The microbes that inhabit our intestines seem to have some influence on our mental health, although at the moment the way in which this impact occurs has been studied more in animals than in people. In mice, for example, it has been observed that when feces of humans with depression are introduced they develop symptoms typical of this disease. In humans, it has been seen that modifying the intestinal ecosystem can reduce anxiety states, but there is a lack of information on what can be done with more serious ailments.
Today, a team led by Jeroen Raes, of the Flemish Institute for Biotechnology, publishes an analysis in which it links the absence of some specific types of bacteria with depression and suggests that a significant number of them can produce compounds capable of affecting our state of mind.
In his work, which is published today in the magazine Nature Microbiology, the authors explain how they took information about the microbiome collected from feces and diagnoses of depression of 1,054 individuals participating in the Flamenco Project of the Intestinal Flora. In their analysis they found that two genera of bacteria, Coprococcus and the Dialister, they were scarce among people suffering from depression.
In people with gastrointestinal disorders, anxiety or depression problems have been detected
"The relationship between the metabolism of intestinal microbes and mental health is a controversial issue in microbiome research," Raes said in a statement from his institution. "The notion that metabolites [producidos por estos microbios] can interact with our brain, and therefore influence our behavior and our feelings, is intriguing, but communication between the gut microbiome and the brain has been explored mainly in animal models, with much less advanced human research, "he adds.
In this work, the authors also analyzed which compounds could produce microbes capable of interacting with our nervous system and crossed that information with the genomic sequences of organisms found in the faeces of people with depression and healthy individuals. In this way, they discovered that the ability of some microorganisms to produce DOPAC, one of the metabolites of dopamine, was associated with a better mental state.
The team of Raes it's been years looking for relationships between the presence of certain bacteria and their effects on health. In previous studies, they saw that those who consumed yogurt regularly had more diverse bacterial ecosystems in the intestine, something that also happened with the consumption of wine or coffee. The opposite happened with the consumption of whole milk or with excessive feeding. In another of the lines of interest in the field of the study of the microbiome, we have begun to find relationships between heart disease and cancer and the presence or absence of some bacteria.
For now, what is known most accurately is the relationship between the microbes we have inside, diet and intestinal health, but the substances that produce some bacteria can affect the levels of inflammation and that also influences the immune system. In some way, microbes are a mechanism that connects different systems of the organism. In people with gastrointestinal disorders, such as irritable bowel syndrome, anxiety or depression problems have been detected, and, in general, it is common for both mental and digestive disorders to occur at the same time. In another line of research that may help to understand Parkinson's, some studies have found that this disease is related to a longer intestinal transit time.
The field of study of the microbiome, and especially the capacity to act on it to improve health, is still in its infancy. Today too, in the magazine Nature Biotechnology, an international team of scientists publishes the discovery of 100 new species of bacteria found in the intestine of healthy people. As it happens when you want to make a change in an ecosystem, touching a species can have undesirable effects on the balance in which you live with others and it seems that to do it effectively there is still much to know about these microscopic inhabitants that suppose, approximately, the 2% of our weight.