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BacteriesBacteries

Composition of the Microbiota

The term “microbiota” refers to all the living bacteria that colonize the human gastro-intestinal system. These bacteria have adapted to the prevailing environment in our internal ecosystem and live in symbiosis with us.

The microbiota is acquired at birth. It changes and develops with age and lifestyle. It’s dominated by bacteria from the Bacteroidetes, Firmicutes, Actinobacteria, and Proteobacteria phyla. The relationship between the microbiota and an individual is characterized by a parallel evolution according to the events that have marked this individual’s life. Since each person’s life is different, the microbiota therefore becomes unique to each one.

The composition of the microbiota may be altered by the diet, among other things. Choose foods such as:

  • Good fats such as monounsaturated and polyunsaturated;
  • Dietary fibres present in seeds, grains, fruits, and vegetables;
  • More complex carbohydrates rather than simple refined sugars such as sucrose;
  • Micronutrients present in a natural diet that doesn’t consist of industrially processed products;
  • Certified and diversified probiotics from recognized sources;
  • High-quality prebiotics such as inulin and other complex polysaccharides.

All these choices not only have direct consequences on the microbial flora that make up the microbiota, but they can also vary the gene expression of certain body tissues such as the liver, the adipose tissues, the intestines, and the muscles. These interactions can lead to an increase or decrease in body fat and can cause metabolic disorders associated with the function of the intestinal wall and the immune system.

LactobacillusLactobacillus

 

Example of the influence of microbiota composition on health

Experimental data from animals and humans suggests that the composition of the microbiota varies according to specific characteristics such as:

  • Obese person vs. thin person;
  • Diabetic vs. non-diabetic;
  • Individuals with certain types of liver disease;
  • Age (from birth to old age).

The intestinal bacteria also play a very important role thanks to their contribution of metabolites, which are beneficial for humans. The following table illustrates a small portion of some of the benefits generated by some of these metabolites.

 

Metabolites

Potential biological functions

Short-chain fatty acids

  1. Reduction of the pH in the colon
  2. Inhibition of the proliferation of pathogenic bacteria
  3. Participation in the synthesis of cholesterol
  4. Involvement in the incidence of human obesity
  5. Influence on insulin resistance and type-2 diabetes

Bile acids

  1. Absorption of dietary fats and fat-soluble vitamins
  2. Maintenance of the functions of the intestinal wall
  3. Contribution to the systemic endocrine system, which regulates the triglycerides, cholesterol, and glucose in the blood

Vitamins such as K, B12, biotin,  folate, thiamine, riboflavin, and pyridoxin

  1. Supplementary endogenous source of these vitamins
  2. Increase in immune function
  3. Epigenetic function on the regulation of cell reproduction