Antioxidants

Antioxidants are compounds that neutralize free radicals — reactive molecules produced by normal metabolism and increased by exercise, pollution, and stress — which in excess cause oxidative stress and cell damage. Dietary antioxidants include vitamin C, vitamin E, carotenoids (beta-carotene), selenium, and a large family of plant polyphenols (in berries, tea, cocoa, colorful produce).

A diet rich in whole-food antioxidant sources — abundant fruits and vegetables — is consistently associated with better health, and this is a core reason such patterns are recommended. However, the once-popular idea that high-dose antioxidant supplements prevent disease has not held up: large trials of isolated antioxidant pills (e.g., high-dose beta-carotene or vitamin E) showed no benefit and some harm.

For athletes there is an additional caveat: exercise-induced free radicals act as signals that trigger adaptation (mitochondrial biogenesis, hypertrophy). Chronically taking high-dose vitamin C and E supplements around training can blunt these adaptations. The practical guidance is to obtain antioxidants from a varied, produce-rich diet rather than high-dose pills (see supplements-skeptical-note).

• Neutralize free radicals; counter oxidative stress.
• Sources: vitamins C and E, carotenoids, selenium, plant polyphenols.
• Whole-food, produce-rich diets are protective; isolated high-dose supplements are not (some harm).
• High-dose vitamin C/E around training can blunt mitochondrial/hypertrophy adaptations.
• Prefer food sources over supplements.

• vitamins-overview — vitamins C and E as antioxidants.
• supplements-skeptical-note — why antioxidant pills aren't recommended.
• muscle-hypertrophy — adaptation signaling that megadoses may blunt.
• recovery-modalities — oxidative stress and recovery context.