Regular intake of fresh fruits and vegetables is recommended in the diet since they are a good source of antioxidants. How do antioxidants help a person maintain health and promote longevity?

Option C is correct. Antioxidants neutralize free radicals, which are unstable molecules such as reactive oxygen species produced during normal metabolism, mainly in the mitochondria during oxidative phosphorylation. Free radicals damage lipids, proteins and DNA, and this oxidative stress is linked to ageing and lifestyle diseases.

• A is wrong. Antioxidants do not activate the enzymes for vitamin synthesis. Vitamin deficiency is a separate nutritional issue.
• B is wrong. Oxidation of carbohydrates, fats and proteins is how the body releases energy. Antioxidants do not stop it, and the idea of energy wastage is a distortion of the concept.
• D is wrong. Antioxidants do not work by switching genes on. Their protective role is chemical, through scavenging free radicals.

The core concept is oxidative stress and the antioxidant defence system, which includes vitamins C and E, carotenoids, polyphenols and enzymes such as superoxide dismutase. For Mains, this connects to diet and public health, and to the debate on whether high-dose antioxidant supplements really extend lifespan. The evidence there is still mixed, so food sources are preferred.

Trap: Aspirants confuse antioxidants with vitamins or enzymes and pick A or D because they sound biological.