintain ‘herd immunity’ and halt the current increase in the numbers of cases occurring.

Bottom line – vaccination works and prevents needless suffering from preventable diseases.

L. rhamnosus GG for treatment of acute pediatric diarrhea: the totality of current evidence

By Mary Ellen Sanders PhD, Executive Science Officer, ISAPP

For the past several years, studies have been adding to the evidence base on the efficacy of Lactobacillus rhamnosus GG for the treatment of pediatric diarrhea. A new systematic review and meta-analysis led by Prof. Hania Szajewska concluded that Lactobacillus rhamnosus GG is effective for treating acute diarrhea in hospitalized children, even when a 2018 null trial (Schnadower et al. 2018) was included.

“Despite a recent large RCT demonstrating no effect of L rhamnosus GG, current evidence shows that, overall, L rhamnosus GG reduced both the duration of diarrhoea (with a higher impact in European countries) and hospitalisation in inpatients.”

The authors acknowledge that the quality of evidence for this conclusion is low: 13 of 18 included studies suffered from problems with randomization, allocation concealment, blinding, and/or follow‐up. However, the rigorous process used to assess the current state of evidence provides confidence in the paper’s conclusions.

In an editorial in Alimentary Pharmacology & Therapeutics, Prof. Eamonn Quigley suggests that reports dismissing L. rhamnosus GG as ineffective (for example, see The Washington University School of Medicine opinion, “Probiotics no help to young kids with stomach virus“) were premature.

As Prof. Quigley points out, it is necessary to put the findings of the null study into context. He states several reasons why the Schnadower et al. 2018 study may not have shown an effect of L rhamnosus GG, even though previous studies had. Notably, the rotavirus vaccination status of the subjects – with two-thirds of the study population having been vaccinated – seemed important. Subgroup analysis showed that the probiotic was more effective among children who had not been vaccinated for rotavirus.

In addition, as discussed in a previous ISAPP blog, the timing of initiating probiotic therapy is likely an important factor. In the null trial, the average time of diarrhea prior to treatment was 53 hours, and subjects were enrolled up to 72 hours after onset of diarrhea – likely too late to have a possibility of positive impact by the probiotic.

For now the ESPGHAN recommendation to initiate L. rhamnosus GG treatment in conjunction with rehydration therapy early after the onset of diarrhea in children can still be supported by the totality of evidence.

Both Prof. Hania Szajewska and Prof. Eamonn Quigley serve on the ISAPP board of directors.

Defining emerging ‘biotics’

By Mary Ellen Sanders PhD

From its inception, ISAPP has been committed to clarity in both the definitions and the contextual use of terms in the fields of probiotics and prebiotics fields. This is reflected in the FAO/WHO probiotic guidelines working group conducted immediately prior to the first ISAPP meeting in 2002, as well as our more recent consensus panels convened on probiotics (2013), and prebiotics (2016). We also have additional panels in progress on synbiotics (convened in May 2019 in Antwerp), fermented foods (scheduled for September) and postbiotics (scheduled for December).

A recently published paper, Emerging Health Concepts in the Probiotics Field: Streamlining the Definitions, addresses definitions of many newer terms in the ‘biotics’ arena, including probiotics, prebiotics, synbiotic, pharmabiotics, postbiotics, probioceuticals, paraprobiotics, oncobiotics, psychobiotics, and live biotherapeutic products. In my opinion, although this paper provides useful discussion of issues surrounding the proliferation of terms in the ‘biotics’ area, it falls short of providing clear direction for the field and indeed may well add to confusion by introducing unnecessary, new and poorly defined terms.

For example, the term ‘symbiotics’ is perpetuated, presumably as a synonym to synbiotic. It was a missed opportunity to clarify that the term ‘synbiotic’ is derived from the Greek root ‘syn’ meaning ‘with’ or ‘together.’ The term ‘symbiotic’ is simply incorrect, adds nothing and should be eliminated altogether.

This paper fails to advance the ISAPP consensus definition of prebiotic, published in 2017, by lead author Glenn Gibson, co-inventor of the terms ‘prebiotic’ and ‘synbiotic’. It is not clear whether the authors disagree with the ISAPP consensus definition, and if so, on what basis. They state that the ISAPP consensus definition is “the most actual definition”, the meaning of which is not clear to me, but then use an outdated definition in their summary box.

Further is the failure to acknowledge the broad scope of the definition of probiotics. Live biotherapeutic products (LBPs), which the paper states is a term that was “recently” introduced by the FDA, has been in use for over at least 15 years by the FDA’s Center for Biologics Evaluation and Research. The authors equate LBPs (which are defined as drugs) with next generation probiotics, yet these do not have to fall under the drug category any more than traditional probiotics are necessarily foods. Next generation probiotics, traditional probiotics or just probiotics can fall under numerous regulatory categories including foods, infant formulas, drugs, supplements, animal feeds, medical foods, foods for special dietary uses, and perhaps even cosmetics or medical devices. Thus, regulatory category is not stipulated by the definition, which is appropriate.

One of the difficulties with sorting through these terms is the lack of any consistent basis for defining them. Some terms, such as pharmabiotics and LBPs, are linked to specific regulatory categories. Others are defined by the nature of how they are comprised: live cells, cell components, or fermentation endproducts. Others are defined by their physiological benefit: psychobiotic, oncobiotic, immunobiotic. Even still, others are defined by their state of innovation: traditional vs. next generation probiotics. This state of affairs makes is impossible to develop a logical framework for categorizing them. Instead, we are left with a long list of substances that might be related, but have little real value. Where does it all stop? Next we will have to sift through thera/metabo/gen/retro/plas/func-biotics or any other pointless terms that can be arbitrarily slapped in front of ‘biotic.’

Certainly, there is nothing to prevent any person from coining a new term for a niche development. The many stakeholders in the broader ‘biotics’ field will, I suppose, determine any given term’s utility. I believe it would have been worthwhile for this paper to make an appeal to scientists to refrain from muddying the water by proposing new terms, and instead use existing terms with appropriate modifiers. For example, use ‘immune-active probiotic’ instead of ‘immunobiotic’, or ‘probiotic drug’ instead of ‘live biotherapeutic product.’ This approach is clearer to regulators and international organizations such as Codex Alimentarius, the US Food and Drug Administration and European Food Safety Authority. To the extent that the definitions of terms need to be clarified, I believe that the ISAPP approach, using groups of 10 or more well-known academic experts in the field reaching a consensus after extensive background search, is preferred over unilateral proclamations as delivered by this paper.

Effects of the food matrix on probiotic’s efficacy: how much should we care?

By Gabriel Vinderola PhD, Researcher at the Dairy Products Institute (National Scientific and Technical Research Council – CONICET) and Associate Professor at the Food Technology and Biotechnology Department, Faculty of Chemical Engineering, National University of Litoral, Santa Fe, Argentina.

The issue of to what extent food components may affect probiotic efficacy when compared to the strain delivered as supplement has lately been the subject of debate. This is especially so in the context of the Codex Alimentarius guidelines on probiotics, presently under development.

When considering the importance of the food formulation delivering the probiotic, it’s worthwhile to keep in mind that people may get their daily probiotic together with an enormous variety of foods. For instance, one person may get the probiotic at breakfast along with a yoghurt or with cereal, whereas another person may choose to consumer a fruit juice, while a third may get the probiotic dose before a meal consisting of pasta, meat and vegetables. In those cases, the same strain can undergo gastrointestinal passage in the context of very different food exposures. Does this suggest that perhaps the specific food format is not so critical? What does research tell us?

An interesting, however in vitro, study was conducted by Grześkowiak et al. (2011). In this work, Lactobacillus rhamnosus GG was recovered from more than 12 foods and supplements and its ability to inhibit food pathogens was assessed in vitro. Authors showed that even when the inhibitory capacity was quantitatively different among isolates, the qualitative probiotic capacity of inhibiting pathogens was present in all of them. That is to say, the probiotic capacity had been retained to a somewhat greater or lesser degree, regardless the matrix.

Few human studies have measured to what extent a health endpoint changes when a probiotic is delivered in different food matrixes. For instance, Saxelin et al. (2010) showed that the administration matrix (capsules, yogurt or cheese) did not influence the faecal quantity of lactobacilli, but affected faecal counts of propionibacteria and bifidobacteria. However no health endpoint was considered in this study. Several studies demonstrate that dairy products are able to confer enhanced protection during gastrointestinal transit in in vitro settings (Vinderola et al., 2000; Sagheddu et al., 2018; da Cruz Rodrigues et al., 2019), suggesting that dairy products may be better at delivering an efficacious dose of probiotic. But again, no clinical endpoint was measured in these studies.

The first comparative study on the probiotic capacity of a strain delivered in food or supplement was reported by Isolauri et al. (1991). Authors demonstrated that Lactobacillus GG either in fermented milk or freeze-dried powder was effective in shortening the course of acute diarrhea. Later on, Meng et al. (2016) found similar patterns of immune stimulation when studying the impact of Bifidobacterium animalis subsp. lactis BB12 administration in yoghurt or capsules on the upper respiratory tract of healthy adults.

As these kinds of studies are scarce, we can look to meta-analysis where the same strain is compared for the same clinical endpoint, but in studies conducted by different groups in different matrixes. For instance, Szajewska et al. (2013) concluded that Lactobacillus GG delivered in capsules or fermented milk significantly reduced the duration of diarrhea and Urbańska et al. (2016) reported that L. reuteri DSM 17938 delivered in either capsules or infant formula reduced the duration of diarrhoea and increased the chance of cure.

In vitro studies find that survival of the probiotic delivered in different food matrices through a (simulated) gastrointestinal transit may quantitatively differ, but no matrix completely eliminates probiotic capacity. Human clinical trials comparing different matrices with a clear health endpoint are scarce, but a general conclusion seems to emerge: regardless of the food matrix, the probiotic effect is achieved.  When the data are assessed through meta-analysis, the top of the “levels of evidence” in the pyramid of evidence-based studies, the probiotic capacity exists for the same strain among different studies, conducted by different research groups, using different food matrices.

In many countries regulators require that the probiotic effect be demonstrated in the same food or supplement that will be offered to consumers. This is a conservative approach in the lack of other evidence, but it may be challenging at the same time for probiotic food development, as any new food, even similar to one already existing, may require new human clinical studies to demonstrate efficacy. This approach may raise economic and ethical concerns too, and be discouraging for the future of probiotics.

Surely additional clinical trials directly comparing effects among different delivery matrices would provide clarity on the importance of this factor to probiotic functionality. Until that time, regulators should enable probiotic food manufacturers to offer a sound scientific rationale that bio-equivalency of different matrices could be expected, and thereby circumvent the requirement need to re-conduct human clinical trials on probiotics delivered in new matrices.

 

References

da Cruz Rodrigues VC, Salvino da Silva LG, Moreira Simabuco, F, Venema K, Costa Antunes AE. Survival, metabolic status and cellular morphology of probiotics in dairy products and dietary supplement after simulated digestion. J Funct. Foods, 2019, 55, 126-134.

Grześkowiak Ł, Isolauri E, Salminen S, Gueimonde M. Manufacturing process influences properties of probiotic bacteria. Br J Nutr. 2011, 105(6):887-94.

Isolauri E, Juntunen M, Rautanen T, Sillanaukee P, Koivula T. A human Lactobacillus strain (Lactobacillus casei sp strain GG) promotes recovery from acute diarrhea in children.

Meng H, Lee Y, Ba Z, Peng J, Lin J, Boyer AS, Fleming JA, Furumoto EJ, Roberts RF, Kris-Etherton PM, Rogers CJ. Consumption of Bifidobacterium animalis subsp. lactis BB-12 impacts upper respiratory tract infection and the function of NK and T cells in healthy adults. Mol Nutr Food Res. 2016, 60(5):1161-71.

Pediatrics. 1991 , 88(1):90-7.

Sagheddu V, Elli M, Biolchi C, Lucido J, Morelli L. Impact of mode of assumption and food matrix on probiotic viability. J Food Microbiol. 2018, 2.

Saxelin M, Lassig A, Karjalainen H, Tynkkynen S, Surakka A, Vapaatalo H, Järvenpää S, Korpela R, Mutanen M, Hatakka K. Persistence of probiotic strains in the gastrointestinal tract when administered as capsules, yoghurt, or cheese. Int J Food Microbiol. 2010, 144(2): 293-300.

Szajewska H, Skórka A, Ruszczyński M, Gieruszczak-Białek D. Meta-analysis: Lactobacillus GG for treating acute gastroenteritis in children-updated analysis of randomised controlled trials. Aliment Pharmacol Ther. 2013 Sep;38(5):467-76.

Urbańska M, Gieruszczak-Białek D, Szajewska H. Systematic review with meta-analysis: Lactobacillus reuteri DSM 17938 for diarrhoeal diseases in children. Aliment Pharmacol Ther. 2016, 43(10):1025-34.

Vinderola G, Prosello W, Ghiberto D, Reinheimer J. Viability of  probiotic- (Bifidobacterium, Lactobacillus acidophilus and Lactobacillus casei) and non probiotic microflora in Argentinian Fresco Cheese (2000). J Dairy Sci. 2000, 83 (9), 1905-1911.

Another day, another negative headline about probiotics?

By Prof. Colin Hill, PhD, APC Microbiome Ireland, University College Cork, Ireland

Scientists have a particular job. We try to discover what is unknown and we want to help to create a better understanding of the underlying forces, both physical and biological, that underpin our amazing universe. It is usually a slow and meticulous process. Gathering data usually takes weeks, or months, or years of work and so there is plenty of time to consider the numerous possible interpretations and the limitations and gaps in our understanding. Everything has to be repeated and subjected to statistical analysis. Finally, we publish our findings and our interpretation of that carefully accumulated data. Even this process takes weeks or months (or years) because of discussions with fellow authors and colleagues, numerous drafts of the manuscript, peer review and editorial comment. We are very aware that whatever we have published will almost certainly be repeated, or built upon, and if we are wrong (in either our data or our interpretation) that it will not withstand the test of time. Thus, we are slow and cautious and often qualify our findings with “this suggests” or “this strongly suggests” and we often finish with the unavoidable conclusion that “more research needs to be done”.

Journalists have a particular job. Journalists have to react quickly, perhaps in minutes or hours, to a breaking story or a commission from their editors, on topics with which they may not be familiar, and write short articles or present short pieces to camera that will appeal to the public and have a clear message. Nuance and complexity must often be left for long-form journalism or that as-yet unwritten novel. Being slow and complete and debating all of the possible interpretations is simply not an option. Finishing up with a cautious, equivocal “on the one hand, but also on the other hand” is also not really an option. Very few journalistic pieces end with “more journalism needs to be done”. It may also be difficult to construct a story along the lines of “some good science was well performed and led to careful and understated conclusions, which should really be repeated before we get too excited”.

It is not surprising then that scientists and journalists can sometimes find themselves at loggerheads. “Do probiotics work?” is a very reasonable question that a journalist can ask a scientist. “Well,” responds the scientist, “that depends on what you mean by ‘work’, and which probiotic you are asking about, and for what condition, and quite often strains are called probiotics but they do not fit the definition, and of course, there was that paper published last year which showed ……”. Cue frustration on both sides. Why can’t the scientist just answer the question? And why can’t the journalist understand that just because a question can be simply stated does not mean that it has a simple answer? Ask a doctor “do pills work?” and you might very well get a similarly convoluted answer, but no one would think it evasive. No wonder the scientist sometimes ends up reading the resultant article in frustration – how did the journalist come to that conclusion, where did all my careful explanations go? Of course, most scientists are imagining his or her scientific colleagues reading the article and wondering at the ‘incomplete’ or ‘trivial’ response. While the journalist may well wonder what planet the scientist lives on if he or she thinks that the editor is going to publish a long essay capturing all of the subtlety of the research.

This almost certainly comes across as me implying that scientists are impeccable purveyors of truth and that journalists are willing to sacrifice truth for simplicity, but I truly am not suggesting that. In almost every instance there is no bad faith involved from either party, it is simply the consequence of the different demands placed on two very different and very valuable roles in society.

So, these things will happen. We will see newspaper articles and online pieces (or editorial comments in journals) that do not contain all the nuance and complexity of the complex paper which it is based. We will see press articles that draw simple and reader-friendly conclusions. “Probiotics quite useless”, “Are probiotics money down the toilet? Or worse?”, etc. So, how should we respond? Do we write erudite articles pointing out the limitations of the commentator, coming across perhaps as arrogant or supercilious? [And yes, of course I use the words erudite and supercilious because it makes me feel better than you.] Do we send angry missives complaining about the article, and perhaps risk drawing further attention to it?

If you are asked by a journalist to comment on a paper, or if your local/national paper or favourite website has published an article that you think is unfair, perhaps the way to respond is to have a few simple questions of your own which can be put to journalists and/or readers. Perhaps we can use a checklist such as the following:

  • Is the article describing an original piece of research and was it published in a reputable, peer-reviewed journal?
  • What evidence is there that the strain or strain mix in question is actually a probiotic? Does it fit the very clear probiotic definition?
  • Was the study a registered human trial? How many subjects were involved? Was it blinded and conducted to a high standard?
  • What evidence was presented of the dose administered and was the strain still viable at the time of administration.
  • Were the end points of the study clear and measurable? Are they biologically or clinically significant to the subjects?
  • Did the authors actually use the words contained in the headline? “Useless”, or “waste of money”, etc?

Once these relatively simple questions are answered, then we can move on to the details and the complexities, but that is not where we should start. Of course, if a study is well performed and reaches a negative conclusion we should absolutely acknowledge that. But we can still point out that one strain or strain mix not working under one set of conditions is only evidence of the fact that one particular strain or strain mix does not work under one particular set of conditions. It does not warrant a blanket condemnation or criticism of all probiotics. Maybe ask the journalist to think about the obvious flaws in the headline ‘Headache pill does not cure cancer, all pills obviously a waste of money!”, and ask why the same standards should not be applied to probiotics?

Scientists and journalists have different roles in society, that is clear, but we can assume a priori that both have clear motives and do not want to mislead readers. Let’s start from there and make it easier for both sides to work together to make the public aware of the very real potential, and very real limitations, of probiotics and prebiotics in preserving health in a society in dire need of practical solutions.

“A healthy woman, a healthy baby, a healthy generation” lessons learned from the 4th Annual Women and their Microbes Conference

By Dr. Mariya Petrova, Microbiome insights and Probiotics Consultancy, Bulgaria

The 4th annual Women and their Microbes conference took place at the beginning of March celebrating the International Women’s day. The first-ever conference outside Europe in Hamilton, Canada brought together top scientists to discuss the importance of women’s health through the prism of women’s specific microbiomes. The theme of the conference was Microbiome Management in Pregnancy with a uniquely designed high-quality program translating the latest research into the clinical setting. I was honored to serve on the organizing committee for this meeting, and I provide highlights below.

Our health starts long before birth. The developing fetus receives information from the mother in the form of hormones and nutrients and uses these to predict the external environment. The fetus then uses this information to adapt its development to better its chances of survival after birth. However, the developing fetus can be “misinformed.” This happens through the maternal factors such as her use of drugs, stress, and diseases such as obesity and asthma. For example, both absolute maternal weight and weight gain during pregnancy affect microbiota development in infants (Carmen Collado et al., 2010). Maternal microbiota can also shape the immune system of the newborns. Therefore, keeping women on the right course before pregnancy and healthy during pregnancy must be a priority. This will later be translated into a healthier life for the infant through adulthood. Many of us associate healthy pregnancy with women taking the right nutrients and minerals such as folic acid, B12 vitamins, and iron and we are not wrong. But microbes also play an essential role in health. Microbes are a crucial factor providing nutrients, immune protection and regulating host physiology. Particular strains of Lactobacillus sp. and Bifidobacteria sp. can produce vitamin B12 and folic acid in the gut (Magnusdottir et al., 2015), which may be very beneficial during pregnancy. Of interest, this production increases when paired with prebiotics. Not only that, but microbes are increasingly recognized as important in reproduction, pregnancy, and development. Fertilization doesn’t happen in a sterile environment. Distinct bacterial communities are present in the female reproductive tract, but semen health and male fertility are also important (Weng et al., 2014). So don’t forget the “Y” in the equation – fathers also play a role in the health of their offspring. Gestational tissue microbes can also play an important role in development. More research is needed to better understand these microbiomes and the extent to which they can be influenced by maternal diet and health state.

What if the things go wrong – adverse pregnancy outcomes. Preterm birth is an ongoing challenge with rates steadily growing and with limited approaches for prevention. It results in 75% of neonatal morbidity and mortality. High numbers (55-80 %) of preterm births are associated with dysbiosis and a shift of the vaginal microbiota towards a more diverse state (Freitas et al., 2018). It seems likely that the vaginal microbiome can protect against adverse pregnancy outcomes. However, it appears that both antibiotics and probiotic therapy used to date are not effective at preventing preterm birth. “How to prevent adverse pregnancy outcomes?” is a million dollar question. We need a highly discriminatory diagnostic test that defines versions of ‘abnormal’ vaginal microbiomes. This test needs to be significantly associated with adverse health outcomes. The type of abnormal profile that results in preterm birth needs to be distinguishable from other possible ‘abnormal’ profiles. Such a diagnostic tool needs to be simple enough for a clinical environment and cost-effective. We need to have a safe intervention that can ‘treat’ or normalize a microbiome ideally preconception or early pregnancy.

Where do probiotics fit? Probiotics and prebiotics can enhance the nutrient status of the mother via increasing micronutrient and mineral absorption. During pregnancy, about 3.6% of North American women, 14% of The Netherlands women and 23% of Australian women consume probiotics. A lot of studies focus on the role of probiotics for preventing Group B Streptococcus infections, maternal obesities, postpartum depression, and mastitis. Although results are promising, more studies are needed to make clear conclusions and select the best strains for each condition. Importantly, currently used probiotics do not appear to pose safety concerns for pregnant and lactating women. Nevertheless, consumers’ knowledge regarding probiotics is not very precise. This confusion often may stem from a probiotic market with many different manufacturers, some of which are not legitimate, selling products that are not well defined, with very little clinical evidence. A major effort in educating clinicians, pharmacists and the consumers has been made by creating probiotic guidelines. Dragana Skokovic Sunjic has been working in the last ten years in publishing and updating the “probiotic chart.” The probiotic chart summarizes commercially available probiotic supplements or foods sold in Canada or the USA that have published clinical evidence for the particular strain(s) present in each product. Of note, for products containing multiple strains, evidence must be provided for the specified combination and not extrapolated from the evidence for the separate probiotic strains. At present these guidelines are used by primary care providers, specialists (pediatrics, GI), academic teaching hospitals, universities and others.

With the increasing number of microbiome studies, we are witnessing a paradigm shift in the scientific literature with more people focusing on the importance of microbes in human health. Women’s health is a cornerstone for successful reproduction, with important implications for the health of the next generation. Initiatives such as Women and their Microbes are crucial to link the science and medicine together to bring awareness within the healthcare and academic community.

Reading, writing, and making an impact

Bob Hutkins, University of Nebraska-Lincoln, Department of Food Science and Technology and Leslie Delserone, University of Nebraska-Lincoln, University Libraries

For scientists who study probiotics and prebiotics, these are exciting times.  Every day, there are new discoveries and new opportunities.  There certainly are many challenges – obtaining grants, recruiting and mentoring students and postdocs, editorial duties, and maintaining competitive research programs.

But perhaps the most challenging activity is keeping up with the literature. Back in our respective graduate school days, there were only a handful of journals that required regular reading (and most arrived via regular mail in print).  One of us even remembers waiting for mail delivery to learn about the latest science.

There are now dozens of journals that publish high-quality papers on probiotics, prebiotics, fermented foods, gut health, and other relevant topics.  No longer does one have to wait for the latest scientific report – most of us are bombarded with emailed journal highlights, tables of contents, and latest science alerts.

The figure below illustrates this situation.  In 2001 (when ISAPP was formed), there was about 1 probiotic-oriented paper published per day. Now, with prebiotics included, there are more than ten new papers in the literature every single day!

Indeed, just since 2015, there have been more than 12,000 papers on probiotics and prebiotics listed in PubMed. Add in fermented foods, gut health, and methods papers, and those numbers will easily double or triple.

For researchers, clinicians, and other scientists, there are simply too many papers to read and digest.  Thus, for better or worse, many scientists perform a literature triage of sorts, reading papers mainly from so-called high-impact journals.

As a result, probiotic and prebiotic papers published in the top journals inevitably get the most attention, whether deserved or not.  An unfortunate consequence is that papers in other journals sometimes are over-looked.  Perhaps that’s one reason why, based on searches of several citation indexes, about a fourth of all papers published in our field never get cited at all!

So which papers in our field attracted the most attention or had the greatest impact?  Until recently, the only metrics used to assess impact were the journal’s impact factor and an article’s citation score – how many times a particular paper had been cited by other papers. This is no longer the case, as noted below.  But assuming citation numbers actually reflect impact, we’ve compiled a short list of the most important papers in our field.

To do this, we used two multidisciplinary online indexes, Web of Science Core Collection (WoS) and Scopus. The WoS indexes more than 20,000 journals, while Scopus covers more than 30,000 peer-reviewed journals; we limited the WoS search to its Science Citation Index Expanded.  We separately searched the terms probioti* and prebioti* in the article title, looking for papers and reviews published since 1990, and sorting the results for “times cited” or “cited by” from highest to lowest.

For probiotics, there were more than 10,000 (WoS) and 13,600 (Scopus) articles and reviews. As expected, several of the most cited papers were reviews.  Surprisingly, two were reviews on use of probiotics in aquaculture. Indeed, Verschuere et al. (2000) was the second and third most cited study in WoS and Scopus, respectively.  The 2014 ISAPP consensus paper (Hill et al., 2014) was the 2nd and 3rd most cited paper (Scopus and WoS respectively, with 920 and 1,034 citations as of late March 2019).

And the top probiotic paper in our field since 1990?  That would be a Lancet report that described results of an RCT in which Lactobacillus GG was administered to pregnant women and newborns with atopic eczema as the clinical end-point (Kalliomäki et al., 2001). This paper garnered more than 1,500 citations within the WoS, and 1,953 as tracked by Scopus. Among the authors of this study is current ISAPP president, Seppo Salminen. Incidentally, the 4-year follow-up to that same study (Kalliomaki et al., 2003) was the 4th most cited paper in both indexes!

For prebiotics, there were more 3,000 papers listed.  Leading the list of most cited papers is the seminal Gibson and Roberfroid (1995) paper in the Journal of Nutrition that “introduced the concept”.  Papers by Glenn Gibson and his colleagues dominate the list of most cited prebiotic papers.  But the most cited primary research paper on prebiotics was another clinical study from Finland (Kukkonen et al., 2007).

As noted above, citations are no longer the only way to measure impact.  After all, clinicians, industry scientists, and government regulators and policy makers also read and apply published information.  If a paper leads to a new treatment or technology, could there be a greater impact for the social good?

Consider the science paper with perhaps the greatest overall societal impact in the past 20 years. That would be Brin and Page’s 1998 paper published in what at the time was a relatively obscure journal, Computer Networks and ISDN Systems. The article began, in case you haven’t read it, with these six simple words, “In this paper, we present Google”.

Until recently, paper impacts were difficult to measure. But now we have Altmetrics, Twitter, and other ways to assess impact. Given that it usually takes at least a year before a published paper receives a citation in the WoS and Scopus environments, social media provide a way to gauge impact in real-time.  Indeed, a recent editorial in Nature Cell Biology (2018) suggests that plenty of scientists embrace social media. Evidently, many use it to sort through information as quickly as their fingers can tap.

 

Anonymous. 2018. Social media for scientists. Nature Cell Biology 20(12): 1329. doi: 10.1038/s41556-018-0253-6

Brin, S., and L. Page. 1998. The anatomy of a large-scale hypertextual Web search engine. Computer Networks and ISDN Systems 30(1-7):107-117. doi: 10.1016/S0169-7552(98)00110-X

Gibson, G.R., and M.B. Roberfroid. 1995. Dietary modulation of the human colonic microbiota: Introducing the concept of prebiotics. Journal of Nutrition 125(6):1401-1412. doi: 10.1093/jn/125.6.1401

Hill, C., F. Guarner, G. Reid, G.R. Gibson, D.J. Merenstein, B. Pot, L. Morelli, R.B. Canani, H.J. Flint, S. Salminen, P.C. Calder, and M.E. Sanders. 2014. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology and Hepatology 11(8):506-514. doi: 10.1038/nrgastro.2014.66

Hutkins, R.W. 2019. Microbiology and Technology of Fermented Foods, 2nd ed.; Hoboken, N.J., Ed.; Wiley-Blackwell: Hoboken, NJ, USA

Kalliomäki, M., S. Salminen, H. Arvilommi, P. Kero, P. Koskinen, and E. Isolauri. 2001. Probiotics in primary prevention of atopic disease: A randomised placebo-controlled trial. Lancet 357(9262):1076-1079. doi: 10.1016/S0140-6736(00)04259-8

Kalliomaki, M., S. Salminen, T. Poussa, H. Arvilommi, and E. Isolauri. 2003. Probiotics and prevention of atopic disease: 4-year follow-up of a randomised placebo-controlled trial. Lancet 361(9372): 1869-1871. doi: 10.1016/S0140-6736(03)13490-3

Kukkonen, K., E. Savilahti, T. Haahtela, K. Juntunen-Backman, R. Korpela, T. Poussa, T. Tuure, and M. Kuitunen. 2007. Probiotics and prebiotic galacto-oligosaccharides in the prevention of allergic diseases: A randomized, double-blind, placebo-controlled trial. Journal of Allergy and Clinical Immunology 119(1):192-198. doi: 10.1016/j.jaci.2006.09.009

Verschuere, L., G. Rombaut, P. Soorgeloos, and W. Verstraete.  2000. Probiotic bacteria as biological control agents in aquaculture.  Microbiology and Molecular Biology Reviews 64(4):655-671. doi: 10.1128/MMBR.64.4.655-671.200

Probiotics: Money Well-Spent For Some Indications

Eamonn M M Quigley MD, Houston Methodist Hospital and Weill Cornell Medical College, Houston, Texas, USA; Hania Szajewska MD, The Medical Univesrity of Warsaw, Department of Paediatrics, Poland; Dan Merenstein MD, Department of Family Medicine, Georgetown University

We read with interest and some concern the Medical News and Perspectives article by Jennifer Abbasi titled “Are Probiotics Money Down the Toilet? Or Worse?” (Abbasi 2019).  As researchers committed to the study of fecal microbiota transplant, prebiotics and probiotics, we find the title overly sensationalist for an article that ultimately provides a more nuanced view. It is unfortunate that the author focused on studies which either did not report on any clinical outcome and hence provide limited insight on the effectiveness of probiotics, or, whose null results likely reflect the late timing of the intervention while failing to refer to many high-quality studies that illustrate the subtlety of commensal and probiotic bacterial actions or clinical efficacy. Tanoue and colleagues provide a reminder that commensal engagement with the immune system is selective and precise (Tanoue et al. 2019). As Dr Knight points out, it would be surprising to witness the same response to any intervention in all individuals (Abbasi 2019). Efforts to individualize medical interventions, including probiotics, are worthwhile, but not yet realized. Until then, available evidence must be critically considered, but not ignored.  We wholeheartedly agree with the call for high quality clinical studies of probiotics but assert that it is also important to stress the challenges of performing clinical studies that seek to demonstrate clinical benefits in healthy human subjects; they require large study populations and are consequently very expensive. That clinical studies have been performed and demonstrated robust and clinically meaningful outcomes was illustrated by the study of Panigrahi where they demonstrated that an intervention comprising a probiotic plus prebiotic reduced sepsis among high-risk infants in rural India (Panigrahi et al. 2017). In the meantime, meta-analyses of smaller studies can provide insights into clinical benefit or harm. For example, systematic reviews and meta-analyses have consistently supported a role for probiotics in the prevention of Clostridium difficile–related illness, leading a JAMA review to state: “moderate-quality evidence suggests that probiotics are associated with a lower risk of C. difficile infection” (Goldenberg et al. 2018). Balanced with the low number needed to harm, probiotic interventions are attractive clinical options. We also question Abbasi’s focus on colonization as there is little, if any, evidence that this is necessary for probiotic activity.

We stress the obligation to provide a balanced view of the field which provides equal emphasis on successes as well as failures. No two probiotics (or probiotic cocktails) are alike; we should not expect they all have the same clinical impact.

 

References

  1. Abbasi J. Are probiotics money down the toilet? Or worse. JAMA 321(7):633-635. doi:10.1001/jama.2018.20798
  2. Tanoue T, Morita S, Plichta DR, et al. A defined commensal consortium elicits CD8 T cells and anti-cancer immunity. Nature. 2019;565:600-605.
  3. Panigrahi P, Parida S, Nanda NC, et al. A randomized synbiotic trial to prevent sepsis among infants in rural India. Nature. 2017;548:407-412.
  4. Goldenberg JZ, Mertz D, Johnston BC. Probiotics to prevent Clostridium difficile infection in patients receiving antibiotics. JAMA 2018;320:499-450. 

 

Acknowledgements:

Conflicts of interest:

All three authors are members of the Board of Directors of ISAPP

Eamonn M M Quigley holds equity in Alimentary Health and has served as a consultant to Alimentary Health, Allergan, Axon Pharma, Biocodex, Glycyx, Menarini, Pharmasierra, Salix and Vibrant.

Hania Szajewska reports no conflicts

Dan Merenstein has served as a consultant to Bayer, Debevoise & Plimpton, Pharmavite and Reckitt Benckiser

Challenges ahead in the probiotic field – insights from Probiota2019

By Dr. Mariya Petrova, Microbiome insights and Probiotics Consultancy (MiP Consultancy), Bulgaria.

Recently, I attended the Probiota Conference, which brings together representatives from industry and academia on the topic of probiotics and related fields. The goal of many of the speakers at the conference was to provide insight about how to translate scientific discoveries for, and share commercial insights with, end consumers. I would like to share a few points that caught my attention.

Do good science. End-consumers rely on news coverage of science, which unfortunately is too often more sensationalist than accurate. Prof. Gregor Reid’s talk, “Disentangling facts from fake news,” noted that news article titles such as “Probiotics labeled ‘quite useless’” and “Probiotics ‘not as beneficial for gut health as previously thought’” – after research was published last year in Cell (here and here) – were misleading to end-users and of great concern to people in the field of probiotics who are familiar with the totality of the data. Researchers have a responsibility to situate their results in the context of existing evidence. However, Prof. Reid also observed that “too many products are called probiotics with strains not tested in humans”; “too many products are making un-verified claims”; “too many journalist don’t have expertise in science”; “too many rodent studies making association with human health”; “researchers making up their own terms without defining them”. So how do we solve this? Do good science and communicate results clearly, accurately and without bias – to journalists, to peers and to end-users. (See related ISAPP blogs here and here).

Understand the probiotic mode of action. Understanding probiotic modes of action may be the most challenging issues ahead of us. Currently, we have too little understanding of mechanisms by which probiotics provide health benefits. Probiotic strains are living microorganisms, which most likely work through multiple mechanisms and molecules, but we indeed need more in-depth research. When I reflect on my own experience and the struggles to do molecular studies, I can appreciate how difficult this research is. Although others may be focused on screening the microbiome and developing bioinformatics tools, I applaud the researchers trying to develop deeper understandings of how probiotics function, which will enable more rational approaches to probiotic selection and use. (See related ISAPP blog here.)

New names, new glory. The forthcoming reclassification of the Lactobacillus genus was discussed. We are faced with the largest taxonomic upheaval of this genus in history, including many economically important species. The current Lactobacillus genus will be split into at least ten genera. The species and strain names will not change, but many species will have different genus names. Researchers are expected to propose that all new genera names will begin with the letter “L.” The reclassification can help us better understand the mode of action of industrially important probiotics and help tailor probiotic applications. The changes will be communicated with regulatory bodies such as EFSA and FDA. Name changes could also have consequences for medical stakeholders and may lead to potential issues with intellectual properties. Consumers of probiotic products will likely be less affected by this change, but an educational website targeted to consumers could be beneficial. (See related ISAPP blog here.)

EFSA claims as expected. EFSA claims and regulations were also discussed. To date, approximately 400 health claims applications have been submitted to EFSA without any approved. Experts advised to keep the claims simple and easy. EFSA’s strict approach to claims may have the advantage of compelling industry to conduct studies that better support health claims. Responsible companies are adapting to regulatory requirements and are developing good products, and they will probably succeed in meeting claim standards. Nevertheless, it seems that although health claims are deemed important to companies and medical representatives, end-users of probiotics obtain information from other sources. Obtaining health claims is only one piece of the puzzle. Also important is providing science-based information to end-users, especially those keen on keeping their good health through nutrition.

Be transparent. Don’t forget to disclose the strains you use on product labels. Strains designation is one key way to distinguish your product and it is an important way to communicate to your consumer exactly what is in your product. Surprisingly still, some scientific papers fail to report the strains they used to perform their clinical trials. The field is moving towards more transparency with high-quality clinical trials, the best-selected strains for certain condition and clear designation of the probiotic strain on the label. (See related ISAPP infographics here, here and here)

Educate, educate and again educate. Often discussed at the conference was the subject of educating the end consumers. Companies should take a proactive approach to engage consumers and promote understanding of the available evidence where probiotics can promote health. It is difficult for consumers to differentiate science-based evidence from journalistic sensationalism or researcher self-aggrandizement. A major obstacle is also the ready availability in the marketplace of unproven products containing strains that have been tested only in animal models or not proven experimentally at all. Taking the need for reliable communications on probiotics and probiotics to end-users very seriously, ISAPP has developed a range of science-based videos and infographics. The infographics include topics such as how to read the labels of the probiotics products (USA and EU versions) and a probiotic checklist. Thanks to the enthusiastic work of many volunteers, some ISAPP infographics can now be found in 10 different languages.

Despite having great discussions, one thing keeps troubling my mind: Where is the field of probiotics going and how will it look like in 10 or 20 years? The fight for probiotics is not over, despite the progress we have made so far.

The Children of Masiphumelele Township

Gregor Reid PhD MBA FCAHS FRSC, Professor, Western University and Scientist, Lawson Health Research Institute, London, Canada

Just off the main road from Cape Town, South Africa to Simon’s Town, sits Masiphumelele township where challenges of poverty, malnutrition, HIV and the risk of violence face people every day.

It is also the location for the Desmond Tutu HIV Foundation Youth Centre, a safe haven that provides adolescent-friendly sexual and reproductive health services alongside educational and recreational activities for youth living in Masiphumelele and surrounding areas.

To understand some of the dangers that children face, in 2017, about 270,000 people in South Africa were newly infected with HIV, adding to one of the highest HIV prevalence rates in the world. The Tutu Youth Centre aims at helping educate youth to reduce their risk of becoming another HIV statistic.

I was invited there by University of Cape Town Professor Jo-Ann Passmore, a woman not only recognized for her research but whose passion for helping others is reflected in her warm smile (4th from left in group photo). She asked if I would be interested in holding a workshop to illustrate to the youth how using sachets of probiotic bacteria could empower them. I jumped at the chance. On an afternoon break from the Keystone Symposium, thirty researchers joined me along with Jo-Ann and my wife Debbie, a teacher of children with learning disabilities.

After a tour of the areas where children learn on computers, play games in safety, or have personal discussions about sexual health, everyone filled the room with a stunning backdrop of the Nobel Laureate’s image. Having been privileged to meet the Archbishop when he was hosted by St. Joseph’s Healthcare Foundation in 2008, it was a nerve-tingling experience for me.

Giving a lecture on beneficial microbes is hard enough to peers sitting in the back of the room, but to do so with young South Africans was more somewhat daunting. However, it proved to be a lot of fun especially when we had to identify kids who were good leaders (the boys all pointed to a girl), who liked to make stuff and sell it to others (two boys stood out). By the end, we had picked the ‘staff’ of a new company.

The next step was for four groups to decide on the company’s name, what products they’d make from the probiotic sachets (the options were many including yoghurt, cereals, fruit juices, maize), what marketing tools they would use and who they would target to obtain a respectable income.

Interestingly, several of the conference participants seemed less engaged, as if they had never considered how microbiology research could affect real lives. In front of them were children facing huge challenges on a day-to-day basis. In one group, the kids were quiet until my wife brought out pens and paper, then they went to town designing products, names and labels. A lesson for me on how different people need different stimuli to become engaged. The faculty left early to beat the traffic back to Cape Town, so unfortunately, they did not hear the outcome of the children’s work.

When we re-assembled to present the results, I was impressed with what could be created in such a short time. My favourite was the Amazing Maize, a bottle shaped like a corn cob with the idea it would contain fermented maize. It emphasized the importance of marketing and for products to taste and look good to be purchased.

It has been over ten years since Archbishop Tutu applauded us for the Western Heads East project and thanked us for empowering women and youth and contributing to nutrition in Africa. Since then, thanks to the huge efforts of Western staff and students, and more recently IDRC funding and partnerships especially with Yoba-for-life, Heifer International and Jomo Kenyatta University of Agriculture and Technology, over 260,000 people in east Africa are now consuming probiotic yoghurt every week. The children of the South African townships were maybe too young to join in this new wave of microenterprises, but at least now they have heard about it and the importance of fermented food and beneficial bacteria.

In the background of the workshop several wonderful women committed to start up a new production unit using the Yoba/Fiti sachets developed by Yoba-for-life. I left them some sachets for them to try out the process.

But it was me who left with the biggest lesson on how precious each life is, and how those of us with the knowledge, need to provide the means for others to use their own talents to fulfill the purposes of their lives.

No better way than to start with the children.

Humpty Dumpty and the Microbiome

Prof. Colin Hill, Microbiology Department and Alimentary Pharmabiotic Centre, University College Cork, Ireland (@colinhillucc)

When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.”

Microbiome science is an evolving discipline, and new terminology is an important part of any developing field.  But precise language is important, especially in a multidisciplinary field with researchers from many diverse scientific backgrounds.  Language provides us a means of communicating with brevity and accuracy, but this is effective only if the reader is deriving the correct (intended) information from the author.

For example, is there a difference between ‘microbiome’, ‘microbiota’ and ‘microflora’?  Are the terms interchangeable, or would it be useful to have them mean related but distinctly different concepts?  I have heard people state that ‘microbiota’ refers to the microbial content of an environment, whereas ‘microbiome’ refers to the microbes AND their environment (the biome).  I have heard others suggest that ‘microbiome’ actually refers to the genetic content of a particular microbiota, in the same way that the genome is the genetic content of an organism.  Some definitions assert that the microbiome/microbiota/microflora only describes the microbial cells (bacteria, archaea and fungi) in a particular niche, while others include non-cellular microbes such as viruses and bacteriophage in their definition.  It has also been pointed out that ‘microflora’ is a misnomer, since technically the term ‘flora’ is reserved for the kingdom Plantae.

A few other examples.  Do we all know what is meant when someone uses the term ‘metagenomics’?  Also, people often refer to analysing the microbiome by 16S – but they are really only analysing the bacterial fraction of the microbiome, the ‘bacteriome’.  Of course ‘16S’ itself is not a valid term – it is 16S rRNA genes that are being analysed.  Would a clear distinction between microbiome, bacteriome, phageome, mycome, virome, archaeome and all the other ‘omes’ help or hinder our understanding of the subject under discussion?  Should most studies actually use the term ‘faecal bacteriome’ rather than ‘gut microbiome’, since it is almost always faeces that is under investigation, and usually only the bacterial component?

I am not going to call out any individuals for abuse of language, since I am pretty sure I could look at my own output and find lots of examples of poorly expressed concepts.  But does any of this matter or am I simply being pedantic? I think it does matter, since if terms are poorly defined it may lead to confusion on the part of the reader (or listener), whereas the authors (or speakers) may know exactly what they mean – neither more or less, as suggested by Humpty Dumpty.

ISAPP has convened consensus panels on the meaning of some very commonly used terms such as probiotic1 and prebiotic2, but there is a limit to this activity, and consensus panels cannot be convened for every new term.  Even with these consensus papers, we still have a plethora of additional terms surrounding beneficial microbes, including paraprobiotics (killed microbes), psychobiotics (originally defined as probiotics with a mental health benefit, but the definition has recently been expanded to any exogenous influence whose effect on the brain is bacterially-mediated3), synbiotics (probiotics and prebiotics administered simultaneously – a term for which ISAPP is convening another Consensus Panel in 2019), live biotherapeutics, etc, etc.  One site I saw referred to bacteriophage as a prebiotic, using the argument that they can influence a microbiome in a selective manner to achieve a beneficial outcome.  This is surely a good example of where the ISAPP definition could provide clarity since prebiotics have to be utilised in order to qualify for the term. Other terms we often use without an agreed consensus as to their meaning are ‘dysbiotic’ (when we could use disturbed, or different, or disrupted), ‘unculturable’ (when we usually mean ‘not yet cultured as far as I know but I haven’t really tried’), ‘hypothetical genes’ (when we actually mean ‘function unknown’), ‘stability’, ‘resilience’, etc.  It may be useful to have some kind of standardised microbiome dictionary, or an accepted glossary of terms.  This is not a new idea (so few of mine ever are), and Julian Marchesi and Jacques Ravel published a lovely short paper to this effect in 20154.  The World Microbiome Day website also has a very short Glossary5.

Obviously, words must be the servants of the author and should not restrict expression or limit our ideas, and in many instances context can make it abundantly clear what meaning is intended by the author.  But in general, a strict definition is not the enemy of understanding, but makes it easier for author and reader to share common ground.

Who should create and curate such a Microbiome Glossary?  Ideally it would be interactive, perhaps along the line of a wiki page, where people could provide their newly coined terms along with a strict definition and arrive at a consensus for commonly used terms.  Reviewers of journal papers and reviews could help, by challenging authors on what terms they use, and whether or not they are the appropriate ones.

Meanwhile, I have to go back to the lab to do some comprehensive metagenomics on the gut microbiome – by which I mean that a competent scientist who works with me is going to go into the lab and conduct a particular form of 16s rRNA gene analysis to profile the more abundant members of the bacteriome of a portion of a faecal sample which has been collected, stored and extracted according to our in-house protocols.  Obviously!

 

  1. Hill et al., 2014. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the scope and appropriate use of the term probiotic.  Nat. Rev. Gastroenterol. Hepatol. 11, 506.
  2. Gibson et al., 2017. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics.  Nat. Rev. Gastroenterol. Hepatol. 14, 491.
  3. Sarkar et al., 2016. Psychobiotics and the Manipulation of Bacteria–Gut–Brain Signals.  Trends in Neurosciences 39, 763
  4. Marchesi JR and J. Ravel. 2015. The vocabulary of microbiome research: a proposal.  Microbiome 3, 31
  5. http://worldmicrobiomeday.com/glossary-of-microbiome-terms/

Importance of understanding probiotic mechanisms of action

By Prof. Sarah Lebeer, Universiteit Antwerpen, Belgium

At present, we do not fully understand the mechanistic basis of many well established probiotic health benefits. This limits our ability to predict which probiotics are likely to be effective.

For instance, prevention of antibiotic-associated diarrhea and necrotizing enterocolitis are health benefits that are well substantiated by meta-analyses, which combine results on many probiotic strains. But what the effective strains have in common from a mechanistic perspective is not known. We cannot yet pinpoint one or a few molecules produced by these strains that might drive the clinical effects. This is likely due to interplay between both host and probiotic factors. These health conditions are complex pathologies and the probiotic strains are living micro-organisms likely working through multiple mechanisms and molecules.

This is in contrast to some more clearly defined situations. Lactose maldigestion results from a deficiency in the enzyme lactase, which is required for converting lactose to glucose and galactose in the small intestine. If lactose is not broken down, it reaches the colon and is fermented by the gut microbiota, leading to symptoms. Some probiotic bacteria (including those present in yoghurt) contain lactase, which can reduce the typical symptoms of lactose digestion.

Several colleagues and I published a recent paper (Kleerebezem et al. 2019) discussing the importance of understanding mechanisms of action. We argue that such knowledge will enable: “(i) selection of more effective probiotic strains; (ii) optimization of probiotic product manufacturing and quality assurance, (iii) improved design of probiotic formulation, and (iv) support of the design of effective clinical trials with the best chance of realizing benefits to human health.”

While knowledge of the mechanism of action is not necessary for translation to effective products, it provides important insights that can improve actions throughout the translational pipeline.

The strain-specificity of different mechanisms of action is another point that will be clarified by future mechanism-focused research. Different probiotic strains clearly express different mechanisms, but some mechanisms are also shared (Sanders et al. 2018). How different host- and probiotic-specific factors interact to achieve a clinically successful intervention remains to be unraveled.

I have IBS – should I have my microbiome tested?

By Prof.  Eamonn Quigley, MD. The Methodist Hospital and Weill Cornell School of Medicine, Houston

I am a gastroenterologist and specialize in what is referred to as “neurogastroenterology” – a rather grandiose term to refer to those problems that arise from disturbances in the muscles or nerves of the gut or in the communications between the brain and the gut.  Yes, the gut has its own nervous system – as elaborate as the spinal cord – which facilitates the two-way communication between the brain and gut.

The most common conditions that I deal with are termed functional gastrointestinal disorders (FGIDs) among which irritable bowel syndrome (IBS) is the most frequent. I have cared for IBS sufferers and been involved in IBS research for decades. But while much progress has been made, IBS continues to be a frustrating problem for many sufferers. No, it will not kill you, but it sure can interfere with your quality of life. Dietary changes, attention to life-style issues (including stress) and some medications can help but they do not help all sufferers all of the time. It is no wonder, therefore, that sufferers look elsewhere for relief. Because, symptoms are commonly triggered by food, there are a host of websites and practitioners offering “food allergy” testing even though there is minimal evidence that food allergy (which is a real problem, causes quite different symptoms and can be fatal) has anything to do with IBS. Nevertheless, sufferers pay hundreds of dollars out of pocket to have these worthless tests performed.

Now as I sit in clinic I am confronted by a new phenomenon – “microbiome testing”. I cringe with despair when a patient hands me pages of results of their stool microbiome analysis. Has their hard-earned money been well spent? The simple answer is NO! Let me explain. First, our knowledge of the “normal” microbiome is still in evolution so we can’t yet define what is abnormal – unless it is grossly abnormal. Second, we have learned that many factors, including diet, medications and even bowel habit can influence the microbiome.  These factors more than your underlying IBS may determine your microbiome test results.  Third, while a variety of abnormalities have been described in the microbiome in IBS sufferers, they have not been consistent. Someday we may identify a microbiome signature that diagnoses IBS or some IBS subgroups – we, simply, are not there yet. Indeed, our group, together with researchers in Ireland and the UK, are currently involved in a large study looking at diet, microbiome and other markers in an attempt to unravel these relationships in IBS.

There have been a lot of exciting developments in microbiome research over the past few years. One that has caused a lot of excitement comes from research studies showing that the microbiome can communicate with the brain (the microbiome-gut-brain axis). It is not too great a leap of faith to imagine how such communications could disturb the flow of signals between and brain and the gut and result in symptoms that typify IBS. We also know that some antibiotics and probiotics can help IBS sufferers. Indeed, about 10% of IBS suffers can date the onset of their symptoms to an episode of gastroenteritis (so-called post-infection IBS). All of this makes it likely that the microbiome has a role in IBS; what we do not know is exactly how. Is the issue a change in the microbiome? Is it how we react to our microbiome? Is it the bacteria themselves or something that they produce? Could our microbiome pattern predict what treatments we will respond to? These are fascinating and important questions which are being actively studied. In the meantime, I feel that microbiome testing in IBS (unless conducted as part of a research study) is not helpful.

If you are interested in our research study please contact me at equigley@nullhoustonmethodist.org

 

Related Reading:

Microbiome analysis: hype or helpful?

A clinician’s guide to microbiome testing

Here’s the poop on getting your gut microbiome analyzed

 

probiotics calendar

Probiotics in the Year 2018

Prof. Daniel Merenstein MD, Georgetown University School of Medicine

Messages about probiotics seem to be everywhere. It is difficult for me to keep up with the emails, links, and stories I am sent by friends and colleagues. I am regularly asked my opinion about new studies. Null trials seem to really generate the most interest, with some people looking for limitations of the study and others generally over-extrapolating the null results, seemingly at times to generate the brashest headlines.

Today I want to take a step back and share how I see probiotics in 2018.

I just reviewed a 109-page NIH grant focused on a probiotic intervention for use in a resource poor area. Throughout the grant, the authors never once defined probiotics—presumably because the definition is so commonly known. They did define ‘prebiotics’ but they never felt the need to define probiotics. Imagine that: 2018, and probiotics no longer need to be defined lest the authors seem pedantic. This would not have been the case even five years ago.

Probiotics are backed by real science, they are here to stay, and they are impacting both how we practice medicine and how consumers care for their own health. These are real products with some robust outcomes supported by well-done, independent studies. That is worth emphasizing: there is level 1 evidence for certain products and indications. On the other hand, the use of many probiotics is not evidence-based and expectations about some are not realistic. In the real world, products do not work for every indication or study population. Effect sizes and effectiveness for most indications are often small. One of my true hesitations about fecal microbial transplantation* is how nearly every study has over 90% effectiveness. That gives me cause for concern.

Thus, when there is a null trial the skeptics shouldn’t over extrapolate and the probiotic devotees should not attack the authors. We can look to studies on other treatments as an example: In November of this year NEJM published an article that showed a new antibiotic did not work well for gonorrheal pharyngeal infections. What I didn’t see were any headlines stating, “Antibiotics don’t work for pharyngeal infections.” But headlines involving probiotics often make erroneously broad generalizations. There clearly are indications for which no probiotic has been or will be shown to work. Selling a probiotic for that indication is clearly unethical. But considering the robust evidence base we have for the indication of probiotics for gastroenteritis, it is inappropriate – after 2 null trials – for headlines to read, “Probiotics Do Not Ease Stomach Flu” or “Probiotics No Better Than Placebo for Gastroenteritis”.

This fall I spoke about probiotics at two conferences, the annual meetings of the American Academy of Family Physicians (AAFP) and the annual meeting of the Academy of Nutrition and Dietetics  (FNCE). I had never spoken at either conference. With the help of a colleague, I gave two talks at AAFP; both were over-registered with all 600+ spots taken. At the FNCE, the talk was also over-registered with 350 in attendance. The level of interest in probiotics was astonishing.

What I learned from my talks is that as long as there are well-designed studies demonstrating benefits, professionals are open to probiotics and will use them correctly. Further, both the FNCE and AAFP audiences shared similar concerns: can you trust that probiotic product labels are truthful regarding contents, and are there any safety concerns? Good science and quality oversight need to continue to address these important concerns.

2018 was a great year for the advancement of probiotics in mainstream medicine. However, I think for physicians to fully embrace probiotics, the probiotic industry will better need to police itself and make sure the products they sell are what they say they are. Then they need to communicate this on the product label, using a valid quality seal (such as offered by USP), so physicians and consumers will be confident about what they are using. If the science continues to advance and we communicate about it responsibly, the use of probiotics will be used appropriately and more frequently – as they should be.

 

*For all my colleagues in the gastroenterology world who have fallen in love with fecal transplant for recurrent C. diff,  the totality of evidence as of this writing is:  187 total patients, 5 studies (2 enema, 2 colonoscopy and 1 via-nasoduodenal tube), and punchline, TWO studies were blinded. The one with the lowest rate of success was the only one that was placebo-controlled and blinded. The other blinded study was donor versus patients’ own stools. Stew on that and feel free to correct me.  

YOGURITO –the Argentinian social program with a special yogurt

Dra. María Pía Taranto, CERELA-CONICET, Argentina and Prof. Seppo Salminen PhD, University of Turku, Finland

It is widely accepted that technologies play a central role in the processes of social change. The Argentinian experience has documented that yogurt can be a promising tool for promoting social development.  The program is called “Scholar Yogurito, the social probiotic” and the probiotic product is called “Yogurito”. This social program began with the development of a probiotic food, in the form of yogurt. This yogurt contains the probiotic strain Lactobacillus rhamnosus CRL1505, whose functional and technological characteristics are widely documented by CERELA-CONICET researchers. These researchers conducted clinical studies that demonstrated that the consumption of this probiotic product improves natural defenses and prevents respiratory and intestinal infections, the infectious events of greatest relevance in childhood. The “Yogurito Social Program” benefits some 300,000 schoolchildren in the province of Tucumán and some 50,000 in other provinces and municipalities of Argentina. This social transfer project, implemented in 2008 in the province of Tucumán, is a paradigm of interaction between the scientific sector, the manufacturing sector and the state, to improve the quality of life of highly vulnerable populations.

The social and economic implications for such translational research are significant and especially pertinent for people living in poverty, with malnutrition and exposure to environmental toxins and infectious diseases including HIV and malaria. This example of probiotic applications illustrates the power of microbes to positively impact the lives of women, men, and children, right across the food value chain. The researchers are looking for grants that would enable them to compare outcomes of schools given Yogurito to schools with no participation in the program.

 

Additional 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.

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. Benef Microbes. 2018 Sep 18;9(5):707-715. doi: 10.3920/BM2018.0015.

 Senior Researcher Maria Pia Taranto and the Yogurito product

 

Maria Luz  Ovejero, a teacher at Primary School 252 Manuel Arroyo y Pinedo, explains probiotics to 4-6 year old children in Tucuman province in Argentina

Where does our food come from – why should we care?

Dr. Karen Scott, The Rowett Institute, University of Aberdeen,  Scotland

The food we eat feeds our microbes, gives us energy and nutrition, and keeps us healthy. The choices we make about our food clearly affects our health, but also has a huge effect on the world around us. We need to make more effort to choose correctly.

Sometimes it seems that everywhere we look, someone has an opinion on what we should be eating. Television is full of programmes telling us how and what to cook – suitable for a range of abilities. In supermarkets we are continually targeted with special offers and promotions, encouraging us to buy things we do not need, that are not on our shopping list. In magazines there are page long adverts, letting us know many reasons why our lives will be enriched if we purchase product Y, and perhaps even how we will be missing out if we do not. Even newspapers print articles telling us which foods are “super” this week, and will endow us with youthful skin, long life, and/or a svelte figure. Next week there will be another article with a new superfood, and one demoting last week’s superfood to the “standard” food, or even demonising it completely.

Yet even with all this focus on what we should be eating, do we really care about where our food comes from? Shouldn’t we really be more concerned with the provenance and sustainability of our food, rather than whether it is “super”?

Quinoa is a grain with a high nutrient content, high protein content (including all nine essential amino acids) and is also a source of some essential micronutrients and vitamins. By popular measures, a “superfood”. Quinoa is primarily grown in South America (Peru, Chile and Bolivia) where it is an important dietary staple. The increased demand and resultant export of quinoa has contributed considerably to the Peruvian economy. On the other hand, the cost increases associated with the increased worldwide demand means that the local Andean population now struggle to afford to include this healthy food in their own diets. Additionally the enlarged land area now used for quinoa production has reduced the amount of land available to grow alternative crops, and this reduced diversity has a negative impact on soil quality and on wildlife. Not so “super”.

Another healthy food-fad with a negative environmental impact is avocado. The current demand for avocados as part of the ‘green smoothie’ revolution has resulted in considerable deforestation in Mexico to make way for avocado plantations. Avocado trees also need a lot of water, which, given that they are frequently grown in climates with problems of drought, is clearly not sustainable.

The other factor is price – we are constantly persuaded that we should be looking for the best deal, getting those “2-for-1 offers”, or buying our food in the specific supermarket “saving you the most on your weekly shop”. The reality is that we spend a smaller % of our income on food today than we ever have – and this is not because we eat less, far from it. But if we think about it, it is not the large supermarket that loses money when it introduces offers. Buy one get one free offers on, for example fruit, usually mean that the farmer is only getting paid for one of every two oranges sold. Is this fair? If you ask a people doing their food shopping if they think that milk should cost more than water – most people would say “yes of course”. Yet at the milk counter in the supermarket they automatically reach for the “special offer”, cheapest product. Sometimes the farmer gets paid less for the milk he sells the supermarket than it costs to produce. Again if you asked people in the shop if they thought this was fair, they would no doubt say no, but they still reach for the “special offer”, cheapest product. This is already driving smaller dairy farmers out of business. Is this what we want? We as consumers, as well as the supermarkets, have to take responsibility.

Similarly with meat products and eggs. Most people, when asked about the best and most humane ways to look after animals on farms, prefer the low density, outside methods often depicted in children’s story books. Yet when we reach the meat counter in the supermarket we are more likely to reach for the cheaper product than the one from the farm which assures humane conditions, but which may cost twice as much. Such farming methods are more expensive to run, so the products have to cost more. We have to make more effort to include our instinctive morality when we are actually making purchases of food.

We have also become accustomed to being able to buy anything, at any time of year. If we want to buy fruit that is out-of-season in our own country, it will be in-season somewhere else and can be flown across the world for display in our local supermarket. When we ask people if they care about global warming – most will agree that it is a big problem, threatening the world. Yet they will buy specific fruits or vegetables that have been flown 1000s of miles, in aeroplanes contributing CO2 emissions, without a thought. Locally produced food, eaten in season, completely avoids this non-essential contribution to global warming.

Feeding our microbes is easy – they just eat our leftovers. But perhaps we also need to think about them. Food produced in intensively farmed conditions contains more pesticide and antibiotic residues than foods produced less intensively. Depending where we live, imported foods may have fewer controls on additives and production methods than those produced locally. Although specific studies have not been carried out to gauge the effect of such residues on our microbes, it is likely that there will be an effect. The healthy compounds in fruits develop best when they are allowed to ripen on the bush/tree and are not harvested unripe and then transported across the world. Our ancestors ate fresh foods in season and produced locally. People living in remote areas of the modern world without access to the diverse range of foods in a supermarket have a more diverse, healthy microbiota than those of us consuming “western diets”. Our microbes do not need, and potentially do not want, intensively produced foods.

Many of us are in the fortunate position of being able to afford to pay a bit more for our food, and thus to support it being produced in the way we would prefer if we stopped to think about it. This is why we DO have to stop to think and not automatically reach for the cheapest product on the shelf.  If we do not support farmers who are producing food in the most humane way, they will go out of business and we will be left with no choice but to buy mass-produced, often imported, food. Is this really what we want?

We have become so accustomed to paying less for our food, and looking for bargains, that we seem to care less about the quality and provenance than the price. Unless we change our outlook we will affect whole populations and environments forever. We need to stop the disconnect between our thoughts about what our foods should be, and what we actually buy, and we need to do it before it is too late.

International Dairy Summit 2018 in Daejeon in South Korea

By Prof. Seppo Salminen PhD, University of Turku, Finland

The International Dairy Federation (IDF) convenes annual meetings that bring together scientists and industry professionals to discuss issues foremost to the production of safe and nutritious dairy products globally. Since probiotics find a home in so many dairy foods worldwide, ISAPP and IDF have some overlapping interests.

ISAPP president, Prof. Seppo Salminen of University of Turku, spoke at IDF’s International Dairy Summit 2018 on the potential for fermented foods to fight diseases and improve nutrition. He emphasized that many fermented foods contain a diverse collection of live microorganisms, which likely support our gut microbiota, perhaps even promoting gut microbiota resilience. Further, he stated, “Fermented dairy products, especially yoghurt, which combines milk, microbial starter cultures and pre-digested nutrients for human use, can be considered for future food-based dietary guidelines or recommendations focusing on beneficial microbe intake for gastrointestinal and other health effects.”

Another speaker, Prof Bruno Pot, discussed the global situation with regard to health claims for fermented dairy products. He focused on the situation in the European Union, where the only allowed health claim for probiotics is the benefit from live bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) in yoghurt reducing symptoms of lactose maldigestion. He reported that yoghurt is becoming a mainstream food in Asia. Key growth drivers in Asia are the perceptions that yoghurt is a healthy product with its beneficial impact on the digestive and immune systems, and they offer a good source of protein and calcium. The symposium also explored ways to enrich food through product development and innovation, particularly to provide nourishment for vulnerable populations. The potential for new ingredients such as milk protein hydrolysate-calcium complexes as calcium sources in yoghurt production was recognized.

David Everett, Chair of IDF’s Standing Committee on Dairy Science and Technology, reported: “Holding the 6th edition of the Symposium on Fermented Milks in Asia is of tremendous value as the scientific research on fermented dairy and the interest in these products is growing in the region.”

Forthcoming changes in Lactobacillus taxonomy

Mary Ellen Sanders PhD, Executive Science Officer, ISAPP

I was privileged to be included in a small meeting of scientists, both academic and industry, who met last week in Verona to discuss changes in Lactobacillus taxonomy. The first objectives of the meeting were to clarify with industry the need for the proposed changes and to clarify the methodology that will be used. The second objectives were to discuss at large potential consequences and approaches to address them.

Changes to the Lactobacillus genus

Experts from the Taxonomic Subcommittee for Lactobacilli, Bifidobacteria and Related Organisms agreed that the genus Lactobacillus is too heterogeneous and dividing this genus into several genera is inevitable. The need for this taxonomic ‘correction’ has been known for a long time, but until recently, the methodologies needed to reliably group the current Lactobacillus species into new genera were not available. But earlier this year, a paper by Salvetti et al (2018) analyzed 269 Lactobacillus and related (e.g., Pediococcus, Leuconostoc, Fructobacillus, Oenococcus) species and showed that the Lactobacillus genus comprises 10 phylogroups (see box). Each of these phylogroups represents at least one new genus. These same 10 phylogroups were observed using three separate approaches [phylogenetic analysis of 16S ribosomal DNA sequences, whole genome sequence analysis, leading to the comparison of 72 shared housekeeping genes (the core genome), and the comparison of average amino acid identity and percentage of conserved proteins], providing strong evidence that these groupings are robust. Commercially important Lactobacillus probiotic strains span at least 7 of those newly defined phylogroups; food fermentation lactobacilli cover even more.

lactobacillus_info

Although these 10 phylogroups were identified by this study, the current genus Lactobacillus could ultimately be resolved into 10 or up to 23 genera, depending on the cut-off values used for the different approaches. If researchers choose to split the genus into fewer new genera, it increases the chance that taxonomic changes will be needed in the nearer future. If they split the genus into more genera, it increases the chance that nomenclature will remain stable.

The names of the new genera are not decided. New names must be published (or validated) in the International Journal of Systematic and Evolutionary Microbiology. The authors of the publication will propose the new genus names. All species will be retained and their species names will not change. To minimize disruption, researchers will try to propose new genera names that begin with the letter “L”. Because “Lactobacillus” is a masculine Latin noun, the new genus names must be masculine for the species names to be retained.

A silver lining

Critics of these changes may suppose that adhering to taxonomic convention is their only purpose. But a classification system that better reflects genetic relatedness of the species may reap other benefits. As evidence for clinical benefits accumulates (summarized in open access review “Probiotics for Human Use”, 2018) and investigations provide insight into probiotic mechanisms of action, a clearer image of mechanisms and functions associated with particular taxonomic groups may emerge. The concept of core, shared benefits that were not strain-specific but linked to higher taxonomic groupings was explored in two ISAPP publications [Hill et al. (2014) and more in depth in Sanders et al. (2018)]. Reconsideration of clinical evidence and its relationship to new genera might prove enlightening.

What can be done to minimize confusion?

The meeting attendees brainstormed potential complications that might result from changing genus names. Company representatives in general considered that internal changes could be managed, although resources would be required to update names on all different paperwork and labels associated with commercial products (for example, marketing materials, product information, certificates of analysis, labeling, import/export certificates). The 2002 WHO/FAO probiotic guidelines, as well as the 2017 CRN/IPA guidelines, indicate that the genus, species and strain designation should be included on product labels. Further, the name used should reflect current nomenclature. This requirement is reflected in some national regulations. Therefore, genus name changes will necessitate label changes.

Further, it was emphasized that a clear document should be prepared and endorsed by reputable organizations (EFSA, NIH, FDA, medical organizations, and others). The document should: (a) indicate the name changes, (b) provide a clear, concise statement of why the changes were needed, and (c) emphasize that only the names, not the strains, would be different. This could be leveraged by companies to communicate with all stakeholders. End-users of probiotic products would likely not be a significant communication challenge. Authorities involved with probiotic safety (FDA with GRAS and EFSA with QPS) likely will manage these changes, as they are science-based. More of a concern was communication with other regulators, both at the level of national agencies responsible for probiotic-specific regulations (including countries with positive lists of species that are acceptable as probiotics) as well as authorities involved in import/export of product. Some potential issue with intellectual property may be envisaged, especially in a transition period during which the new names are not routinely used yet.

The bottom line: Name will change but the strains will stay the same 

The current Lactobacillus genus will be split into at least 10, and perhaps as many as 23, genera. No species names will change, but many species – including commercially important ones – will have a different genus names, hopefully beginning with the letter “L”.  Because of the tremendous heterogeneity of the current Lactobacillus genus, Prof. Paul O’Toole concluded his presentation saying “the status quo is not an option.” Some disruptions can be expected from this massive change, but the probiotic field would benefit from embracing these changes and developing strategies to minimize any difficulties resulting from them.

 

Additional information:

The International Committee on Systematics of Prokaryotes (ICSP) and the International Code of Nomenclature of Bacteria are responsible for the naming of bacteria. The subcommittee of the ICSP responsible for naming lactobacilli is the Taxonomic Subcommittee for Lactobacilli, Bifidobacteria and Related Organisms.

The meeting was convened by the Lactic Acid Bacteria Industrial Platform and chaired by Esben Laulund of Chr Hansens, who also chairs IPA Europe. A full report of meeting conclusions is expected to be published in a scientific journal by the end of 2018. Abstracts and program will to be posted on the LABIP website in due time.

The taxonomic hierarchy for Lactobacillus currently is: Domain: Bacteria; Division/Phylum: Firmicutes; Class: Bacilli; Order Lactobacillales; Family: Lactobacillaceae; Genus: Lactobacillus. The lowest order of taxonomy is the subspecies; the strain designation has no official standing in nomenclature. There are currently over 230 recognized species of Lactobacillus, and approximately 10 new species are added each year.

happy_baby

Probiotics and D-lactic acid acidosis in children

Prof. Hania Szajewska PhD, The Medical University of Warsaw, Department of Paediatrics, Poland and Prof. Seppo Salminen PhD, Faculty of Medicine, Functional Foods Forum, University of Turku, Finland

See related post ‘Brain Fogginess’ and D-Lactic Acidosis: Probiotics Are Not the Cause

In their recent study, Rao and colleagues1 incriminated probiotics in the induction of D-lactic acidosis (1). Many who benefit from probiotics could be frightened—on the basis of this report—into stopping them, with potentially negative impacts on their health (2). Some probiotic bacteria, including some specific components of the intestinal microbiota, may produce D-lactic acid. Indeed, if plasma D-lactic acid rises sufficiently, it is clinically relevant, causing D-lactic acidosis. D-lactic acidosis has mainly been observed in subjects with short bowel syndrome. However, some authorities have regulated the use of D-lactic acid producing bacteria in infant and weaning foods, but the reasoning for normal infant population has been debated. Even in adults, the safety of D-lactic acid producing bacteria has been challenged, but apart from short bowel patients no evidence on clinical problems has been reported (3).

For this reason, we conducted a review and examined whether D-lactic acid-producing bacteria, acidified infant formulas and fermented infant formulas were potential causes of paediatric D-lactic acidosis (4).

We identified five randomised controlled trials conducted between 2005-2017 with 544 healthy infants. Additionally, some case reports and experimental studies were considered. No clinically relevant adverse effects of D-lactic acid-producing probiotics or fermented infant formulas in healthy children were identified. The only known cases of paediatric D-lactic acidosis were observed in patients with short bowel syndrome (4). It is of importance that human milk also contains lactic acid bacteria and bifidobacteria, some of which may produce D-lactic acid. Some stress situations, such as exercise, may elevate human milk lactate concentrations.  Thus, breast milk D-lactate content needs to be analysed more carefully to compare with fermented infant formulas.

Taken together, our results suggest that neither the probiotics that were evaluated in the studies we reviewed nor fermented infant formulas cause D-lactic acidosis in healthy children.

 

  1. Rao, S. S. C., Rehman, A., Yu, S. & Andino, N. M. Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis.  Transl. Gastroenterol.9, 162 (2018). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6006167/
  2. Sanders, M. E., Merenstein, D. & Merrifield, C. A. Probiotics for human use.  Bull.43, 212–225 (2018). https://onlinelibrary.wiley.com/doi/10.1111/nbu.12334
  3. Quigley E.M.M, Pot B., Sanders M.E. ‘Brain fogginess’ and D-lactic acidosis: probiotics are not the cause. Transl. Gastroenterol.9, 187 (2018). https://www.nature.com/articles/s41424-018-0057-9
  4. Łukasik, J., Salminen S., Szajewska H. Rapid review shows that probioticsand fermented infant formulas do not cause D-lactic acidosis in healthy children. Acta Pediatrica 107, 1322-1326 (2018). https://www.ncbi.nlm.nih.gov/pubmed/29603358

FDA/NIH Public Workshop on Science and Regulation of Live Microbiome-based Products: No Headway on Regulatory Issues

September 20, 2018

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

On September 16, 2018, the US Food and Drug Administration’s Center for Biologics Evaluation and Research (CBER) and National Institute of Allergy and Infectious Diseases (NIAID) collaborated on the organization of a public workshop on “Science and Regulation of Live Microbiome-based Products Used to Prevent, Treat, or Cure Diseases in Humans”.  I was present at this meeting along with ISAPP vice-president, Prof. Daniel Merenstein MD, who lectured on the topic of probiotics and antibiotic-associated diarrhea.

Prof. Dan Merenstein speaking at CBER/NIAID conference

While regulatory issues are often discussed at other microbiome conferences, the fact that this meeting was organized by the FDA suggested it was a unique opportunity for some robust discussions and possible progress on regulatory issues involved with researching and translating microbiome-targeted products. The regulatory pathways to drug development seem clear enough, but regulatory issues for development of functional foods or supplements are less clear. Jeff Gordon and colleagues have previously pointed out regulatory hurdles to innovation of microbiota-directed foods for improving health and preventing disease (Greene et al. 2017), and at the 2015 ISAPP meeting, similar problems were discussed (Sanders et al. 2016).

The meeting turned out to be mostly about science. Some excellent lectures were given by top scientists in the field (see agenda below), but discussion about regulatory concerns was a minimal component of the day. Questions seeding the panel discussions focused on research gaps, not regulatory concerns: an unfortunate missed opportunity.

Bob Durkin, deputy director of the Office of Dietary Supplements (CFSAN), left after his session ended, suggesting he did not see his role as an important one in this discussion. One earlier question about regulatory perspectives on prebiotics led him to comment that the terms ‘probiotic’ and ‘prebiotic’ are not defined. From U.S. legal perspective he is correct, as there are no laws or FDA regulations that define these terms. But from a scientific perspective, such a statement is disappointing, as it shows the lack of recognition by U.S. regulators of the widely cited definitions developed by top researchers in these fields and published in 2014 and 2017, respectively.

Two issues not addressed at this meeting will require clarification from the FDA:

The first is how to oversee human research on foods or dietary supplements. CBER’s oversight of this research has meant most studies are required to be conducted under an Investigational New Drug (IND) application. From CBER’s perspective, these studies are drug studies. However, when there is no intent for research to lead to a commercial drug, the IND process is not relevant. Even if endpoints in the study are viewed as drug endpoints by CBER, there should be some mechanism for CFSAN to make a determination if a study fits legal functions of foods, including impacting the structure/function of the human body, reducing the risk of disease, or providing dietary support for management of a disease. When asked about this, Durkin’s reply was that CFSAN has no mechanism to oversee INDs. But the point was that without compromising study quality or study subject safety, it seems that FDA should be able to oversee legitimate food research without forcing it into the drug rubric. CBER acknowledged that research on structure/function endpoints is exempt from an IND according to 2013 guidance. But FDA’s interpretation of what constitutes a drug is so far-reaching that it is difficult to design a meaningful study that does not trigger drug status to them. For example, CBER views substances that are given to manage side effects of a drug, or symptoms of an illness, as a drug. Even if the goal of the research is to evaluate a probiotic’s impact on the structure of an antibiotic-perturbed microbiota, and even if the subjects are healthy, they consider this a drug study. With this logic, a saltine cracker eaten to alleviate nausea after taking a medication is a drug. Chicken soup consumed to help with nasal congestion is a drug. In practice, many Americans would benefit from a safe and effective dietary supplement which they can use to help manage gut disruptions. But in the current regulatory climate, such research cannot be conducted on a food or dietary supplement in the United States. There are clearly avenues of probiotic research that should be conducted under the drug research oversight process. But for other human research on probiotics, the IND process imposes research delays, added cost, and unneeded phase 1 studies, which are not needed to assure subject safety or research quality. Further, funders may choose to conduct research outside the United States to avoid this situation, which might explain the low rate of probiotic clinical trials in the United States (see figure).

The second issue focuses on actions by CBER that have stalled evidence-based use of available probiotic products. This issue was discussed by Prof. Merenstein in his talk. He pointed out that after the tragic incident that led to an infant’s death from a contaminated probiotic product (see here; and for a blog post on the topic, see here), CBER issued a warning (here) that stated that any probiotic use by healthcare providers should entail an IND. This effectively halted availability of probiotics in some hospital systems. For example, at Johns Hopkins Health-system Hospitals, the use of probiotics is now prohibited (see below). Patients are not allowed to bring their own probiotics into the hospital out of concern for the danger this poses to other patients and staff. This means that a child taking probiotics to maintain remission of ulcerative colitis cannot continue in the hospital; an infant with colic won’t be administered a probiotic; or a patient susceptible to Clostridium difficile infection cannot be given a probiotic. Available evidence on specific probiotic preparations indicates benefit can be achieved with probiotic use in all of these cases, and denying probiotics can be expected to cause more harm than benefit.

It might be an unfortunate accident of history that probiotics have been delivered in foods and supplements more than drugs. The concept initially evolved in food in the early 1900’s, with Metchnikoff’s observation that the consumption of live bacilli in fermented milk had value for health. Probiotics have persisted as foods through to the modern day, likely because of their safety. The hundreds of studies conducted globally, including in the U.S. until 10-15 years ago, were not conducted as drug studies, even though most would be perceived today as drug studies by CBER. This has not led to an epidemic of adverse effects among study subjects. True, serious adverse events have been reported, but the overall number needed to harm due to a properly administered probiotic is negligible.

According to its mission, the FDA is “…responsible for advancing the public health by helping to speed innovations that make medical products more effective, safer, and more affordable and by helping the public get the accurate, science-based information they need to use medical products and foods to maintain and improve their health.” Forcing human research on products such as yogurts containing probiotics to be conducted as drug research, when there is no intent to market a drug and when the substances are widely distributed commercially as GRAS substances, does not advance this mission. Further, CBER actions that discourage evidence-based use of available probiotics keeps effective and safe products out of the hands of those who can benefit.

A robust discussion on these issues was not part of the meeting earlier this week.  Researchers in the United States interested in developing probiotic drugs will find CBER’s approaches quite helpful. Yet researchers interested in the physiological effects of, or clinical use of, probiotic foods and supplements will continue to be caught in the drug mindset of CBER. CFSAN does not seem interested. But without CFSAN, human research on, and evidence-based usage of, probiotic foods and supplements will continue to decline (see figure), to the detriment of Americans.

Human clinical trials on “probiotic”
1992-September 20, 2018

 

 

 

Role of citizen science in research on fermented foods

By Prof. Sarah Lebeer, Universiteit Antwerpen

Spontaneous vegetable fermentations, with their rich flavors and potential health benefits, are regaining popularity among chefs and the general public. Famous Michelin star chefs, such as Belgium’s Kobe Desramaults, have implemented fermented vegetables in their recipes and offer fermented vegetable juices as non-alcoholic alternatives to wine. Serendipity was surely at play when I made contact with Kobe and his team, and had the opportunity to explore the microbial life of many of his fermented food and beverages.

Thanks to this spontaneous collaboration, I became intrigued by fermented vegetables as a promising alternative to dairy probiotic matrices. They have several benefits:

  • they are lactose-free
  • they contain no milk allergens
  • they are naturally vitamin-, antioxidant- and fiber-rich
  • they are vegan, satisfying the growing dietary trend

 

Together with prof. L. De Vuyst – a fermented food specialist from the VUB University in Brussels – we attracted a talented PhD student Sander Wuyts to study Lactobacillus’ role in the spontaneous fermentation process of carrot juices. I admit that fermented carrot juice is not the tastiest beverage I ever drank, but the fermentation process turned out to be scientifically intriguing: it appeared to be a robust, man-made microbial ecosystem dominated by lactic acid bacteria. We now often use this fermentation process in my lab as a model to study various aspects of niche-adaptation and niche-flexibility of lactic acid bacteria (LAB). And if you mix carrot juice with another fresh vegetable juice, such as cucumber, you’ll be surprised by its interesting light acidic flavor!

But perhaps the most rewarding part about our fermented-vegetables project was that we managed to carry out a Citizen Science project with the Flemish name, Ferme Pekes. You could translate it as ‘Fantastic Carrots’ 😊. Forty citizens volunteered to set up their own carrot juice fermentations at home and delivered with great enthusiasm samples of different time points. The carrots originated from their own garden, the supermarket or organic stores. Our analysis indicated that origin or organic compared to conventional product did not impact the microbial community composition. But we also could show that the LABs – first Leuconostoc then Lactobacillus – out-competed the undesirable Enterobacteriaceae after 3 to 13 days of fermentation. Longer times were needed for carrots derived from winter storage.

Our analyses (phylogenetic placement and comparative genomics, which was recently published in Applied and Environmental Microbiology) also indicated that a high LAB diversity was achieved in the different spontaneous fermentations. This is of interest if you believe it is important to let our immune system come into contact with a large and naturally diverse dose of beneficial bacteria. This idea has been promoted through the years as the hygiene hypothesis or microbial deprivation theory and aligns perfectly with the surge of interest in the health benefits of naturally fermented foods. See the recent ISAPP blog from Prof. Colin Hill, who advocates for the idea of a recommended daily allowance of consumption of live microbes.  (See also a related ISAPP blog here.) Such guidelines should be taken with precaution: the fermentations must be done properly with regard to food safety (see ISAPP blog on Making Safe Fermented Foods at Home).

Citizen Science refers to projects where citizens are actively involved in scientific studies, although it has various definitions and descriptions. In our case, it allowed us to obtain a much larger and more diverse set of samples than we could have created in the lab. Furthermore, the opportunity to directly (on e.g. workshops for adults and kids or at delivery of their samples) or indirectly (as a response to articles in the popular press) communicate with citizens helped us greatly in identifying which other research questions might be of importance for the general public. This approach is increasingly implemented in the fermented food and microbiome field. There are examples of fantastic projects such as on sourdough from Rob Dunn, Benjamin Wolfe and colleagues, the Global FoodOmics initiative and the Flemish Gut Flora project, which will also be presented by Dr. Gwen Falony at our next ISAPP meeting in Antwerp. I am not aware of a Citizen Science project in the probiotic or prebiotic area, but it might be a good idea for a joint ISAPP initiative, for science communication, the creation of richer datasets, validation/confirmation of probiotic efficacy, inspiration for future research questions, for example.

rdamicrobes

Recommended daily allowance (RDA) for microbes?

By Prof. Colin Hill, Alimentary Pharmabiotic Centre, Food for Health Ireland, University College Cork

In this months’ issue of The Biochemist (August 2018) I explored the concept of whether or not there could be a health benefit to ingesting large numbers of safe microbes in our diet (see the open access article here).  This was an effort, though I should stress not a scientifically rigorous effort, to consider the long history of encounters between humans and ingested microbes.

This opinion piece was prompted by a series of open questions which have often puzzled me.  Why is so much of our immune system focussed on the gut?  Why not simply let the microbes and food constituents pass through and get digested without such strict surveillance?  Surely it would be more metabolically favourable to only react to those microbes that breach our epithelial barriers?  Why does our enteric nervous system devote so much of its resources to the gut?  Why is there a generally beneficial effect of many probiotics across so many health conditions?  Why is mother’s milk designed to promote the growth of microbes?

Could the solution to all of these questions be down to a very simple answer? Because the gut ‘expects and requires’ constant encounters with microbes for full functionality. Given that humans evolved into a microbial world, and that we have consumed a diet rich in microbes for most of our evolutionary history, it makes sense that our enteric systems would be designed to appropriately deal with microbes of all types, selecting out those which can cause damage and destroying them, accommodating those which will become part of our microbiomes and letting the rest pass through.  Surely we are monitoring and controlling our ‘microbial’ organ in the same way that our eukaryotic organs are monitored and controlled.

Could it be that the rise in autoimmune diseases could be, at least in part, due to an immune system primed to expect more microbes than it currently sees?  Should we recommend that a daily dose of safe microbes should be included in dietary guidelines – in the form of more safe raw foods, more fermented foods and more probiotics? It must be emphasized that some serious pathogens must be controlled or eliminated from food – not ALL live microbes are safe. But the goal can be to process only when needed for safety reasons, so foods can be a source of the safe microbes they harbour.

Lots of questions, and not many answers.  But I for one am taking account of this concept in my daily diet and am deliberately eating more microbes – I’ll let you know how it goes!

smile

Probiotics for oral health: start young

By Dr. Mary Ellen Sanders

Prof. Wim Teughels from the Department of Oral Health Sciences, Leuven University, spoke at the 2018 ISAPP meeting on the topic of probiotics and prebiotics for oral health. He embraced the opportunity to speak to this audience in part hoping he could convince researchers to consider incorporating oral health endpoints in their future clinical trials.

He did a spot-on lecture, which precisely summarized available evidence for probiotics and prevention of dental caries, management of periodontal disease and reduction of Streptococcus mutans in the oral cavity. This area of research is gaining traction (see here).

One study he discussed is particularly interesting by Stensson et al. 2014 tracked caries in children at 9 years of age. This single-blinded, placebo-controlled study administered L. reuteri ATCC 55730 to mothers during the last month before their baby’s birth and to the children through age one. The number of children receiving the L. reuteri probiotic without caries was significant higher (82%) than in the placebo group (58%).  Although there are studies available that show a larger impact, the interesting aspect of this study is that it tests a very early intervention in life that seems to have an effect up to 9 years later. It is an important paper because it opens up the notion of early interventions in life, during microbial ecology development. The main message here is you don’t need to wait until there are teeth to start working on dental health later in life. In fact, interventions for dental health can start during pregnancy and by this:

We do not know what would have happened if the probiotics were given during the whole 9 years of life. Dentists who are interested in prevention should be interested in such data.

Several meta-analyses have summarized data for dental caries and management of periodontal disease. These reviews are useful in that they summarize the totality of evidence. But combining data on different strains might not be justified, as different strains may utilize different mechanisms to achieve effects, and therefore should not be considered as the same intervention. See here, here, here and here.

In sum, there appears to be a growing body of evidence that probiotic administration may impact several indicators of oral health: dental caries, gingivitis and periodontitis. More research is needed to understand the impact of probiotic supplementation on the oral microbiota and if clinical benefits are mediated by microbiota changes. It’s also important to understand which strains will deliver the strongest benefits, although L. reuteri has several, positive studies, and the importance of dose and temporal factors with dosing.