In a review of scientific data, the Food and Drug Administration has found almost no evidence that tomatoes or the antioxidant lycopene have any effect in cancer prevention.

The review, published online July 10 in the Journal of the National Cancer Institute, examined 81 studies of lycopene and concluded that none produced any credible evidence to support a relationship between consumption of the antioxidant either in food or dietary supplements, and the risk for prostate, lung, colorectal, gastric, breast, ovarian, endometrial or pancreatic cancer.

The authors also examined 64 observational studies of tomato or tomato product consumption and cancer risk. Twenty-five of them were eliminated because they were a republication of old data or because they had deficiencies that prevented drawing scientific conclusions.

Of the 39 remaining studies, the authors found no evidence that tomato consumption reduced the risk of lung, breast, colorectal, endometrial or cervical cancer. They concluded that it was at best very unlikely that eating tomatoes had any effect on the risk for pancreatic, prostate, gastric or ovarian cancer.

There is no basis, the authors write, for manufacturers to make health claims for lycopene as a food ingredient or a dietary supplement, and they said claims about the effect of tomatoes on prostate, ovarian, gastric and pancreatic cancer should be qualified by noting that such assertions are unlikely, uncertain or lacking in scientific evidence.

A separate scientific study, published last week in the Journal of the American Medical Association, found that a low-fat diet rich in fruits and vegetables had no benefit in preventing the recurrence of breast cancer. Earlier studies had claimed the opposite.