5 a day force, new evidence

The impact of vegetables, fruits and fiber on rectal cancer have a role to play in reducing rectal cancer risk with findings from new study suggesting high intakes could cut risk by up to a third with whole grain foods as a particularly strong anti-cancer agent. In contrast, refined grains could actually increase risk, say the researchers.

High intakes of vegetables, fruits and wholegrain foods reduces the risk of rectal cancer by 28 per cent, 27 per cent and 31 per cent, respectively, according to researchers from the university of Utah in the US, who also found that high intakes of refined grains could up the risk of rectal cancer by 42 per cent.

Data from 952 incident cases of rectal cancer were compared with data from 1205 population based controls living in Utah or enrolled in the Kaiser Permanente Medical Care Programs in northern California. Participants were asked to recall foods eaten, the frequency at which they were eaten, the serving size, and whether fats were added in the preparation.

The researchers found that high vegetable intakes - more than five servings a day - were associated with a 28 per cent reduction in the risk of rectal cancer in both sexes combined. High fruit intakes, more than five, were significantly protective, reducing risk by 27 per cent. Legume intake did not alter the risk of rectal cancer, say the scientists.

High fiber diet - more that 34 grammes a day reduced risk of rectal cancer by a staggering 66 per cent while intake of wholegrain products, more that three servings a day was associated with a 31 per cent reduced risk of rectal cancer. Refined grains products, in excess of 4.5 servings a day, were associated with an increased risk of 42 per cent.

'The results suggest that plant foods may be important in the etiology of rectal cancer in both men and women. Age at diagnosis appears to play an important role in the association,' said the researchers.

The paper, 'Plant foods, fiber, and rectal cancer,' by M. L. Slattery, K. P. Curtin, S. L. Edwards and D. M. Schaffer was published in the American Journal of Clinical Nutrition (2004) 79:274-281.