A study asked some African Americans to follow an African diet and a group of rural Africans to follow an American diet. In only 2 weeks, the African Americans showed a dramatic drop in risk factors for colon cancer and the Africans saw their risk factors rise.
The study, published in Nature Communications, asked 20 African American volunteers to eat a high-fiber, low-fat diet similar to one historically eaten in Africa. They asked 20 rural African volunteers to eat a diet high in fat and low in fiber-a lot of meat and cheese-similar to what is usually eaten in Western countries. They found that the changes in diet resulted in changes in biomarkers of cancer risk in the mucosa, the lining of the intestines.
Changes were seen in the microbiome, the bacteria that live in the intestinal system and changes seen in the metabolism of the microbiome. One of the main reasons for the change in risk factors was this change in microbial metabolism, according to the researchers. There is no way to tell how much a change in diet would have led to more or fewer cases of cancer in the individuals included in the study, but the changes seen do signify a change in cancer risk.
The Americans had a rise in the production of butyrate, which is a by-product of the metabolism of fiber in the intestines and which has some anti-cancer effects, the researchers said. When the Americans ate an African-style diet, they experienced a 2.5-fold increase in butyrate levels. There was considerably less inflammation seen in the colon in the African Americans.
The researchers said that they were surprised by how fast and how dramatically the effects were seen.
The rates of colon cancer in African Americans is 65 cases in 100,000 people; which is much higher than in people living in rural Africa, where it is 5 cases per 100,000 people.