Antioxidants slow aging and prevent disease. Life is a continuous balancing act between free radicals (fires) and antioxidants (fire extinguishers). We want to fully oxygenate the tissue, which generates free radicals, but we also want to protect healthy tissue from excess oxidative destruction, using anti-oxidants. Fresh whole fruits and vegetables are loaded with well studied anti-oxidants (like bioflavonoids). Anti-oxidants include beta-carotene, C, E, selenium, zinc, riboflavin, manganese, cysteine, methionine, N-acetylcysteine, and many herbal extracts (i.e. green tea, pycnogenois, curcumin).
What To Do: Go for the color. The rich color of sweet potatoes has more anti-oxidants than white potatoes. Same for red grapes vs. white, dark green leafy vegetables (like collards and spinach) vs iceberg lettuce. Take anti-oxidants as supplements: about 1000 mg of vitamin C, 25,000 iu of beta-carotene, 400 iu of vitamin E, 200 mcg of selenium, and perhaps others.