In the past 50 years, there have been over 30,000 studies on vitamin E. Despite this, the most recent studies indicate that most adults around the world consume less than the recommended amount of vitamin E with many potential adverse health consequences.
Question: What does vitamin E do in the body?
Answer: Vitamin E is well known for its antioxidant function in cells. Although oxidation is a natural process in cells and is necessary for energy production, uncontrolled oxidation can damage cells. Vitamin E is important in preventing excessive amounts of this oxidative damage to cells.
More recently, it has become appreciated that vitamin E has nonantioxidant functions that help regulate a variety of cellular processes, even including gene expression.
Q: What are the consequences of vitamin E deficiency?
A: Vitamin E deficiency that persists over time can adversely affect many body functions. Consequences that have been identified include impaired immune function, increased risk of cardiovascular disease, declining cognitive function, nonalcoholic fatty liver disease, age-related macular degeneration, poor bone health, muscle weakness and increased damage from the effects of air pollution.
Q: What are good food sources of vitamin E?
A: Naturally occurring vitamin E occurs in many forms, but the form recognized to meet human requirements is alpha- tocopherol. Vitamin E is a fat-soluble vitamin that needs fat to promote efficient absorption. Typically, vitamin E is found in foods with oils. Major food sources include vegetable oils, nuts, whole grains, and foods like breakfast cereals that are fortified with vitamin E. Some of the richest food sources are foods like sunflower seeds and almonds and the oils extracted from them. However, it takes over 300 calories of these foods to provide the recommended 15 milligrams per day for a man.
Consequently, people with low calorie needs may find it difficult to consume enough high vitamin E foods to get adequate amounts of this essential nutrient. In this case, it may be beneficial to consume a vitamin E dietary supplement.
Q: How safe are vitamin E supplements?
A: For those who have difficulty meeting vitamin E needs with foods, dietary supplements containing vitamin E can be a good option. In 2000, the Institute of Medicine indicated the tolerable upper intake level for vitamin E was 1,000 milligrams (1,500 IU) per day from food and supplements combined.
The major concern for excess vitamin E intake is the risk of internal bleeding due to poor blood clotting which is most likely in those with low vitamin K intake or those taking anticoagulant medications. The Expert Group on Vitamins and Minerals in the United Kingdom has recommended a “Safe Upper Limit” of 800 IU per day from dietary supplements. Without a good medical reason and guidance by a physician, higher doses for extended periods of time would seem to be ill advised.
Although many of us do not consume recommended amounts of vitamin E, there may be no obvious adverse effects in the short run. It may take years or even decades of inadequate intake of vitamin E before health is compromised. By the time the damage is done, it is likely too late to reverse it.
Alan Titchenal, Ph.D., C.N.S., and Joannie Dobbs, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dobbs also works with University Health Services.
