Final answer:
The incorrect proposed mechanism is 'serving as prooxidants against cancer cells.' Antioxidants help by reducing oxidative stress, enhancing immune function, and neutralizing free radicals.
Step-by-step explanation:
The mechanism by which antioxidants help prevent cancer that is NOT proposed is c) Serving as prooxidants against cancer cells. Antioxidants are known for their role in reducing oxidative stress, enhancing immune function, and neutralizing free radicals. Substances like Vitamin C and Vitamin E, as well as ß-carotene, which can be converted to vitamin A, serve as antioxidants. These nutrients prevent damage by free radicals, which are highly reactive due to their unpaired electrons. The free radicals, formed not only by metabolic processes but also by environmental factors like radiation and pollution, can cause cellular damage that can lead to cancer.
Antioxidants like Vitamin A, C, E, and selenium work by being oxidized themselves to halt destructive reaction cascades initiated by free radicals. For example, Vitamin C is a radical scavenger in the blood, whilst Vitamin E scavenges radicals in fats, neutralizing them before they can cause more damage.