Final answer:
The free radical theory of aging attributes the aging process and age-related diseases to oxidative stress caused by reactive oxygen species, which damage cellular components. Antioxidants like B-carotene and vitamins C and E play a key role in preventing this damage. Autoimmune reactions may also be influenced by oxidative stress, with the immune system attacking itself, leading to a variety of inflammatory conditions.
Step-by-step explanation:
The free radical theory of aging suggests that oxidative stress from reactive oxygen species (ROS) contributes to aging by causing cellular damage. While there are two versions of this theory, the one that posits that oxidative damage leads to age-related diseases is more broadly accepted. Nonetheless, a significant body of research indicates that oxidative stress is linked to the aging process, and interventions that reduce this stress, such as calorie-restriction, have been shown to extend lifespan in some laboratory animals, although results in primates have not mirrored these findings. The detrimental effects of ROS include permanent damage to cellular components like lipids, proteins, and DNA, leading to diseases including cancer and various neurodegenerative disorders.
Antioxidants play a crucial role in combating this damage by neutralizing free radicals, thereby preventing the chain reactions that result in oxidative degradation. Substances like B-carotene and vitamins act as antioxidants, with vitamin E being unique as it converts to a less reactive form after stopping free radicals, with vitamin C helping to restore vitamin E to its original form.
Further exploration into autoimmune reactions also touches upon the idea that damage caused by ROS may expose 'hidden' self-antigens, leading to an autoimmune response. In this state, the body's immune system mistakenly attacks its own tissues, causing inflammation and requiring treatments like immunosuppressive drugs.