Tomato Research Heating Up

Study finds cooked tomatoes have more antioxidants than raw

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By
HealthDay Reporter

FRIDAY, April 26, 2002 (HealthDayNews) -- If you want to boost the cancer and heart disease-fighting ability of your diet, try adding some cooked tomatoes.

Whether it's sauce on your spaghetti or pizza, tomato soup or even ketchup, the latest research says heated tomatoes have higher levels of lycopene and other antioxidants.

"It's a popular misconception that processed foods have a lower nutritional value," says study author Dr. Rui Hai Liu, an assistant professor of food sciences at Cornell University. "But we found that processed tomatoes have higher antioxidant activity and lycopene than fresh tomatoes."

Lycopene is the substance that gives tomatoes their red color. Tomatoes are the main dietary source of lycopene, although it is also found in watermelon, papaya and pink grapefruit. Previous studies have shown lycopene may help prevent prostate, lung and stomach cancer, and even heart disease, according to the American Cancer Society.

For this study, which appears in the current issue of the Journal of Agriculture and Food Chemistry, the scientists heated tomatoes to just over 190 degrees Fahrenheit for two, 15 and 30 minutes.

Total antioxidant levels rose by 28 percent after two minutes and as high as 62 percent after a half an hour. Lycopene levels rose 6 percent at the two-minute mark, 17 percent after 15 minutes and 35 percent after 30 minutes.

Additionally, according to Liu, cooking makes the lycopene in tomatoes more "bioavailable," which means it's more readily absorbed and used by the body.

The only drawback to cooking tomatoes is that they lose some vitamin C content, Liu says. After two minutes, vitamin C levels were down 10 percent. After a half hour, they were down by almost 30 percent.

"What we see here is another study that points to the fact that processing can actually enhance the availability of some nutritional factors," says Melanie Polk, director of nutrition education for the American Institute for Cancer Research.

"The bottom line is that you should get fruits and vegetables however you can -- fresh, cooked, canned or frozen. Just get them!" she says.

What To Do

For more information about lycopene and its health benefits, go to the American Cancer Society or read this article from the Canadian Food Information Council on C-Health.

To learn more than you ever thought you could possibly know about the tomato, visit the California Tomato Commission.

SOURCES: Rui Hai Liu, M.D., assistant professor, food sciences, Cornell University, Ithaca, N.Y.; Melanie Polk, director, nutrition education, American Institute for Cancer Research, Washington D.C.; April 2002 Journal of Agriculture and Food Chemistry

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