Anticancer effect of "5 a day" fruit and vegetable servings is negligible

It is widely believed that cancer can be prevented by high intake of fruits and vegetables. However, inconsistent results from many studies have not been able to conclusively establish an inverse association between fruit and vegetable intake and overall cancer risk.

People who eat more fruit and vegetables than average may have a slightly reduced risk of getting cancer, a big study concludes, but the benefit is much smaller than previous studies suggested.

The European Prospective Investigation Into Cancer and Nutrition (EPIC) was a 9 year prospective study of nearly 500 000 Europeans. It concluded that the protective effect of eating fruit and vegetables is “very small” (J Natl Cancer Institute 2010).

Associations between reduced cancer risk and increased intake of total fruits and vegetables combined and total vegetables for the entire cohort were similar (200 g/d increased intake of fruits and vegetables combined, HR = 0.97); 100 g/d increased intake of total vegetables, HR = 0.98); intake of fruits showed a weaker inverse association (100 g/d increased intake of total fruits, HR = 0.99).

The reduced risk of cancer associated with high vegetable intake was restricted to women (HR = 0.98). Stratification by alcohol intake suggested a stronger reduction in risk in heavy drinkers and was confined to cancers caused by smoking and alcohol.

References:

Study finds that anticancer effect of “5 a day” is less than expected. BMJ, 2010.
Fruit and vegetable intake and overall cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). J Natl Cancer Inst. 2010 Apr 21;102(8):529-37. Epub 2010 Apr 6.