Vitamin E and human health: Rationale for determining recommended intake levels

The recent literature provides strong evidence that vitamin E intakes much higher than the current recommendations can contribute to and/or improve human health. In fact, the available data indicate that at higher-than-current recommended intake levels, vitamin E affects several functions related to human health. For example, Vitamin E is required to protect polyunsaturated fatty acids (PUFAs) against auto-oxidation. The amount of vitamin E needed to protect PUFAs against oxidative damage is at least 0.4–0.8 mg vitamin E per gram PUFAs and may be in excess of 1.5 mg/g when diets contain higher-than-average levels of long-chain PUFAs. Based upon studies of vitamin E kinetics and metabolism, a daily vitamin E intake of 135–150 IU is suggested. Important functions such as protection against oxidative damage, immune response, and the propensity of platelets to adhere to the vessel wall are related to vitamin E intakes. Vitamin E intake of 40 IU/d was the least amount demonstrated to inhibit low-density lipoprotein oxidation; a dose-dependent effect was seen up to 800 IU/d. Vitamin E intakes of at least 60 IU/d enhanced immune responses and intakes of 200 IU–400 IU/d decreased platelet adhesion to the vessel wall. Based upon the effects of modulating these functions, it is hypothesized that vitamin E plays a pivotal role in the prevention of cardiovascular diseases. Indeed, many observational studies have reported vitamin E to reduce the risk of cardiovascular disease. Recent intervention studies corroborate these findings. Of equal importance, there is a solid body of literature that demonstrates that these and much higher vitamin E intakes are safe.