It took scientists years after the discovery of vitamin E in 1922 to figure out what it did. At first, two teams of researchers, one from the University of California at Berkeley and the other from the University of Arkansas, believed the vitamin was essential for reproductive function. The UC scientists had found that the diet they were feeding female laboratory rats didn’t support normal pregnancy, while the Arkansas team had discovered that a similar diet was missing something that resulted in sterility in male rats. As often happens in science, the two groups collaborated and identified the missing nutrient as a fat-soluble factor with vitamin-like properties.
This missing factor was named E because it was the next vitamin to be discovered after vitamin D. The new vitamin, which was added to rat chow, subsequently prevented miscarriage and sterility. Not surprisingly, E was first touted as the “sex” vitamin.
It’s taken decades to determine how vitamin E functions and what human diseases it might prevent. Its antioxidant properties were shown to help protect against heart disease, while researchers at Tufts University found that E was critical to immune support and for preventing cataracts and other vision problems. The National Cancer Institute investigated E’s cancer-fighting powers, and Swiss researchers discovered that certain components of this vitamin had important functions beyond their antioxidant powers.
Eight Amazing Es
Vitamin E is actually a generic term for a family of eight related compounds (isomers) including tocopherols (alpha, beta, gamma, delta) and tocotrienols (alpha, beta, gamma, delta). However, only alpha tocopherol is used for measuring vitamin activity, and this is designated in international units (IU). The stated label supplement claims for vitamin E activity, therefore, refer only to alpha tocopherol, regardless of which other tocopherols the product contains.
In the past few years, research has found that the other tocopherols and tocotrienols exhibit biological activity that is distinct from that of alpha tocopherol. Consequently, most vitamin E preparations contain the other tocopherol isomers.
Each new discovery adds to the reputation of mighty E, which Americans take to prevent cardiovascular disease and cancer. Or at least they did before the media fallout in November 2004.
The Vitamin E Controversy
A paper presented at the annual meeting of the American Heart Association and later published in the Annals of Internal Medicine suggested that doses of vitamin E above 400 IU/day might actually increase the risk of dying. This research took the medical community by surprise and obviously caused real concern among consumers. In fact, a poll commissioned by the Dietary Supplement Information Bureau revealed that among 1,051 adults, 18 percent were less likely to take the vitamin after reading about this study. However, the same poll also found that Americans believe in the benefits of vitamins and E in particular.
The response from the scientific community was swift. Top nutritionists and researchers quickly pointed out that this research, a meta-analysis of 19 published studies, was badly flawed and inconclusive. Ten of the studies in this review involved people who already had serious chronic diseases or were at high risk for disease, and some investigations involved too few people to be meaningful. Some of the studies also reported inconsistent results. Nevertheless, the meta-analysis lumped together all research that used some form of vitamin E.
The researchers themselves reported that their analysis was, at best, an estimate. Fortunately, a subsequent survey of the literature by scientists at the Council for Responsible Nutrition in Washington, DC, demonstrated that vitamin E—up to 1,600 IU per day—is safe.