OREGON STATE UNIVERSITY

Studies confirm value of antioxidants in heart disease

11/12/1998

CORVALLIS, Ore. - In addition to a healthy diet and exercise, a body of research now indicates that most people could significantly lessen their risk of atherosclerosis and heart disease with supplementation of specific antioxidants and vitamins, says a nutrition expert at Oregon State University.

The completed, published studies, and others under way, suggest a good approach might be the "200 rule" - 200 milligrams per day of vitamin C, 200 international units of vitamin E, and 200 micrograms of selenium - along with 400 micrograms of folate and three milligrams of vitamin B6.

The recommendations were made by Balz Frei, a professor and head of the Linus Pauling Institute at OSU and one of the nation's leading researchers on the value of vitamins and other micronutrients in disease prevention, therapies and optimal health.

"Recent evidence indicates that this type of vitamin regimen can be associated with a significantly reduced risk of heart disease," said Frei, who was one of several scientists speaking at OSU to a recent professional conference of pharmacists on the latest findings about dietary supplements and natural products on health and disease processes.

"In addition to taking these supplements, the best advice and most effective way to lower chronic disease risk and optimize health is to eat a diet low in fat, with lots of fruits and vegetables, exercise regularly and avoid smoking," Frei said.

The old advice that a person gets in an average diet all of the antioxidant vitamins and other nutrients needed for optimal health, Frei said, is yielding to a range of recent studies which find moderate levels of antioxidant dietary supplementation may have powerful impacts on some of the world's leading health problems, especially heart disease.

Scientists are also learning more about the actual biological and cellular mechanisms that may explain why some antioxidant vitamins can play a valuable role, Frei said.

Some of the recent studies and findings in this field include:

 

  • Elderly men and women with the highest plasma levels of vitamin C had a 47 percent lower risk of dying from heart disease.

     

  • Vitamin C supplementation substantially improves blood vessel relaxation in patients with heart disease, diabetes, hypertension and other illnesses, and can relieve the pain of angina pectoris.

     

  • An intake of about 100-200 international units of vitamin E daily is associated with a substantially lowered risk of heart disease.

     

  • Second, non-fatal heart attacks were reduced by about 75 percent in heart disease patients taking 400-800 international units of vitamin E daily.

It appears the value of antioxidant vitamins as they relate to heart disease, Frei said, is their ability to deal with the formation and presence of free radicals and "reactive oxygen species" that are left behind in the normal process of respiration and energy production. These reactive oxygen species can damage various biological molecules, including the lipids in LDL, or "bad" cholesterol.

This oxidized LDL, Frei said, appears to be at the root of the earliest atherosclerotic lesions in blood vessels, and has a number of other effects that also contribute to atherosclerosis and heart disease.

Antioxidants such as vitamins C and E, however, can prevent the formation of reactive oxygen species, scavenge them before they cause damage to other biological molecules, or prevent oxidative damage from spreading.

Vitamin C also appears to preserve the biologic activity of nitric oxide. This naturally occurring compound in the body helps blood vessels dilate, inhibits platelet aggregation and helps prevent the formation of the blood clots that can block arteries and trigger a heart attack or stroke.

Continued research at OSU and elsewhere will shed further light on the exact mechanisms by which some vitamins and other natural products can be of value in preventing or treating heart disease and other health problems, Frei said.

There is increasing support by the National Institutes of Health and other agencies for more work in this area, he said. Also, Frei and other scientists at the Linus Pauling Institute are collaborating with federal committees that are considering revisions to the recommended daily allowance for various nutrients, including antioxidant vitamins.