People who consume more high fibre in their diet are less likely to develop colorectal cancer, claims a study published online today by the BMJ.
UK and Dutch researchers have found that eating a diet rich in high fibre, particularly from cereal and whole grains, is associated with less risk of bowel cancer.
Colorectal cancer is the third most common cancer globally with 1.2 million new cases diagnosed every year.
It is already known that taking dietary fibre and whole grains helps protect against cardiovascular disease, but its association with colorectal cancer risk is less clear.
A positive association between dietary fibre and less likelihood of colorectal cancer has been around for decades, but studies attempting to explain the association have had inconsistent results.
The researchers set out to investigate the association between intake of dietary fibre and whole grains and risk of colorectal cancer as part of the World Cancer Research Fund/American Institute for Cancer Research’s Continuous Update Project (CUP).
They analysed the results of 25 prospective studies involving almost two million participants and found that although the overall reductions in risk of bowel cancer were small, there was a clear gradient in risk associated with the amount of dietary fibre.
Compared with the lowest levels of fibre intake, each 10g a day increase in intake of total dietary fibre and cereal fibre was associated with a 10% reduction in risk of colorectal cancer.
By adding three servings (90 g/day) of whole grains, this was associated with about a 20% reduction.
The researchers said increasing intake of dietary fibre and whole grains was also likely to reduce the risk of cardiovascular disease, type 2 diabetes, overweight and obesity, and possibly overall mortality, hence the various health benefits of increasing fibre intake were a persuasive incentive to do so.
The authors said their results provided further support for public health recommendations to increase fibre intake, particularly cereal fibre and whole grains, to help prevent colorectal cancer.
However, they stressed that further studies were needed to clarify the results for different types of fibre and subsites within the colorectum, and in populations with different lifestyles and dietary characteristics.
They concluded: “Our meta-analysis suggests that a high intake of dietary fibre, particularly from cereal and whole grains, is associated with a reduced risk of colorectal cancer. And they suggest that any further studies should report more detailed results to be included in future analyses.”
In an accompanying editorial, Professor Anne Tjønneland from the Danish Cancer Society, said: “Although a high intake of whole grain can be recommended, research is still needed to explain the biological mechanisms responsible for the beneficial effects of these foods in detail, including the effects of different types of grain.”