By Maureen Williams, ND
Healthnotes Newswire (August 16, 2007)—Your mother was right when she told you to eat your broccoli: new research suggests that eating vegetables in the cruciferous family—such as broccoli, cabbage, Brussels sprouts, cauliflower, collards, mustard greens, kale, and turnips—might prevent bladder cancer.
Cruciferous vegetables are rich in glucosinolates, compounds that break down through cooking or crushing into indoles and isothiocyanates (ITCs). Both indoles (particularly indole-3-carbinol) and ITCs have demonstrated anticancer properties in laboratory studies.
Eating a lot of cruciferous vegetables has been associated with lower risk of lung and colorectal cancers, and some research has also found lower risk of breast and prostate cancers, though the findings are inconsistent. Indole-3-carbinol supplements from cruciferous vegetables have become popular with people trying to treat or prevent cancer, partly due to evidence that it changes estrogen metabolism and might reduce its cancer-causing potential. Preliminary research suggests that supplementing with indole-3-carbinol might be helpful in treating precancerous lesions of the cervix.
In the current study, published in the International Journal of Cancer, 697 people with newly diagnosed bladder cancer were matched with 708 healthy people of similar age, gender, and ethnicity. The amount of cruciferous vegetables eaten and daily ITC intake were calculated for each person based on an interview and answers to a diet questionnaire.
At the end of the study, the people without bladder cancer had eaten more cruciferous vegetables and had higher ITC intake than the people with bladder cancer. Eating more cruciferous vegetables reduced risk by 29% compared to those who ate less, and when the participants were divided into four groups based on ITC intake, those in the group with the highest intake had 41% less chance of bladder cancer than those with the lowest.
The protective effect was more prominent in men, older people, and smokers, especially heavy smokers. “The stronger effect in ever smokers [people who have ever smoked, even if they have quit] and heavy smokers is not surprising,” the authors said, citing previous evidence that ITCs can reduce the cancer-causing effects of some tobacco compounds.
“Our data provide strong evidence that consumption of ITCs from cruciferous vegetables protects against bladder cancer,” the researchers stated in their conclusion. This adds to a growing body of research showing that eating vegetables in general, and cruciferous vegetables in particular, can help people avoid cancer. The National Cancer Institute currently recommends eating five to nine servings of fruits and vegetables per day; but a separate recommendation for cruciferous vegetables might be in order based on the mounting evidence of their anticancer effects.
(Int J Cancer 2007;120:2208–13)
Maureen Williams, ND, received her bachelor’s degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice in Quechee, VT, and does extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.
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