Vitamin E Supplements: Good in Theory, but Is the Theory Good?

摘要

Much of the U.S. public has a deep, and seemingly unshakable, faith in the health benefits of nutritional supplements (1). Use of these products has increased so rapidly in recent years that a third of all adults, and half of those older than 55 years of age, report taking at least 1 supplement daily (2). The shelves of pharmacies, grocery stores, and “nutrition centers” are well stocked with a dazzling variety of nutritional supplements, and for sound business reasons; supplements accounted for an estimated $18.8 billion in sales in the United States in 2003 alone (3). Many of these supplements are promoted to the public as “antioxidants,” a fuzzily defined category that includes vitamins C and E, some carotenoids, and many other phytochemicals and plant extracts. Vitamin E is the most widely used of the individual products, and it is taken daily as a specific supplement (usually containing 400 IU of α-tocopherol) by 22% of U.S. adults older than 55 years of age (2).