Exercise Benefits
(See Table 5 for a summary of the following exercise related studies.)
During exercise, everything speeds up: the heartrate, breathing rate, metabolism, and, along with these things, free radical production. With proper conditioning, the body adapts to the increased oxidative load by producing extra antioxidant enzymes, especially superoxide dismutase. Nutritive antioxidants may provide additional benefits. For instance, results from human studies show the following:
- Vitamin E supplementation reduces oxidative stress and lipid peroxidation rates during exercise, as measured by breath pentane.
- Vitamin E supplementation decreases the exercise-induced increase of several substances which indicate muscle tissue breakdown.
- Vitamin E and C supplementation helps reduce cytokine and interleukin-1, inflammatory factors which promote tissue breakdown during strenuous exercise.
- Vitamin E supplementation has been shown to improve handing of glucose and insulin action (see studies on diabetes), which are vital during exercise.
- No well-designed study to date supports the idea that supplementation leads to improved athletic performance (speed, endurance, muscle strength, etc.). However, the benefits to the athlete are more subtle, since many studies support supplementation enhances antioxidant protection inside the body.
Evans, W. Vitamin E, Vitamin C, and Exercise. American Journal of Clinical Nutrition. Vol. 72(suppl), pp.647S-52S, 2000.
Professional athletes undergo rigorous training to maintain optimal physical performance. In Spain, professional basketball players of the first league (ACB) are highly competitive, have long seasons, two daily training sessions, and up to two weekly games. The recuperation time is minimal, and oxidative stress potentially excessive.
In this study from Barcelona, Spain, 24 professional, ACB league basketball players (average age 24) received either an antioxidant formulation supplement or placebo for 32 days during a regular competitive season. The supplement contained 600 mg vitamin E ("alpha-tocopherol acetate"), 1000 mg vitamin C, and 32 mg beta-carotene. Before and after the 32 day trial period, blood samples were taken and measured for vitamin levels, lipid peroxide concentrations, and total antioxidant status (how well the antioxidants neutralize a certain amount of free radicals). The main findings:
- Lipid peroxide concentrations decreased 14% in the supplemented group, compared to an insignificant 3% in the placebo group.
- The total antioxidant status of both groups did not change substantially.
- The supplemented group had a 32.2% increase in vitamin E concentrations, while the placebo group showed a 7.3% reduction.
- The supplemented group had a small 4.3% reduction in vitamin C concentrations, while the placebo group showed a substantial 70.9% reduction.
- The supplemented group had a huge 286% increase in beta-carotene concentrations, while the placebo group had only a 6.8% increase.
While the increases in vitamin concentrations were expected for the supplement group, the findings dramatically showed how supplementation prevented the large loss of vitamin C in players on placebo. Apparently, rigorous physical exertion places great oxidative stress on the body, and supplementation with antioxidant nutrients help provide significant protection. The authors state in conclusion, "The results of this study suggest that the administered vitamin antioxidant mixture decreases oxidative stress and avoids the development of a marginal vitamin C status in professional basketball players during habitual training."
Schroder, H., Navarro, E., Tramullas, A., Mora, J., Galiano, D. Nutrition Antioxidant Status and Oxidative Stress in Professional Basketball Players: Effects of a Three Compound Antioxidant Supplement. International Journal of Sports Medicine. Vol. 21, pp.146-50, 2000.
In this excellent review article, the authors summarize key findings from numerous studies on vitamin E and exercise.
- Early, poorly designed studies suggest vitamin E enhanced physical performance of athletes. Later, better designed studies refuted the earlier work and showed no significant physical performance benefits came from supplementation with vitamin E.
- Exercise promotes production of extra free radicals. Strenuous endurance exercise may enhance oxidation of LDL, a key factor in causing and worsening atherosclerosis.
- The bodies of well-conditioned athletes produce more antioxidant enzymes to cope with the increased oxidative load. However, the demonstrated benefits of vitamin E in exercise suggest supplementing with an additional 100 mg vitamin E daily is prudent.
- For "week-end warriors", the sudden increase of physical activity may present the body with more free radical activity than it can handle, potentially leading to more serious oxidative damage. Based on studies, taking 200 mg vitamin E in this case makes sense.
The authors conclude, "Supplementation with 100 to 200 mg of vitamin E daily can be recommended for all endurance athletes to prevent exercise-induced oxidative damage and to reap the full health benefits of exercise."
Takanimi, Y., Iwane, H., Kawai, Y., Shimomitsu, T. Vitamin E Supplementation and Endurance Exercise. Sports Medicine. Vol. 29, Issue 2, pp.73-83, 2000.