African diet cuts risk of bowel cancer

Eating habits have a directt effect on the kinds of bacteria found in the bowel and therefore on the risk of bowel, or colorectal, cancer. This has been demonstrated by an interdisciplinary study in which microbiologists from Wageningen University were involved.Bowel cancer is more common among? African Americans than black South Africans: 65 cases per 100,000 people asopposed to fewer than 5. This is partly attributed to the American diet, which contains more animal protein and? longchain fatty acids, and less fibre. The two groups prepare their food differently too. The international research team published an article in Nature Communications in April describing their study of the role of fat and fibre. They put African Americans on a high-fibre, low-fat diet for two weeks, and rural Africans on an American-stylehigh-fat, low-fibre diet.Big differences exist between these two groups, including the composition of their gut flora and the concentrations of the bacteria?s fermentation products, such as short-chain fatty acids.The researchers found that in both cases the temporary change in diet had a big impact on the bacteria and metabolic products which are seen as risk factors for developing bowel cancer. Among the Americans morerisk-reducing butyrate was released, while among the Africans levels of the harmful production of secondary bile salts went up.Moreover, among the Africans on the American diet, more biomarkers for bowel cancer were found in the colorectal mucosa. These are substances associated with a raised risk because they can lead to abnormalities in the colorectal mucosa, which can result in bowel cancer. Among the Americans on an African diet, by contrast, these biomarkers went down.Info: erwin.zoetendal@wur.nl, Wageningen World, 2015/3