Probiotics

Dietitian Nutritionist, I explain the role of probiotics, where to find them (…) especially for sensitive people in the intestine.

The intestine is a key organ for the proer functionning of the organism. The mucosa corresponds to an epithelium with a surface area of 300m2 and is bristling with villi and microvilli. It’ s a boundary between the external environment and the interior of the organism.

The mucous membrane acts as filter (nutients, allergens, toxins, bacteria, viruses, antibodies, antibacterial substances). This defense system consists of the intestinal immune system.

The intestinal flora, it’s divided into three groups :

• The dominant flora composed of the Bifidobacteroides strains,
• The subdominant flora composed of strains Streptococcus and Lactobacillus,
• Contaminant flora, potentionally pathogenic but theoretically absent.

The endogenous flora is the set of microbial species cohabiting in the digestive tract and capable of multiplying there. The exogenous flora or passage, represents the species crossing the digestive tract without being able to colonize it.

The gastrointestinal tract contains about 100 000 billion bacteria, with 400 different species (10 times more bacteria than the cells that make up our body) !

The different roles of the intestinal flora

• Barrier effect,
• Neutralization of toxic products,
• Surface of absorption of the intestinal mucosa,
• Renewal of intestinal cells,
• Intestinal transit,
• Synthesis of certain vitamins B (B9, B12) and K,
• Actions of endogenous secretons : bile acids (deconjugation, oxidation, dehydroxylation), cholesterol, steroid hormones, urea and ammoniogenesis,
• Action on nutrients : degradation of carbohydrates, proteins and aromatic amino acids, hydrolysis of lipids, production of short chain fatty acids,
• Physicochemical changes,
• Actions on pH varations.

Disruptive factors of intestinal flora

The intestinal flora is in a state of dynamic equilibrium. This balance can be modified by differents factors :

• Unbalanced diet ( excess sugar, alcohol, ow in fiber, chemical, …)
• Medicines (antibiotics, corticosteroids, non steroidal anti inflammatory drugs, laxatives, …)
• Stress (Professional, family, …)
• Sports leading to peristaltic disorders ( 10km, marathon, trail, triathlon, …)
• Aging,
• Travel, climate change,
• Colonization of pathogenic germs (Salmonella, Candida albicans … ).

Interest of supplementation in pre- and probiotics

Probiotics are living microorganisms (most often bacteria, Streptococcus, Lactobacillus, Bifidobacterium, ect ) which, when administrered in a sufficient amount, can have a beneficial effect on humans, natbly by improving the balance of the intestinal flora. They are naturally present in yogurts and fermented milks (ribot milk, kefir, koumis …)

Prebiotics (Fructo-, Galacto-Oligosaccharides, Inulin, ect ) are non-digestible food additives or ingrédients that benefically affect the host by selectively stimulating the growth or activity of certain colon bacteria.

The latter are found on the diet in vegetables and fruits : artichoke, asparagus, beet, banana, strawberry, chicory, flax, onion, honey, leek and cereals such as rye and barley.

The benefits of Prebiotics and probiotics are many !

• Balance of the intestinal mucosa,
• Improved calcium absoprtion at the colon,
• Improvement of the non-pathogenic microflora of the individual,
• Prevention of infectious diseases, food intolérances and allergies such as lactose or gluten,
• Improved immune properties …

Interest in sports

Physical activity can lead to digestive problems during and after exercise. Moderate or intense, it can weaken the immune system, favoring infections of the respiratory tract, increase the phenomena of intolerance to certain foods, decrease digestion and fermentation of food.

It is therefore interesting to use probiotics in sprotsmen, whether amateur or Professional, in ordre to limit this symptoms. A supplementation in Probiotics (with or without Prebiotics), before a major competiton, avoids certain underperfomations, especially in all sports disciplines characterized by shock waves disrupting the digestive tract (semi- and marathon, mountain race, trail …).

Sportingly.

Nicolas AUBINEAU
Sports Dietitian Nutritionnist