SEATTLE, WASHINGTON. There is abundant evidence that a high intake of fruits and vegetables is protective against many types of cancer. Researchers at the Fred Hutchinson Cancer Research Center now report that the intake of vegetables, but not fruits, is significantly associated with prostate cancer risk. Their study involved 628 men from the Seattle area between the ages of 40 and 64 years who had been diagnosed with prostate cancer between January 1 and December 31, 1996. An age-matched sample of 602 men without prostate cancer served as the control group. All participants were interviewed and completed a 99-item food frequency questionnaire that included 12 fruit items and 21 vegetable items. The participants were asked to estimate their intake of the foods (ranging from "never or less than once per month" to "2+ per day") over the 3-5 years preceding the date of diagnosis or date of interview (for controls).
The intake of fruit did not significantly affect prostate cancer
risk. However, men who consumed 28 or more servings of vegetables
per week were found to have a 35 per cent lower risk than men who
consumed fewer than 14 servings per week. When limiting the
analysis to cruciferous vegetables only the protective effect was
found to be even more pronounced. Men who ate three or more
servings of cruciferous vegetables (broccoli, cauliflower, brussel
sprouts, cabbage) per week had a 41 per cent lower risk of
developing prostate cancer than did men who ate less than one
serving a week. A high intake of lutein plus zeaxanthin (2000
micrograms/day or more) was associated with a 32 per cent decrease
in risk, but this association was not statistically significant.
The researchers found no correlation between the intake of tomato
products or lycopene and prostate cancer risk.