STUDY: Antioxidant vitamins lessen response to cholesterol drugs

Thursday, August 9th 2001, 12:00 am
By: News On 6

DALLAS (AP) _ Extra doses of vitamins such as C and E may blunt some benefits of widely prescribed cholesterol-lowering drugs, a new study concludes.

Some research suggests that the so-called antioxidant vitamins, intended to offset the harmful effects of oxygen, may help keep arteries healthy, while other reports have disputed this idea.

The latest study compared patients with coronary artery disease who were taking a mix of antioxidant vitamins and drugs to those who were taking drugs alone. The study used the vitamin niacin and the drug Zocor, which lowers artery-clogging LDL cholesterol while increasing beneficial HDL cholesterol.

It found that the volunteers' HDL levels failed to rise as much as expected when they mixed the vitamins with their cholesterol drugs.

``It looks like antioxidant supplements in general ... have no value of their own'' and may actually interfere with cholesterol drugs' ability to boost HDL, said Dr. B. Greg Brown of the University of Washington at Seattle, one of the researchers.

The one-year study was published in the August issue of Atherosclerosis, Thrombosis and Vascular Biology, a journal of the American Heart Association. It involved 153 patients ages 33 to 74 who had heart disease and high LDL levels.

The patients were randomly assigned to one of four treatment groups: drug therapy with Zocor and niacin; a combination of the antioxidant vitamins E, C and beta carotene plus selenium; drug therapy and the antioxidant supplements; or a placebo.

The patients receiving antioxidants and drugs had an average HDL increase of 18 percent, compared with 25 percent among those who received drugs alone. HDL remained unchanged with vitamins alone or the placebo.

A component of HDL cholesterol called HDL(2), which is thought to account for much of HDL's benefit, was especially affected. Its levels increased by 42 percent with drugs alone but remained unchanged in patients who also received antioxidants.

In an editorial, Dr. Lewis H. Kuller of University of Pittsburgh said the results, along with other disappointing findings about vitamins, make a compelling case against recommending antioxidant supplements to prevent or treat coronary artery disease.

``It will be important that physicians advise their patients that the use of antioxidants could be hazardous,'' he said.

But Dr. Kenny Jialal of the University of Texas Southwestern Medical Center at Dallas criticized the study's small size and disagreed with the conclusion that patients should be warned off antioxidants.

Jialal, a member of the antioxidant panel of the Institute of Medicine, noted that vitamin E has been shown in other studies to reduce the risk of heart disease.