WASHINGTON: Just three servings a month of raw broccoli or cabbage can reduce the risk of bladder cancer by as much as 40%, researchers reported this week. Other studies show dark-coloured berries can reduce the risk of cancer too - adding more evidence to a growing body of research that shows fruits and vegetables, especially richly coloured varieties, can reduce the risk of cancer.

Researchers at the Roswell Park Cancer Institute in Buffalo, New York, surveyed 275 people who had bladder cancer and 825 people without cancer. They asked especially about cruciferous vegetables such as broccoli and cabbage. These foods are rich in compounds called isothiocyanates, which are known to lower cancer risk. The effects were most striking in non-smokers, the researchers told a meeting of the American Association of Cancer Research. Compared to smokers who ate fewer than three servings of raw cruciferous vegetables, non-smokers who ate at least three servings a month were almost 73% less likely to be in the bladder cancer group, they found.

A second team of researchers from Roswell Park tested broccoli sprouts in rats. They used rats engineered to develop bladder cancer and fed some of them a freeze-dried extract of broccoli sprouts. The more they ate, the less likely they were to develop bladder cancer, said Yuesheng Zhang, who led the research. They found the compounds were processed and excreted within 12 hours of feeding. That suggests the idea that compounds are protecting the bladder from the inside, said Zhang.