Eating a high-fibre diet may not actively prevent colon cancer, recent research has found.

People who eat a lot of fibre in the form of vegetables, cereals and fruit are marginally less likely to develop colon cancer.

But the effect is outweighed by other factors, according to writers for the Journal of the American Medical Association.

People have been encouraged to eat fibre since the 1960s when British physician Denis Burkitt cited its protective properties.

Birkitt had observed a low incidence of colon cancer among Africans and thought their high-fibre diet was responsible.

But more recent analysis has shown the link weakens when other dietary factors, such as red meat, milk and alcohol are considered.

“We did not find support for a linear inverse association between dietary fibre intake and the risk of colorectal cancer,” the US writing team concluded.

However, a high-fibre diet based on whole plant foods has been shown to help prevent other diseases such as heart disease and diabetes, it claimed.