No evidence lycopene thwarts cancer: FDA

NEW YORK (Reuters Health) - Claims for the cancer-preventing potential of tomatoes and lycopene should be sharply limited, the US Food and Drug Administration has concluded.

There is no credible evidence that intake of lycopene, the pigment that gives tomatoes their bright red color, cuts the risk of any type of cancer, report Dr. Claudine Kavanaugh and colleagues of the FDA's Center for Food Safety and Applied Nutrition, College Park, Maryland, in an article published online July 10 in the Journal of the National Cancer Institute.

"No credible evidence" exists that tomatoes prevent lung, colorectal, breast, cervical or uterine cancers, the investigators state, while there is only "very limited evidence" that tomatoes can reduce the risk of prostate, ovarian, gastric and pancreatic cancer.

But the FDA's conclusions should not be interpreted as confirmation that tomatoes are not beneficial in warding off prostate cancer, Dr. Edward Giovannucci of the Harvard School of Public Health writes in an editorial accompanying the report.

"Although it may be premature to espouse increased consumption of tomato sauce or lycopene for prostate cancer prevention, this area of research remains promising," Giovannucci notes.

The FDA began reviewing data on tomatoes and lycopene after a coalition of tomato product and supplement makers requested permission to make qualified claims that their products prevented cancer. The agency evaluated 145 studies of lycopene, tomato, or tomato product intake and cancer risk to come to its conclusion.

In his editorial, Giovannucci points out that today many prostate cancers are identified very early with the PSA test. Studies that supported a preventive effect of lycopene or tomatoes were largely done before the PSA era, or in countries where the PSA test isn't widely used, meaning the cancers involved were more advanced, he explains.

It's therefore possible, Giovannucci says, that tomatoes and lycopene could be helpful in preventing more advanced-stage cancer, but may have no effect on the earlier-stage, and more possibly benign, disease identified by PSA tests.

SOURCE: Journal of the National Cancer Institute, online July 10, 2007.