Women that have been treated with synthetic retinoids that accumulate in fat may require several drug free years or longer before the increased risk to the fetus subsides. The best sources of vitamn A are highly pigmented vegetables and fortified margarine. Topical forms of vitamin A are used in the treatment of several conditions including acne , psoriasis and to reverse the damage resulting from sun exposure . It mainly acts as an antioxidant of lipids, protecting cell membranes and preventing damage to membrane associated enzymes. The manifestation of a deficiency is rare in the US because it is present in many foods and there are large total body stores.
Vitamin E is present as alpha, beta and gamma tocopherols.
Less information is available about the action of the beta and gamma tocopherols, but they appear to have different antioxidant effects. A supplement that contains all forms may provide the greatest benefits. There are several conditions in which vitamin E supplementation may have a beneficial effect but these remain to be proven by long-term studies. It may slow the progression of Alzheimer's disease, prevent heart disease , improve immune function in the elderly, reduce the risk of cataracts and decrease the pain associated with arthritis. There is no known syndrome associated with vitamin E deficiency in adults but in premature infants, anemia may be seen.