Mental Health

Probiotics In Your Diet May Help Manage Depression, Study Says

Researchers have found that probiotics, the foods or supplements that contain microbes, could help reduce the effects of depression. The new study adds to the growing evidence of how the gut microbiome influences the brain. 

The findings, published in the journal BMJ Nutrition, Prevention & Health, come from the review of 71 studies that focused on the effects of probiotics and prebiotics on adults with depression and/or anxiety disorders. The studies came out between 2003 and 2019. 

Researchers identified 12 main probiotic strains, including Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium bifidum. However, only seven studies showed "significant improvements" in mental health after taking pre- or probiotics compared with no treatment. 

In the review, researchers from the University of Brighton and Croydon University Hospital in the United Kingdom found that probiotics help manage depression in two ways. First, it cuts the production of inflammatory chemicals, such as cytokines, and supports the functions of tryptophan in the gut-brain axis.

Another way they help ease depression is by treating other underlying conditions. In some people, the disorder occurs because of pre-existing health problems, such as impaired insulin production and irritable bowel syndrome (IBS).

However, the researchers did not find any clear positive effects of probiotics on people experiencing anxiety. The team also noted their review has some limitations, such as short-term study periods and small number of participants.

"We are still learning about the numerous, complex communication pathways between the brain and the gut," Geoffrey Preidis, spokesperson for the association and a pediatric gastroenterologist at Baylor College of Medicine and Texas Children's Hospital, told CNN.

Long-term follow-ups are important to determine how long probiotics could help manage depression and the potential side effects on people are prolonged use. But Preidis expressed confidence that future research could help address those limitations. 

"Future clinical trials will address this knowledge gap, so we must continue to evaluate the rapidly changing evidence in this exciting field," he said.

Researchers should try to identify the strains that directly help reduce the effects of depression, according to John Cryan, professor and chair of the department of anatomy and neuroscience and principal investigator at the Alimentary Pharmabiotic Center, University College Cork.

"We know that strains really matter, and this review is not able to identify what it is about specific strains that render them with beneficial effects," he said. "As this review highlights, there is a great need for longitudinal studies for different psychobiotic strains and diets both as standalone or as adjunctive therapies in anxiety and depression."

Depression The National Institutes of Health considers depression as one of the most common mental disorders in the United States, with 17.3 million adults reporting at least one major depressive episode in 2017. Pixabay