Antioxidant Supplements

By Sam Hutchison BS, NASM-CPT

In today’s culture, antioxidants have become synonymous with healthy living. They can be seen in sports drinks, energy bars and supplements which are marketed to provide better health and function. Antioxidants can also be found in natural foods like berries, whole grains, dark chocolate and some vegetables (1). It is important tounderstand how antioxidants function so that there can be optimal benefits. For this to happen, oxidative stress must be understood.

What is oxidative stress?

Oxidative stress is a process that occurs within all of us one way or another. This can occur through environmental factors such as smoking, UV light radiation, and exposure to chemical toxins as well as within the body such as acute exercise. It is the process taking an electron from an oxygen molecule causing it to become unstable. These unstable molecules are called free radicals. Due to the loss of an electron, that unstable oxygen molecule seeks electrons from cells within the human body (i.e., to pair with another molecule in order to return to a stable structure) (2). This process subsequently damages the structures of these cells, leading to the effects of aging and disease.

It is antioxidants role to neutralize these free radicals and allow the damaged components to be repaired (2).  Antioxidants are synthesized within the body or they are received from our nutrition including ascorbic acid (vitamin C), glutathione (made in our bodies from the amino acid cysteine), and flavanols/flavonoids (compounds found in plant sources), which are found in an assortment of whole foods and supplements (1).

Choosing Wisely

Although the benefits of antioxidants seem extraordinary and claims to their benefits are everywhere, they are only one piece of the puzzle.  Certain amounts of oxidative stress are necessary in order for our body to adapt to environmental stressors. Acute exercise produces a healthy amount of oxidative stress necessary to signal changes within the body such as the creation of new cell structures, bodily antioxidant stimulation and insulin sensitivity (2). These significant events can be inhibited by antioxidant supplementation.  A 2008 study showed that endurance athletes who took Vitamin C supplements demonstrated lower rates of mitochondrial production, and fewer improvements in VO2max and in time to exhaustion tests after an eight week training protocol (3).  This study provided evidence supporting the belief that antioxidant supplementation may interfere with the signaling process needed for these events to provide significant benefit.

Another study conducted was one that looked into a more diseased population. A seven year study was conducted to measure the effects of a vitamin C supplement on blood glucose levels (4). This study was designed to determine whether antioxidants had an effect on diabetes prevention. In the end, researchers found inconclusive evidence that vitamin C supplementation had an effect on reducing the free radicals thought to cause high blood glucose levels in diabetes.

Although some research may not support the benefits of supplementing antioxidants, the benefits of antioxidants found in natural plant sources should not be omitted from ones diet. Whole foods containing antioxidants have additional components that aid in optimizing how antioxidants are utilized within the body (1, 5).

In closing, although antioxidants may provide health benefits, buying supplements can become an expensive venture, even when purchased occasionally. It is important to have an understanding of their function within the body, follow research not advertising claims, and recognize the differences between antioxidants attained from supplements versus whole foods. The importance of understanding the general concepts of antioxidants can help someone become well informed of what their exact purpose is within the body and make proper health choices.



  1. Insel P., Ross D., McMahon K., et al. Nutrition. 4th ed. Sudbury, MA: Jones and Bartlett; 2011.
  2. Farrell PA, Joyner MJ, Caiozzo VJ. ACSM’s Advanced Exercise Physiology 2nd ed. Baltimore, MD: Lippincott, Williams & Wilkins; 2012.
  3. Gomez-Cabrera MC, Domenech E, Romagnoli M, Arduini A, Borras C, Pallardo FV, Sastre J, Vina J. Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance (2008) Am J Clin Nutr; 87:142-149
  4. Czernichow S, Couthouis A, Bertrais S, Vergnaud AC, Dauchet L, Galan P, Hercberg S Antioxidant supplementation does not affect fasting plasma glucose in the Supplementation with Antioxidant Vitamins and Minerals (SU.VI.MAX) study in France: association with dietary intake and plasma concentrations. (2006) Am J Clin Nutr; 84(2):395-399
  5. National Institute of Health. Antioxidants and Health: An Introduction (2010) U.S. Department of Health and Human Services.

Sam Hutchison BS, NASM-CPT is the Content Development Coordinator at the National Academy of Sports Medicine. He is a graduate of Northern Arizona University where he ran track for two years and was named to the Big Sky Academic All-Conference team. He majored in Exercise Science with a minor in chemistry.

Previous post

Stronger Than Ever

Next post

The Question of Handedness

The Author

National Academy of Sports Medicine

National Academy of Sports Medicine

Since 1987 the National Academy of Sports Medicine (NASM) has been the global leader in delivering evidence-based certifications and advanced specializations to health and fitness professionals. Our products and services are scientifically and clinically proven. They are revered and utilized by leading brands and programs around the world and have launched thousands of successful careers.


  1. July 28, 2013 at 11:16 pm — Reply

    Interesting info

  2. July 30, 2013 at 6:33 pm — Reply

    Good To Know Information

  3. September 27, 2013 at 5:41 pm — Reply

    Thank you for the info. Well written..

  4. Abdul Gaffar
    February 9, 2016 at 5:25 pm — Reply

    We’ve read about them, read about them, and perhaps even talked about them with our friends. Antioxidants, it seems, have created quite a huge wave in the scientific community that is devoting countless journals and magazine articles about their many benefits. Antioxidants are substances that work on free radicals, or more particularly work to counteract the damaging effects of these harmful oxygen byproducts.

  5. January 19, 2017 at 9:04 pm — Reply

    […] Antioxidants: Antioxidants have made their way into our bottles to combat the free radicals that come from the oxidative stress of exercise. Antioxidants are already in the foods we regularly eat, foods rich in vitamins A, C, and E including berries, whole grains, some vegetables and even chocolate (1). As supplements these gems are touted as being able to prevent muscle tissue damage, improve recovery, and boost aerobic endurance, but some researchers question these claims due to insufficient data (2). (For more on antioxidants) […]

Leave a reply

Your email address will not be published.