Yogurt helps with depression - scientists
“Our discovery sheds light on how Lactobacillus, which lives in the gut, influences mood disorders by tuning the human immune system,” explains Alban Gauthier from the Department of Neurobiology at the University of Virginia, lead author of the study.
The human intestine is home to countless bacteria, fungi and viruses; more microorganisms live in and on humans than there are cells in the body. The more scientists study these microorganisms, their influence on physiological processes and their interactions, the more clear the conclusion becomes that they are critical to the health of the immune system, mental health and numerous other aspects of human well-being. Microbiota - the name given to the community of these microorganisms - can suffer from painful conditions, poor nutrition and other circumstances, and this becomes the cause of human diseases, including cancer.
I would, of course, want to learn how to influence a person’s health by influencing not his body itself, but the microbiome, which, in theory, should correct many of the chronic pathologies or conditions.
Previous attempts to manipulate gut flora with beneficial bacteria called probiotics have had mixed results. Much of the problem lies in the sheer complexity of the microbiome. It's estimated that there are 39 trillion microorganisms living inside each of us, so trying to understand what a particular bacteria or fungus does, much less how it interacts with other microorganisms and its host, can be like trying to count the grains of sand on a beach.
Gauthier and his team took an innovative approach to study lactobacilli specifically. “We knew from our previous research that Lactobacillus was beneficial for mood disorders and died when the body was under stress, but the underlying reasons remained unclear, primarily due to technical challenges associated with studying the microbiome,” he says.
Gauthier and his team decided to continue their depression research using a collection of bacteria known as Schedler's modified flora, which includes two strains of Lactobacillus and six other bacterial strains. Thanks to this rarely used bacterial community, the team was able to develop two strains of mice, one with lactobacilli and one without, without using antibiotics.
Gauthier and his colleagues were able to explain exactly how lactobacilli influence behavior and how a lack of bacteria could worsen anxiety in mice. Scientists have found that Lactobaccillacea maintains levels of an immune mediator called interferon gamma, which regulates the body's response to stress and helps prevent the disorder.
Armed with this information, researchers are poised to develop new ways to prevent and treat mental disorders in which lactobacilli play an important role. For example, patients suffering from (or at risk of) depression will be able to take specially formulated probiotic supplements that optimize levels of beneficial lactobacilli.
