Science has only just begun to unravel the complexities of the human digestive tract, but a recent University of Toronto study may bring us one step closer to understanding its role in optimum health—and not just physical health, but mental health as well.

Led by Venket Rao, the pilot study tracked a group of 39 patients diagnosed with chronic fatigue syndrome (CFS) to determine whether or not daily supplementation with probiotics could help ease symptoms of anxiety. CFS is a debilitating condition with a wide range of symptoms that occasionally includes psychological problems such as anxiety, panic attacks, irritability and depression.

During a period of two months, each participant received at random a daily supplement of either 24 billion active cultures of the strain Lactobacillus casei or a placebo. Upon analysis of the results, it was discovered that not only did those in the Lactobacillus group show a significant decrease in anxiety symptoms compared with those taking the placebo, but that stool samples revealed noticeably higher levels of both Lactobacilli and Bifidobacteria.

Lactobacilli and Bifidobacteria are among the most prevalent beneficial bacteria found in the human digestive tract, where trillions of microscopic organisms make up the majority of the body’s immune defences. These healthy bacteria or probiotics (literally meaning “for life”) play a vital role in overall digestive and immune health by helping to crowd out disease-causing microbes that can jeopardize good health.

The University of Toronto study, published in the March 2009 issue of the journal Gut Pathogens, was among the first designed to confirm a link between the vast bacterial environment in the gut and its effect on psychological and emotional well being, and researchers are hoping that the promising results prompt further exploration into the gut-brain relationship.

Click here to view the complete findings

*1998-2009. Mayo Foundation for Medical Health and Research.