Scientists searching for the underlying causes of mental illness have discovered a surprising contributor — it appears the bacteria that live in your gut may play a major role in your mental health and well-being.

CBC Radio science columnist Torah Kachur spoke to researchers such as Karen Madsen at the University of Alberta who are studying the types of bacteria that live in your gut and how they affect your behaviour, via a nerve that travels between the gut and the brain.

"You know the whole term, 'listen to your gut'? It’s kind of taking on a whole new meaning," Kachur told Rebecca Zandbergen, host of CBC's Radio West.

Kachur explained that there are "good" bacteria, like Bifidiobacterium and Lactobacillus, that are present in yogurt. They produce a happy signal called GABA, which acts on the nervous system to curb depressive symptoms and anxiety.

Meanwhile, "bad" bacteria like the Clostridium family, of botulism fame, live in our guts and dine on our Western diets of high fat, high sugar and processed foods, Kachur said. She added that these bacteria can produce toxins that are released into the bloodstream and could affect the brain.

Kachur recommends eating food high in probiotics, such as yogurt, sauerkraut, kimchi and miso soup; and avoiding high fat and high sugar diets, in order to promote the growth of bacteria that are good for your mental health.

"We've got to nurture and take care of our microbes."