Vitamin E has become a symbol of high benefits and high consequences within the medical community. Research has established that vitamin E can potentially prevent blood clots and heart disease, but that too much enhances bleeding by preventing essential blood clotting. Recent research has aimed to understand why this happens, and to establish the ideal amount of vitamin E to consume in order to maximize benefit and minimize these dangerous risks.
Vitamin E is fat-soluble, and most commonly found in foods as alpha-tocopherol (there are eight forms of vitamin E). By killing off free radicals, alpha-tocopherol is able to help relieve inflammation and high blood pressure, potentially decreasing blood clot and subsequent heart disease risk. This makes vitamin E an antioxidant, in fact one of the most widely available forms of this popular type of compound. Almonds, Avacados, Olives and Spinach are just a few of the many foods that contain vitamin E.
Unfortunately vitamin E is not only beneficial. Past research has established that vitamin E interferes with the functions of vitamin K, which is responsible for often necessary blood clotting. This in turn can result in spontaneous and uncontrolled, and often very dangerous, bleeding. This bleeding can take the form of nose bleeds, or an inability to stop bleeding from wounds. The exact mechanism by which this interaction between vitamin E and vitamin K takes place is not known, but it is thought to surely exist.
The most representative study of both the benefits and risks of vitamin E consumption was performed over ten years on more than 40,000 healthy women over 45 years of age. By taking 600 IU per day (against a placebo for the control group) over ten years, there was a 24% decrease in heart disease related deaths. In elderly women specifically, there was a 26% decrease in heart deaths, and a 49% decrease in cardiovascular deaths (which includes strokes and heart attacks).
The numbers above represent an enormous benefit, but unfortunately they don’t tell the whole story. Lead author of the current study, Dr. Maret Traber, notes that “in some people high doses of vitamin E increase the tendency to bleed. Women enrolled in the study had an increase in nose bleeds.”
Though there is not an understanding of why vitamin E interferes with vitamin K, as a precaution, the U.S. Food and Nutrition board has suggested an upper limit of 1500 IU of vitamin E per day.
Dr. Traber, through reviewing these past research efforts, has attempted to establish how vitamin E interferes with vitamin K. Dr. Traber has found one potential explanation, that due to a “shared metabolic pathway” in the liver between vitamin E and vitamin K, when vitamin E levels increase, vitamin K levels decrease. Unfortunately, this suggestion is far from conclusive, and this is acknowledged by the author, who makes a final suggestion to other researchers: “Several different explanations could account for the interaction between the two vitamins. We need more research to understand the delicate balance between vitamins E and K.”
Source: Defeat Diabetes Foundation: Traber, Maret. Molnar, Amy. Nutrition Reviews press release. October 2008.