A high fiber intake appears to reduce the risk of colon cancer, but had no impact on rectal cancer.

Previous research on the link between high fiber intake and colorectal cancer has been controversial - some studies show a protective effect and others do not. Researchers for the US National Cancer Institute now report on a comparison between 3,600 people with at least one adenoma in the bowel - a polyp which often precedes cancer - and 34,000 individuals with no polyps.

Those in the top 20 per cent of dietary fiber intake had a 25 per cent reduced risk of adenoma compared to those in the bottom 20 per cent. The difference in intake was about 24 grams a day and the protective effect most significant for fiber from grains, cereals and fruits. There was no link between fiber intake and rectal cancer.

Meanwhile, a European study reveals similar results. A study of over half a million individuals showed that those eating 35 grams a day of fiber, on average, had a 25 per cent reduced risk of colorectal cancer, compared to those eating 10 grams a day or less. A more detailed analysis showed that the greatest reduction in risk was in left-sided colon cancer.

Source

The Lancet 3rd May 2003