High-Fiber Diet May Reduce Colon Cancer Risk; Colorectal Cancers Affected by Gut Bacteria

Switching to a high-fiber diet could help minimize the risk of developing colon cancer. The discovery was made in an experiment involving diet swapping by volunteers from the United States and South Africa.

The findings suggest that a certain bacteria found in the gut could be responsible for the development of the disease. According to UK Cancer Research, further study is needed to confirm this information. The international study was published in the journal Nature.

In the research, the two groups swapped their typical diets. For two weeks, the US African-American volunteers were told to eat a low-fat, high-fiber African diet while the rural African volunteers were told to eat more junk food, according to Tech Times.

"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," Dr. Stephen O'Keefe of Pittsburgh School of Medicine and principal investigator, as reported by Medical Xpress. 

"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," he said. "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."

While Dr. O'Keefe was practicing in South Africa, he noticed that his patients from rural areas rarely had colon cancer or polyps in the intestines - a possible cancer precursor which made him investigate. The volunteers only ate meals prepared by the team, using typical ingredients and cooking styles that are normally used to prepare each group's food. The team then investigated fecal and colon content samples for their research.

They were able to find that the two-weeks diet swapping was enough to affect the number of biomarkers linked to colon cancer risk. The diet change was reflected in the rate of cell turnover in the intestinal lining, bacterial metabolic activity, fiber fermentation levels, and inflammation.

"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," said Jermey Nichoslon of London's Imperial College and co-author of the study via CBS News.

O'Keefe found the results to be 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," he added.