Exercise Basics

October 09, 2006

Vitamins and Minerals can boost performance and offer Protection Antioxidants can lower cell damage associated with exercise stress

Scientists from the Linus Pauling Institute at Oregon State University found that marathon runners who supplemented with the antioxidant vitamins C and E for six weeks prior to running a 50 km race prevented the cell damage normally associated with stress. Cells are damaged by oxidation the exposure to oxygen when fatty acids within cells degrade through contact with unstable molecules known as free radicals. Free Radicals result from many causes including aging, chemical exposure, environmental stress and radiation.

Researchers believe free radicals are major agents of the cell tissue damage associated with AlzheimerÌs disease, diabetes, heart disease and stroke among others. But rather than subject the very ill to potentially harmful study conditions researchers tested the free radical / antioxidant theory on marathon runners, who suffer cell damage through strenuous exercise.

During the double-blind study, 11 of the 22 runners took 1000 mg of vitamin C and 400 IU of vitamin E per day, while the rest took a placebo. Researchers drew blood samples to measure levels of antioxidants, inflammation and oxidation before the supplementation period began, three weeks into the supplementation period, one hour before the race and for six more days. Inflammation increased in all the runners following the race, yet only the placebo group had significant increases in oxidation; levels often seen in those who have had a heart attack. The runners who had taken the vitamins C and E had normal oxidation levels, leading the scientists to conclude that marathon runners may benefit from taking antioxidant supplements. (1.)

The mineral zinc may increase your capacity for vigorous exercise

A recent study suggests that zinc may increase the capacity for vigorous exercise. Researchers found that zinc impacted heart-lung function in men during exercise. Doctors tested the effects of low zinc intake on physical performance in 14 men, aged 20 to 31. the men were divided into two groups, one supplementing with 3.8 mg of zinc per day and the other with 18.7 mg per day. After a six-week non-supplemental period, the groups switched treatments.

Doctors found that peak respiratory function was inferior in the low-zinc group compared to the high-zinc group, and concluded that low zinc intake is associated with zinc deficiency and may impair physical performance. The recommended daily allowance for zinc in men is 11 mg and the upper limit is 40 mg per day. (2.)

Magnesium supplements can boost womenÌs capacity for exercise

Low magnesium levels caused women to work harder during exercise, according to a recent study. Even during moderate activity, the women required more energy and oxygen for the same amount of work when magnesium levels were low than when magnesium levels were adequate.

In the first 35-day control phase of the study, 10 postmenopausal women aged 45 to 71 took 200 mg of magnesium per day, and ate a diet consisting of 112 mg of magnesium. In the next 93-day depletion phase of the study, the women stopped taking magnesium supplements and ate a diet that provided less than half the Recommended Dietary Allowance (RDA) of magnesium for their age. In the final 49-day replenishment phase of the study, researchers attempted to bring the body back into magnesium balance by restoring the supplemental and dietary intakes for magnesium from the first phase of the study.

Researchers found that, after the low-magnesium phase, the women had lower muscle levels of magnesium, lower red blood cell counts and, during peak physical activity, had higher heart rates, averaging ten beats per minute more, than when magnesium levels were adequate. The researchers concluded that the women had to work harder, and used more energy and oxygen, when magnesium levels were low.

The RDA for magnesium for those over age 31 is 320 mg per day for women and 420 mg per day for men. Nuts, wheat germ and whole grains are high in magnesium and, along with a daily magnesium supplement, can help the body save energy and run more efficiently. (3.)

References: (1.) Free Radical Biology and Medicine; 2004, Vol. 36, no. 10, 1329-41. (2.) American Journal of clinical Nutrition; 2005, Vol. 81, No. 5, 1045-51. (3.) Journal of Nutrition; 2002, Vol. 132, 930-5.