The higher rates of colon cancer in Americans of African origin compared to South Africans are usually attributed to diets containing more animal protein and fat and less fibre. O’Keefe et al. investigated (in a paper published in Nature Communications) the role of fat and fibre in this association by conducting 2-week-long food changes in volunteers from both populations: African-Americans received an African-style diet high in fibre and low in fat, while rural Africans received a high-fat, low-fibre ‘Western’ diet.
The authors noted, when compared with the participants’ usual diets, the food changes led to “remarkable reciprocal changes in mucosal biomarkers of cancer risk”. The dietary switch also changed the microbiota and metabolome in ways known to affect cancer risk.
O’Keefe SJD, et al. (2015) Fat, fibre and cancer risk in African Americans and rural Africans. Nature Communications doi:10.1038/ncomms7342