Which vitamins serve as antioxidants?

Vitamin C, Vitamin E, and beta-carotene are recognized for their roles as antioxidants, which is why this answer is correct. Antioxidants are compounds that help neutralize free radicals—unstable molecules that can cause oxidative stress and damage to cells.

Vitamin C is a water-soluble vitamin that can directly scavenge free radicals and regenerate other antioxidants in the body. Vitamin E, a fat-soluble vitamin, protects cell membranes by neutralizing free radicals that can damage fats in these membranes. Beta-carotene, a precursor to vitamin A, contributes to the antioxidant defense system by providing protection against oxidative damage.

In contrast, the other options contain vitamins that either do not serve significant antioxidant roles or are involved in different physiological functions. For example, vitamins A, B, and D are essential for various bodily processes, but only vitamin A has a recognized antioxidant capacity through its activity as retinol. Thiamin, riboflavin, and niacin are primarily involved in energy metabolism and do not have significant antioxidant properties, while vitamin K and B12 are crucial for blood clotting and nerve health, respectively, without substantial antioxidant function.