If the various folds, villi, microvilli and crypts are smoothed out, the surface of the intestinal mucosa is equivalent to about 200 m². And the suggestive numbers do not end there. In fact, in the human intestine there are about 400 bacterial species, both anaerobic (bifidobacteria), mainly located in the colon, and aerobic (lactobacilli), concentrated especially in the small intestine.
In addition to the bacterial flora, in our intestine there are fungi, clostridia and viruses, which, in conditions of equilibrium, do not exert any pathogenic effect.
Under normal conditions, the bacterial flora is in perfect symbiosis with the organism.
We recall that by "symbiosis" (from the Greek: life together) s "means a particular relationship of coexistence between two organisms, from which both derive their own benefit.
In the symbiotic relationship between the human organism and the intestinal flora, man (host) provides undigested material for the sustenance of bacteria. On the other hand, these microorganisms (symbionts) perform various functions useful to man.
When the bacterial flora and the organism live in perfect harmony, we speak of eubiosis.
Development of the Intestinal Microflora
During pregnancy, the intestine of the fetus is perfectly sterile, but is colonized by billions of bacteria immediately after birth. These microorganisms settle in the intestine, entering from the outside through the mouth and anus.
The first months of life are very important for building a healthy and balanced bacterial population. In fact, breast milk promotes the proliferation of bifidobacteria, a strain that is particularly beneficial for human health.
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The bacteria present in our intestine ferment the undigested material, generally consisting of polysaccharides of plant origin. Following this fermentation, the bacterial flora produces short-chain fatty acids, such as acetic, propionic and butyric acid. These molecules are very important for our well-being, as they represent an energy source for the epithelial cells of the intestine. It also appears that butyric acid protects against colon cancer.
PROTECTIVE FUNCTION AGAINST INVASION OF PATHOGENIC BACTERIA
The bacterial flora enhances the barrier effect of the intestinal mucosa, thanks to the trophic function mentioned above.
The symbiotic bacterial population also produces antimicrobial substances, thanks to which it prevents the adhesion of pathogens to the intestinal epithelium. This effect is enhanced by the "physical obstacle that the" friendly "microflora exerts by occupying the possible adhesion sites to the walls of the intestine.
Finally, the bacterial flora modulates components of the intestinal immune system with a pro-inflammatory action.
ADDITIONAL FUNCTIONS
- Promotes digestive processes and absorption, keeping the intestinal mucosa healthy and effective;
- Prevents ailments such as colitis, diarrhea and constipation;
- It produces some vitamins, primarily vitamin B12 and vitamin K;
- It produces some amino acids (arginine, glutamine and cysteine);
- It intervenes in the metabolism of bile acids and bilirubin.
Over time, intestinal diseases such as diverticula, Crohn's disease and tumors of the digestive system can also appear.
In case of dysbiosis, an impairment of intestinal permeability can also occur, since the trophic function of the symbiont microflora is lost. As a result, allergies and autoimmune diseases can develop. In fact, due to the altered permeability, certain molecules can be absorbed and recognized as foreign by the immune system, which reacts by triggering allergic reactions or real autoimmune diseases.
A further negative consequence of dysbiosis is the absorption of real toxic substances, especially harmful to the liver and pancreas. The consequence of these processes can be, in the best of cases, the appearance of digestive problems, but also and above all the "onset of chronic fatigue not attributable to other causes.
Finally, dysbiosis increases the stasis time of fecal material in the intestine, causing the alteration of various nutrients. For example, the alteration of amino acids can lead to the formation of toxic amines (lysine: cadaverine; ornithine: putrescine; tryptophan: indole and skatole).
and many refined foods;The pollutants contained in food (dyes, solvents, hormones, pesticides, etc.) also negatively affect the stability of the intestinal microflora.
to the patient of probiotics (viable microorganisms capable of maintaining or improving the intestinal bacterial flora). In order to be able to speak of probiotics, and not of simple lactic ferments, these microorganisms must:
- Being alive and biochemically active;
- Resist the action of gastric acid and bile;
- Adhere to the intestinal epithelium;
- Produce antimicrobial substances against pathogens;
- Maintain their vitality within the digestive tract.
Many of the lactic ferments contained in yogurt do not possess these characteristics and are therefore unable to positively influence the intestinal bacterial flora.
The second measure consists in the intake of prebiotics, ie substances that arrive undigested in the colon, where they are fermented by the local bacterial flora. The metabolites that are formed thus provide nutrients useful for the growth of beneficial bacterial species.
Prebiotics are contained, albeit in limited concentrations, in various foods such as: chicory, artichoke, leeks, asparagus, garlic, soy and oats. In pharmaceutical preparations containing these substances, on the other hand, mainly FOS (fructo-oligosaccharides) and inulin, a fructose polymer, are added.
Finally, to improve the vitality of our intestinal bacterial flora, it is essential to avoid any source of stress as much as possible and adopt a correct lifestyle, supported by a "balanced diet."
