Many people take antioxidant supplements to neutralize free radical damage caused by intense exercise. However, athletes who take antioxidant supplements may be doing more harm than good.
A study published in the June issue of Journal of Medicine & Science in Sports & Exercise, found that antioxidant supplements reduce the major mitochondrial benefits of athletic endurance training. Although the study was done with rats, the implications for humans is eye-opening.
Researchers found that, much like humans, rats who ran on a treadmill increased the enzymes that are necessary to increase the number and size of mitochondria in their cells. However, rats who trained on a treadmill and were given two strong antioxidants (vitamin E and alpha lipoic acid), didn't increase the enzymes necessary to increase the number and size of mitochondria.
Another study from Germany, followed volunteers who performed 90 minutes of high intensity exercise five days a week for four weeks. The subjects displayed various health benefits, including improved insulin sensitivity (which helps control blood sugar levels). However, when the volunteers took antioxidant supplements (400 IU of vitamin E and 1,000 mg of vitamin C) they failed to shown any improvements insulin sensitivity.
What's Going On?
We know that exercise speeds up the process in the body that convert food to energy, and one of the by-products of that process is the creation of free radicals. Left unchecked, free radicals can lead to cell damage. But that's not the end of the story. During exercise, the body has its own system to take care of this. While we exercise, our body produces tremendous amounts of natural antioxidants to neutralize the free radicals. The research seems to show that by taking megadoses of antioxidant supplements, we effectively turn off this natural process and allow more free radicals (oxidants) accumulate and more cell damage to occur.
To read more about why athletes are discouraged from taking extra antioxidant supplements, read Dr. Gabe Mirkin's blog post, Antioxidant Pills Reduce Exercise Benefits.
Dr. Mirkin's final recommendation for athletes is this:
"Exercise every day, and get the antioxidant vitamins and other nutrients your body needs from foods, not from pills. Eat a wide variety of foods including large amounts of fruits, vegetables, whole grains, beans, nuts and other seeds. If you want to take Recommended Dietary Allowances of vitamins in pills, go ahead; there is little evidence that you will harm yourself. However, when you take large doses of any vitamin, you don't have the foggiest idea whether you are harming or helping yourself. I do not recommend large doses of vitamins to anyone."
Read More About Antioxidants & Athletes
- Do Antioxidant Supplements Help Athletic Performance?
- Antioxidants and Free radicals
- Antioxidant vitamins, exercise and muscle damage: another nail in the coffin?
- Swan song for antioxidant supplements?
- Antioxidant protection for athletes: is it time to ditch the pills?
- Food vs. Pills
- Do Antioxidants Help or Hinder Your Workouts
- AHA Advisory - Forget Antioxidant Supplements Are Antioxidant Supplements Worth the Money?
Source
Medicine & Science in Sports & Exercise, June 2011 - Volume 43 - Issue 6 - pp 1017-1024
Antioxidants prevent health-promoting effects of physical exercise in humans. PNAS. March 31, 2009
