Magnesium, zinc, and chromium nutriture and physical activity

Magnesium, zinc, and chromium are mineral elements required in modest amoun ts to maintain health and optimal physiologic function. For physically acti ve persons, adequate amounts of these micronutrients are needed in the diet to ensure the capacity for increased energy expenditure and work performan ce. Most physically active individuals consume diets that provide amounts o f magnesium and zinc sufficient to meet population standards. Women tend to consume less of these minerals than is recommended in part because they ea t less food than men. Inadequate intakes of magnesium and zinc have been re ported for participants in activities requiring restriction of body weight. Dietary chromium is difficult to estimate because of a lack of appropriate reference databases. Acute, intense activity results in short-term increas es in both urine and sweat losses of minerals that apparently diminish duri ng recovery in the days after exercise. Supplemental magnesium and zinc app arently improve strength and muscle metabolism. However, evidence is lackin g as to whether these observations relate to impaired nutritional status or a pharmacologic effect. Chromium supplementation of young men and women do es not promote muscle accretion, fat loss, or gains in strength. Physically active individuals with concerns about meeting guidelines for nutrient int ake should be counseled to select and consume foods with high nutrient dens ities rather than to rely on nutritional supplements. The indiscriminate us e of mineral supplements can adversely affect physiologic function and impa ir health.