At this time of year of celebrations, toasts and copious meals, we should not forget the importance of the intestinal flora for the overall health of our organism. Even for emotional well-being, memory or the immune system, the state of the microbiota is key, so it is advisable to take care of it at Christmas too.
95% of serotonin, a neurotransmitter closely related to the control of emotions and mood, is produced in the gut. Similarly, the microbiota is a producer of γ-aminobutyric acid (GABA), which provides relaxation, calming, anxiolytic and antidepressant effects, and which acts through receptors in the gut, reaching the brain via the vagus nerve and other pathways.
The digestive system is thus a second brain capable of modulating emotional states. There is evidence of the relationship between the microbiota and pathologies such as attention deficit disorder or borderline personality disorder. It also has an impact on cognitive processes such as learning and memory, on emotional processes (for example, on our stress management), or on our social behaviour.
GABA is also involved in the regulation of immune processes, e.g. by inhibiting the release of pro-inflammatory cytokines, as well as in the stimulation, maturation and differentiation of lymphocytes and different immune structures.
In addition, the main functions of the intestinal flora include digestive, defence against colonisation by pathogens, metabolic, trophic, stabilisation of the epithelial barrier (permeability), immune, regulation of peristalsis and modulation of the gut-brain axis.
It is also immunomodulatory, protective, muconutritive, primary saccharolytic, neuroactive and proteolytic. Certain bacteria maintain the physiologically acidic pH in the intestinal lumen and the integrity of the selective barrier against pathogens provided by the intestinal wall. They also maintain the energy supply to the mucosal cells and contribute to the integrity of the mucus layer lining the intestinal mucosa. Not forgetting that several types of fungi, yeasts and viruses are also part of the intestinal ecosystem.
A diet rich in ultra-processed foods, low in fibre and saturated fats often results in a loss of diversity of microbial populations and, therefore, an increase in cardiovascular and metabolic pathologies, etc. It is therefore advisable to increase the consumption of foods rich in fibre (fruit, nuts and vegetables) and a diet low in saturated fats.
Fermented foods, such as yoghurt, help to improve gut microbiota. But protein overload in the diet, combined with disorders of the protective microbiota and changes in the pH of the intestinal lumen, favour the growth of proteolytic bacteria, the excess of which leads to an increase in the body's toxic load, as well as liver overload.
It has long been known that the bacteria in our gut produce vitamins, and also consume them, along with other factors such as tryptophan, a basic amino acid for the synthesis of neurotransmitters. More or less consumption of these products is associated with more or less recent memory. In this sense, poor impulse control is associated with a certain diet, which in turn determines changes in the microbiota.
Another of the best characterised elements is vitamin B1. It has been found that patients with obesity who have less memory have a microbiota with bacteria that sequester vitamin B1 within them, limiting its absorption by our intestine. The cognition disorders to which the microbiota is related are reduced immediate and short-term memory.
From a cardiological point of view, diet and lifestyle are fundamental to good cardiovascular health, and are becoming increasingly important. "Intestinal bacteria are capable of producing substances that regulate cardiovascular balance, so a heart-healthy diet ensures a good gut microbiota," says Julián Pérez Villacastín, director of the Cardiovascular Institute of the Hospital Clínico de Madrid.
The model studied at the Clinic, in whose development Adriana Ortega Hernández, Rubén Gómez Gordo and Javier Modrego, from the Vascular Biology and Microbiota Laboratory, have also participated, is a heart failure whose evolution is very similar to that which naturally develops in patients with hypertension. "In this model, we have observed that first the intestinal microbiota was altered, and then the cardiac function and structure," they say in this article. article by Medical Journal.
Skin microbiota
But there is another part of our body where the microbiota also plays a fundamental role. This is the microbial flora that inhabits our skin, which mainly has a protective function. On the one hand, by controlling the development of harmful germs and, on the other hand, by stimulating the immune system. Therefore, if we neglect our ecological skin system, we are more likely to develop infections and immune diseases such as atopic dermatitis.
In the words of Marta Mayor, member of the Barcelona College of Pharmacists' Dermopharmacy and Medical Devices Committee, a Medical JournalThe microorganisms of the microbiota secrete bioactive molecules, such as antimicrobial peptides, bacteriocins, betadefensins, free fatty acids, etc., which act directly on pathogens, preventing their entry and survival. They also work indirectly, stimulating the production of immune mediators in keratinocytes and dermal cells, which also act on pathogens, preventing their entry.
In fact, the most widespread harmful habit on the skin is over-cleansing and, in turn, using inappropriate products.
José Antonio Rodríguez Piedrabuena is a specialist in Psychiatry and Psychoanalysis, and in management training, group and couple therapies.