Study: Fiber Fails To Prevent Colon Cancer

B O S T O N, October 13 -- The belief that a diet high in fiber can prevent colon cancer continues its downward spiral, with a new report further discrediting the once highly regarded theory.

A team of European researchers reporting Thursday in the British journal Lancet found fiber as an additive to food did not seem to prevent the formation of potentially cancerous polyps in the colon.

But doctors say your morning bowl of bran shouldn’t be dumped entirely: fiber, which is found in fruits, veggies, nuts and grains, probably still can lower cholesterol, improve bowel regularity and help diabetics control their blood sugar.

The Lancet study comes on the heels of two high-profile reports published in the New England Journal of Medicine in April that found no link between colon cancer prevention and a high-fiber diet, consumed either as a supplement or as part of a whole food. The association has been nearly dogma among health-care professionals for decades.

In fact, the Food and Drug Administration in 1993 approved claims that low-fat diets rich in fiber-containing grain products, fruits and vegetables “may reduce risk of certain cancers,” allowing food manufacturers to advertise those properties on the sides of cereal boxes.

But this week, the agency announced it would not permit any dietary supplement manufacturer to make the more direct claim that fiber can reduce the risk of colon cancer, in light of more current evidence.

History of a Hypothesis So how did the theory of fiber and cancer risk ever come to pass? The idea dates to an observation made by Dr. Denis Burkitt, a British missionary doctor who in the early 1970s compared colon cancer rates between America and Africa. He attributed the high cancer incidence in affluent Western countries to diets high in animal fats, and the low cancer rates in poorer countries such as Africa to the diets high in plant-based fiber.

Initially, research in animals and observations of large populations seemed to bear out his theory.