Studying bacteria effects on PTSD

Researchers at St. Joseph’s Healthcare in Hamilton are embarking on a ground breaking study — thanks to substantial funding from the U.S. Navy. The United States Office of Naval Research has put up $1.5 million to back a study of the effects of probiotic bacteria on post traumatic stress disorder.

Connections have been drawn before between the bacteria in our stomachs and our moods, but this research will take things a step further to see if probiotics can actually reduce stress by balancing bacteria levels in the gut. A group of doctors at the McMaster Brain Body Institute in St. Joe’s will be experimenting on distressed lab mice to see whether feeding them probiotic bacteria reduces their anxiety.

The U.S. Navy obviously has great faith in this research in order to pony up such a large sum. The results of the study could indicate strategies for anxiety and PTSD prevention and treatment in military personnel, including dietary changes. Now, it’s too soon to tell whether eating probiotic rich foods like kefir and yogurt have an impact. The research is still preliminary and involves feeding the mice very specific bacteria. But if reaching the right microbial balance in mice proves effective, researchers will examine whether supplements or bacteria rich foods have the same impact on humans.

Dr. John Bienenstock is the Director of the McMaster Brain Body Institute: “Would it be a reasonable thing to do to take certain bacteria or to balance your bacteria in situations where you’re likely to actually encounter the sort of conditions that lead to PTSD.”

Researchers are also interested in learning whether small amounts of antibiotic can help balance out bacteria in the gut to reach an ideal “low stress” level.


  1. Wow what a giant privilege for our Canadian doctors to study PTSD and whether probiotics can change anxiety levels. I wish them much success with the study

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