Biotics in animal and human nutrition

Episode 22: Biotics in animal and human nutrition

/in Podcast, Season Two /by Laura

Biotics in animal and human nutrition

 

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The Science, Microbes & Health Podcast 

This podcast covers emerging topics and challenges in the science of probiotics, prebiotics, synbiotics, postbiotics and fermented foods. This is the podcast of The International Scientific Association for Probiotics and Prebiotic (ISAPP), a nonprofit scientific organization dedicated to advancing the science of these fields.

Biotics in animal and human nutrition, with Prof. Kelly Swanson

Episode summary:

In this episode, the ISAPP podcast hosts join guest Prof. Kelly Swanson PhD from University of Illinois at Urbana-Champaign, to discuss the role of biotics in animal and human nutrition. They review the criteria for prebiotics and synbiotics, then discuss how we gain knowledge about nutrition and the role of biotics in animals compared to humans.

Key topics from this episode:

  • A good argument can be made that biotics are essential for our diet; they are beneficial even if efficacy is sometimes difficult to prove.
  • Nutrients have an impact on the host’s health and simultaneously on the host-associated microbes.
  • Health benefits are essential to the FDA definition of fiber.
  • Antibiotics’ effect on the microbiota: short-term effects may be minor, but we still don’t know the long-term effects.
  • The synbiotics definition, criteria for products to meet this definition, and the health outcomes from using these biotic substances.
  • The difference between complementary and synergistic synbiotics.
  • When studying biotics in companion animals (cats and dogs), can results from one host be extrapolated to another host? Final studies should be in the target host.
  • Biotics are important in veterinary medicine and a popular topic of study.
  • Predictions about the future of nutrition science as informed by the microbiome.

Episode links:

Additional resources:

About Prof. Kelly Swanson:

Kelly Swanson is the Kraft Heinz Company Endowed Professor in Human Nutrition at the University of Illinois at Urbana-Champaign. His laboratory studies the effects of nutritional interventions, identifying how diet impacts host physiology and gut microbiota. His lab’s primary emphasis is on gastrointestinal health and obesity in dogs, cats, and humans. Much of his work has focused on dietary fibers and ‘biotics’. Kelly has trained over 40 graduate students and postdocs, published over 235 peer-reviewed manuscripts, and given over 150 invited lectures at scientific conferences. He is an active instructor, teaching 3-4 nutrition courses annually, and has been named to the university’s ‘List of Teachers Ranked as Excellent by Their Students’ 30 times. He serves on advisory boards for many companies in the human and pet food industries and non-profit organizations, including the Institute for the Advancement of Food and Nutrition Sciences and International Scientific Association for Probiotics and Prebiotics.

Genetically modified microorganisms for health

Episode 21: Genetically modified microorganisms for health

/in Podcast, Season Two /by Laura

Genetically modified microorganisms for health

 

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The Science, Microbes & Health Podcast 

This podcast covers emerging topics and challenges in the science of probiotics, prebiotics, synbiotics, postbiotics and fermented foods. This is the podcast of The International Scientific Association for Probiotics and Prebiotic (ISAPP), a nonprofit scientific organization dedicated to advancing the science of these fields.

Genetically modified microorganisms for health, with Dr. Carlos Gómez-Gallego

Episode summary:

In this episode, ISAPP podcast host Dan Tancredi joins guest Carlos Gómez-Gallego PhD, from University of Eastern Finland, to discuss genetically modified microorganisms. They go over what genetically modified microorganisms are, their potential benefits over non-modified microorganisms, and how they might improve human health–in particular, diseases of the metabolic and immune systems.

 

Key topics from this episode:

  • Genetically modified microorganisms are those that have been modified using genetic engineering, giving them abilities they do not normally have. Functions can be either conferred or deleted. Different genetic engineering tools can be used – e.g. to make them produce therapeutic compounds, or make them increase degradation of toxins or harmful compounds.
  • One advantage over non-modified microorganisms is the potential to have continuous delivery of a therapeutic compound, and the potential to deliver it to a localized area in order to avoid unwanted interactions.
  • Genetically modified microorganisms have promise in metabolic and immune-linked disorders such as non-alcoholic fatty liver disease (NAFLD).
  • In NAFLD, genetically modified E. coli Nissle can secrete hormones that are under-regulated or under-expressed. His group modified bacteria by introducing a plasmid that allowed it to produce aldafermin, an analog of the human hormone fibroblast growth factor 19 (FGF19).
  • With genetically engineered microorganisms, we must consider the benefits but also the risks. However, if it’s a therapeutic for a disease with few or no alternatives, there’s a strong case for developing them.
  • To increase efficacy and safety of these microorganisms, it’s possible to introduce sensors that produce the therapeutic in response to different stimuli. Also, it’s important to modify the bacteria so their use is controlled and they cannot spread. They can also be modified to avoid transmission of genes.
  • Are there market-approved genetically modified microorganisms? No approved ones yet, but some are in Phase 1 and Phase 2 clinical trials.

Episode links:

About Dr. Carlos Gómez-Gallego:

I am a Senior Researcher at the Institute of Public Health and Clinical Nutrition (University of Eastern Finland). I have completed two university degrees, one in Biology and another in Food Science and Technology, and an MSc in Nutrition and Health. I subsequently completed a Ph.D. from the University of Murcia, where I investigated the effect of infant formula processing on the content of polyamines and bioactive peptides, and their impact on intestinal microbiota and immune system development during lactation.

My research and interests are primarily focused on advancing the understanding of the impact of diet, food, and bioactive compounds on human microbiota and their association with human health. As part of the BestTreat project (https://besttreat.eu/index.html), I have co-supervised two PhD students (Johnson Lok and Valeria Ianone) who evaluated the potential use of engineered E. coli Nissle 1917 producing human hormones for the treatment of non-alcoholic fatty liver disease (NAFLD) in a mouse model. The first publication has already been submitted, and the second is currently in process.

More info about my publications:
Research Gate https://www.researchgate.net/profile/Carlos-Gomez-Gallego
UEF connect https://uefconnect.uef.fi/en/person/carlos.gomez-gallego/#information

How to navigate probiotic evidence and guidelines for pediatric populations

Episode 20: How to navigate probiotic evidence and guidelines for pediatric populations

/in Podcast, Season Two /by Laura

How to navigate probiotic evidence and guidelines for pediatric populations

 

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The Science, Microbes & Health Podcast 

This podcast covers emerging topics and challenges in the science of probiotics, prebiotics, synbiotics, postbiotics and fermented foods. This is the podcast of The International Scientific Association for Probiotics and Prebiotic (ISAPP), a nonprofit scientific organization dedicated to advancing the science of these fields.

How to navigate probiotic evidence and guidelines for pediatric populations, with Dr. Hania Szajewska

Episode summary:

In this episode, the ISAPP podcast hosts talk about evidence and guidelines for probiotics in pediatric populations, with Prof. Hania Szajewska MD PhD, of the Department of Paediatrics at the Medical University of Warsaw, Poland. They talk about some of the inconsistencies between different medical organizations’ guidelines for pediatric probiotic use, and how clinicians can move forward with recommendations based on the best available evidence.

 

Key topics from this episode:

  • Guidelines exist on probiotic use for gastroenterological issues in children, but there are differences (especially regarding acute gastroenteritis) between guidelines from different medical societies: European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) and The American Gastroenterological Association (AGA).
  • Realistic expectations are necessary when prescribing probiotics. Different probiotics have different benefits, but they are not a ‘magic bullet’. For example, the evidence shows certain probiotics for acute gastroenteritis reduce diarrhea by an average of one day. This could have a big impact on the quality of life of the end user, but for clinicians it may not sound like a lot so they must set expectations accordingly.
  • The market is overflowing with probiotic products, many of which do not have proven efficacy. This makes it difficult for end users and healthcare professionals to distinguish the best products.
  • Always look for evidence-based probiotics with documented efficacy for the indication for which they are intended.
    • Physicians have the ethical duty to prescribe evidence-based products (that is, clinically proven, effective products).
    • The exact strains and doses matter.
  • Formal training and education of healthcare professionals regarding the beneficial effects of microbes, the microbiome, and probiotics are currently lacking.
  • Is it more valuable to know probiotics’ mechanism of action, or to have evidence from clinical trials that they are effective?
    • Ideally we would have both, but since we don’t know the exact mechanism for all probiotics, positive evidence from clinical trials is crucial. 
    • We also need to make clear to healthcare professionals and end users what to expect from taking probiotics. For example, some probiotics reduce the chances of developing antibiotic-associated diarrhea by 50%. For colic, some probiotics can reduce the crying time by half an hour. These are modest benefits but for the affected individual they may be impactful.
  • For vulnerable populations such as preterm infants, we need high-quality products with proven safety and efficacy.

 

Episode abbreviations and links:

 

About Prof. Hania Szajewska: 

Hania Szajewska, MD, is Professor and Chair of the Department of Paediatrics at the Medical University of Warsaw and the Chair of the Medical Sciences Council. Among her various functions, she served as the Editor-in-Chief of the Journal of Pediatric Gastroenterology and Nutrition; a member of the Council and then as the General Secretary of the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN); the Secretary of the ESPGHAN Committee on Nutrition. Most recently, she joined the Board of Directors of the International Scientific Association for Probiotics and Prebiotics (ISAPP). Prof. Szajewska has broad interests in pediatric nutrition but her research focuses on the effects of early nutritional interventions on later outcome; and the gut microbiota modifications such as with various biotics (probiotics, prebiotics, synbiotics, postbiotics). She is or has been actively involved in several European Union-funded research projects. She is an enthusiastic advocate for the practice of evidence-based medicine. Prof. Szajewska has co-authored more than 400 peer-reviewed publications and 30 book chapters. Citations >18,141. Hirsch index 72 (WoS, March 2023).

Questioning the existence of a fetal microbiome, with Dr. Kate Kennedy

Episode 19: Questioning the existence of a fetal microbiome

/in Podcast, Season Two /by Laura

Questioning the existence of a fetal microbiome, with Dr. Kate Kennedy

 

Podcast: Play in new window | Download

Subscribe: Apple Podcasts | Google Podcasts | Spotify | RSS

The Science, Microbes & Health Podcast 

This podcast covers emerging topics and challenges in the science of probiotics, prebiotics, synbiotics, postbiotics and fermented foods. This is the podcast of The International Scientific Association for Probiotics and Prebiotic (ISAPP), a nonprofit scientific organization dedicated to advancing the science of these fields.

Questioning the existence of a fetal microbiome, with Dr. Kate Kennedy

Episode summary:

In this episode, the ISAPP podcast hosts tackle the debate on the existence of a fetal microbiome, with guest Kate Kennedy PhD of McMaster University in Canada. They talk about Kennedy’s recent co-first-authored paper in Nature, which concludes that it is not biologically plausible that the fetus harbors live microorganisms, and that previous microbial sequencing studies on the fetal microbiome did not account for the many sources of contamination.

 

Key topics from this episode:

  • During the last 10 years, a lively debate has emerged on whether humans harbor living microorganisms prior to birth. Some scientists have looked at fetal and placental tissues and amniotic fluid, and have ostensibly detected microbial DNA. But those results are being questioned, with the argument that the signals being found are not biologically plausible.
  • Kennedy et al. published an article in Nature that re-analyzed data and brought in experts from different related fields to help interpret the data. The conclusion is that the fetal microbiome does not exist. Previous studies have likely seen contamination during sampling, since it’s nearly impossible to collect samples in a sterile way following vaginal delivery; contamination can happen at different stages so stringent controls are needed across all these areas of potential contamination. Furthermore, live microorganisms in the fetus does not fit with what we already know in related fields of science.
  • The popularity of microbiome research may have made scientists interested in this topic, although sequencing by itself may not be sufficient to settle the question of whether a fetal microbiome exists.
  • Human cells have Mitochondrial DNA, which is bacterial in origin. In 16S rRNA gene sequencing, there is some overlap in what is amplified, and this could include mitochondrial DNA, giving misleading results. This was not accounted for in some of the initial fetal microbiome studies.
  • Bringing together disparate disciplines is inherently challenging. It’s very important to work to understand each other and understand the host and biological situation you’re dealing with.
  • If there were even small numbers of bacteria present in the fetus it would have huge implications for our understanding of fetal biology and immunology. One question would be: how is the fetus limiting growth of any microbes it harbors?
  • Despite the likelihood that the fetal microbiome does not exist, the fetus is not unprepared for the microbial onslaught after birth. The maternal microbiota and immune system can educate the fetus immunologically in the absence of fetal colonization.

 

Episode abbreviations and links:

 

About Dr. Kate Kennedy: 

Kate completed her PhD on the role of the maternal gut microbiome in perinatal programming in the lab of Dr. Deborah Sloboda at McMaster University. She previously completed her BSc and MSc in Biology at the University of Waterloo. Her research explores host-microbiome relationships in pregnancy, early-life, and aging to understand their role in modulating health and disease risk.  

Episode 18: The definition of postbiotics

/in Podcast, Season Two /by Laura

 

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The Science, Microbes & Health Podcast 

This podcast covers emerging topics and challenges in the science of probiotics, prebiotics, synbiotics, postbiotics and fermented foods. This is the podcast of The International Scientific Association for Probiotics and Prebiotic (ISAPP), a nonprofit scientific organization dedicated to advancing the science of these fields.

The definition of postbiotics, with Dr. Gabriel Vinderola and Prof. Seppo Salminen

Episode summary:

In this episode, the ISAPP podcast hosts join guests Gabriel Vinderola, PhD, Principal Researcher at the
National Scientific and Technical Research Council (CONICET) and Associate Professor at University of Litoral in Argentina, and Seppo Salminen, PhD, Professor at University of Turku in Finland, to discuss the relatively recent definition of postbiotics and what kinds of substances are included in this category. They talk about the criteria for something to qualify as a postbiotic, common mechanisms of action for postbiotics, and how postbiotic science has brought new perspectives on the study of probiotics.

 

Key topics from this episode:

  • What are postbiotics? Dr. Vinderola and Prof. Salminen dive deep into the definition of postbiotics created in 2021 and what it entails.
  • Postbiotics, similar to probiotics, prebiotics, and synbiotics, must provide health benefits to the host.
  • The nature of the postbiotic preparation is important for its health benefits. When the inactivation process is changed, this can lead to altered health benefits, and clinical studies must be repeated to ensure the desired health benefits are maintained.
  • They explain why “inanimate” was chosen to describe the microorganisms / components in a postbiotic preparation. 
  • What is the mode of action, or how do postbiotics work? 
    • Postbiotics show similar mechanisms of action to probiotics, except for ones requiring viability, since postbiotics will not grow and produce metabolic byproducts in the host.
    • Postbiotics can benefit the host via physical interaction with the host epithelial and immune cells.
    • A primary mechanism of action is likely to be through activation of the immune system, through which postbiotics can affect inflammation and some disease conditions. 
    • Postbiotics may also affect the microbiome composition and ability to inhibit pathogens.
  • From a regulatory point of view, inanimate microorganisms may represent an easier category to prove safe for users. For industry, postbiotics may be more convenient with a longer shelf life.
  • Some controversy still exists around the ISAPP-led postbiotic definition, and this has led to valuable discussions that are crucial to scientific progress. So far the authors of the definition have defended their stance.

 

Episode abbreviations and links:

 

Additional Resources:

Postbiotics. ISAPP infographic (also available in Japanese and Spanish).

Behind the publication: Understanding ISAPP’s new scientific consensus definition of postbiotics. ISAPP blog post.

Definition of postbiotics: A panel debate in Amsterdam. ISAPP blog post.

 

About Dr. Gabriel Vinderola: 

Gabriel Vinderola graduated at the Faculty of Chemical Engineering from the National University of Litoral (Santa Fe, Argentina) in 1997. He obtained his Ph.D. in Chemistry in 2002 at the same University. He collaborated with several research teams in Canada, Spain, France, Italy, Germany, Brazil and Finland. He is presently Principal Researcher of the National Scientific and Technical Research Council (CONICET) and Associate Professor at the Food Engineering Department of his home Faculty. He participated in 1999 in the development of the first commercial cheese carrying probiotic bacteria in Latin America. In 2011, he was awarded the prize in Food Technology for young scientists, by the National Academy of Natural, Physic and Exact Sciences from Argentina. He published more than 120 original scientific publications in international refereed journals and book chapters. From 2020 to present, he serves as a member of the board of directors of the International Scientific Association for Probiotics and Prebiotcis (ISAPP). He is engaged in science communication to the general public through Instagram (@gvinde).

 

About Prof. Seppo Salminen: 

Seppo Salminen, MSc, MS, PhD, is a Senior Advisor, Functional Foods Forum (FFF) at the University of Turku. His areas of expertise are gut microbiota, probiotics and prebiotics, nutrition and food safety, and EU regulations. Seppo teaches the topics of lactic acid biotechnology, functional foods and EU legislation and conducts research into food and health, intestinal microbiota, probiotics, prebiotics, functional foods, food legislation, health claims, and novel foods.

Episode 17: Using metabolomics to learn about the activities of gut microbes

/in Podcast, Season Two /by Laura

 

Podcast: Play in new window | Download

Subscribe: Apple Podcasts | Google Podcasts | Spotify | RSS

The Science, Microbes & Health Podcast 

This podcast covers emerging topics and challenges in the science of probiotics, prebiotics, synbiotics, postbiotics and fermented foods. This is the podcast of The International Scientific Association for Probiotics and Prebiotic (ISAPP), a nonprofit scientific organization dedicated to advancing the science of these fields.

Using metabolomics to learn about the activities of gut microbes, with Dr. Anisha Wijeyesekera

Episode summary:

In this episode, the ISAPP podcast hosts address the topic of metabolomics with Dr. Anisha Wijeyesekera, PhD, a Lecturer in the Department of Food and Nutritional Sciences at the University of Reading, United Kingdom. Dr. Wijeyesekera gives an overview of how metabolic profiling works, including the information provided by different biological samples, and discusses how metabolomics can be used to piece together the contributions of microbes to host health.

 

Key topics from this episode:

  • Dr. Wijeyesekera introduces the field of metabolomics and describes it as an essential part of systems biology. Metabolic profiling provides a real-time snapshot of the multiple metabolic processes going on in a system at the time the sample was collected.
  • Metabolites are the end products of metabolism; the gut microbiota is the most metabolically active of the microbiomes in the human body.
  • Methodology depends on what information you hope to uncover from your samples. Different biological samples (e.g. stool, urine, plasma) provide different pieces of information; this is cross-referenced with information on metabolic pathways.
  • One application of metabolomics is in identifying biomarkers that can predict patient outcomes. Identifying differences in microbes as well as metabolites could lead to the development of dietary-based supplements for patients to take alongside clinical treatments.
  • Changes in microbial composition may not be that meaningful if the bugs that change are doing the same thing in the end; this is what metabolomics helps uncover.
  • Metabolomics gives you insights into mechanisms when you have a probiotic or prebiotic trial with clinical outcomes. 
  • Short-chain fatty acids are metabolites that are frequently associated with health; changes in these is a clue that the gut microbiota has been impacted by the intervention.
  • Bile acids are metabolites that come from diet. Microbes convert primary bile acids to secondary, which circulate throughout the body. You can measure bile acids to see how gut microbiota are affected by an intervention.
  • Metabolomics is very promising and may be used in more probiotic and prebiotic studies in the future.

 

Episode abbreviations and links:

 

About Dr. Anisha Wijeyesekera:

Anisha is a Lecturer in the Department of Food and Nutritional Sciences at the University of Reading, United Kingdom. She previously worked at Imperial College London, where she also obtained her PhD (in Biochemistry). Anisha’s research applies a combined microbial and metabolic phenotyping approach, to better understand the tripartite relationship between diet, gut microbiota and human health. At the University of Reading, she conducts in vitro and in vivo studies for functional assessment of the gut microbiota, particularly in response to prebiotics and probiotics. The ultimate aim is to use this information to tailor nutritional or other interventional therapy to improve health outcomes.

Episode 16: The honey bee microbiome and potential for probiotics

/in Podcast, Season Two /by Laura

 

Podcast: Play in new window | Download

Subscribe: Apple Podcasts | Google Podcasts | Spotify | RSS

The Science, Microbes & Health Podcast 

This podcast covers emerging topics and challenges in the science of probiotics, prebiotics, synbiotics, postbiotics and fermented foods. This is the podcast of The International Scientific Association for Probiotics and Prebiotic (ISAPP), a nonprofit scientific organization dedicated to advancing the science of these fields.

The honeybee microbiome and potential for probiotics, with Dr. Brendan Daisley

Episode summary:

In this episode, the ISAPP podcast hosts cover the honey bee microbiome with Brendan Daisley, PhD, who is currently a post-doctoral fellow at the University of Guelph in Canada. Daisley explains how the honeybee microbiome is unique, why it’s important for bee health, and the potential for probiotic applications as well as the practicalities of how live microorganisms are delivered to hives.

 

Key topics from this episode:

  • Daisley’s research is motivated by declining bee populations and finding ways to find ways to stop this.
  • He originally researched how probiotics could have detoxification functions in humans; this led to the question of whether probiotics could help reduce the toxicity of pesticides in bees and possibly affect resistance to infectious diseases.
  • Each individual bee has a microbiome of its own. Unlike other insects, bees have a core, defined microbial community in their guts.
  • Surprisingly, no one has successfully derived a completely germ-free honey bee. Microbiota-depleted bees do exist, however.
  • Research is ongoing on how microbes may even enable life in bee species — e.g. the recent finding that pupation in stingless bees is triggered by fungi.
  • Bees are affected by pesticides; many pesticides also have antimicrobial effects, but regulatory agencies do not track these effects.
  • Supplementing bees with beneficial strains of microbes can improve bee health and resistance to infectious diseases. However, no good baseline studies have been done on the bee gut, so it’s difficult to know what’s ‘normal’ and what is missing. The Canadian Bee Gut Project aims to determine this.
  • It’s possible to try finding bees that may have had less exposure to pesticides, but it’s difficult to determine past exposure because bees are traded and sent all over the world.
  • Wolbachia is a valuable endosymbiont for bees, and acts like a ‘secondary mitochondria’ in their cells. Currently it is hardly ever found in honey bees, possibly because of chronic exposure to tetracycline.
  • Probiotics can be delivered to bees using a “BioPatty” or a spray-based formula; the delivery method is very important. Supplementing the hive with certain probiotics can suppress outbreaks of American Foulbrood disease when they happen.
  • Daisley and colleagues used 3 probiotic strains, which remain present in the bee host for several weeks. 
  • As far as potential prebiotics for bees, it has been observed that pollen fibers can beneficially modulate the honey bee microbiome.
  • The healthy honey bee microbiome should be dominated by lactic acid bacteria.

 

Episode abbreviations and links:

 

About Dr. Brendan Daisley:

Dr. Brendan Daisley is a postdoc at the University of Guelph (Allen-Vercoe lab) and the current President of the Students and Fellows Association of ISAPP. He graduated from his PhD in Microbiology & Immunology at Western University in 2021 (supervisor: Dr. Gregor Reid), during which he received several national awards including the Armand Frappier Outstanding Student Award, adjudicated by The Canadian Society of Microbiologists. Brendan has a broad range of experience in environmental application of probiotics to honey bees and, notably, he was the first to introduce the theory of ‘missing microbes’ within the field of honey bee microbiome research. During his PhD, he helped coordinate several large field trials across North America (mostly in Ontario and California) showing that supplementation of probiotic lactobacilli strains to honey bees could improve colony-level health outcomes. During his postdoc work, he has developed a microbiome database tool (BEExact) for improved detection of uncultivated ‘microbial dark matter’, established a bioreactor model of the honey bee gut microbiome (the RoBEEgut), and co-founded the Canadian Bee Gut Project (https://beegutproject.uoguelph.ca) – a nationwide crowdsourcing initiative that aims to deeply sequence thousands of bee microbiome samples to increase our knowledge on the multifactorial drivers of honey bee mortality.

Episode 15: A primer on prebiotics

/in Podcast, Season Two /by Laura

 

Podcast: Play in new window | Download

Subscribe: Apple Podcasts | Google Podcasts | Spotify | RSS

The Science, Microbes & Health Podcast 

This podcast covers emerging topics and challenges in the science of probiotics, prebiotics, synbiotics, postbiotics and fermented foods. This is the podcast of The International Scientific Association for Probiotics and Prebiotic (ISAPP), a nonprofit scientific organization dedicated to advancing the science of these fields.

A primer on prebiotics, with Dr. Karen Scott

Episode summary:

In this episode, the ISAPP podcast hosts talk about prebiotics with Karen Scott, PhD, who is an ISAPP board member and Senior Research Fellow at Rowett Institute, University of Aberdeen, Scotland. Scott describes what prebiotics are, as well as the latest thinking about how they fit within an overall healthy diet and how they confer health benefits through the gut microbiota.

Key topics from this episode:

  • Dr. Scott and colleagues at the Rowett Institute began many years ago by working on anaerobic bacteria from the rumen of animals, then started to focus on the bacteria in the human large intestine.
  • Prebiotics (see definition below) stimulate the growth of beneficial bacteria in the human gut, and in doing so, benefit host health.
    Prebiotics alone cannot guarantee health: they must be consumed in addition to a healthy regular diet, which helps support thediversity of all gut microbes.
  • Prebiotics are not necessarily supplements; they are found in high amounts in many foods such as bulb-based vegetables, banana, and plantain. Around 5g of prebiotic per days is beneficial for health.
  • Not all prebiotics are equal: they each stimulate the growth of particular groups of bacteria. By definition, they must be selectively utilized (that is, some bacteria but not others must use them), and this differentiates prebiotics from fiber.
  • Some prebiotics are shown to improve gut transit (i.e. reduce constipation). One common example of the benefit of prebiotics has to do with bone health: metabolism of prebiotics in the colon tends to lower the pH; this increases calcium absorption for supporting bone health. Other benefits involve the production of short-chain fatty acids.
  • Bifidobacterium have traditionally been a group of bacteria targeted by prebiotics. Some Bifidobacterium produce lactate, and other bacteria produce butyrate (important for colonic health) from lactate. In healthy adults, there are bacteria that are equally or more important than bifidobacteria, however.
  • Prebiotics can target other body sites besides the gut.
  • Prebiotics that can be used by a bacteria in pure culture are not necessarily used by those bacteria within the ecosystem of the human gut.
  • New experimental platforms exist to see which bacteria are producing specific compounds on the growth of a specific substrate. But a model may not represent what is happening in the host, so this must be specifically tested.
  • Human milk oligosaccharides are a great example of how prebiotics are important to human health. Formula is often supplemented with prebiotics because of ample evidence that oligosaccharides (naturally present in human milk, but mimicked synthetically) enable growth of specific bacteria in the baby’s gut that are very important for immunity and other aspects of health.
  • Overall, to support bacteria in your gut and overall health, Dr. Scott recommends consuming a diverse diet: “eat a rainbow”. If you cannot, a prebiotic supplement is advisable.*

Episode abbreviations and links:

Dr. Karen Scott works at the Rowett Institute, a renowned centre focused on nutrition and human health.

ISAPP published the scientific consensus definition of prebiotics.

An early review co-authored by Dr. Scott, covering gut microbiota functions and their impact on host health via diet.

A review on prebiotics to support calcium absorption and therefore bone health.

Dr. Scott refers to a new tool: the Exploris 240 Orbitrap mass spectrometer, which is interfaced with an atmospheric pressure matrix assisted laser desorption ionisation (AP-MALDI) source and direct infusion. This theoretically allows scientists to measure the distribution and composition of complex gut bacterial communities, whilst simultaneously assessing metabolite production from the constituent microbes, allowing them to better understand the cooperation and competition between different human gut microbiota species.

Additional resources:

Prebiotics. ISAPP infographic.

Understanding prebiotics and fiber. ISAPP infographic.

The many functions of human milk oligosaccharides: A Q&A with Prof. Ardythe Morrow. ISAPP blog post.

 

About Dr. Karen Scott:

Dr. Karen Scott is a Senior Research Fellow at the Rowett Institute, University of Aberdeen. She leads a research team investigating the (molecular) mechanisms by which key members of the gut microbiota interact with the diet and host, at different life-stages. The fermentation products of gut bacteria contribute to gut health, and are differentially expressed on different substrates, including prebiotics. In vitro bacterial growth studies utilising our large culture collection of gut anaerobes (in pure culture, mixed culture, fermentor systems, and also with human cells) and bioinformatic analyses illustrate niche-specific processes and bacterial interactions. Resident bacteria are also an important reservoir of transferable antimicrobial resistance genes, and other work investigates the evolution and spread of resistance from farm to fork.