No, according to the latest, and one of the biggest and best-designed studies published recently in the Journal Cancer Epidemiology, Biomarkers, and Prevention.

The research, led by nutritionist and epidemiologist Ulrike Peters of the Fred Hutchinson Cancer Research Center in Seattle, began with 28,000 men, from whom researchers took and froze blood samples. Researchers then followed the men for up to eight years, during which time, 692 of the participants developed prostate cancer. Then they compared blood levels of lycopene, the ingredient in tomatoes that had been thought to protect against prostate cancer.

To their disappointment, Peters said, the team found no association between blood levels of lycopene and a diagnosis of prostate cancer. The study contradicts a study in 2006 that found a hint of a protective effect for tomato consumption as well as a 2004 meta-analysis (in which data are pooled from numerous studies) that also suggested a modest protective effect for high tomato consumption.

Perhaps even more disturbing, the new study found that high blood levels of a different molecule, beta-carotene, was actually linked to a higher risk of aggressive prostate cancer, the latest in a series of worrisome studies about beta-carotene, which is found in many colorful vegetables and is a precursor to Vitamin A.

Taken all together, the lycopene studies show that “we don’t have the evidence to jump into lycopene supplements,” said Karen Collins , nutrition adviser to the American Institute for Cancer Research, a nonprofit group based in Washington that funds research on diet and cancer. “But we do still recommend eating tomatoes, cooked and raw, not because they have magical powers but because they are a great source of many nutrients and are part of a good, plant-based diet.”