Jun, 4, 2009
Vitamin Supplements Reduce Exercise Benefits
Those of you who knew me ten years ago would say that I’m eating my words today when I say that Vitamin Supplements Reduce Exercise Benefits! But the facts are now starting to pile up to prove it.
I’ll be the first to admit I used to be a proponent of large doses of both Vitamin C and Vitamin E for their anti-oxidant properties. After all, the research clearly demonstrated that oxidative free radicals were bad for us, and that supplementing with high doses (1000mg Vitamin C and 400IU Vitamin E) reduced the effects of the bad free radicals in our systems.
The downside to science is that sometimes you have to eat your words. So folks.. I’m admitting it to the world here.
It has been long known that exercise helps you live longer as well as being a valuable tool in Type 2 diabetes and insulin resistance management (1,2,3,4,5) . It has also been long known that exercise produces oxidative free radicals which have been shown to cause tissue damage (6,7,8). However the endlessly suprising human body that it is continues to defy us just when we think we know everything.
From the cited research above it would make sense to supplement the diet with antioxidant nutrients. But the latest study (9) examined the effects of supplementing with 1000mg Vitamin C and 400IU of Vitamin E on the benefits of exercise on diabetes risk and glucose metabolism.
Professor Ristow of the Department for Human Nutrition at the Institute for Nutrition , University of Jena in Germany stated that “Exercise causes repeated boosts of free radicals, which according to our results, induce a health-promoting adaptive response in humans.” “Subsequently, our body activates molecular defense systems against stress, and metabolizes carbohydrates more efficiently, both of which prevents diabetes, and possibly other diseases.”
Ristow explained that, “Blocking these boosts of free radicals by antioxidants accordingly blocks the health promoting effects of exercise, and that short term doses of free radicals may behave like a vaccine, helping the body to boost defenses against chronic stressors and building a long term adaptive response.”
The conclusion of the researchers was that, “Exercise-induced oxidative stress ameliorates insulin resistance and causes an adaptive resonse promoting endogenous antioxidant defense capacity. Supplementing with antioxidants may preclude these health-promoting effects of exercise in humans.”
This study definitely shows a clear negative effect on exercise benefits on supplementing with antioxidants. However, as always this is just a small piece of the larger puzzle. Are there still some population groups that may benefit from certain nutritional supplements? Very likely! Will more studies come out supporting this one? For certain. Will others come out showing benefits of antioxidant supplements in some cases? Yes again.
There is a mountain of research documenting the cellular protective effects of antioxidant nutrients, so how is it that they can be bad? Why is this stuff so damn confusing? Well folks, apply some common sense. If you are exercising with low-high intensity, for moderate durations (I’ll always argue against marathons!), you will produce some free radicals. But the duration of their production will be short. If you have a diet with 10-15 servings of vegetables and fruit, you’ll be getting tons of antioxidant nutrients. And your body, the master chemist that it is, will know exactly how much of which antioxidants and in which combinations, and in what quantities will be needed to keep you healthy.
Of course smoking, and a diet severely lacking in nutrients might be a reason to supplement with a broad spectrum vitamin and mineral supplement. A recent study (10) showed conflicting results with regards to protective effects of antioxidants in smokers, even showing an increased number of cancers with Beta Carotene supplementation compared to placebo. However, after reading the study thoroughly I think the study could have been done better. First, the study was using mostly men in their sixties who had been heavy smokers for many years. Second, the study used very low dose supplementation when all the previous research on cigarette smoke oxidative stress on tissues being prevented with much higher doses of antioxidants. And finally, the use of isolated nutrients has been established to be less effective than using whole families of nutrients. In the case of Beta Carotene, which is from the carotenoid family, perhaps using it in conjunction with alpha- and gamma-carotene, lutein, and lycopene would have demonstrated a positive effect. Lycopene compared to beta carotene appears to be the most effective at reducing cancers in humans (11)
In the end, there needs to be far more study of these issues to be able to say anything conclusive, but if you are an otherwise healthy individual eating a diet rich in vegetables and fruits and you don’t put much garbage in your body, and you exercise to stay strong and healthy, you’re probably best to avoid high doses of antioxidant nutrients.
Stick to a varied and colourful plate of food, train hard and enjoy your life!
If you have any questions or comments about this article, please post them below!
1: Ann Epidemiol. 2009 Apr;19(4):253-6.
2: Ned Tijdschr Geneeskd. 2002 Aug 10;146(32):1479-83.
3: Sports Med. 2001;31(8):571-6.
4: Diabetes. 2007 Nov;56(11):2655-671.
5: Lakartidningen. 1998 Sep 16;95(38):4062-7
6: Jialal I, Fuller CJ, Huet BA. The effect of alpha-tocopherol supplementation on LDL oxidation. A dose-response study. Arterioscler Thromb Vasc Biol, 1995, 15: 190-198.
7:Halliwell B. Free radicals, antioxidants, and human disease: curiosity, cause, or consequence? Lancet, 1994, 344: 721-724.
8: Machlin LJ, Bendich A. Free radical tissue damage: protective role of antioxidant nutrients. FASEB J, 1987, 1: 441-445.
9: Proc Natl Acad Sci U S A. 2009 May 26;106(21):8665-70.
10: The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Eng J Med. 1994, 330:1029-1035.
11:Ford, J.G. Nutrient in tomatoes is found to lower an individual’s risk of lung cancer. Presentation at 1997 Annual meeting of the American Association for Cancer Research
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