Vitamin E is an antioxidant that helps protect cells from damage caused by free radicals. These are unstable molecules with missing electrons that form when cells burn oxygen. Adequate levels of vitamin E are necessary for proper functioning of the reproductive system, nerves and muscles.

Vitamin E’s antioxidant properties also prevent the oxidation of low-density lipoprotein (LDL) cholesterol, the so-called “bad” cholesterol. This may lower the risk of heart disease and stroke.

Vegetable oils are the best source of vitamin E. These include oils made of soybean, corn, canola, sunflower, cottonseed and safflower. Foods made of oil such as certain types of margarine and salad dressings are good sources of vitamin E. Experts usually recommend that people get all of their vitamin E from their diets rather than from supplements. However, in some cases supplementation may be advised.

Deficiency of vitamin E is rare but may occur in premature babies with very low birth weights. It also may occur in people who have conditions that are associated with poor fat absorption, such as cystic fibrosis and Crohn's disease. Vitamin E deficiency may cause several symptoms, including leaving people more vulnerable to damage caused by free radicals.

Excessive levels of dietary vitamin E do not appear to pose health problems. However, taking high levels of a vitamin E supplement does appear to cause health problems, such as impairing the blood-clotting action of vitamin K, leading to an increased risk of bleeding.

Vitamin E is a fat soluble vitamin present in lipids and fat tissues of the body. It is an antioxidant that helps protect cells from damage caused by free radicals. These are unstable molecules with missing electrons that form when cells burn oxygen. Vitamin E is most effective when taken with vitamin C, another antioxidant.

Two classes of chemicals in food provide the body with vitamin E: tocopherols and tocotrienols. There are eight different forms (isomers) of vitamin E. They include:

• Alpha, beta, gamma and delta tocopherol
• Alpha, beta, gamma and delta tocotrienol

The various types of vitamin E have different potencies, with alpha-tocopherol being the most accessible for the body and the form most frequently used in supplements. The Food and Nutrition Board of the National Academy of Sciences has issued the following recommended dietary allowances (RDAs) for vitamin E. The figures are expressed in milligrams of alpha-tocopherol equivalents (mg/a-TE):

Food and supplement labels list the amount of vitamin E in international units (IU) rather than milligrams. For conversion purposes, 1 milligram of alpha-tocopherol equivalent is equal to 1.5 international units.

Adequate levels of vitamin E are necessary for proper functioning of the reproductive system, nerves and muscles. Vitamin E’s antioxidant properties help protect the body’s cells from damage caused by free radicals. These are unstable molecules with missing electrons that form when cells burn oxygen. Antioxidants such as vitamin E neutralize such electrons by binding with them, which prevents them from causing damage.

Vitamin E’s antioxidant properties prevent the oxidation of low-density lipoprotein (LDL) cholesterol, the so-called “bad” cholesterol. It is believed that tocopherols (vitamin E in the body) attach to lipoproteins and prevent them from attaching to artery walls and or blocking blood vessels. This may lower the risk of heart disease and stroke. Vitamin E also prevents the oxidation of polyunsaturated fatty acids.

Vitamin E may help prevent some types of cancer and may help prevent degenerative diseases of the cardiovascular, neurological and respiratory systems. Because it is an antioxidant, vitamin E protects essential fatty acids and vitamin A levels in the body. Vitamin E also protects the lining of blood vessels and sexual glands from damage caused by food chemicals, pesticides and inhaled toxins.

For years, people have made various health claims on behalf of vitamin E. It has been said that vitamin E boosts sexual potency, cures infertility, prevents aging, enhances athletic performance, cures heart disease and prevents Parkinson’s disease. To date, there is no evidence that any of these claims is true. Research is continuing into the question of whether or not vitamin E helps protect the eyes against cataracts (clouding of the lens).

Deficiency of vitamin E is rare but may occur in premature babies with very low birth weights. It also may occur in people who have conditions that are associated with poor fat absorption, such as cystic fibrosis and Crohn's disease. People on low-fat diets may experience vitamin E deficiency because they may not get enough unsaturated vegetable oil in their diets. People who use the dietary fat substitute olestra may have reduced absorption of vitamin E. Other factors associated with vitamin E deficiency include:

• Genetic abnormalities in the alpha-tocopherol transfer protein
  
  
• Zinc deficiency

Vitamin E deficiency causes red blood cells to break open, causing their contents to spill out. This probably occurs as a result of oxidation of polyunsaturated fatty acids inside the cell membranes. Vitamin E deficiency may leave people more vulnerable to damage caused by free radicals as a result of environmental and food chemical exposure.

Other symptoms of prolonged vitamin E deficiency include:

• Impaired vision and speech
• Loss of muscle coordination and reflexes
• Neuromuscular dysfunction of the spinal cord and retina

Unsaturated vegetable oils are the best source of vitamin E. These include oils made of soybean, corn, canola, sunflower, cottonseed and safflower. Foods made of unsaturated oil such as some margarines and salad dressings are good sources of vitamin E. This vitamin also is added to processed foods as a preservative.

Typically, any food containing unsaturated fats is a good source of vitamin E. Good sources of vitamin E include:

• Asparagus
• Corn
• Egg yolks
• Green, leafy vegetables
• Liver
• Nuts, especially almonds and hazelnuts
• Olives
• Peanut butter
• Seeds, especially sunflower seeds
• Wheat germ

Examples of certain foods and the amount of vitamin E (ATE, in milligrams) they contain include:

Vitamin E is also easily destroyed during heat processes such as deep-fat frying. For this reason, it is best to obtain vitamin E from fresh or lightly cooked foods.

Experts usually recommend that people get all of their vitamin E from their diets rather than from supplements. However, in some cases supplementation may be advised. For example, people who cannot absorb fat due to certain illnesses (e.g., Crohn’s disease or cystic fibrosis) require a vitamin E supplement because dietary fat is necessary to absorb this vitamin from food. People who cannot secrete bile (which aids fat digestion) may require a special water-soluble form of vitamin E.

Vitamin E supplements are available in both natural and synthetic forms. Natural forms typically are labeled with the letter “d” (e.g., d-gamma-tocopherol). Synthetic forms typically are labeled “dl” (e.g., dl-alpha-tocopherol).

Vitamin E supplements can cause side effects when taken in large amounts or when taken with medications such anticoagulants. As a result, supplements should not be taken without first consulting a physician.

Preparing questions in advance can help patients have more meaningful discussions with health professionals regarding their conditions. Patients may wish to ask their doctor or registered dietitian the following questions related to vitamin E:

1. How will I know if I am getting too little or too much vitamin E?
   
   
2. What foods do you suggest I eat to increase my intake of vitamin E?
   
   
3. Who can I talk to about planning a diet with an appropriate amount of vitamin E?
   
   
4. What is the likely source of my vitamin E deficiency?
   
   
5. Will I have to undergo other tests or procedures to locate and treat the source of my vitamin E deficiency?
   
   
6. Do you advise taking vitamin E supplements?
   
   
7. What type of supplement do you recommend?
   
   
8. What are the risks or side effects associated with this supplement?
   
   
9. Should I take this supplement with food?
   
   
10. How can I make sure my child is getting enough vitamin E in school meals?