Vitamins and Calcium Supplements (cont.)
Betty Kovacs, MS, RD
Betty Kovacs, MS, RD
Betty is a Registered Dietitian who earned her B.S. degree in Food and Nutrition from Marymount College of Fordham University and her M.S. degree in Clinical Nutrition from New York University. She is the Co-Director and Director of nutrition for the New York Obesity Research Center Weight Loss Program.
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
In this Article
What is it, and what does it do?
Vitamin E represents a family of eight fat-soluble antioxidant vitamins. Each form has its own function. Alpha-tocopherol is the most important E vitamin in humans. Vitamin E is involved in maintaining cell integrity, and it protects vitamin A and essential fatty acids from oxidation in the body cells.
How much do I need to consume?
The Recommended Dietary Allowances (RDA) for vitamin E is based on the alpha-tocopherol form. The recommendations below are in milligrams (mg) and International Units (IU). You can use the milligrams when looking at the content in food and the International Units when looking at the content in supplements.
The RDA for vitamin E is:
There is insufficient information to establish an RDA for vitamin E for infants. In this case, an Adequate Intake (AI) has been established:
What are sources of vitamin E?
There are many foods rich in vitamin E. The most common ones are fortified cereals, green leafy vegetables, vegetable oil, eggs, and nuts. The content of vitamin E in food is based on the alpha-tocopherol content:
You can find more sources at http://www.nal.usda.gov/fnic/foodcomp/Data/SR20/nutrlist/sr20a323.pdf.
Do I need to take a vitamin E supplement?
Most research shows that we do not consume an adequate amount of vitamin E, but a deficiency is rare. According to the USDA, the intake of vitamin E by women 19 to 50 years is less than 90% of the RDA. The average consumption for American adults is 7 to 9 mg compared to the recommended 15 mg. There is, however, a possibility that we are consuming more than we think. Many people under-report their fat intake, so there is a chance that you are reaching your recommended amount of vitamin E if you do consume a large amount of the oils that contain it. Unfortunately, the amount of oil that it would take to reach the recommendations is high, and with that comes a lot of calories. It would be best to consume a variety of the foods that contain vitamin E with limited amounts of oil and take a supplement for what you are missing.
There is some evidence that vitamin E supplements help protect against heart disease, but this evidence is controversial. In a study of approximately 90,000 nurses, the incidence of heart disease was 30%-40% lower in those with the highest intake of vitamin E from supplements, not from food. This study was looking at what happened to these nurses without any kind of intervention. The studies that gave people vitamin E supplements have not seen any protection against heart disease. The reason for the difference is still unclear, so there is more research being done to determine what role vitamin E plays in protecting against heart disease. At this time, the American Heart Association does not recommend antioxidant
Some cancers develop from oxidation damage to DNA. In the Alpha-Tocopherol Beta Carotene (ATBC) study, scientists found a 32% reduction in the incidence of prostate cancer among subjects taking alpha-tocopherol supplements compared to those not taking the vitamin. However, several studies have found no benefit of vitamin E in preventing lung and breast cancers. More randomized controlled trials are needed to determine the effect of vitamin E on cancer risks.
Alzheimer's disease is a degenerative brain disease with progressive loss of mental capacity, thought in part to be due to oxidation. High doses of alpha-tocopherol supplementation in one study slowed the progression of Alzheimer's disease. Although these results are promising, large-scale placebo-controlled prospective trials will be required to determine the role of a-tocopherol supplementation in the treatment of Alzheimer's disease.
When purchasing vitamin E supplements, you will see that they are often sold as alpha-tocopheryl acetate. This form of alpha-tocopherol protects its ability to function as an antioxidant. A "DL" on the label means that it's the synthetic form and is about half as active as the natural form, which is listed as "D."
What happens if I don't have enough vitamin E?
Dietary vitamin E deficiency is common in developing countries and among people with fat-malabsorption diseases. The main symptoms are hemolytic anemia and neurologic deficits.
Is there such a thing as too much vitamin E?
Vitamin E can act as an anticoagulant, which means that it can increase the risk of bleeding problems. This means that people taking warfarin (Coumadin) should not take vitamin E supplements without their doctor's approval. The Tolerable Upper Limit (UL) was set at the highest dose unlikely to result in bleeding problems.
There are UL set for vitamin E:
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