Vitamin E (tocopherol) is a fat-soluble vitamin with antioxidant properties; it protects cell
membranes from oxidation and destruction, found in a variety of foods including oils, meat,
eggs, and leafy vegetables. Their serums levels are strongly influenced by concentration of serum
lipids, and do not accurately reflect tissue vitamin levels. Effective vitamin E levels are
calculated as the ratio of serum alpha-tocopherol per gram total lipids.
Absorption of dietary vitamin E requires effective pancreatic exocrine function and fat absorption,
unless provided in a synthetic water-soluble form. Also, a specific protein (alphatocopherol
transfer protein) is required for effective transport and use. Signs and symptoms of
vitamin E deficiency include hemolysis, neuromuscular disorders, ataxia, and peripheral neuropathy.
Because of an abundance of tocopherols in the human diet, its deficiency is rare except
in individuals with pancreatic insufficiency or other conditions causing substantial fat malabsorption,
or protein-energy malnutrition and may be caused by rare genetic defects affecting
vitamin E metabolism or transport. No syndrome of acute vitamin E toxicity has been described.
In premature infants, high-dose vitamin E treatment was associated with increased risk
for sepsis. Chronic intake of supplements in excess of 400 IU daily has been associated with increased
risk of hemorrhage and all-cause mortality.