High fiber does not reduce colorectal cancer risk

Reported by Susan Aldridge, PhD, medical journalist

After other factors are taken into account, it appears that a high fiber intake does not, after all, have an effect on colorectal cancer risk.
There has been conflicting evidence over whether dietary fiber – in the form of cereals, fruits and vegetables – is protective against colorectal cancer. Now researchers at the Harvard School of Public Health report a survey of all the evidence and conclude fiber is not protective after all.

The studies covered nearly quarter of a million people in the U.S. and Europe. In the U.S. fruit and vegetables were the main fiber contributors and in Europe cereals were the main source. Fiber intake varies from 14 to 28 grams per day for men and 13 to 24 grams per day for women. A simple analysis suggested the highest fiber intakes were linked to a 16 per cent decrease in colorectal cancer risk. But when all other confounding factors were accounted for – age, red meat, milk, alcohol intake – the association between dietary fiber and cancer disappeared. But it is still worth including plenty of fiber in your diet, for it is known to protect against other chronic conditions such as heart disease and diabetes.

Source
Journal of the American Medical Association 14th December 2005 Volume 294 pages 2849-2857

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