Africans and African-Americans who swapped diets for just 2 weeks had gut changes suggesting their risk of bowel cancer also changed, researchers say.

In the experiment, 20 African-Americans from Pittsburgh, USA, and 20 rural South Africans swapped diets by eating meals prepared by researchers that were typical of ingredients and cooking techniques of the other group, with the rural African diet being high in fibre and low in fat.

Before-and-after colonoscopies found individuals in each group took on gut changes typical of the norm for the other group, including reduced or increased fibre fermentation and inflammation associated with cancer risk.

African-Americans in the study had an increase in butyrate production when they switched to the high-fibre, low-fat diet. Butyrate is a by-product of the breakdown of dietary fibre by bacteria in the gut and is believed to be protective against cancer. People with inflammatory bowel disease seem to lack butyrate-producing bacteria in their guts.

Last Reviewed: 03/07/2015



1. Nat Commun 2015; online 28 Apr