Related topics: •  Cancer •  Heart Health Center •  Vitamin A •  Vitamin C

While most of us rarely see the sweet potato except around Thanksgiving, experts say we may want to pull the under-appreciated root out of the ground more often. Not only is it the vegetable with the highest concentration of vitamin A (for strong eyes and immune system), it's also one of the best sources of the lesser-known but just as vital vitamin E.

Vitamin E plays an essential role in body metabolism, and cell growth and function. It is also important in the formation of red blood cells and may help prevent life-threatening blood clots. Recent studies, however, have raised doubts about the effectiveness of taking vitamin E supplements to prevent cancer or heart problems. In fact, taking vitamin E in doses of 400 IU or more per day may lead to an increased risk of death in patients with certain conditions.

Vitamin E captured the attention of cardiologists in 1993, when a Harvard University study showed that men who took vitamin E had a 35 percent lower risk of heart disease than those who didn't take the supplement. These results bolstered the theory that vitamin E helps keep heart problems at bay by preventing so-called bad cholesterol (LDL) from mucking up your arteries.

These findings may be one reason that 37 million people in the United States take vitamin E supplements every day. But despite a parade of other studies supporting the role that E plays in preventing heart disease, more recent findings call for caution. A November 2004 report from the American Heart Association (AHA) announced that vitamin E might actually be harmful in high doses. According to the AHA, a review of 19 studies found that people who took at least 400 IU of vitamin E per day were 10 percent more likely to die than those who took a placebo. This doesn't mean that vitamin E is unhealthy -- it remains an important part of a balanced diet. Doses of less than 200 IU per day were not linked to increased deaths. In March 2005, a study of almost 10,000 patients published in the Journal of the American Medical Association (JAMA) reported that daily, long-term vitamin E supplementation (400 IU) did not prevent heart attack or stroke in patients with diabetes or vascular disease. In fact, it appeared to lead to a higher risk of heart failure.

As for whether vitamin E can actually prevent heart disease or cancer in healthy people, the jury is still out. A July 2005 JAMA study of almost 40,000 healthy women found that taking 600 IU of vitamin E every other day did not help to prevent heart problems or cancer, nor did it affect their overall mortality. The AHA says more research is needed to understand the potential health benefits of vitamin E and the right dose to take to get them. In the meantime, the AHA does not endorse vitamin E supplements, except for use by people who can't absorb the vitamin from their diet.

The government recommends 22.5 international units (IUs) a day (more if you take vitamin E in its synthetic form) for adults. Some studies have found the antioxidant has protective effects on the arteries of people taking 100 IU a day.

Don't take more than 200 IU without consulting your doctor, however. High daily doses can cause bleeding among people who are taking anti-clotting drugs. You should also consult your doctor before taking an E supplement if you're on blood-thinning medications, take aspirin or ginkgo regularly, or plan to undergo surgery soon.

The symptoms can vary from person to person. Many people lose sensation, are unable to feel pain, or experience muscle weakness when they don't get enough vitamin E. People with severe deficiency or young people born with an inability to absorb the vitamin may also suffer from blindness and anemia.

You can get the recommended daily allowance of vitamin E by eating a healthy combination of different foods. Vitamin E is most commonly found in small amounts in vegetable oils, nuts, fatty fish such as tuna and salmon, whole grains, and dark, leafy vegetables. To get your RDA, you could snack on three tablespoons of sunflower seeds or an ounce of almonds. If you prefer to mix up your foods in a healthful meal, you could eat a small spinach salad topped with two tablespoons of sunflower seeds, a bowl of tomato soup made with milk, and a peanut butter sandwich.

Vitamin E often doesn't survive long periods of storage, so don't count on getting much from that jar of wheat germ that's been sitting in the back of your fridge for a year. Since it's a fat soluble vitamin, substantial losses wouldn't occur if you're cooking in water. However, frying or cooking with a lot of oil could cause a loss of vitamin E.

If you tend to skimp on vegetables, nuts, and whole grains, you may benefit from taking a supplement. Be aware, however, that many studies have found that the form of vitamin E found in supplements does not deliver the same benefits as the pure form of the vitamin found in the foods you eat. And as researchers found in 2005, high doses may be unhealthy or even dangerous.

If you do opt for supplements, look for one with the prefix "d-" (rather than "dl-") on the label. This indicates vitamin E from natural sources, which is more potent and easier for your body to use than the synthetic version. Taking the supplement with food will also help you absorb the E.

-- Psyche Pascual is the articles editor at Consumer Health Interactive.

Further Resources

James A. Joseph and Daniel A.Nadeau. The Color Code: A Revolutionary Eating Plan for Optimum Health. Hyperion, 2002.

Martin Katahn. The Tri-Color Diet: A Miracle Breakthrough in Diet and Nutrition for a Longer, Healthier Life. Norton &Co., 1996.

Varro E. Tyler, PhD. Herbs of Choice: The Therapeutic Use of Phytomedicinals. Pharmaceutical Products Press, 1994.

Andrew Weil, M.D. Natural Health, Natural Medicine. Houghton Mifflin, 1995, 1998.

References

Last updated June 30, 2009
Copyright © 2001 Consumer Health Interactive

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