(First of a two-part series on vitamin E.)
Vitamin E used to be dubbed the vitamin in search of a disease. No longer. Researchers now think Vitamin E’s powerful antioxidant function almost surely protects against heart disease. Researchers are also hopeful that vitamin E might cut the risk of certain cancers, boost the immune system, prevent muscle inflammation and soreness after exercise — and perhaps slow aging of skin by defending against the damaging effects of smog, smoke and sun. This month we focus on the heart.
Ironically, if you follow the typical heart-healthy, low-fat diet, you’re probably not getting enough E. Surveys show that 70% of Americans don’t come close to meeting the Daily Value (DV) of 30 International Units (IU) for this vitamin from food sources. And given the popularity of fat-free salad dressings, mayonnaise and margarine, all shy of E, the shortfall will likely only get worse.
That’s because E is a fat-soluble vitamin (actually it’s a group of substances called tocopherols) found mostly in high-fat foods, such as vegetable oils, mayonnaise, salad dressings, margarine, nuts, seeds and wheat germ. The few low-fat sources include whole grains and green leafy vegetables.
But is concern over dietary E moot? Most studies show that to reap E’s greatest protective rewards, it takes amounts available only from supplements.
Here, EN sorts through the most promising recent research on vitamin E and heart disease to answer the continuing controversy: To E or not to E?
How E Can Prevent Heart Disease.
One in three Americans will die from heart disease, the leading cause of death in the U.S. Research suggests antioxidants can reduce this risk by 20% to 30%. Vitamin E has an edge over antioxidants like vitamin C or beta-carotene because it is soluble in fat.
Vitamin E is carried through the bloodstream by low-density lipoprotein (LDL) cholesterol, the “bad” cholesterol that builds up on artery walls, eventually restricting blood flow and leading to a heart attack or stroke. But LDL-cholesterol is only “bad” when it is oxidized. That’s where vitamin E comes to the rescue; it blocks LDL oxidation.
What is oxidation? It involves chemical reactions that occur as a result of contact with substances such as pollution, smoking and ultraviolet light. It spawns “free radicals,” which damage the body’s cells, just as metal rusts and cut fruit turns brown.
The Case for Supplements. Researchers at the University of Texas Southwestern Medical Center in Dallas tested the minimum dose of E needed to prevent the oxidation of LDL-cholesterol. Lower levels — 60 IU and 200 IU — had no effect, but 400 IU of E was significantly protective.
Large surveys of habits, however, lend evidence for somewhat lower levels in preventing heart disease. In the Nurses’ Health Study of 90,000 women, those who had taken at least 100 IU of vitamin E for more than two years had 41% less risk of heart disease than those who had not supplemented their diets.
Similar results have been found in men. The Health Professionals Follow-Up Study surveyed 50,000 men aged 40 to 75 and found a 39% decrease in heart disease risk in those who took at least 100 IU of vitamin E.
New research from the University of Southern California School of Medicine in Los Angeles provides more clear-cut evidence that vitamin E can indeed prevent the narrowing of arteries that precedes heart attacks and strokes. In a study of over 50 middle-aged men and women, there was far less plaque buildup on artery walls in those who had been taking daily doses of 100 IU of vitamin E.
The Case for Food. Muddying the issue a bit is a recent study offering evidence that vitamin E solely from foods can be protective. The Iowa Women’s Health Study looked at the diets of over 30,000 postmenopausal women for seven years. Women who got at least 10 IU of E per day from foods were 62% less likely to die of heart disease than women who ate less than 5 IU of E per day. There was no evidence that additional vitamin E from supplements decreased risk further.
How could the Iowa Women’s Health Study and the Nurses’ Health Study differ so much? Eric Rimm, Sc.D., of Harvard’s School of Public Health points out that the Iowa questionnaire did not ask for details about duration and dosage of supplements. Apparently, few of the women took high-dose supplements. He also speculates there could be additional benefits from specific tocopherols found in vitamin E-rich foods but not found in supplements.
Can E Help Fight Heart Disease? To date, only one study has shown a direct benefit of vitamin E on existing heart disease. In the Cambridge Heart Antioxidant Study (nicknamed CHAOS), half the 2,000 men and women — all with heart disease — received a placebo. The other half was divided into two groups: One took 800 IU of vitamin E for two years; the other took 400 IU for one year.
After just six months, the risk of non-fatal heart attack dropped 77% in both supplement groups. After a year and a half, all those receiving vitamin E supplements had a quarter of the number of heart attacks as the control group. Surprisingly, the 400-IU group did better than the 800-IU group.
No Easy Answer. Where does all this leave us? While recent research strongly suggests vitamin E helps protect against heart disease, researchers cannot agree on how much or in what form.
Conservative advice would be to meet the DV of 30 IU through vitamin E-rich foods. But since studies show little risk of adverse effects to amounts below 1,000 IU, taking a supplement of 100 IU to 400 IU of E a day seems prudent.
Harvard’s Rimm personally pops 200 IU a day, but notes that, “We shouldn’t expect a single entity to significantly lower our risk. You need a combination of a low-fat, high-fiber, fruit and vegetable-rich diet, plus exercise. But the benefits of [supplementing with] vitamin E do outweigh the risks.”
Despite vitamin E’s safety record, however, it may not be wise to combine E supplements with aspirin and fish oils, particularly for anyone with a bleeding disorder. That’s because all three substances reduce the body’s clotting ability — one reason they all help lower heart disease risk — which when combined might raise the potential for trouble in the form of hemorrhagic stroke. But this risk is mostly theoretical; it has never been adequately demonstrated. Still, you may want to discuss E with your doctor before you supplement.
The Bottom Line. Though not everyone agrees with the idea of supplements, in EN’s view there is ample rationale for taking vitamin E to reduce heart disease risk and sufficient evidence of its safety. How much is enough? Next month, we’ll tackle that issue as well as discuss food sources of E and natural-source vitamin E versus synthetic.
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