Absorption, transport and distribution of vitamin E.

Vitamin E is the term used for eight naturally occurring fat-soluble nutrients called tocopherols. alpha-Tocopherol is essential, has the highest biological activity and predominates in many species. In humans vitamin E is the most important lipid soluble antioxidant and deficiency may cause neurological dysfunction, myopathies and diminished erythrocyte life span. alpha-Tocopherol is absorbed via the lymphatic pathway and transported in association with chylomicrons. In plasma, alpha-tocopherol is found in all lipoprotein fractions but mostly is associated with apo B-containing lipoproteins. alpha-Tocopherol is associated with very-low-density lipoprotein when it is secreted from the liver. In the rat, about 90% of total body mass of alpha-tocopherol is recovered in the liver, skeletal muscle and adipose tissue. Most alpha-tocopherol is located in the mitochondrial fractions and in the endoplasmic reticulum, whereas little is found in cytosol and peroxisomes. New clinical evidence from heavy drinkers and from experimental work in rats suggests that alcohol may increase oxidation of alpha-tocopherol. Increased demand for vitamin E has also been observed in premature infants and patients with malabsorption, but there is little evidence that the healthy population requires supplementation of vitamin E to a well-balanced diet.