Fat, fibre and cancer risk in African Americans and rural Africans.

Nature communications (2015-04-29)
Stephen J D O'Keefe, Jia V Li, Leo Lahti, Junhai Ou, Franck Carbonero, Khaled Mohammed, Joram M Posma, James Kinross, Elaine Wahl, Elizabeth Ruder, Kishore Vipperla, Vasudevan Naidoo, Lungile Mtshali, Sebastian Tims, Philippe G B Puylaert, James DeLany, Alyssa Krasinskas, Ann C Benefiel, Hatem O Kaseb, Keith Newton, Jeremy K Nicholson, Willem M de Vos, H Rex Gaskins, Erwin G Zoetendal
ABSTRACT

Rates of colon cancer are much higher in African Americans (65:100,000) than in rural South Africans (<5:100,000). The higher rates are associated with higher animal protein and fat, and lower fibre consumption, higher colonic secondary bile acids, lower colonic short-chain fatty acid quantities and higher mucosal proliferative biomarkers of cancer risk in otherwise healthy middle-aged volunteers. Here we investigate further the role of fat and fibre in this association. We performed 2-week food exchanges in subjects from the same populations, where African Americans were fed a high-fibre, low-fat African-style diet and rural Africans a high-fat, low-fibre western-style diet, under close supervision. In comparison with their usual diets, the food changes resulted in remarkable reciprocal changes in mucosal biomarkers of cancer risk and in aspects of the microbiota and metabolome known to affect cancer risk, best illustrated by increased saccharolytic fermentation and butyrogenesis, and suppressed secondary bile acid synthesis in the African Americans.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Hydrogen peroxide solution, 30 % (w/w) in H2O, contains stabilizer
Supelco
Hematoxylin
Sigma-Aldrich
Hematoxylin, certified by the Biological Stain Commission
Sigma-Aldrich
Hydrogen peroxide solution, 34.5-36.5%
Sigma-Aldrich
Hydrogen peroxide solution, contains potassium stannate as inhibitor, 30-32 wt. % in water, semiconductor grade, 99.999% trace metals basis