Watermelon red means lycopene rich

Diets rich in lycopene, the primary pigment in tomatoes, can reduce a man’s risk of developing prostate cancer, data suggest. Now Agriculture Department scientists have found that watermelon is a far better source of the so-called carotenoid than tomatoes are and at least as well absorbed by the body.

New chemical analyses by USDA scientists show that the red part of the watermelon can have about 40 percent more lycopene than an equivalent weight of uncooked tomatoes has. More importantly, a second study finds, raw watermelon’s lycopene is available to the body, whereas little of a tomato’s lycopene is absorbed unless it’s first cooked.

Nutritionists Beverly A. Clevidence and Alison J. Edwards of USDA’s Agricultural Research Service laboratory in Beltsville, Md., recruited 23 healthy men and women for three separate 3-week trial sessions. In each phase, the scientists administered all the food that the volunteers ate.

During one session, each person downed a diet low in lycopene. During another phase, the scientists supplemented that diet each day with 3 cups of watermelon juice bearing 20 milligrams of lycopene. In a third session, half the recruits received daily tomato juice servings containing 20 mg of lycopene, and the rest received enough watermelon juice to provide 40 mg of the compound.

In this experiment, the tomato juice was a canned, heat-processed product, but the watermelon was squeezed and frozen–but never cooked.

In both trials during which volunteers drank extra juice of either kind, the recruits’ blood-lycopene concentrations increased to double those measured at the start of the trial, Edwards told Science News.

Clevidence says that this is the first study to show that the body takes up lycopene from watermelon.

Besides conferring some protection against prostate and other cancers, studies indicate that lycopene may help resist sunburn. For people who want a natural source of the plant pigment but have little appetite for cooked or processed tomatoes, watermelon offers a sweet alternative.

Janet Raloff is the Editor, Digital of Science News Explores, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer, specializing in toxicology. To her never-ending surprise, her daughter became a toxicologist.

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