This is the 100th blog post! And to celebrate, nothing better than sharing 100 concepts to know about the different subjects of our profession: the intestinal microbiota, probiotics and prebiotics.

Intestinal microbiota

1.The most talked about microbiota is the intestinal microbiota


2.However, there are other microbiota: oral, skin, vaginal, pulmonary


3.Nevertheless, 95% of our bacteria are concentrated in the gastrointestinal tract


4.The gut microbiota is made up of about 100,000 billion microorganisms


5.Which represents almost 10 times the number of human cells


6.These bacteria are 10 to 50 times smaller than our cells


7.Bacteria, fungi, viruses and parasites are the main constituents of the microbiota


8.There are on average 800 to 1000 different bacterial species in the gut microbiota


9.Contains nearly 3.3 million genes


10.Meaning 150 times more genes than the human genome


11.Its mass is estimated at 1-2 kg


12.It is acquired at birth, due to the immaturity of the newborn’s immune system


13.Everyone’s microbiota is unique, it can be likened to an identity card or a fingerprint


14.This is explained by the fact that one third of the microorganisms making up the microbiota are common to all, while the remaining two thirds are specific to each


15.It is at the age of 2-3 years that the intestinal microbiota is considered mature


16.Its wealth and diversity can be affected by many factors


17.Indeed, diet, mode of delivery, gestational age, maternal flora, lifestyle, taking medications influence the composition of the intestinal microbiota


18.It is relatively stable over time, although it may evolve transiently


19.Within the intestinal microbiota, there is a dominant microbiota composed of bacteria that thrive in the absence of oxygen (99% of bacteria in the digestive tract are affected); a sub-dominant microbiota made up of bacteria which can develop in the presence and / or absence of oxygen, and a transient microbiota, where microorganisms are generally provided by food (fermented foods, dietary supplements based on probiotics, etc.)


20.The diversity and number of microorganisms present in the digestive tract varies considerably from mouth to colon


21.The maximum concentration of microorganisms is in the colon


22.These differences in colonization depend on the environment conditions of the digestive tract: oxygen, pH, transit time, bioavailability of nutrients, etc.


23.The intestinal microbiota is important for our health thanks to metabolic, trophic and defense functions


24.It acts on the essential metabolisms of digestion: carbohydrate, lipid and protein metabolisms


25.It ferments the undigested part of the alimentary bolus at the exit of the small intestine in the colon


26.This fermentation generates gases and benefic metabolites such as short-chain fatty acids (butyrate, propionate, acetate) which are real nutrients for colon cells


27.In addition, these short-chain fatty acids improve digestive comfort and provide energy


28.The intestinal microbiota also participates in the synthesis of certain vitamins such as vitamin K and group B vitamins


29.It acts on the maturation of the digestive tract such as the thickness of the intestinal mucosa, the size of the villi, the production of mucus, etc.


30.It is essential in the maturation of the intestinal immune system


31.It is a barrier, making it possible to limit the adhesion and spread of pathogens within our body


32.It also develops cellular and humoral responses adapted to aggression, aimed at protecting us


33.Indeed, almost 70% of the immune system is hosted in our intestines


34.The intestinal microbiota also houses nearly 200 million neurons, which form the enteric nervous system


35.This earned him the designation of “second brain”


36.A close link exists between the intestinal microbiota and the brain


37.They both communicate in a variety of ways: blood, immune, endocrine, and nerve ways


38.The intestinal microbiota is a balanced ecosystem that is constantly self-regulating


39.This balance can be upset under if the intestinal microbiota is attacked. This is dysbiosis


40.It results, among other things, in intestinal hyperpermeability: the intestine is altered and allows the passage of undesirable molecules in the bloodstream which can potentially lead to pathologies


41.This is due to the fact that the tight junctions no longer fulfill their role: the intestine is then like a sleve whose meshes have become too large…


42.Dysbiosis can have many causes: bacterial, viral or parasitic infections, abrupt change of environment, immune deficiency, unsuitable diet, medication, etc.


43.This imbalance can cause intestinal discomfort: transit problem, diarrhea, constipation, etc.


44.But also, be responsible for digestive pathologies such as IBD (Inflammatory Bowel Diseases)


45.Or extra-digestive pathologies like allergies, metabolic disorders (diabetes, obesity) …


46.It is possible to consume probiotics and prebiotics to restore the intestinal microbiota


47.Prebiotics are non-digestible fibers from our diet

48.These are mainly short chain carbohydrates


49.Their goal is to selectively stimulate the bacteria making up the intestinal microbiota, such as Bifidobacteria


50.Prebiotics then serve as a substrate for beneficial bacteria which will ferment them in order to transform them into short-chain fatty acids


51.They also help increase the weight of stools and improve their consistency


52.Many other benefits can be granted to them: improved calcium absorption, prophylactic effect against allergies or diabetes, protection against gastrointestinal infections, etc.


53.Inulin and fructo-oligosaccharides are the most represented prebiotics in our diet quantitatively


54.They are contained in certain fruits and vegetables (bananas, chicory, chicory, etc.) and in certain cereals (wheat, rye, etc.)


55.Other prebiotics exist, such as galacto-oligosaccharides, a component of breast milk


56.Consuming probiotics is also possible to rebalance the intestinal microbiota


57.According to WHO, they are living microorganisms which, when ingested in sufficient quantity, have beneficial effects on health


58.Certain “dead” probiotics (tyndallized probiotics) can also act positively on our health


59.Probiotics help maintain the balance, integrity and diversity of the intestinal microbiota


60.However, not all microorganisms are probiotics. They must meet a number of criteria


61.Security criteria: such as identification, included in a list, deposit in a collection, etc.


62.Functional criteria: such as resistance to stomach acid, digestive enzymes, bile; adhesion to mucus and / or epithelial cells; persistence in the gastrointestinal tract…


63.Technological criteria: they must be stable and viable in the finished product while retaining their health benefits


64.Probiotics are divided in different categories: lactic ferments capable of transforming carbohydrates into lactic acid (such as Cockles, Lactobacilli and Bifidobacteria); yeasts (such as Saccharomyces cerevisiae boulardii); spore-forming probiotics, capable of withstanding extreme conditions (Bacillus coagulans for example)


65.Their name is composed first of the genus (written with a capital letter), followed by the species and then the strain. The genus and the species must be in italics (example: Lactobacillus rhamnosus GG)


66.The most well-known probiotic that has been the subject of the greatest number of scientific studies is Lactobacillus rhamnosus GG


67.The most studied yeast is Saccharomyces cerevisiae boulardii

68.Probiotics can be found in lacto-fermented products such as certain dairy products, pickles, sourdough bread, fermented drinks such as kefir or kombucha…


69.In fact, only milk fermented by these two probiotics can be called “yogurt”: Lactobacillus bulgaricus and Streptococcus thermophilus


70.Probiotics can also be consumed in the form of food supplements


71.There are even supplements or croquettes with probiotics for our 4-legged friends


72.The properties of a probiotic depend on the strain


73.As a result, not all strains have the same benefits


74.Probiotics produce their effects according to different mechanisms of action. They act by competition for the sites of adhesion or for the nutrients, by production of bacteriocin, by reinforcing the barrier effect of the intestinal microbiota and by stimulating the immune defenses


75.They confer numerous benefits on the host health by rebalancing the intestinal microbiota


76.They strengthen the barrier function of our body


77.They improve intestinal ecology, whether in bacterial richness or diversity


78.Some have immunostimulatory effects


79.Some improve the symptoms linked to metabolic syndromes (obesity, diabetes, inflammation)


80.Some improve the allergic state (atopic dermatitis, allergic rhinitis, food allergy)


81.Some others protect against certain respiratory, gastrointestinal, vaginal, Helicobacter pylori infections, etc.


82.They act on intestinal comfort thanks to the improvement of many symptoms: bloating, diarrhea, constipation, intestinal pain, transit, etc.


83.They allow an improved digestion of lactose


84.Some decrease the risk of developing chronic inflammatory bowel disease (Crohn’s disease, ulcerative colitis)


85.Some decrease the cholesterol level


86.Some impact mood, anxiety, stress and cognition


87.Probiotics have many other specificities, but unfortunately, 100 points would not be enough to list them all!


88.Probiotics follow a 5-step manufacturing process


89.The first step is the strain selection


90.The second step consists in carrying out pre-cultures: the strain is transplanted or not in a selective medium


91.The third step is the selected strain culture: the preculture is inoculated in a first fermenter, the content of which will then be conveyed to another fermenter


92.Several factors should be considered during this step such as temperature, acidity, aeration and agitation

93.Harvesting is the fourth production step: the manufactured biomass is recovered by centrifugation, which allows the bacteria and metabolites to settle in the culture broth. The result is like a “cream”


94.The last step consists in drying the ferments by lyophilization


95.Lyophilization is a dehydration operation passing through a rapid freezing step followed by drying where the crystallized water is sublimated


96.After drying, the ferments are in the form of a “cake”, which will be crushed in order to obtain a powder


97.Many precautions must be taken during the various steps of the manufacture of probiotics in order to ensure their stability and viability, because they are living ingredients


98.At the regulatory level, it is not authorized to note the term “probiotic” on product packaging in certain European states, because considered as a generic claim


99.They therefore have other names on the packaging of products that you can buy: lactic ferments, microbiotic strains …


100.The unit corresponding to the probiotics which is to be annotated on the label is CFU for Colony-forming Unit