Is exercise good for our digestive health?

Like the rest of our body, our digestive system has everything to gain from physical activity (sidenote: Physical activity Any bodily movement produced by skeletal muscle contraction resulting in an increase in energy expenditure (EE) relative to resting EE”. Examples of physical activity include walking, cycling, active play, sports, housework, gardening, and DIY. Source: Caspersen CJ, Powell KE, Christenson GM. Physical activity, exercise, and physical fitness: definitions and distinctions for health-related research. Public Health Rep. 1985 Mar-Apr;100(2):126-31. ) . When we exercise in moderation (at less than 50% of maximal oxygen consumption or VO2max (sidenote: VO2max A criterion specific to each athlete, VO2max is the maximum quantity of oxygen that the body can extract from the air and transport to the muscle fibers to meet their needs during exercise. The higher the VO2max, the better the performance. When this criterion is low, sporting ability is limited, and specific training will be needed to boost it. ) ) :

• gut transit receives a boost;
• the mucous membrane lining the digestive tract is left in better condition.

A scientific study has shown that, following three months of moderate physical activity, gastrointestinal motility (contractions of the muscles in the digestive tract required to move food through it) is improved, and as a result transit is accelerated, reducing the time that future stools spend in the digestive system and therefore the period of contact between any pathogens present in these stools and the gut barrier. The same is true after just one week of moderately intense cycling. In other words, sport (sidenote: Sport Structured leisure-time physical activity which may include physical exercise where participants adhere to a common set of rules (or expectations) and where a goal is defined.
Source: Khan KM, Thompson AM, Blair SN et al. Sport and exercise as contributors to the health of nations. Lancet. 2012 Jul 7;380(9836):59-64. ) is good for the digestive system, as long as you’re not obsessed with the clock and don’t push yourself too hard. ¹

The same applies to the gut mucosa that lines the walls of our digestive tract. Sport in moderation thus goes hand in hand with a healthy mucosa that perfectly fulfills its barrier function. ¹

Your microbiota needs exercise, so get your sneakers on.

Is this a direct consequence of good digestive health? Moderate exercise keeps your gut microbiota in top form. Physical exercise therefore ticks all the right boxes ¹ :

• it improves the composition and functioning of the gut microbiota, promoting the establishment of a rich and beneficial flora; 
• it promotes the synthesis of molecules that modulate immunity and others with antimicrobial properties that effectively protect against pathogen attack. 

These initial research findings should encourage you to get off the couch. Doing a little exercise leads to greater diversity in the Firmicutes bacterial phylum, contributing to a healthier gut environment. ² Sedentary teenagers who take up half an hour of moderate-intensity running, four times a week, have a modified flora (and reduced moodiness), with an increased abundance of Coprococcus and Blautia. ³ Make sure to exercise regularly: professional rugby players boast a healthy microbiota. ^4,5

Lastly, there appears to be a link with the intensity of practice ⁶ : the higher the level of martial artists, the more diverse and rich in beneficial bacteria their gut microbiota. 

Physical exercise is even said to have therapeutic value: at moderate intensity, exercise seems to effectively reduce irritable bowel syndrome (from which many endurance athletes suffer). Another reason to take up regular exercise. ¹

Exercise, but not to excess.

Burn calories, but not at any price. As with everything, too much can be harmful: 60 minutes of very intense endurance training (at 70% of VO2max (sidenote: VO2max A criterion specific to each athlete, VO2max is the maximum quantity of oxygen that the body can extract from the air and transport to the muscle fibers to meet their needs during exercise. The higher the VO2max, the better the performance. When this criterion is low, sporting ability is limited, and specific training will be needed to boost it. )  capacity) leads to abdominal pain, nausea, and diarrhea. ¹ Other factors, such as altitude, ambient temperature, poor hydration, and age, also appear to influence levels of discomfort.

Runners are twice as exposed as those practicing other endurance sports, such as cycling or swimming. Most affected are sticklers for discipline, with the phenomenon 1.5 to 3 times more common among elite athletes (sidenote: Athlete A competitive sportsman or sportswoman who strives for a high level of performance through training.
Source: Rousseau AS. Nutrition, santé et performance du sportif d’endurance / Nutrition, health and performance of endurance athletes. Cahiers de Nutrition et Diététique. 2022 eb ;57(1) : 78-94 ) than among amateurs. ¹ 30%-50% of athletes suffer from digestive problems, which rises to 90% for those taking part in ultra-endurance challenges (sidenote: Ultra-endurance challenges Extreme events often lasting more than six hours and covering over 100 km (or much more), at times in difficult conditions. For example, the Ironman triathlon covers 226 km in total, including a 3.8 km swim, a 180.2 km bike ride, and a 42.195 km marathon on the same day; the Race Across America is 4,860-km bike race that must be completed in a maximum of 12 days; and the Iditarod Trail Invitational sees participants run, bike, and ski their way through 1,600 km of snow in Alaska. ) . ⁷ Images of marathon runners suffering from mid-race diarrhea are easy to find online.

What explains this epidemic of gastrointestinal disorders among athletes? The fact that their bodies dedicate all their energy to providing muscles with needed oxygen. Intense physical exercise causes the blood system to go into overdrive, with instructions given to immediately redistribute blood flow to the muscles, to the detriment of our gut and digestive system. At the same time, the body activates our sympathetic nervous system, which makes our heart beat faster when we’re scared, affecting transit. This dual mechanism explains the pain, nausea, and diarrhea. ⁷

The main concern is that the troubled digestive system causes the microbiota it hosts to become unwell. So, whether you’re an amateur or a professional, training too hard, or disproportionately to your physical level, can change the composition and function of your microbiota, which is known as dysbiosis.

The more intense the physical activity, the more rapid and profound the disturbance. ⁸ The result is increased gut permeability, where the membrane of the digestive tract can no longer act as barrier and border guard. Bacterial toxins and pro-inflammatory molecules can then enter the athlete’s body, potentially impacting overall health. ¹

Why is regular physical activity important for our health? Why is it so hard to get (back) into exercising?

A sedentary lifestyle (sidenote: Sedentary lifestyle “Waking behavior characterized by an energy expenditure close to the resting energy expenditure in a sitting or lying position.” Example: time spent sitting or lying down during the day outside sleep time, whether at work or school, on motorized transport, or during leisure activities, particularly in front of screens.
Source: OMS, Organisation mondiale de la Santé. Lignes directrices de l’OMS sur l’activité physique et la sédentarité: en un coup d’œil. 2020 Nov 25. 17 pages. ISBN: 9789240014862 )  seriously damages your health: insufficient physical activity is associated with a 20% to 30% increased risk of death.¹ Conversely, regular physical activity (sidenote: Physical activity Any bodily movement produced by skeletal muscle contraction resulting in an increase in energy expenditure (EE) relative to resting EE”. Examples of physical activity include walking, cycling, active play, sports, housework, gardening, and DIY. Source: Caspersen CJ, Powell KE, Christenson GM. Physical activity, exercise, and physical fitness: definitions and distinctions for health-related research. Public Health Rep. 1985 Mar-Apr;100(2):126-31. )  is associated with multiple muscular, cardiorespiratory, cardiovascular, bone, and weight management benefits.¹ However, it’s not always easy to get (back) into it.

Practicing an endurance sport (sidenote: Sport Structured leisure-time physical activity which may include physical exercise where participants adhere to a common set of rules (or expectations) and where a goal is defined.
Source: Khan KM, Thompson AM, Blair SN et al. Sport and exercise as contributors to the health of nations. Lancet. 2012 Jul 7;380(9836):59-64. ) , whether running, cycling, swimming, or aerobics, requires a number of physiological adaptations from the body, and not just in the muscles. Prolonged physical activity:

• induces a loss of water and electrolytes (notably sodium and chlorine) through sweating, which is designed to cool the body; 
• depletes reserves of glycogen (sidenote: Glycogen A form of carbohydrate (“sugar”) storage in the body, mainly in the liver and muscles. ) , used to feed our moving muscles; 
• increases inflammation due to the stress of exertion, etc.

While this is all for a good cause, it can be quite a challenge for the body; but here the gut microbiota may come very much in hand.

Does microbiota help improve our sporting performance?

Incredible as it may seem, recent scientific studies have shown that our gut microbiota helps us overcome the hydration, energy, and inflammatory challenges posed by sporting activity.

As you’re well aware, for sustained physical effort, hydration is key. In fact, certain gut bacteria may help transport fluids and solutes across the gut barrier, thereby maintaining hydration.

Another essential ingredient for sport and performance is energy. Here once again our gut flora gives us a boost, by helping muscles that have run down their glycogen reserves during endurance sports. Bacteria in the gut microbiota ferment fibers that our body is unable to digest, extracting valuable short-chain fatty acids (SCFAs (sidenote: Short chain fatty acids (SCFA) Short chain fatty acids (SCFA) are a source of energy (fuel) for an individual’s cells. They interact with the immune system and are involved in communication between the intestine and the brain. Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25. ) ) that serve as an emergency fuel for muscles during exercise. ²

The effects of this energy boost are far from negligible: SCFAs provide more than 10% of humans’ daily caloric requirements. ³ The benefits of SCFAs go much further, since they promote the storage of glycogen reserves in muscles prior to exercise, delaying the time when the body requires emergency fuel. ²

Lastly, SCFAs are also thought to reduce inflammation induced by intense physical effort. ^{2, 4, 5}

At times, the mechanism is particularly ingenious, with bacteria transforming a waste product of the athlete (sidenote: Athlete A competitive sportsman or sportswoman who strives for a high level of performance through training.
Source: Rousseau AS. Nutrition, santé et performance du sportif d’endurance / Nutrition, health and performance of endurance athletes. Cahiers de Nutrition et Diététique. 2022 eb ;57(1) : 78-94 ) ’s metabolism into a useful resource. This seems to be the case with the gut bacterium Veillonella atypica, which is associated with the performance of marathon runners. ⁶

How is this possible? When runners’ muscles have used up all their glycogen reserves, they start fermenting to produce energy, which produces a waste product called lactate (the cause of cramps). This is when good old Veillonella comes into play, by transforming lactate into propionate, which the muscles use as an energy source. Thus the athlete’s performance is naturally boosted. ⁷

However, to benefit from these “boost” molecules, you need the right bacteria in your digestive tract, and you must feed them appropriately. Without them, micro-organisms can even generate products that are harmful to our performance. ^2,4,7

It's a faithful relationship. For the third year, Biocodex Microbiota Institute is celebrating World Microbiome Day running with two objectives: raise awareness among lay public about the importance of microbiota and valorize microbiota research through the Biocodex Microbiota Foundation national grant winners.

A look back at the latest microbiota research rewarded by Biocodex Microbiota Foundation

They are scientists, professors, physicians specialized in different specialties (gastroenterology, pediatrics, neurology, cardiology, microbiology, pharmacokinetics…). They come from Portugal, Finland, Belgium, Mexico, United States… They have made major advances in the role of the microbiota on health and associated diseases… And they all have won the Biocodex Microbiota Foundation national’s grant!

Since 2017, The Biocodex Microbiota Foundation rewards national research initiatives which aim to understand the interaction between microbiota and different diseases. On World Microbiome Day 2022, in order to give visibility to researchers, the Biocodex Microbiota Institute gives the floor to the national grant winners through dedicated interviews.

What did the Biocodex Microbiota Foundation national research grant allow them to do? What impact have their research results on patient care? Available on the HCPs’ dedicated section, these testimonies give us a clear idea of the variety and diversity of research projects currently underway. These interviews will be activated via the Institute Twitter’s account during 10 days and Biocodex Microbiota Foundation’s LinkedIn by June 27st. Don’t hesitate to share and spread the good new!

About the Biocodex Microbiota Institute

The Biocodex Microbiota Institute is an international hub of knowledge dedicated to microbiota. The Institute educates the lay public and healthcare professionals on the importance of microbiota on healthcare and well-being.

About the Biocodex Microbiota Foundation

Since 2017, the Biocodex Microbiota Foundation has been working to improve science's understanding of the human microbiota. Each year, the Foundation contributes to the funding of global research on microbiota via grants awarded to innovative scientific research projects. Calls for projects are regularly launched on a specific theme related to the microbiota, with the most promising projects then selected by an international scientific committee made up of independent experts.

BMI-22.38

Practical and discreet, tampons and menstrual cups are widely used by women during their period. But there's a downside, especially when these devices aren't changed regularly: blood stagnates, creating a favorable environment for bacteria to multiply. And if the bacteria include S. aureus, there is a risk of menstrual TSS.

Often found on the skin, but more rarely in the vagina, S. aureus secretes a particularly virulent toxin capable of attacking our most vital organs, such as the liver, kidneys and lungs. It all starts with a high fever and/or rash, sometimes accompanied by a drop in blood pressure. In cases where the toxin reaches the organs and causes them to fail, coma and death are possible. ¹

Simple steps to avoid menstrual TSS

Fortunately, menstrual TSS is rare. Today, 1 to 3 out of every 100,000 women using intravaginal devices (tampons, cups) are thought to be affected in the United States. Far fewer than in the 1980s, when the marketing of highly absorbent carboxymethylcellulose tampons led to an epidemic of cases (10 women per 100,000). Their withdrawal in favor of cellulose or cotton fiber tampons has helped bring the numbers down. ²

The role of vaginal microbiota

Finally, a recent study suggests that vaginal microbiota also play a part in prevention. ¹ Not all women have the same vaginal microbiota, and there are five main types:

• Three are considered healthy, dominated by Lactobacillus crispatus, L. gasseri and L. jensenii, respectively; 
• one is considered a transitional state, dominated by L. iners ; 
• one is deemed unbalanced, composed of a wide variety of bacteria including Gardnerella vaginalis, and associated with bacterial vaginosis.

A recent study shows that the last two types could make TSS more likely. Conversely, microbiota dominated by L. crispatus, L. gasseri and L. jensenii seem to be protective, because they acidify the vaginal environment (which S. aureus does not appreciate), and probably also via other complex mechanisms. The bacterium L. jensenii is particularly protective. The study even sees it as a potential probiotic for women who have already experienced TSS and want to prevent a recurrence.

High fever and rash, hypotension and even multiple organ failure: although rare, menstrual TSS can be life-threatening for the women affected, often young girls. At the heart of this infection is the bacterium Staphylococcus aureus, which produces the toxin TSST-1 (toxic shock syndrome toxin-1). The production of this toxin depends on the vaginal environment: favorable conditions include the presence of oxygen (increased by tampons and cups), a low concentration of glucose, and a neutral pH. Hence the protective role of the vaginal microbiota, characterized by a prominence of lactobacilli, which acidify the vaginal environment.

But the drop in estrogen and the lower concentration of vaginal glucose (linked to loss of mucous membrane) at the onset of menstruation reduce the abundance of these lactobacilli. Could these conditions make menstrual TSS more likely? To find out more, researchers ¹ simulated different vaginal environments in vitro to measure their effects on TSST-1 production.

Mimicking vaginal flora in vitro

Before delving further into the experiments conducted, let's recall that in women, five major types of vaginal flora (community state types or CST) have been identified:

• Three are considered healthy, dominated by Lactobacillus crispatus (CST-I), L. gasseri (CST-II) and L. jensenii (CST-V), ; 
• one is considered transitional, dominated by L. iners (CST-III) ; 
• and one is deemed dysbiotic and associated with bacterial vaginosis, composed of a polymicrobial community including Gardnerella vaginalis (CST-IV). 

The researchers therefore created vaginal environments representative of these five types and varied the glucose concentrations in them. 

Protective conditions and bacteria

At high sugar concentrations, toxin production by S. aureus was greatly reduced, repressed by carbon catabolite control protein A (CcpA). But vaginal microbiota also seemed to play an important role. A comparison of the different flora types shows that toxin production may be increased when the flora is transitional (III) or dysbiotic (IV); these two flora types may also promote the inflammation generated by S. aureus.

Conversely, L. crispatus and L. jensenii limited toxin production, whether in the presence or absence of glucose. L. jensenii even proved capable of blocking toxin production in the strong presence of oxygen, and reducing the virulence of S. aureus. This makes it the most protective of the lactobacilli studied. For the authors, it would also be the best candidate in the search for a probiotic for women who have already experienced TSS and want to prevent a recurrence.

The noose tightens around glyphosate Classified as a “probable carcinogen” by the International Agency for Research on Cancer (IARC) – but not by regulatory agencies (see text box) – and suspected of being an endocrine disruptor, glyphosate may also cause various neurodevelopmental and neurobehavioral disorders.

So suggests an analysis by a team of Belgian and Polish researchers, who sifted through studies on the toxic effects of glyphosate (experiments on cell cultures and animal models, clinical cases, epidemiological studies, etc.). ¹

According to them, glyphosate (sidenote: Glyphosate Glyphosate is the active compound in Roundup, a “broad-spectrum” weedkiller introduced by Monsanto in 1974. It kills all weeds by blocking the 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase enzyme, which is involved in the synthesis of certain amino acids essential to their growth. Extremely effective, easy to use, and inexpensive, glyphosate is the most widely used pesticide in the world. Three hundred and fifty million hectares of crops in 140 countries are currently treated with glyphosate. It is considered a probable human carcinogen by the International Agency for Research on Cancer (IARC) and is also thought to be an endocrine disruptor (although this remains controversial). Since 2000, when its patent expired, it has been used in a large number of agricultural herbicides. In several countries, including France, the Netherlands, and Belgium, it is banned for private use and in public spaces. )  and its metabolites, such as aminomethylphosphonic acid (AMPA), the adjuvants found in the composition of glyphosate-based herbicides (surfactants), or the heavy metals in these preparations, exert what they describe as “devastating” effects at various levels.

Gut microbiota

Scientific studies on animals have shown that prolonged exposure to glyphosate-based herbicides leads to a change in the composition of the gut microbiota that favors pathogenic bacteria. 

A 16S rRNA analysis of 141 bacterial families showed a deviation in the Firmicutes-to-Bacteroidetes ratio, a significant marker of dysbiosis (sidenote: Dysbiosis Generally defined as an alteration in the composition and function of the microbiota caused by a combination of environmental and individual-specific factors. Levy M, Kolodziejczyk AA, Thaiss CA, et al. Dysbiosis and the immune system. Nat Rev Immunol. 2017;17(4):219-232.   ) , as well as a decrease in the abundance of beneficial bacteria, such as Enterococcus spp. and Bacillus spp. Some pathogenic bacteria, such as E. coli, Salmonella spp., and Clostridia spp. also became resistant to glyphosate as a result of this exposure.

In the studies, these changes in the microbiota were associated with increased oxidative stress and inflammation levels. Glyphosate exposure may also cause anatomical changes in the jejunum and duodenum.

Gut-brain axis

By destabilizing the gut microbiota, glyphosate herbicides appear capable of disrupting the functioning of the gut-brain axis, mediated by the vagus nerve, as well as that of the hypothalamic–pituitary axis. This may lead to neuronal and endocrine dysfunction, with multiple hormonal, emotional, cognitive, or behavioral consequences.

Neurons

Glyphosate may cause a variety of neuronal disturbances, which may or may not be linked to the microbiota and the gut-brain axis. Individuals with high exposure (farmers and chemical plant workers) are known to be at greater risk of neurodegenerative diseases. These diseases may be linked to a decrease in axon projections from neurons and the degeneration of the myelin sheath of motor and sensory nerves caused by glyphosate. Glyphosate also appears to inhibit neuronal differentiation and growth, with the disappearance of certain axon branches and dendritic underdevelopment potentially leading to neuromuscular and locomotor disabilities.

Blood-brain barrier (BBB)

The BBB is a selectively permeable membrane that regulates the transport of molecules, immune cells, xenobiotics, and pathogens between blood vessels and the microenvironment of the central nervous system, thus contributing to paracrine and endocrine signaling. In co-cultures of endothelial cells and neurons (a model for studying the BBB), exposure to glyphosate for 24 hours had a range of adverse effects, including the depletion of tight junction proteins, increased vascular permeability, and altered neuronal activity.

Nerve communication

As an organophosphate, glyphosate inhibits the enzyme acetylcholinesterase, which may lead to paralysis, memory impairment, psychomotor disorders, and anxiety. 

A study of adolescents living in agricultural regions of the Andes found a correlation between acetylcholinesterase markers and depression. Glyphosate herbicides may also cause a disruption to monoaminergic transmission linked to major depression. 

The French Gut is part of a vast international project, the "Million Microbiome of Humans Project" (MMHP), which brings together several research institutes around the world. The MMHP's ambition is to create the world's largest database on human microbiota, by collecting one million microbial samples from the intestines, mouth, skin and reproductive tract of volunteer subjects. The French Gut, led by INRAE in partnership with public and private players involved in the microbiota field, will make a significant contribution to the development of this international database by collecting 100,000 French intestinal metagenomes.

The French Gut can count on the strong support of the Biocodex Microbiota Institute. The objectives of this project are to recruit 100,000 participants, and to raise awareness among the general public, including healthcare professionals, of the fascinating powers of the intestinal microbiota, particularly its role in the onset of a number of pathologies.

A shared objective: to highlight the importance of the effects of the intestinal microbiota on our health

The Biocodex Microbiota Institute shares the same ambition as Le French Gut: to raise awareness among the general public and train healthcare professionals in the major importance of the microbiota, particularly the impact of dysbiosis on our health. Since 2017, the Biocodex Microbiota Institute:

BMI 22.46

Microorganisms are living beings invisible to the naked eye, sometimes called “microbes” or “germs”. They’re generally made up of a single cell and can be found everywhere: from the depths of the ocean to the bottom of our gut, in the air, soil, plants, and rivers.

Microorganisms: tireless workers behind the scene 

Microorganisms are essential to life on Earth thanks to their superpowers. These include a key role in the decomposition of plant and animal waste, or in carbon and nitrogen fixation. They’re essential links in the functioning of terrestrial ecosystems and key to the health of living beings.

Our bodies, too, form a true ecosystem, where populations of billions of “friendly” microorganisms live in harmony, providing us with a vast range of services. These populations are known as our “flora” or “microbiota (sidenote: Microbiota Microbiota are the communities of microorganisms – mainly bacteria, but also viruses, fungi, and archaea – that colonize the human body. The type, number, and distribution of these microorganisms vary considerably from one area of the body to another. The gut microbiota – also known as the gut flora – contains the largest number of microorganisms. The gut microbiota is also the most studied. In humans, microbiota are also found in the vagina (vaginal microbiota), on the surface of the skin (skin microbiota), in the urinary tract (urinary microbiota) and respiratory tract (pulmonary microbiota), and in the ear-nose-throat area (ENT microbiota). These numerous microbiota interact with each other and take part in digestive, metabolic, immune, and neurological functions. ) ”. This type of microbial community can be found not only in animals and plants, but also in soils and the oceans¹.

Microbiota are the communities of microorganisms – mainly bacteria, but also viruses, fungi, and archaea – that colonize the human body.

The gut microbiota – also known as the gut flora – contains the largest number of microorganisms. It is also the most studied.

A bacterium for every service rendered to mankind

• By fixing atmospheric nitrogen in the soil at the root of legumes, Rhizobium bacteria promote their growth while limiting the need for chemical fertilizers;
• Bacteria Lactobacillus acidophilus and Streptococcus thermophilus transform milk into yogurt;
• The fungus Penicillium roqueforti transforms curdled and fermented milk into blue cheese or Roquefort;
• Viruses called “phages” allow us to cure certain infections caused by antibiotic-resistant bacteria;
• The yeast Saccharomyces cerevisiae transforms sugars from wheat or barley into alcohol to make beer;
• Lastly, a collection of bacteria, fungi, and archaea allow water purification in wastewater treatment plants.

The saga of microorganisms

• 3.4 to 3.7 billion years ago: Appearance of the first bacteria and archaea (the first forms of life on Earth).
• 1665: English scientist Robert Hooke observes microorganisms (mold) under the microscope for the first time.
• 1674: Dutch draper Antonie van Leeuwenhoek observes bacteria under the microscope for the first time, naming them “animalcules”.
• 1838: German naturalist and zoologist Christian Gottfried Ehrenberg coins the term “bacteria”.
• 1857: Louis Pasteur demonstrates the role of bacteria in fermentation.
• 1882: Robert Koch discovers the bacillus responsible for tuberculosis.
• 1918: Spanish flu epidemic caused by the H1N1 virus (25 million deaths).
• 1930: First observation of a virus using an electron microscope.
• 1917: Félix d’Hérelle and Frederick Twort discover bacteriophages.
• 1929: Alexander Fleming discovers penicillin (antibiotic).
• 1977: Carl Woese discovers bacterial archaea.
• 1995: Craig Venter’s team sequences the first bacterial genome in its entirety.
• 2019: COVID-19 pandemic (SARS-CoV-2 virus).

If you thought microbes were only fit to be eliminated, by now you can see you were wrong. The vast majority of microbes are essential to human life and activity. They’re also essential to the functioning of our body and to good health.

Mutually beneficial value exchange^{3, 7, 8}

Our bodies are home to a varied multitude of “commensal” microorganisms – as opposed to pathogenic microorganisms – with which we have a truly symbiotic relationship. In exchange for food and shelter, these microbes provide us with invaluable services.

In the gut, bacteria in the microbiota feed on dietary fiber – which we’re unable to break down – and release essential compounds known as “short-chain fatty acids (sidenote: Short chain fatty acids (SCFA) Short chain fatty acids (SCFA) are a source of energy (fuel) for an individual’s cells. They interact with the immune system and are involved in communication between the intestine and the brain. Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25. ) ”. These molecules nourish gut cells, contributing to their growth and differentiation, and reinforcing their barrier function. Microbes also synthesize useful bioactive substances, such as amino acids and vitamins (K2, B5, B6, etc.).

They also play a role in the maturation of immune cells, particularly numerous in the gut wall, and, by occupying the terrain and synthesizing certain antibacterial proteins called bacteriocins, protect us against the proliferation of pathogenic microorganisms. Lastly, they synthesize metabolites (sidenote: Metabolites Small molecules produced during cellular or bacterial metabolism. For example, short-chain fatty acids are metabolites produced by intestinal microbiota during fermentation of non-digestible complex carbohydrates (fibers, etc.). Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25.  Lamichhane S, Sen P, Dickens AM, et al An overview of metabolomics data analysis: current tools and future perspectives. Comprehensive analytical chemistry. 2018 ; 82: 387-413 ) capable of regulating some of our physiological functions, notably our immune and neuronal functions. For example, the microbiota and the brain are in permanent communication via the so-called microbiota-gut-brain axis.

How to pamper your microbes ^{3, 7, 8}

The health of our microbiota depends on many factors: genetics, age, living environment, mode of birth, etc. But the most powerful modulator of the gut microbiota remains our diet. A “healthy” microbiota, i.e. one that is rich and diversified, requires a diet that includes a sufficient variety of plants (fruits, vegetables, oilseeds, whole grains, legumes, etc., which provide the right “substrates”, or food, for the microorganisms), as well as live bacteria (fermented foods such as sauerkraut, kombucha, kefir, etc.).

Our diet should not include too many harmful foods, such as those containing emulsifiers and sweeteners. 

Cutting back on certain medications (antibiotics, antacids, laxatives, anxiolytics, etc.), moderating alcohol and tobacco consumption, and regular physical activity are also excellent ways to promote a healthy microbiota.
 

Microbes are responsible for a multitude of infectious diseases: the rhinovirus for colds, the SARS-CoV-2 virus for COVID-19, the Salmonella bacterium for gastroenteritis, the Candida fungus for candidiasis, etc. Fortunately, we now have antimicrobials (antibiotics, antivirals, antifungals, etc.) that can treat the majority of infections caused by microorganisms.

Recognized as a public health issue by the WHO, antimicrobial resistance may kill up to 10 million people per year by 2050 (as many as cancer).¹⁰ The WHO recommends limiting the use of antimicrobials, particularly antibiotics, in livestock farming, human healthcare, and agriculture, but above all calls for new, more effective treatments for infections.

Imbalances: the breeding ground for lifestyle diseases ^{3, 5, 8}

Microorganisms aren’t only responsible for infectious diseases. Did you know that microorganisms also play a role in obesity, diabetes, osteoporosis, cancer, vascular diseases, and neurodegenerative diseases (Parkinson’s, Alzheimer’s, etc.) ?

Studies show that people suffering from these illnesses have an imbalance in their microbiota known as “dysbiosis (sidenote: Dysbiosis Generally defined as an alteration in the composition and function of the microbiota caused by a combination of environmental and individual-specific factors. Levy M, Kolodziejczyk AA, Thaiss CA, et al. Dysbiosis and the immune system. Nat Rev Immunol. 2017;17(4):219-232.   ) ”. Dysbiosis is characterized by a loss of richness and diversity in microbial populations, particularly in the gut. Numerous studies have shown that such imbalances can have a negative impact on the way our body functions, and can contribute to the onset or aggravation of disease.

The data currently available fail to give a precise answer as to whether dysbiosis causes disease or disease causes dysbiosis. However, studies suggest that it may be possible to maintain good health by ensuring the microbiota is rich and diversified, i.e. “healthy”, or by rebalancing it.

Modulate the microbiota to prevent or even cure disease!

There are several ways to positively modulate the gut microbiota in cases of dysbiosis or disease ^{3, 7} :

• Diet and lifestyle (see above);
• Prebiotics (inulin, galactooligosaccharides [GOS], fructooligosaccharides [FOS], and lactulose): these compounds are capable of specifically feeding groups of beneficial bacteria, such as Bifidobacterium and Lactobacillus, thus encouraging their proliferation¹¹;
• Probiotics (specific strains of live bacteria or yeast with proven health benefits): to date, scientific evidence of their efficacy is limited to childhood diarrhea, antibiotic-associated diarrhea, certain inflammatory bowel diseases, and necrotizing enterocolitis, but their therapeutic potential is the subject of much research^11.
• Bioactive metabolites (sidenote: Metabolites Small molecules produced during cellular or bacterial metabolism. For example, short-chain fatty acids are metabolites produced by intestinal microbiota during fermentation of non-digestible complex carbohydrates (fibers, etc.). Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25.  Lamichhane S, Sen P, Dickens AM, et al An overview of metabolomics data analysis: current tools and future perspectives. Comprehensive analytical chemistry. 2018 ; 82: 387-413 ) : have the ability to modulate the physiology of target microorganisms;
• Fecal microbiota transplantation (FMT): involves transferring the gut microbiota of a healthy person into the gut of a sick person. For example, FMT has shown particularly solid results (90% cure rate) for Clostridium difficile infections¹² but may also be useful for alleviating the symptoms of autism ¹³.

Microorganisms are a valuable field of research for scientists. For example, in order to better combat bacterial resistance to antibiotics and develop monitoring tools, scientists need a better understanding of how bacteria exchange genes, how they acquire antimicrobial resistance, and the pathways by which this resistance circulates between the environment, humans, and animals¹⁰.

High-resolution genomics and metagenomics techniques, widely used in human microbiota studies, are powerful tools for exploring microbial dynamics.

Microbiota at the crossroads of research

An ever-increasing number of studies seek to improve our understanding of how microorganisms in the microbiota interact with humans and contribute to the proper functioning of human cells, and to reveal which microbial profiles are most beneficial to health, and which modifications contribute to disease³.

The ultimate goal is to identify new therapeutic avenues and new probiotic bacteria that will make it possible to modulate the microbiota and thus manage certain acute and chronic illnesses more effectively.

As you can see, although microorganisms are invisible and have a bad reputation, they deserve our full respect and attention, since they’re essential to our lives. 

Much mystery still surrounds the communities they form, their interactions with the environment, and the role they play in our organism, but not a day goes by without a new study showing the importance of having them on our side, and thus of strengthening our symbiosis with them.

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Riddle me this: I’m the most widely used herbicide in the world. I’m considered a probable carcinogen by the WHO. Yet I’ve just been re-approved in Europe for ten years. Who am I? 

Answer: Glyphosate.

If you knew the answer, congratulations! However, these three pieces of information are only scratching the surface for glyphosate (sidenote: Glyphosate Glyphosate is the active compound in Roundup, a “broad-spectrum” weedkiller introduced by Monsanto in 1974. It kills all weeds by blocking the EPSPS enzyme, which is involved in the synthesis of certain amino acids essential to their growth. Extremely effective, easy to use, and inexpensive, glyphosate is the most widely used pesticide in the world. It is considered a probable human carcinogen by the International Agency for Research on Cancer (IARC) and is also thought to be an endocrine disruptor (although this remains controversial). Since 2000, when its patent expired, it has been used in a large number of agricultural herbicides. In several countries, including France, the Netherlands, and Belgium, it is banned for private use and in public spaces.
  Source: Muséum d’Histoire Naturelle and Inrae ) ,  a compound now found everywhere, whether in water, the air, or the food we eat, particularly cereals and legumes. ¹

According to a review of studies into the consequences of exposure to glyphosate and the herbicides that contain it, the compound’s effects on the microbiota and brain are “devastating.” ²

Gut bacteria severely disturbed

For example, several studies on animals show that even at low doses, glyphosate increases gut pathogenic bacteria, reduces beneficial bacteria, and strongly impacts the abundance of two major bacterial groups, Firmicutes and Bacteroidetes.

We know that maintaining an adequate Firmicutes-to-Bacteroidetes ratio is a key factor in microbiota balance, and that a variation in this ratio is a marker of dysbiosis (sidenote: Dysbiosis Generally defined as an alteration in the composition and function of the microbiota caused by a combination of environmental and individual-specific factors. Levy M, Kolodziejczyk AA, Thaiss CA, et al. Dysbiosis and the immune system. Nat Rev Immunol. 2017;17(4):219-232.   ) , an imbalance involved in various disorders and diseases.

Glyphosate is also thought to strongly destabilize the gut-brain axis, which is known to influence our behavior, memory, and emotions, as well as our immunity and hormones. A number of studies suggest that, in both rodents and humans, exposure to this herbicide disrupts the gut bacteria involved in the gut-brain axis, particularly those that play a beneficial role against certain mood disorders.

Impact on the entire nervous system

But that’s not all. Glyphosate may also have a significant impact on the blood-brain barrier (the membrane that protects the brain) and could alter the formation and survival of neurons, as well as the transmission of nerve impulses. This could have significant consequences for:

• mental health: anxiety, depression,  suicidal thoughts, etc.;
• cognitive and social abilities: memory impairment, abnormal social or exploratory behavior, etc.; 
• locomotion: paralysis, psychomotor disorders, etc.;
• the risk of neurodegenerative diseases: Parkinson, Alzheimer or Huntington’s disease, multiple sclerosis, etc.

While this summary raises more questions than it answers, it underlines the fact that further work is required to accurately assess the health risks of exposure to glyphosate. Since glyphosate is currently still widely used in many countries, this represents a global public health issue.

Experience the exhibition inauguration 

Discover the photo exhibition

The Biocodex Microbiota Institute entrusted photographer Laurent Hini with the delicate task of unveiling the mechanisms at work.

The project was conceived as a confrontation between a wide-angle photograph of the athlete and an image representing his “microbiota coach”. For the microbiota, a mixed photo and generative visual AI technique was used to materialize the microbiota's function. The action portrait is created using “classic” photographic techniques. Artificial intelligence does not replace photography, but is hybridized with it. It gives substance to the “microbiota coach”. The entire exhibition is based on this balance between the representative and the non-figurative, between the perceptible (the athlete) and the concealed (his microbiota).

Each diptych was then assigned a chromatic dominant: red for energy, orange for balance, white for defense... Color plays an important role in the exhibition: it links the two sections of each diptych and acts as a signpost, guiding the visitor through the exhibition. And it accentuates the plunge into the heart of each microbiota.

In all, we have 5 large-format diptychs for 5 sports associated with 5 microbiota functions. Dive into the heart of each microbiota!

Breakdance, balance 

With Paola Soares da Silva
Did you know? Our microbiota is made up of hundreds of billions of living micro-organisms, invisible to the naked eye. These micro-organisms, such as bacteria, yeasts, viruses, fungi and parasites, cohabit in symbiosis with our bodies, working together to maintain our balanced gut microbiota (or gut flora). A balanced microbiota is characterized by a diversity and abundance of micro-organisms. Microbiota diversity is a key indicator of our health. But this balance remains fragile, and we need to take care of it. Numerous scientific studies show that regular physical activity increases intestinal bacterial diversity in favor of beneficial species. Sport therefore contributes to the balance of the microbiota, preserving this symbiosis essential to our health and well-being.

Basketball, resilience 

With Sidney Attiogbé

Small, invisible... but very resistant! A high-fat diet, stress, infections... A variety of factors can upset the balance of the intestinal microbiota (known as dysbiosis). The good news is that the intestinal microbiota is resilient, i.e. capable of recovering from disruption. Another piece of good news is that physical exercise has been shown to contribute to this resilience. Intense physical exercise is correlated with oxidative stress (a natural phenomenon linked to the production of free radicals in the body). The resilience of the microbiota is essential in more ways than one: it contributes to good digestion and nutrient absorption, combats oxidative stress and inflammation, and strengthens the immune system and helps prevent certain diseases. Convinced? Then get your sneakers!

Rugby, energy 

With Jonathan Laugel and Maxime François

Need a tonic? Tap into your intestinal microbiota! Bacteria in the intestinal microbiota play an important role in energy production for athletes. How do they do it? The intestinal microbiota ferments complex carbohydrates from the diet, which in turn produce short-chain fatty acids (sidenote: Short chain fatty acids (SCFA) Short chain fatty acids (SCFA) are a source of energy (fuel) for an individual’s cells. They interact with the immune system and are involved in communication between the intestine and the brain. Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25. ) (SCFAs), recognized as a vital source of energy for intestinal cells and other body tissues. These in turn contribute to endurance and recovery during exercise. A virtuous circle!

Surfing and hydration 

With Ainhoa Leiceaga
Water, source of life. Hydration is essential for everyone, but even more so for athletes, whose performance and recovery depend on optimal water intake. The intestinal microbiota transports water and electrolytes - minerals that help stabilize the body's hydration level - through the intestinal wall. Scientific studies have shown that the composition of the intestinal microbiota influences the absorption of sodium and other solutes essential for hydration in the blood, thus contributing to hydration. Athletes are at greater risk of dehydration due to the heavy perspiration associated with exercise. A balanced microbiota therefore contributes to the integrity of the intestinal barrier and good hydration of the body, both of which are essential for sports performance.

Judo, defense 

With Raymond Demoniere

Attack and counter-attack! The intestinal microbiota acts as a shield against attacks by pathogenic (sidenote: Pathogens A pathogen is a microorganism that causes, or may cause, disease. Pirofski LA, Casadevall A. Q and A: What is a pathogen? A question that begs the point. BMC Biol. 2012 Jan 31;10:6. ) bacteria. How does it do this? Bacteria are in constant dialogue with the intestinal immune system, enabling it to be on constant alert and, if necessary, to protect the intestinal barrier. Activation of the immune response plays a key role in endurance. Surpass yourself, yes, but first protect yourself! There is a relationship between the intensity of sport and the alteration of the host's immune response. Recent research suggests that the intestinal microbiota may help counter the inflammatory responses triggered by intense exercise. Athletes with a specific gut microbiota composition showed a lower inflammatory state. These anti-inflammatory effects of intestinal microbiota would delay symptoms of fatigue during endurance exercise. Let's hear it! 

A word from the Institute's Scientific Director

This project was born of this questioning... and of an opportunity: the arrival of a year 2024 rich in sporting events in Paris! We immersed ourselves in scientific studies demonstrating the bidirectional relationship between microbiota and physical activity. Hydration, defense, balance, energy and resilience: in these five key functions of our body, the microbiota plays the role of an invisible coach. With the scientific foundations in place, we now needed to reach as many people as possible with a major challenge: making the invisible visible. Photography, combined with artificial intelligence, seemed the best way to illustrate the formidable powers of the microbiota. Invisible but solid! 

Thanks to all the athletes who took part in the project. 

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