"An apple a day keeps the doctor away," and if modern food packaging is to be believed, that's often due to a hefty dose of antioxidants. From sports drinks to protein bars, we're constantly bombarded with foods claiming to be packed with these supposedly healthy compounds. But what exactly are antioxidants, and how many of them do we really need?
Antioxidants are nutrients — including vitamins like E and C — that prevent or slow oxidative damage throughout the body. Without busting out the biochemistry books, when cells use oxygen, they naturally generate free radicals (by-products) which can cause cellular damage. Antioxidants act as free radical bounty hunters that often prevent and repair damage done by the free radicals Oxidant-antioxidant system: role and significance in the human body. Irshad, M., Chaudhuri, PS. Department of Laboratory Medicine, New Delhi, India. Indian Journal of Experimental Biology 2002 Nov; 40(11):1233-9.. Oxidative damage and free radicals can contribute to serious health problems such as heart disease, macular degeneration, and diabetes Sunlight exposure, antioxidants, and age-related macular degeneration. Fletcher, AE., Bentham, GC., Agnew, M., et al. Department of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel Street, London, England. Archives of Ophthalmology 2008 Oct; 126(10):1396-403. Role of oxidative stress in cardiovascular diseases. Dhalla, NS., Temsah, R., Netticadan, T. Institute of Cardiovascular Sciences, St Boniface General Hospital Research Centre and Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada. Journal of Hypertension 2000 June; 18(6):655-73. Oxidative stress and the use of antioxidants in diabetes: Linking basic science to clinical practice. Johansen, JS., Harris, AK., Rychly, DJ., et al. University of Tromso, Tromso, Norway; Medical College of Georgia Vascular Biology Center, Augusta, Georgia, USA. Cardiovascular Diabetology 2005 Apr 29; 4(1):5..
But while many of today's popular health foods contain massive doses of antioxidants like vitamin C, loading the body with as many of the nutrients as possible isn't the cure-all some might hope; in fact, ingesting large quantities of antioxidants might actually contribute to some of the very categories of disease they're touted to prevent. One now-famous study — which was actually stopped early because of the risk to patient health — showed an association between taking beta-carotene supplements with an increased risk of lung cancer in smokers Alpha-Tocopherol and beta-carotene supplements and lung cancer incidence in the alpha-tocopherol, beta-carotene cancer prevention study: effects of base-line characteristics and study compliance. Albanes, D., Heinonen, O., Taylor, P., et al. Division of Cancer Prevention and Control, National Cancer Institute, Bethesda, MA, USA. Journal of the National Cancer Institute 1996 Nov 6; 88(21):1560-70.. And other research has come up short in definitively linking antioxidant supplements to increased longevity or decreased risks of serious disease.
YOUR ACTION PLAN
But while the evidence isn't strong in support of antioxidant supplements as the key to good health, that doesn't mean they don't serve an important purpose in our diets. Consuming nutrients like vitamin C in normal doses — easily acquired in many fresh, whole foods — can help the body function normally and fight off infection. Upping those quantities to thousands of times the daily recommended value probably won't do much additional good.
Luckily, a healthy diet packed with antioxidants is relatively easy to stock up on, so grab a pen and paper and add these to the shopping list for a natural nutrient boost:
Vitamin E: Nuts, whole grains, vegetables, vegetable oil, and liver oil.
Vitamin C: Citrus fruit, tomatoes, green leafy veggies, and strawberries.
Vitamin A: Apricots, cantaloupe, squash, broccoli, sweet potatoes, carrots, kale, collards, and prunes.
Selenium: Brazil nuts, fish/shellfish, red meat, grains, eggs, garlic, and milk.
Flavonoids: Soy, red wine, pomegranate, cranberries, blueberries, and tea.
Lignan: Flax seed, barley, rye, and oats Mammalian lignan production from various foods. Thompson, L.U., Robb, P., Serraino, M., et al. University of Toronto. Nutr Cancer. 1991; 16(1):43-52.
Lutein: Dark green fruits and vegetables such as kiwi, spinach, brussels sprouts, kale, and broccoli.
Originally published May 2011. Updated August 2013.