Antioxidant Vitamins: Defense Against Oxidative Stress
| Vitamin | Antioxidant Mechanism & Clinical Relevance |
|---|---|
| Vitamin E (Tocopherol) | Lipid-soluble antioxidant; prevents peroxidation of polyunsaturated fatty acids in cell membranes and protects RBCs from oxidative damage. |
| Vitamin C (Ascorbic Acid) | Water-soluble antioxidant; keeps iron in the $Fe^{2+}$ (reduced) state, which facilitates intestinal iron absorption. Also regenerates Vitamin E by donating electrons. |
| Vitamin A (Beta-Carotene) | Beta-carotene serves as a potent antioxidant, neutralizing free radicals and protecting tissues from oxidative injury. |
High-Yield Core Realities:
- Synergy: Vitamin C and Vitamin E work in tandem. Vitamin C can recycle oxidized Vitamin E (tocopheroxyl radical) back into its active, reduced state, extending its protective capacity.
- Clinical Application: Increased oxidative stress (e.g., in smokers, chronic inflammatory states) can lead to higher turnover and requirement for these antioxidant vitamins.
- Deficiency Clues: Vitamin E deficiency results in symptoms mimicking Friedreich ataxia due to its role in maintaining membrane integrity in neural tissues. Vitamin C deficiency leads to impaired collagen hydroxylation, resulting in Scurvy.