Should've Had a V8 -- Tomatoes May Help Blood Vessels

From the WebMD Archives

Jan. 20, 2000 (Atlanta) -- There's new evidence from Holland that chowing down on foods such as tomatoes may not only help you ward off cancer, but it may also help keep your arteries free from plaque buildup, a process called arteriosclerosis. That's according to a study in the January edition of the American Heart Association's journal Atherosclerosis. Arteriosclerosis is a general term for the thickening and hardening of arteries due to deposits of plaque. Plaque in the arteries reduces blood flow and leads to heart attacks or strokes.

In this study, researcher J.C.M. Witteman writes that much of the credit for preventing arteriosclerosis appears to belong to a substance called lycopene -- an antioxidant carotenoid. Antioxidants protect from long-term damage due to free radicals, which are produced naturally within the body. Carotenoids are related to carotene, which gives carrots and other vegetables color.

Lycopene is a potent antioxidant that helps to prevent the LDL (or "bad") cholesterol in the bloodstream from being converted to oxidized LDL that forms plaques in arteries and causes heart attacks. Lycopene is found in tomatoes and other brightly colored vegetables, such as watermelon and red grapefruits, but it is absorbed in greater quantities from cooked tomatoes, rather than from fresh ones. Previous research has shown the best sources are tomato paste, sauce, and ketchup.

In this study, part of a larger group known as the Rotterdam Study, researchers at Erasmus University medical school in Rotterdam found that higher levels of lycopene in the blood meant lower levels of artery-clogging plaque. The Rotterdam study includes almost 8,000 persons age 55 or older living in a suburb of this city in the Netherlands. Blood samples were analyzed for concentrations of the major carotenoids, including lycopene. Samples were then classified as having moderate to severe atherosclerosis by the presence of plaque. None of the subjects had taken beta-carotene as a supplement, but some reported intake of A, E, C, or multivitamin supplements.

The researchers found that all the carotenoids were significantly higher in women than men except for lycopene, and the older the subject, the lower the level of most carotenoids. Perhaps more startling, researchers discovered that higher concentrations of lycopene equaled lower plaque, particularly in smokers and former smokers.

"We know smokers have very high levels of free radicals in their system," A. Venketeshwer Rao, PhD, tells WebMD. Rao, who reviewed the study for WebMD, is a professor in the department of nutritional sciences and co-director of the program in food safety at the University of Toronto in Canada.

"I do think the pieces are falling into place" regarding the role of the antioxidant, Rao says. "Oxidation plays an important role in [cardiovascular] risk," Rao adds. "A glass of tomato juice may go a long way in preventing chronic diseases."

The researchers in Holland admit that a single blood specimen may not reflect changes in lycopene or other carotenoids over time, but believe their conclusions are correct. Still, they say, whether lycopene itself is the helpful substance or just occurs alongside another important substance remains to be seen, the Rotterdam investigators write.

Foods High in Lycopene

Tomato, fresh, cooked, or canned
Tomato paste
Tomato juice
Tomato sauce
Apricot, raw or dried
Pink grapefruit
Guava juice
Guava fruit
Papaya fruit