Just three servings a month of raw broccoli or cabbage can reduce the risk of bladder cancer by 40 percent. Other studies show that dark-colored berries can reduce the risk of cancer too, adding more evidence that shows fruits and vegetables, especially richly colored varieties, can reduce the risk of cancer, researchers reported Monday.

One team of researchers at the Roswell Park Cancer Institute in Buffalo, New York, surveyed 275 people who had bladder cancer and 825 people without cancer. They studied especially about cruciferous vegetables such as broccoli and cabbage. These foods are rich in compounds called isothiocyanates, which are known to lower cancer risk.

They found that the effects were most in nonsmokers. Compared to smokers who ate fewer raw cruciferous vegetables, nonsmokers who ate at least three a month were almost 73 percent less likely to be in the bladder cancer group.

Among both smokers and nonsmokers, those who ate this minimal amount of raw veggies had a 40 percent lower risk. Researchers did not find the same effect for cooked vegetables, because cooking can reduce 60 to 90 percent of isothiocyanates

A second team of researchers from Roswell Park tested broccoli sprouts in rats. Dr. Yuesheng Zhang, who led the research, said that the more rats ate, the less likely they were to develop bladder cancer. The compounds were processed and excreted within 12 hours of feeding. That suggests the idea that compounds are protecting the bladder from the inside.

In a third study, a team at The Ohio State University fed blackberries, sometimes called blackcaps, to patients with conditions leading to esophageal cancer. Researchers fed 32 grams of black raspberries to women and 45 grams to men every day for six months. They found that 58 percent of patients had marked less damage, and black raspberries are also rich in cancer-fighting compounds which can help interfere with cancer causing damage.