Tomatoes Show Little Effect in Reducing Cancer Risk

"The FDA should keep dietary advice simple, and not permit health claims for foods like tomatoes and tomato sauce when the agency itself has found that the evidence is weak."

Lonely Lycopene

Though researchers are still unclear on exactly why lycopene does not appear to reduce the risk of cancer alone, one possibility is that it has to work in tandem with other substances in tomatoes to be beneficial.

"Most whole foods -- especially whole grains, soy and beans -- are a complex package of nutrients, fibers, phytochemicals, minerals and some have phytosterols and antinutrients," said Dr. James Anderson, professor of medicine and clinical nutrition at the University of Kentucky.

"Working synergistically, these components may offer benefits not seen with isolated ingredients."

Others agree that the total nutritional value food is more than just the sum of its parts.

"Even if lycopene is the key nutrient in the tomato, it may need the other compounds in the tomato to do its best work," said Keith Ayoob, associate professor of pediatrics at the Albert Einstein College of Medicine.

"This isn't exclusive to tomatoes. Better preliminary results with weight loss were found with dairy calcium than with calcium supplements, and the list could go on."

Absence of Proof, or Proof of Absence?

But while the latest round of research delivers a blow to lycopene, most agree that more studies are needed.

"Nutrition science is constantly evolving," said Ayoob. "Studies aren't perfect, and no one study is ideal, so there have to be many. So many of the epidemiological studies are treated as gospel, and that's wrong."

Others point out that this was a review of previous studies, not a large, randomized clinical trial, which could have yielded stronger results.

"It reaffirms what we keep learning over and over again," said Dr. David Katz, director of the Prevention Research Center at Yale University School of Medicine.

"There is no silver bullet in food. Dietary pattern influences health very powerfully. But that power does not tend to reside in a single food, and certainly not in a single nutrient. Lycopene joins the ranks of vitamin C, beta carotene, and vitamin E in this regard."