Vitamin E Functions and Health Benefits

Vitamin E occurs in eight chemical forms, of which alpha-tocopherol appears to be the only form recognized to meet human requirements. Alpha-tocopherol and vitamin E’s other constituents are fat-soluble and primarily responsible for protecting cell membranes against lipid destruction caused by free radicals, therefore making it an antioxidant. Vitamin E helps to protect and prevent the oxidation of:

1. Polyunsaturated fatty acids, cell membranes
2. Low-density lipoproteins, which may lower heart disease risk
3. Red blood cell membranes
4. Lung cells

When alpha-tocopherol interacts with a free radical, it is no longer capable of acting as an antioxidant unless it is enzymatically regenerated. Vitamin C helps to regenerate some of the alpha-tocopherol, but the remainder is eliminated from the body. Therefore, to maintain vitamin E levels, you ingest it as part of your diet.

Vitamin E has many other important roles and functions in the body such as boosting the immune system by helping fight off bacteria and viruses.  It also enhances the dilation of blood vessels and inhibits the formation of blood clotting.  Vitamin E is critical for normal fetal and early childhood development of muscles, nerves, and red blood cells. Vitamin E can also improve the absorption of vitamin A if dietary intake is low. Despite vitamin E’s numerous beneficial functions when taken in recommended amounts, large studies do not support the idea that taking higher doses of this vitamin will increase its power to prevent or reduce disease risk.^[1][2]

Fat in the diet is required for vitamin E absorption as it is packaged into lipid-rich chylomicrons in intestinal cells and transported to the liver. The liver stores some of the vitamin E or packages it into lipoproteins, which deliver it to cells.

Dietary Reference Intakes for Vitamin E

The Recommended Dietary Allowances (RDAs) and Tolerable Upper Intake Levels (ULs) for different age groups for vitamin E are given in Table 11.2 “Dietary reference intakes for vitamin E”.

Vitamin E supplements often contain more than 400 international units, which is almost twenty times the RDA. The UL for vitamin E is set at 1,000 international units for adults. There is some evidence that taking vitamin E supplements at high doses has negative health effects. As highlighted below, vitamin E inhibits blood clotting and a few clinical trials have found that people taking vitamin E supplements have an increased risk of stroke. In contrast to vitamin E from supplements, there is no evidence that consuming vitamin E-containing foods compromises health.

Dietary Sources of Vitamin E

You can add some nuts to your salad and make your own dressing to get a healthy dietary dose of vitamin E.

Vitamin E is found in many foods, especially those higher in fat, such as nuts and oils. Some spices, such as paprika and red chili pepper, and herbs, such as oregano, basil, cumin, and thyme, also contain vitamin E. (Keep in mind spices and herbs are commonly used in small amounts in cooking and are therefore a lesser source of dietary vitamin E.) See Table 11.3 “Vitamin E content of various foods” for a list of foods and their vitamin E contents. Vitamin E can be easily destroyed by high heat and UV light, so wherever possible, store oils in cupboards and eat raw sources of vitamin E/ avoid cooking sources at a high heat.

Consuming Too Little Vitamin E

Vitamin E deficiencies are rare because it is stored in adipose tissue. However, people with malabsorption disorders, such as Crohn’s disease or cystic fibrosis, and babies born prematurely, are at higher risk for vitamin E deficiency. If a deficiency does occur, this can result in red blood cell hemolysis and therefore anemia, which can affect oxygen transport, and result in fatigue and weakness.

Other symptoms of a vitamin E deficiency include impairments in immunity, and a loss of muscle coordination and reflexes, resulting in impairments in vision, speech, and movement.

Consuming Too Much Vitamin E

Currently, researchers have not found any adverse effects from consuming vitamin E in food. Although that may be the case, supplementation of alpha-tocopherol in animals has been shown to cause hemorrhage and disrupt blood coagulation.  Extremely high levels of vitamin E can interact with vitamin K-dependent clotting factors, causing an inhibition of blood clotting.^[5]