The Recommended Dietary Allowances (RDA) of vitamin E is 10 milligrams for the adult male and 8 milligrams for the adult female. Your RDA of vitamin E can be achieved without supplements by eating plant oils (vegetable oil, margarine, salad dressings), dark green and leafy vegetables, whole cereal grain products, liver, egg yolks, milk fat , nuts, seeds or butter.

Vitamin E is a fat-soluble vitamin and is stored in the body. There is however no known case of toxicity due to excess vitamin E.

Unfortunately, because of the role vitamin E plays in your body as an antioxidant, it has been touted as an "anti-aging" vitamin, which is not true. Vitamin E does combine with oxygen which is beneficial to polyunsaturated fats and vitamin A. Both polyunsaturated oils and vitamin A combine with oxygen and break down. Vitamin E interferes with that break down process. Because of its antioxidant properties, vitamin E is stable to most cooking methods except long cooking at very high temperatures that would break down fat as well.

Vitamin E deficiency has not been proven in humans, but it has in animals. Vitamin E is so widespread in foods that it is difficult to produce a deficiency in humans. Also, because it can be stored in the body, it is difficult to produce a deficiency. I suppose it would be possible to induce a vitamin E deficiency by eating an extremely low fat diet for a prolonged period of time. Other fat soluble vitamin deficiencies would also appear though.

Vitamin E deficiency is difficult to diagnose because the deficiency manifests its self in diverse ways. The Primary  symptoms of deficiency are in the reproductive system,nervous system, muscle tissue,and blood erythrocytes, not all species manifest a deficiency in one or all of these areas. Some symptoms are amplified by dietary polyunsaturated fatty acids. Other Symptoms can be prevented by nonspecific antioxidants (such as selenium or the sulfur-containing amino acids.)

The role of Vitamin E in the prevention of premature aging is a topic of current interest. The theory is that aging is caused by long term exposure to free radicals that damage cellular components. This in turn produces a progressive accumulation of cellular debris that interferes with normal metabolic functions. Vitamin retards this process.

Because vitamin E is necessary for the structural and functional maintenance of all skeletal, cardiac, and smooth muscle, nutritional muscular dystrophy is seen in animals fed a vitamin E-deficient diet. This condition is a result of injury to the lysosomal membrane of muscle cells. The skeletal muscle can be pale, ischemic, and gritty because of calcium deposition. The inability to use creatine increases creatinuria.

Irreversible reproductive system damage occurs in rats fed a vitamin E-deficient diet. If the female does become pregnant,spontaneous abortion or resorption of the embryo results. Ceroid tissue has been found in the uterus and fallopian tubs of vitamin E-deficient rats. This suggests that fat peroxidation leads to tissue damage and irreversible loss of fertility. Reproductive damage from a vitamin E deficiency has not been observed in humans.

Encephalomalacia ( a nervous system disorder) and its clinical signs of ataxia, spasms, and paralysis are seen in vitamin E-deficient chicks. The condition appears to be a result of an imbalance in the dietary ratio of tocopherol to polyunsaturated fats. The disorder, nopt seen in chicks fed a fatfree/vitamin E-deficient diet, can be alleviated or prevented by a nonspecific antioxidant. Brain damage in deficiency states results from lack of the antioxidant.effect of the vitamin.

                           Requirements:

The requirement for vitamin E to prevent overt clinical deficiency symptoms is proportionate to body size and polyunsaturated fat intake. Vitamin E is needed in small  amounts when dietary polyunsaturated fats are minimal. Increasing polyunsaturated fats in the diet increases their concentration in the tissues. The need to protect these fats from oxidation results in an increased need of vitamin E.

Because of the close association with the type and amount of the fat in the diet, dietary amounts are difficult to recommend for all people. The RDA is an average value based on the necessary amount of vitamin E needed for a balanced and mixed diet (1mg = 1.49IU of d-alpha tocopherol). Intake must maintain blood tocopherol levels of 0.5mg to 0.9mg/100 ml, adequate stores in all tissues, and a suitable ratio of vitamin E to polyunsaturated fat. Taking into account the varying potencies of the tocopherol, the RDA's for healthy individuals are:
                                                        MG                                   IU
INFANTS                                       3-4 mg                             4.5 -6.0 IU
CHILDREN                                     6-7 mg                             9.0-10.5 IU
ADOLESCENTS                               10 mg                                     15  IU
ADULT MALES                                10 mg                                     15  IU
ADULT FEMALES                             8 mg                                      12  IU
    Pregnant                                         2 mg                                      15  IU
     Lactating                                     + 3-4 mg                          16.5-18   IU

In contrast to current RDA's, most studies showing health benefits of vitamin E have used daily doses ranging from 200 to 400IU in human subjects. The Alliance for Aging Research recommends a vitamin E intake far in excess of the RDA's or 100 to 1000IU daily, for the goal of health promotion and disease prevention.