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Is Vitamin E Good for the Heart?

来源:www.webmd.com
摘要:IsVitaminEGoodfortheHeart。3,1999(Atlanta)--Thoselookingtoestablishsome“hearthealthy“habitsfortheNewYearmightconsiderincreasingtheirintakeofvitaminE--justdon‘tlooktodoitthroughfood。Whilenumerousstudieshavesuggestedthatvitam......

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Is Vitamin E Good for the Heart?

By Jim Morelli
WebMD Medical News

Dec. 3, 1999 (Atlanta) -- Those looking to establish some "heart healthy" habits for the New Year might consider increasing their intake of vitamin E -- just don't look to do it through food. While numerous studies have suggested that vitamin E has cardioprotective effects, you'd have to overload on seeds, nuts, and oils to get those benefits.

"If you ate enough of your diet would be incredibly high in fat," says Sheah Rarback, RD, an assistant professor of pediatrics at the University of Miami Medical School, and spokesperson for the American Dietetic Association.

The answer, of course, is supplementation. And by now, many people are making it a habit to down a gelatin capsule of vitamin E every day. The question is, is it a good idea for everyone to do so? Rarback says Americans should get the official word in a few months, when the National Academy of Sciences unveils daily recommended intake figures for antioxidants, including vitamin E. "For now, if someone wants to take vitamin E supplements, it has low toxicity and a high potential for benefit," she says. But first, she adds, check with your doctor.

By now, most doctors have probably seen what Rarback is calling exciting and strong research concerning vitamin E's benefits for the cardiovascular system. As an antioxidant, vitamin E is able to detoxify naturally forming chemicals in the body known as "free radicals." These chemicals are a problem because they can attach to -- and thereby change the structure of -- almost anything they come in contact with. That would include such sensitive items as DNA.

Researchers believe heart disease occurs because of the free radical that results when LDL -- commonly known as "bad" cholesterol -- combines with oxygen. The oxidized LDL causes damage to the lining of the arteries, which eventually results in the formation of lesions or "plaques." Laboratory studies have shown vitamin E prevents this damage. Oxidized LDL also causes an immune reaction in the body, the end product of which are "foam cells." These are the fatty streaks doctors have identified as a predictor of cardiovascular disease.

The problem is, clinical studies have yet to answer whether everyone can benefit from taking extra vitamin E. A recent article on the subject in the journal Archives of Family Medicine illustrates the problem. While epidemiologists have found a relationship between taking vitamin E and not having heart problems, no one is really sure if it's the vitamin E that's wholly responsible for the effect. It could be that the study subjects also ate a healthy, balanced diet or exercised regularly.

One clinical trial -- the Cambridge Heart Antioxidant Study (CHAOS) -- found a nearly 50% reduction in heart attacks in those who took daily vitamin E. But the researchers can't say whether taking the supplement will mean a longer life -- though it might be beneficial for those with existing coronary artery disease.

"I have been recommending vitamin E for high-risk cardiovascular patients, people I think are at risk for having a (heart attack) or have had one," says David H. Emmert, MD, co-author of the Archives article. "But preliminary results from a new trial don't really look good from the standpoint of protecting diabetic patients [who are also at high risk for having heart disease]." Emmert says he's not sure whether those negative results will translate over to nondiabetics -- and they haven't stopped him from writing prescriptions for vitamin E, at 400 IUs (international units) a day.

For now, he advises patients of the potential benefits and low incidence of side effects with vitamin E, and lets them come to an informed decision. But, he admits taking vitamin E could turn out to be a waste of time and money -- though generic formulations are quite cheap. After reviewing available data for his recent article, Emmert says his conclusion is that medical science hasn't yet reached a conclusion on vitamin E and that more research is needed.

"I was impressed with the studies we looked at enough to recommend it to cardiac patients," says the co-author of the article, Jeffrey T. Kirchner, DO, a family practitioner at the Lancaster General Hospital in Pennsylvania.

" we're still going to preach lifestyle changes. We're still going to harp on the exercise and nonsmoking regimen," he adds.

 

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作者: JimMorelli 2006-8-16
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