Two UCC scientists who discovered a link between mood and bacteria in the gut are planning to develop a new “psychobiotic” to treat depression.

Professors Ted Dinan and John Cryan have spent 14 years investigating how the trillions of bacteria living in our gut – the microbiota – can control our brains. “What we have discovered is that the microbiota influences our emotions to a very significant extent,” said Prof Dinan, of the Department of Psychiatry and APC Microbiome Institute, University College Cork.

They began investigating how probiotics could have potentially positive effects on mood “What happens in depression, is that for whatever reasons, the microbiota is less diverse and this influences brain function,” said Prof Dinan, who added that a diet rich in fibre, fish, fruit and vegetables was necessary to maintain a sufficiently diverse microbiota. “The Mediterranean diet is probably the best for health in terms of heart, mood and the microbiota.”

Gut flora A few years ago, they began investigating how probiotics – bacteria associated with healthy gut flora such as the Lactobacillus acidophilus and Bifidobacterium lactis that are often advertised in “live” yoghurt – could have potentially positive effects on mood. “We were trying to identify the bacteria, which, when we ingest them, are potentially beneficial.”

The team identified one bacteria, which – when ingested in adequate amounts in humans and animals – reduced anxiety levels.

He said he and Prof Cryan now plan to develop what he described as a “psychobiotic”, or in other words, “a good probiotic product for treating the milder forms of depression”.