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Reuters Health Information 2005. © 2005 Reuters Ltd.
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By David Douglas
NEW YORK (Reuters Health) Feb 24 - Dietary lycopene and other carotenoids may be protective against prostate cancer, Australian and Chinese researchers report in the March 1st issue of the International Journal of Cancer.
This is the first time such findings have been reported in an Asian population, investigator Dr. Andy H. Lee told Reuters Health. The findings confirm those of other studies that have identified lycopene as a protective agent against some types of cancers.
Dr. Lee, of Curtin University of Technology, Perth, and colleagues note that there is a lack of evidence in Asian countries on the possible benefits of dietary carotenoids. Among reasons is the low incidence of prostate cancer.
To investigate further, the researchers conducted a case-control study in southeast China. Involved were 130 patients with histologically confirmed adenocarcinoma of the prostate, and 274 controls. The controls were hospital inpatients without prostate cancer or malignant diseases.
The subjects were interviewed about food consumption and a variety of other matters. After adjustment for factors including, age, total fat and caloric intake as well as a family history of prostate cancer, diet appeared to have an influence.
The risk of prostate cancer declined with increasing consumption of lycopene, alpha-carotene, beta-carotene and other carotenoids. Consumption of foods including tomatoes, spinach and citrus fruits was also inversely associated with cancer risk.
In particular, compared to those with the lowest intake of lycopene, those with the highest had an odds ratio for prostate cancer of 0.18. Corresponding odds ratios were 0.43 for alpha-carotene, 0.34 for beta-carotene, 0.15 for beta-cryptoxanthin and 0.02 for lutein and zeaxanthine.
The researchers call for further studies to establish whether these benefits are associated with whole foods or pure carotenoids. However, they conclude that "carotenoids in vegetables and fruits may be inversely related to prostate carcinogenesis among Chinese men."
Int J Cancer 2005;113:1010-1014.