Probiotics and Mental Health

We can’t deny the existence of the gut-mind connection. Ask anyone who suffers with irritable bowel syndrome or inflammatory bowel disease about the damning impact anxiety and stress has on their digestive tract conditions.

But what if our gut helped us cope better with anxiety and depression?

Researchers at Acadia University, in Wolfville, Nova Scotia, are pondering this very question. Dr. Susan Potter, a clinical psychologist, and Zoë Hunter, an honours psychology student, are investigating whether probiotics can enhance our mental health by improving the state of our gut. 

“Probiotics are food sources such as yogurt, cheese and fermented goods that contain beneficial bacteria that grow naturally in the body and support life. The probiotic connection in humans has been researched in reference to diarrhea, irritable bowel syndrome, immune system regulation, and others, but not yet to anxiety and depression,” said Hunter.

The inspiration for the study came from Dr. Potter watching an episode of CBC television’s The Nature of Things with David Suzuki. The show, titled The Autism Enigma, explored various prevailing theories for the developmental disorder, paying much attention to the bacterial theory: the impact gut bacteria disturbances in infancy may have on brain development. 

Overuse of antibiotics, food allergies and intolerances, or dramatic changes to traditional diet -- particularly in the case of immigrants -- are thought to be common culprits in disrupting the gastrointestinal microbial ecosystem.

Some scientists and parents of autistic children believe that probiotics can provide waves of benign, beneficial bacterial to the gut that outnumber nasty intestinal bugs -- bacteria that may be pathogenic and support the development of many disease conditions, including autism.

While Professor Potter’s area of research isn’t autism, she was intrigued and questioned to what extent an abnormal gut bacterial population might influence human behaviour in general. 

A review of past relevant studies revealed that probiotics can reduce anxiety and depressive-like behaviours in animals, such as mice and piglets, with these symptoms. Researchers propose that probiotics alter the stress receptors in the body.

“There are also anecdotal reports of improvements in anxiety and behaviour among humans following treatment with probiotics. However, controlled studies of the effects of probiotics on anxiety, depression and other aspects of nervous system functioning are needed in humans. This is why we decided to carry out this research,” said Potter. 

““This is the first [human clinical intervention trial] of its kind that we are aware of, ” added Hunter. “Probiotics are so accessible to the general public. The trial has huge clinical relevance. Wouldn't it be great if individuals suffering from anxiety and depression could benefit from simply eating more probiotics like yogurt and cheese?” 

Potter and Hunter launched the Probiotics and the Microbiome (meaning gut microbial ecosystem) study on August 1st and are recruiting participants from across Canada. To be eligible to participate, interested individuals must be Canadian residents over the age of 18 who suffer from symptoms of anxiety or depression, and currently not taking probiotics or antibiotics. 

A detailed list of eligibility requirements and a link to the online questionnaire can be found right here. The study enrollment deadline is September 7th, 2012. 

published in the Vancouver Courier, August 24th, 2012