Which vitamin is an antioxidant essential for protection of cell structure, especially red blood cells?

Which vitamin is an antioxidant essential for protection of cell structure, especially red blood cells?

• A. Vitamin A
• B. Vitamin D
• C. Vitamin E
• D. Vitamin K

Answer: (C)

Vitamin E is the lipid-soluble antioxidant that protects cell membranes from oxidative damage. Red blood cell membranes are rich in polyunsaturated fatty acids, which are prone to lipid peroxidation caused by free radicals. Vitamin E donates a hydrogen atom to lipid radicals, halting the chain reactions that would otherwise damage the membranes. This helps keep red blood cells intact and prevents hemolysis. Vitamin A is primarily involved in vision and immune function, with some antioxidant roles in carotenoids but not the main protector of red blood cell membranes. Vitamin D supports calcium and bone health, not antioxidant protection of membranes. Vitamin K is essential for blood clotting, not for preventing oxidative damage to cell membranes.

Vitamin E is the lipid-soluble antioxidant that protects cell membranes from oxidative damage. Red blood cell membranes are rich in polyunsaturated fatty acids, which are prone to lipid peroxidation caused by free radicals. Vitamin E donates a hydrogen atom to lipid radicals, halting the chain reactions that would otherwise damage the membranes. This helps keep red blood cells intact and prevents hemolysis.

Vitamin A is primarily involved in vision and immune function, with some antioxidant roles in carotenoids but not the main protector of red blood cell membranes. Vitamin D supports calcium and bone health, not antioxidant protection of membranes. Vitamin K is essential for blood clotting, not for preventing oxidative damage to cell membranes.