Low-fibre western diets deter 'good bacteria'

WE ARE what we eat. If this applies to gut bacteria too, it could explain higher rates of allergies and other inflammatory diseases in rich nations.

So says Paolo Lionetti of the University of Florence, Italy, who compared the gut bacteria of children in Burkina Faso and Italy. The stools of the African children contained almost three times as many short-chain fatty acids (SCFAs).

SCFAs are generated by bugs associated with diets containing a very high proportion of vegetables and cereals.

SCFAs kill harmful gut bacteria such as salmonella and help protect against inflammation. Allergies are often the result of an excessive inflammatory response to otherwise harmless agents.

Breastfed infants in both countries had the same gut bacteria profiles, so diet rather than other environmental factors or genes seems to dictate which bacteria colonise the gut.

Glenn Gibson of the University of Reading, UK, says the results could pave the way for allergy treatments based on gut bacteria.