Digestive problems, especially for people over the age of 60 may be due to a change in intestinal bacterial colonies or flora. The balance is thus more heavily weighted towards ‘unfriendly’ bacteria, which may make them more susceptible to gastrointestinal infections and bowel conditions such as irritable bowel syndrome.

Restoration of the friendly bacteria in our gut may help ward off these bowel conditions.

• Glenn Gibson, Professor of Microbiology in the School of Food Biosciences, University of Reading, UK.