Working out? Watch your nutrient levels

Athletes often hear that fluids, carbohydrates and potassium are important to help recovery after vigorous exercise. But what about other vitamins, minerals and antioxidants?

Researchers at the University of Aberdeen Medical School in the UK reviewed studies on the role of micronutrients such as iron, calcium, and vitamins C and E in energy metabolism and sports performance. Iron helps transport oxygen while calcium helps muscles contract and relax. Antioxidants are important for burning your body fat and combating free radical damage.

The rate of energy burned in the muscles is increased between 20 and 100 times during exercise. During this increased energy consumption, the researchers identified that marginal micronutrient deficiencies may appear due to the increased loss of nutrients in sweat and urine. From this data, they concluded that athletes who endured prolonged strenuous exercise should ensure additional intake of vitamins, minerals and antioxidants.

At the Grand Forks Human Nutrition Research Center in North Dakota, researchers conducted a review of the use of magnesium, zinc and chromium supplements by athletes. These three minerals are required in modest amounts to maintain regular health, and have also been recommended to improve sports performance and recovery.

Researchers concluded that supplemental zinc and magnesium might help improve strength and muscle metabolism but that chromium supplementation did not appear in this study to improve muscle building or fat loss. However, chromium does play an important role in balancing blood sugar levels.

Sources: Am J Clin Nutr 2000 Aug;72(2 Suppl):585S-93S; Br Med Bull 1999;55(3):683-90; Fat Wars by B King, Macmillan:1999