"To my mind, that study is definitive," said Kristal. "It's a big study, extremely well executed, properly analyzed, and not biased by PSA screening."
A review of lycopene's effect on cancer by the U.S. Food and Drug Administration, published in July in the Journal of the National Cancer Institute, likewise found "no credible evidence to support an association between lycopene intake and a reduced risk of prostate, lung, colorectal, gastric, breast, ovarian, endometrial, or pancreatic cancer and very limited evidence to support an association between tomato consumption and reduced risks of prostate, ovarian, gastric, and pancreatic cancers," according to that study's authors.
So, with tomatoes, ketchup and pizza sauce crossed off the list of prostate-protecting foods, Key and others continue the search. Kristal, for instance, is on the executive committee of a randomized trial examining the effects of selenium and/or vitamin E on prostate cancer risk in 35,000 men. Results are expected in 2012, he said.
Said Key, "I am optimistic we will find something. This paper is an important piece of work, but it doesn't look like this is the answer."
For more on vitamins and cancer, visit the American Cancer Society.
SOURCES: Tim Key, Ph.D., deputy director, Cancer Research UK Epidemiology Unit, University of Oxford, U.K.; Peter Scardino, M.D., chairman, department of surgery and head, Prostate Cancer Program, Memorial Sloan-Kettering Cancer Center, New York City; Alan Kristal, DrPH, member and associate head, Cancer Pr
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