Fiber fights cancer depending on gut bacteria

A high-fiber diet protects against development of colon cancer, but only if you have the necessary gut bacteria, suggests a new study in mice.

In the study, mice were fed either a low- or high-fiber diet, and some had a type of bacteria in their gut that ferments fiber into a chemical called butyrate, while others did not. All of the mice were then given a cancer-causing chemical so that they would develop colon tumors, Fox News reported.

The number of tumors was 75 percent lower in mice that were fed a high-fiber diet and had the butyrate-producing bacteria in their guts, compared with the other mice. However, the high-fiber diet by itself, without the butyrate-producing bacteria, did not protect against colon cancer; nor did a low-fiber diet with butyrate-producing bacteria.

The researchers noted that healthy colon cells use butyrate for fuel, but cancer cells do not (instead, they use the sugar glucose). Because cancer cells do not use butyrate, the chemical collects inside the cells, potentially causing them to self-destruct, said Scott Bultman, an assistant professor at the University of North Carolina School of Medicine, who presented the research at the meeting of the American Association for Cancer Research.