Eating brown bread or wholegrain cereals three times a day cuts the risk of bowel cancer by a fifth, a major study has shown.
But surprisingly, researchers found no ‘significant evidence’ that eating more legumes such as beans, peas, lentils, and peanuts, or consuming a lot of fruit and vegetables, guarded against bowel cancer.
The researchers, including experts from Imperial College London and the University of Leeds, looked at previous studies that involved almost two million people.
They found a strong link between diets rich in whole grain cereals and protection against bowel cancer – the third most common in Britain.
For every 10g a day increase in fibre intake, there was a 10 per cent drop in risk of bowel cancer.
It had been suggested since the 1960s that fibre helped the function of the intestines, protecting people from bowel cancer. But previous research provided no support for the assumption.
The latest findings, however, based on an analysis of 25 studies, showed that adding three servings (90g/3oz) of wholegrain food to a daily diet brought a 20 per cent reduction in the risk of bowel cancer.
The researchers said: ‘A high intake of dietary fibre, in particular cereal fibre and whole grains, was associated with a reduced risk of colorectal cancer.’
The findings were published in the British Medical Journal.
Professor Anne Tjonneland, of the Danish Cancer Society, reviewed the analysis for the journal and said it adds to the current evidence of the many health effects of whole grains.
Epidemiologist Dr Dagfinn Aune, of Imperial College London, said there was a clear gradient in risk reduction associated with increasing amounts of dietary fibre.
The researchers said there were ‘biologically plausible’ explanations for the benefits of dietary fibre, including its high content of folate and magnesium, which have both been associated with a reduced risk of bowel cancer.
Bowel cancer is diagnosed in 38,500 people a year in the UK, and kills more than 16,000.