More Evidence on the Protective Effects of Antioxidants

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Aug. 8, 2000 -- Thanks to the work of researchers at the University of California, Irvine, and a pack of lab rats, scientists may be one step closer to understanding one of the underlying causes of high blood pressure.

The researchers were able to pinpoint a chemical in the body called nitric oxide that may be involved in the development of high blood pressure. And they were able to show that changing the levels of this chemical by using antioxidants can lower high blood pressure.

Natural antioxidants include vitamins C and E, carotenoids, and selenium. They are able to rid the body of substances called free radicals, which are produced on a regular basis in the body just from daily wear and tear and can do damage to bodily tissues.

The researchers found that free radicals can also lower the amount of nitric oxide in the body. Nitric oxide helps lower blood pressure by opening up the blood vessels.

By giving the rats antioxidants, the researchers were able to increase nitric oxide levels and thus lower the animals' blood pressure.

Study author N.D. Vaziri, MD, tells WebMD people shouldn't just "run out and eat antioxidants; it could make the system far worse." He says no one is sure which antioxidants, and in what amounts, may reduce high blood pressure in humans. "The road ahead is far more complex than what appears on the surface," he says.

Instead, he says a balanced diet is a body's best bet. Vaziri is professor of medicine and head of the nephrology and hypertension division of the University of California, Irvine, School of Medicine.

James Joseph, PhD, chief of the Neuroscience Laboratory at the Human Nutrition Research Center on Aging at Tufts University, agrees with Vaziri. "One thing that is clear, not only from this study but also from other studies, is that diets that contain a lot of antioxidants may offer some protection against this.

"My gut feeling is you are better off with the good diet," says Joseph. "If somebody wants to get up every morning and take a multivitamin, I don't see anything wrong with that, but I wouldn't run out and buy vitamin C and E supplements. If you eat [enough] servings of fruits and vegetables a day, I think you can get enough to really raise your antioxidant levels so that you don't need to worry about loading up on all these supplements in the store."

The study appears in the latest issue of Hypertension: Journal of the American Heart Association.

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