Vitamin E

What it does

Vitamin E is the body's main fat-soluble antioxidant. It sits within cell membranes, which are built from fats that are vulnerable to a damaging chain reaction called lipid peroxidation. Vitamin E interrupts that chain, protecting the delicate fatty structures of cells — including the membranes of red blood cells and nerve cells — from oxidative damage. This membrane-protecting role is its defining function.

By guarding fats from oxidation, vitamin E helps protect other fat-soluble molecules too, and it works as part of a team: vitamin C can regenerate "used" vitamin E, and the mineral selenium supports a parallel antioxidant system, so these nutrients back each other up. Vitamin E also has roles in immune function and in keeping blood vessels healthy by influencing how platelets and cells lining the vessels behave.

Deficiency is rare in healthy people because vitamin E is widespread in vegetable oils, nuts, seeds and green vegetables, and the body stores it. When deficiency does occur — usually because of a problem absorbing dietary fat — it tends to affect the nerves and muscles. As a fat-soluble vitamin taken in supplements, very large doses are not automatically safe and can interfere with blood clotting.