Tocoferol

Tocoferol is a group of fat-soluble compounds that function as vitamin E in humans. The most biologically active form is alpha-tocoferol; beta-, gamma-, and delta-tocoferol also contribute to activity.

Chemically, tocopherols have a chromanol ring with a hydrophobic side chain. They are classified as alpha, beta, gamma, or delta based on ring substitutions. Tocotrienols, with unsaturated tails, are related compounds. Natural forms (designated with d-) are generally more active than synthetic (dl-) forms.

Dietary sources include vegetable oils (sunflower, safflower, olive, corn), nuts and seeds, fortified cereals, and leafy greens. Recommendations are usually given as alpha-tocopherol equivalents; adults commonly need about 15 mg per day, varying by country. Vitamin E is fat-soluble and absorbed with dietary fats.

Absorption and transport: after intestinal uptake, tocopherols are packaged into chylomicrons and enter the bloodstream. They are stored in the liver and adipose tissue and distributed to tissues via lipoproteins; excess is excreted in bile and feces.

Biological role: tocopherols act as lipid-soluble antioxidants, protecting membranes and lipoproteins from peroxidation. They support immune function and may contribute to neural protection. They work with other antioxidants such as vitamin C and carotenoids.

Deficiency is rare but can occur in fat-malabsorption or very low-fat diets; in infants, deficiency can cause hemolytic anemia and neuromuscular problems. High-dose supplements can affect vitamin K metabolism and bleeding risk; dietary intake from food is generally safe.