Vitamin E is a fat-soluble vitamin that exists as tocopherols, with alpha-tocopherol being the most potent form used by the human body. It acts as an antioxidant to protect cells from free radical damage and is involved in immune function, heart health, muscle tone, and preventing oxidative damage to other vitamins. Good food sources include various plant-based oils, nuts, seeds, and vegetables. The recommended daily intake for adults is 15 mg, though toxicity is rare even at high supplement levels above 400-1000 IU daily.