1 Aug 2015

Microbial moods

From This Way Up, 12:25 pm on 1 August 2015
Microbial environment inside the human gut.

Microbial environment inside the human gut. Photo: Courtesy of Pacific Northwest National Laboratory. (CC BY-NC-SA 2.0)

The microbes living inside us can contribute to the symptoms of anxiety and depression, a new study has revealed.

Dr Chris Smith of The Naked Scientists told This Way Up's Simon Morton that the average human intestine is home to 2 kilograms of bacteria. But these bugs aren't passive passengers: new research is suggesting that they may play an active role in mood and mental illness.

Using experimental mice, McMaster University gastroenterologist Premysl Bercik found that the presence of microbes in the intestines is responsible for producing the symptoms of anxiety.

"His team believe that chemical signals produced by the intestinal microbes travel to the brain via the bloodstream", Dr Smith said, "or are picked up by nerves supplying the intestines themselves, with the result that they alter brain chemistry and mood".

Dr Smith says the implications of the work, published this week in Nature Communications, are significant as they could mean that one day depression could be better managed with pre- and pro-biotics, or perhaps even a microbial transplantation from someone in a better mood than you.