The Reminder is making its archives back to 2003 available on our website. Please note that, due to technical limitations, archive articles are presented without the usual formatting.
While vitamin E from dietary sources is needed to maintain good health, people often take vitamin E supplements in the belief that they may prevent disease. Recent studies, however, have suggested that the use of high doses of vitamin E may actually increase the risk of heart disease and cancer in people who are at high risk for these diseases. Vitamin E is the term used for a group of fat-soluble antioxidants, which act in the body to protect against cell damage. Vitamin E supplements are usually sold in a form that protects the ability of the supplement to act as an antioxidant. The recommended dietary allowance (RDA) of vitamin E for people aged 14 years and over, including pregnant women, is 22 IU of natural source vitamin E per day, or 33 IU from synthetic sources. See 'Found' on pg. Continued from pg. The RDA for breastfeeding women is 28 IU natural/42 IU synthetic. The tolerable upper intake level for adults is 1,000 mg per day of any form of vitamin E supplements. Vitamin E is found naturally in such foods as vegetable oils, seeds and nuts, wheat germ and, in small amounts, some green leafy vegetables. The vitamin is also added to some foods as an antioxidant, but only in small amounts. Vitamin E deficiency is rare in humans. Since vitamin E is a fat-soluble vitamin, deficiency usually occurs only in people with syndromes where fat is poorly absorbed. However, because most dietary vitamin E is found in oils, very low-fat diets can result in low intakes of vitamin E if food choices are not made carefully. To maintain vitamin E levels, it is important to eat a variety of antioxidant-rich foods such as fruits, vegetables, whole grains, and moderate amounts of healthy unsaturated fats (such as those found in fish, olive oil, canola oil, some vegetable oils, nuts, and flaxseed) as part of a healthy diet. In general, an intake of vitamin E (for example as part of multivitamin supplementation) of up to 40 IU is considered to be a ÒnormalÓ dose. Supplements are available that provide from 1.5 IU to 1,500 IU per day. Those providing 400 IU per day or more are considered to be Òhigh doseÓ or Òmegadose.Ó Currently, vitamin E is not authorized for sale in Canada for the purpose of preventing any particular disease. Health Canada is developing guidelines for vitamin E that will recommend precautionary measures for people aged 55 years or older who have heart disease or diabetes, and for people who have, or have previously had, cancer. These people are advised to consult their doctor before taking doses of vitamin E of 400 IU or more. Also, people who are taking blood thinners, or have been diagnosed with a bleeding disorder and/or a vitamin K deficiency should consult their doctor before taking vitamin E. While most studies have found that people who consume diets rich in vitamin E are at a lower risk of developing heart disease or cancer, studies that looked at supplementation with high doses of vitamin E gave conflicting results. Risks? Recently published studies have suggested that vitamin E supplements not only fail to prevent heart disease and cancer, but may actually harm people who take high doses over a long term. However, these studies are limited by the fact that they involved people 55 years or older who already had heart disease or diabetes; people with cancer or who previously had cancer; and people who may be at higher risk of developing these diseases. These studies have limitations. It is difficult to interpret how the results might apply to healthy people taking high doses of vitamin E. Although there are justifiable concerns over certain at-risk groups of consumers, more research is needed, especially focusing on the long-term use of high-dose vitamin E supplements.
