By Liliana Zura Bravo, Researcher at the Institute for Research and Postgraduate Studies, FAMEDSA.
Mental health is a public health issue, which generates consensus among professional organizations, doctors, and consumers alike. This topic has become especially relevant, due to the COVID-19 pandemic that has affected the entire planet, leaving an indelible mark on our society. Among the reported mental health stressors affecting people are: social isolation, overburdened health systems, short and long-term symptoms, death, media panic, boredom, food insecurity, limited outdoor exposure, financial losses, and changes in dietary patterns, including consuming more comfort or fast food.
Recent scientific research based on nutritional approaches has generated great interest by indicating the consumption of probiotics to control depression and anxiety. According to the FAO, probiotics are live microorganisms that, when administered in adequate amounts, cause health benefits to the host. The most commonly used species are Lactobacillus and Bifidobacterium.
The multiple benefits of probiotics for the human body have been described in many scientific studies, mainly highlighting their potential to reduce the population of pathogens, stabilize the intestinal microbiota, increase the absorption of minerals, relieve constipation, stimulate the immune system, reduce serum cholesterol levels, decrease antihypertensive effects, and prevent urogenital infections. It has also been reported that probiotics play a very important role in the prevention of diseases such as childhood diarrhoea, osteoporosis, food allergies, and atopic diseases. It has also efficacy in controlling inflammatory bowel diseases, reducing the severity of diarrhoea and protecting against colon and bladder cancer.
In recent years, probiotics have gained notoriety in the field of mental health as preclinical and clinical studies have pointed to their potential benefit by stimulating the intestinal production of 5-hydroxytryptophan (5-HTP), which is the precursor of serotonin, a neurotransmitter and neuromodulator of great relevance in the regulation of moods, physiological functions and behaviours in animals along the entire phylogenetic scale, including humans.
Another product generated in the intestine is gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter of the central nervous system. Therefore, it has been proved that, through the gut-brain axis, these substances can reach the central nervous system. Due to this mechanism, the term "psychobiotics" was coined to define those probiotics that have a potential action on the central nervous system. For a better understanding, it should be said that the most well-known probiotics for the Chilean society are natural yoghurt, dark chocolate, and sauerkraut.
Finally, it is necessary to emphasize that the gut microbiota influences the gut-brain axis and, therefore, directly affects the central nervous system. Physiologically, the gut-brain axis encompasses the neuronal, endocrine, nutritional and afferent and efferent immunity signals between the central nervous system and the gastrointestinal system. Therefore, maintaining a healthy diet along with the consumption of probiotics can be a practical and natural alternative for the treatment of disorders as important as depression and anxiety.