This food that you all have in your fridge protects against stress and depression

 An American study reveals that the Lactobacillus bacteria, present in fermented foods such as yogurt, could positively influence our mental well-being. Conversely, a deficiency seems to worsen stress and mood disorders.

Much more than a simple player in digestion, the intestinal microbiota is emerging as an unexpected protagonist in the world of neuroscience. Recent studies suggest that the microorganisms that inhabit our gut could exert a significant influence on the functioning of our brain. One of the latest, published in Brain, Behavior, and Immunity , looked at the link between microbiota dysbiosis , stress and mood disorders .

Lactobacillus bacteria, present in yogurt, may improve mood

The researchers based themselves on an already known phenomenon: the fact that a disruption of the Lactobacillus bacteria in the intestine was frequently observed in patients suffering from stress or mood disorders.

The bacteria genus Lactobacillus is composed of Gram-positive organisms that are commonly associated with lactic acid fermentation, a biological process that converts sugars into lactic acid. In the context of human health, certain species of Lactobacillus are considered probiotics beneficial to the body. They are often present in fermented products such as yogurt , sauerkraut  or kefir . These lactic acid bacteria can contribute to the balance of intestinal flora by promoting the growth of beneficial microorganisms and inhibiting the proliferation of pathogenic bacteria.

“We knew from our previous research that Lactobacillus was beneficial in improving mood disorders and that it disappeared following psychological stress, but the underlying reasons remained unclear, mainly due to the challenges techniques associated with the study of the microbiota,” explains Alban Gaultier, MD at the University of Virginia and co-author of the study.

Lactobacillus deficiency worsens depression

To better understand the mechanism of action of lactobacilli, researchers studied these bacteria in mice colonized with “modified Schaedler flora” – a microbial community altered to eliminate the two indigenous species of Lactobacillus: L. intestinalis and L. . murinus. They then found that mice without Lactobacillus had elevated stress responses and attenuated IFNγ (interferon gamma) levels .

IFNγ, or interferon gamma, is a protein produced by the immune system in response to infections, promoting defense against pathogens. In addition to activating immune cells, it regulates the inflammatory response as well as the body's response to stress. “Lactobacilli maintain levels of an immune mediator called interferon gamma, which regulates the body's response to stress and helps prevent depression ,” a statement said. Furthermore, the transfer of the microbiome from stressed mice to germ-free recipients triggered depressive and anxious behaviors.

To summarize, a deficiency in lactobacillus could worsen depression and anxiety. A discovery which could allow the development of new treatments, based on supplementation with probiotics rich in Lactobacillus, for example. Until then, you can already benefit from the benefits of these good bacteria by tasting fermented foods ( yogurt , kefir, kimchi, etc.) – especially if you are at risk of depression.