Tomato Extract May Have Role in Slowing Prostate Cancer

Men Who Used Lycopene Supplement Had Smaller, Less Aggressive Tumors

A tomato extract called lycopene – found naturally in tomatoes, pink grapefruit, watermelon, and other foods – might have a role in slowing the progression of prostate cancer, according to a small study of men undergoing surgical removal of their prostate.

Twenty-six men with prostate cancer who were scheduled to have their prostate removed were randomly assigned to receive a 15 mg capsule of lycopene twice daily for three weeks, or no supplementation. Following surgery, the prostates of men from both groups were compared.

Study author Omer Kucuk, MD, says the study was undertaken with the expectation that the supplement would only effect microscopic molecular features of the tumors, not their actual size or aggressiveness.

So when the results came in, Kucuk and colleagues were startled: the men who used the lycopene supplement actually had smaller tumors than the men who did not. Even more intriguing, the tumors taken from the men who used lycopene supplement were more likely to be confined to the prostate, and less likely to have advanced beyond it.

Kucuk cautions that the study is very small and that men should not be advised to start using lycopene supplements on the basis of this study alone. “These results are promising and provocative,” Kucuk tells WebMD. “But based on this I would not tell men to start taking supplements.”

He is professor of medicine at Wayne State University School of Medicine in Detroit. The study appeared in the August issue of the journal Cancer Epidemiology, Biomarkers and Prevention.

Kucuk notes that some previous studies have shown that men who consume foods with lycopene have a diminished risk for prostate cancer. The 15 mg supplement used in the study is equivalent to a very substantial amount of tomato product: approximately a cup of tomato paste or five pounds of tomatoes, according to Kucuk.

But nutritional experts say it can be difficult to attribute effects like the ones seen in Kucuk’s study to any one food. At least one other study looking at diet and prostate cancer found that tomatoes offered no special protection against prostate cancer.

That study, published last year in the Journal of the National Cancer Institute, found that men who consumed broccoli, cauliflower, brussel sprouts, cabbage, and kale had lower risk for prostate cancer. But tomato products did not have the same effect.

Nutrition expert Jeffrey Blumberg, PhD, cautions that larger and longer trials need to be done using lycopene supplement, especially in men who do not yet have prostate cancer, before the results seen in Kucuk’s study can be verified.

But Blumberg says the differences that were seen in the tumors after just three weeks on the supplement — especially the fact that they were less likely to have advanced beyond the prostate — is fairly remarkable.

“These are people who had prostate cancer for some time,” Blumberg tells WebMD. “If it is true that the intervention had this effect in just three weeks, that is dramatic.”

He is professor of nutrition and chief of the antioxidants research laboratory at Tufts University School of Nutrition Science and Policy in Medford, Mass.

In any case, Kucuk and Blumberg agree that foods with lycopene are likely to be most beneficial as part of an overall healthy diet. “This is one more study showing that you should eat your fruits and vegetables,” Blumberg says.

© 2001 WebMD Corporation. All rights reserved.

Written by Mark Moran for the WebMD, and published on, February 17, 2002. Embedded links may no longer be active (Ed. 12.28.10)

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