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Can food change our behaviour?

There's therapeutic potential in the discovery that bacteria residing in our gut influences brain function.
Can food change our behaviour?

Drs. Steve Collins (right) and Premik Bercik have discovered that gut bacteria influence brain function

We've all heard phrases such as “mood food” and “You are what you eat.” But do we really understand them?

It's true that certain foods – coffee and chocolate are examples – contain chemicals that stimulate the brain. Now, emerging evidence indicates that food may play a more subtle role in actually modulating our behaviour by influencing the composition and activity of bacteria hosted by the human body.

The gut contains vast communities of bacteria that reside in harmony with our bodies. We share our diets with these microbes and the nature of our diet influences the types of bacteria that we harbour.

Recent work by researchers in the Farncombe Family Digestive Health Research Institute and in the Brain Body Institute has provided clear evidence that these resident bacteria influence brain function. For example, young mice raised in a germ-free environment have a different chemical profile in the brain and show less anxiety than mice raised under normal circumstances. In addition, the behaviour of adult mice can be changed by perturbing their resident bacterial composition, such as by administering oral antibiotics.

These observations show that our gut bacteria influence brain function, most likely via the production of metabolites. This research has therapeutic potential for the management of behavioural disorders.
Studies from the laboratory of Drs. Premek Bercik and Stephen Collins in the Farncombe institute have shown that specific commensal bacteria, administered as food additives in the form of probiotics, can induce changes in brain chemistry and reduce anxiety-like behaviour in mice. The researchers – in collaboration with Dr. Elena Verdu, of the institute – have also shown that specific probiotic bacteria can restore normal feeding behaviour in mice whose eating patterns had become distorted after a stomach infection.

Thus, it may be possible to influence a spectrum of behaviours, ranging from appetite to mood, by providing specific probiotic bacteria or by promoting the selective growth of these within the gut by modifying dietary components.

Bercik is now conducting a clinical trial of a probiotic on the Irritable Bowel Syndrome (IBS), the most common gastrointestinal condition seen in our society. Up to 60 per cent of IBS patients exhibit such behaviours as anxiety or depression. Bercik will determine whether this Lactobacillus probiotic will improve not only gastrointestinal symptoms but also reduce psychiatric symptoms.

“The notion that our resident gut bacteria might influence brain chemistry and behaviour is novel and much of the original work has been conducted here at McMaster” says Collins. “The possibility that we may be able to alter behaviour by modifying the bacterial composition of the gut, using probiotics or dietary modification, is exciting. But I have to stress that we must be cautious in extrapolating our work into humans at this time. We must await the results of clinical studies.”