According to an international study published in Nature Communications conducted by scientists at the University of Pittsburgh School of Medicine, African-Americans and Africans who swapped their regular diets for just 2 weeks altered their risks of developing colon cancer, revealed by alterations in their gut bacteria.
Lead author Stephen O’Keefe, a professor of medicine at the Pitt School of Medicine, noticed that his rural South African patients rarely had intestinal polyps or even colon cancer. However, in a Western scenario, colon cancer is the 2nd-leading cause of cancer death in the African-American demographic.
“The African-American diet, which contains more animal protein and fat, and less soluble fiber than the African diet, is thought to increase colon cancer risk. Other studies with Japanese migrants to Hawaii have shown that it takes only one generation of Westernization to change their low incidence of colon cancer to the high rates observed in native Hawaiians. In this project, we examined the impact of a brief diet change on the colon in a controlled setting where we didn’t have to worry about the influence of smoking and other environmental factors on cancer risk,” explained Dr. O’Keefe.
A total of 20 African-American and 20 rural South African volunteers between 50 and 65 years old had their in-home diets assessed and their meals altered. They ate meals that scientists prepared using both techniques and ingredients typical of the opposite group. Fecal and colon samples from each volunteer were examined after the two-week study period.
The diet change was brief but it was enough to observe that each group experienced an opposite cancer risk rate and characteristics.
“We can’t definitively tell from these measurements that the change in their diet would have led to more cancer in the African group or less in the American group, but there is good evidence from other studies that the changes we observed are signs of cancer risk,” noted co-author Jeremy Nicholson, Imperial College London.
In short, increasing the amount of fiber in the diet (to 5 times more) evidenced reduced cancer risk and eating less animal fat and proteins also proved helpful.
“These findings are really very good news. In just two weeks, a change in diet from a Westernized composition to a traditional African high-fiber, low-fat diet reduced these biomarkers of cancer risk, indicating that it is likely never too late to modify the risk of colon cancer,” concluded Dr. O’Keefe.