Research still suggests vitamin E may boost immunity and benefit brain.
Vitamin E has had its share of ups and downs. Over the years, it has gone from being called a vitamin without a clear need, to a cure-all for everything from heart disease to cancer, to the current state of negative research that has experts questioning past results. But the roller coaster ride isn't over just yet. So, hang on. While it's tough to tell what's around the next curve, here's a look at what we know and what we have yet to learn about vitamin E.
Best Known Benefit. Vitamin E is known as a premier antioxidant, which allows it to fend off free radicals, protecting cells from oxidative damage. Once it has worked its antioxidant magic, the vitamin does double duty by being recycled back into its active form with the help of other antioxidants, mainly vitamin C. It's this synergy with other antioxidants that suggests vitamin E may be important in reducing the risk of developing certain chronic diseases.
Minding Your Brain. Experts believe inflammation and oxidative stress play critical roles in the development of dementia and Alzheimer's disease (AD). And research clearly suggests a link between antioxidants like vitamins E and C, which act as anti-inflammatory agents, and protection against cognitive decline.
Researchers recently looked at the occurrence of AD in more than 4,700 men and women, aged 65 and older, and found that those taking a vitamin E supplement (more than 400 International Units a day) and vitamin C (at least 500 milligrams a day) suffered less AD. In the same study, however, those who took either vitamin alone showed no protective effect. This highlights the importance of the E-C synergy and perhaps explains previous negative results for E alone.
In another study of 15,000 women in their 70's, Harvard researchers found that women taking E and C supplements scored better on cognitive status tests than women who had never taken either vitamin.
In two earlier studies, older people with vitamin E-rich diets (11 to 23 IU a day or more) were less likely to develop AD. Yet, a study published last year that looked at 980 older New York City residents found no link between AD and high intakes of vitamin E from food or supplements.
If vitamin E does help prevent or slow cognitive decline, it's unclear exactly how it works or if supplements make a difference. So until more research rolls in, vitamin E's role in brain health remains a promise, not a clear connection.
Keeping Away Cancer. Several studies have tried to demonstrate a link between vitamin E intake and cancer protection, but most have been inconclusive. The greatest promise of protection has been seen with prostate cancer. To find out more, the National Cancer Institute has initiated a study that will look at the combination of vitamin E and selenium versus a placebo in men 55 years of age or older. But results are several years away.
How much E we get early in life may also influence cancer risk. Recent results from the Nurses' Health Study found that women with diets rich in vitamin E during high school had a lower risk of breast cancer later in life.
"These findings are tantalizing," says Phil Taylor, M.D., chief of the Cancer Prevention Studies Branch at the National Cancer Institute, "but the association is far from proof."
Helping Heart Disease. E's potential as a safeguard against heart disease seems to have lost some of its luster. Earlier population studies suggested that high intakes of vitamin E protect against heart disease. But large-scale clinical studies have failed to confirm the findings. Though many still believe E's benefit for heart disease is real, the verdict is still out, say experts. Vitamin E supporters say it may help protect blood vessel walls from thickening and keep platelets and other blood components from getting sticky, all of which thwart atherosclerosis.
Boosting Immunity. Vitamin E also plays an important role in keeping the immune system strong. Researchers at Tufts University in Boston gave healthy, older adults 200 IU daily of E for about eight months and found an improvement in immune function. Because immunity declines with age and 40% of older people do not get the recommended intake of E, the researchers suggest that older adults take a supplement.
Questions Linger. Some experts speculate that differences in the way natural versus synthetic E is absorbed and made available to the body may be to blame for seemingly contradictory study results. Moreover, gammatocopherol, a type of E found mainly in food, may be more important than previously thought--a possible reason why some studies have found that E supplements, which typically contain only alpha-tocopherol, offer no benefit.
The Bottom Line. EN's take on E? The details on E's benefits have yet to be finalized, but E clearly remains an important nutrient for good health.
* Boost your E intake with nuts, fortified cereals and other foods naturally rich in E (see sidebar, left).
* Take 200 IU of vitamin E a day with a meal, to improve absorption. This amount offers some benefits, but is low enough to avoid potential drug interactions.
* Select a natural source supplement (see sidebar, above) that includes gamma tocopherol.
* A note of caution to those who take statin drugs or blood thinners: Large doses of vitamin E may interfere with or increase the effect of these medicines. Check with your doctor before taking E supplements.
Good Food Sources of E Food Amount IU Vitamin E * Almonds 1 oz. (24 nuts) 5 Wheat germ oil 1 tbsp. 26.2 Almonds, dry roasted 1 oz. 7.5 Safflower oil 1 tbsp. 4.7 Corn oil 1 tbsp. 2.9 Soybean oil 1 tbsp. 2.5 Turnip greens, 1/2 c. 2.4 frozen, boiled Mango, raw 1 2.3 Peanuts, dry roasted 1 oz. 2.1 Mixed nuts 1 oz. 1.7 Mayonnaise 1 tbsp. 1.6 Broccoli, frozen, 1/2 c. 1.5 chopped, boiled Spinach, frozen, 1/2 c. 0.85 boiled Kiwi 1 0.85 * IU = International Units. Source: www.nih.gov
RELATED ARTICLE: Which E supplement?
Vitamin E is a family of eight compounds--four tocopherols and four tocotrienols--all of which have some vitamin E activity, though alpha-tocopherol is the most active form.
The current Recommended Dietary Allowance for E is 15 mg (22 IU) a day of alpha-tocopherol. Supplements from natural sources contain d-alpha tocopherol, which the body prefers. Synthetic E is labeled dl-alpha tocopherol and typically contains a variety of synthetic E compounds, half of which go unused by the body. Therefore, synthetic E is only half as effective as natural E.
EN's Recommendation: Look for an all-natural, mixed-tocopherol supplement that includes gamma tocopherol and provides about 200 IU a day total.
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|Date:||May 1, 2004|
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