Eating more cereals and whole grains could reduce the risk of developing colorectal cancer, a BMJ study says.

英国医学杂志一项研究显示，多吃谷类食品能降低患结肠直肠癌的几率。

Researchers from Imperial College London found that for every 10g a day increase in fibre intake¹, there was a 10% drop in the risk of bowel² cancer.

But their analysis of 25 previous studies found that fruit and vegetables fibre did not reduce risk.

A cancer charity called for more detailed³ research on the quantity and type of fibre to eat.

Eating fibre and whole grains is known to help protect against cardiovascular（心血管的） disease, but experts say that any link with colorectal cancer is less clear because studies have not had consistent results.

Reviewing the results of all previous observational studies in this area, researchers in London, Leeds and the Netherlands analysed data provided by almost two million people.

Their conclusion, published in the British Medical Journal, is that increasing fibre intake, particularly cereal fibre and whole grains, helps prevent colorectal cancer.

Whole grains include foods such as whole grain breads, brown rice, cereals, oatmeal（燕麦） and porridge.

Dagfinn Aune, lead study author and research associate in the department of epidemiology（传染病学） and biostatistics（生物统计学） at Imperial College London, said their analysis found a linear（线的） association between dietary fibre and colorectal cancer.

"The more of this fibre you eat the better it is. Even moderate amounts have some effect."

Adding three servings (90g per day) of whole grains to diets was linked to a 20% reduction in the risk of colorectal cancer, researchers said.

Cancer Research UK data shows that the lifetime risk of being diagnosed with colorectal cancer in the UK is estimated to be one in 14 (6.9%) for men, and one in 19 for women (5.4%).

However, the study said there was no evidence that fibre in fruit and vegetables played a part in reducing risk.

A previous study which showed a reduction in risk with high intake of fruit and vegetables suggests that compounds other than fibre in fruit and vegetables could account for this result, said the authors.

They also said that the health benefits of of increasing fibre and whole grains intake was not restricted to colorectal cancer.

"It is also likely to reduce the risk of cardiovascular disease, type 2 diabetes⁴, overweight and obesity⁵, and possibly overall mortality," the researchers said.