Gut Microbiome May Be Linked to Stress Resilience
Researchers have found that bacteria in the gut are related to how the body experiences stress. According to the portal, the composition of the microbiome was important for mental health. The bacteria have been shown to produce substances that affect inflammatory processes, stress hormones, and the generation of mood-related neurotransmitters. These include short-chain fatty acids and tryptophan metabolism products.
In addition, the waste products of the bacteria maintain the protective barrier of the intestines and limit the entry of harmful substances into the blood. It can also affect the level of inflammation in the body.
In animal studies, when the number of certain beneficial bacteria has decreased, there have been signs of anxiety and depressive behavior. When certain bacteria and their products were added, scientists noted improvements in brain function and stress adaptation.
So far, scientists believe that the data are insufficient to recommend probiotics or diets as a way to prevent mental disorders. The microbiome varies greatly from person to person, so more research is needed. In doing so, researchers believe that maintaining a healthy microflora can significantly improve both digestion and mental health.
Indeed, scientists have found a connection: resistance to stress does depend on the composition of the gut microflora. This relationship is explained by the so-called "bowel-brain" axis, a two-way communication channel that carries signals between the bowel and the central nervous system through the nervous, immune and endocrine systems.
How it works
Intestinal bacteria produce substances that affect inflammation, stress hormone levels, and the production of mood-related neurotransmitters. Among such substances:
Short-chain fatty acids (QCFA). They maintain the integrity of the intestinal barrier, limiting the release of harmful substances into the blood and reducing systemic inflammation.
Tryptophan metabolic products.
Tryptophan is a precursor to serotonin, an important neurotransmitter that regulates mood. Certain bacteria (such as Bifidobacterium and Paraprevotella) increase the availability of tryptophan for its synthesis.
Other metabolites. They can also affect how the nervous system functions.
In addition, the microbiota is involved in the synthesis of other neurotransmitters: dopamine, norepinephrine, and GABA (gamma-aminobutyric acid), which helps relax and reduce anxiety
What research shows
Animal experiments show a causal relationship:
In mice without microbes (GF mice), the hypothalamic-pituitary-adrenal axis (HPA axis) responded more strongly to stress (elevated corticosterone levels) than mice with normal flora.
The colonization of mice without microbes with Bifidobacterium infantis bacteria normalized the stress response.
The introduction of bifidobacteria increased the resistance of mice to chronic stress of social damage.
In humans, taking probiotics (e.g. Lactobacillus helveticus, Bifidobacterium longum) for 30 days reduced anxiety and depression while also lowering cortisol levels.
Important Refinements
Despite the compelling evidence, scientists emphasize several points:
Individual differences. The microbiome varies greatly from person to person, so it is difficult to extrapolate test results from all to all.
Two-way communication.
Stress affects the microbiota, but changes in the microbiota (for example, due to antibiotics or diet) can also affect mental status.
More research is needed. It is too early to recommend probiotics or special diets as a method of preventing mental disorders.
Extensive clinical trials are required.
Thus, maintaining a healthy microflora can contribute to improving both physical and mental health. However, this is only one factor and should be considered in conjunction with other stress management techniques.
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