Deficiencies:

Vitamin E deficiencies are not common in humans, but do occur in people that can’t absorb dietary fat i.e. someone with Abetalipoproteinemia. You need dietary fat to absorb vitamin E from the gastronial tract and therefore individuals that don’t naturally absorb fat may require supplements. Deficiencies can also occur in premature babies.

Someone suffering from vitamin E deficiencies can result in poor nerve conduction and people with the disease Abetalipoproteinemia can have problems such as poor nerve transmissions, weak muscles and blindness. The diseases caused by vitamin E deficiency vary widely according to species. The deficiency may cause disorders of reproduction; abnormalities of muscle, liver, bone marrow, and brain function; hemolysis of RBCs; defective embryogenesis; and exudative diathesis, a disorder of capillary permeability.

Infants are born in a state of relative vitamin E deficiency, with plasma -tocopherol levels below 5 µg/mL (11.6 µmol/L). The smaller and more premature the infant, the greater the degree of deficiency that may occur. Vitamin E deficiency in premature infants persists during the first few weeks of life and can be attributed to limited placental transfer of vitamin E, low tissue levels at birth, relative dietary deficiency in infancy, intestinal malabsorption, and rapid growth. As the digestive system matures, vitamin E absorption improves, and blood vitamin E levels rise.

Toxicity:

In general there are no serious adverse effects known as of yet to taking vitamin E supplements in excess. Adults that have taken relatively large amounts of vitamin E (400 to 800 mg/day of d--tocopherol) for months to years without any apparent harm. Occasionally however, muscle weakness, fatigue, nausea, and diarrhoea have occurred in persons taking 800 to 3200 mg/day.