chapter  11
30 Pages

Assessment of Mineral Status of Athletes

ByHenry C. Lukaski, Angus G. Scrimgeour

The burgeoning awareness of the fundamental biological roles that trace elements and minerals play in the development of physical fitness and the attainment of peak performance (Table 11.1) fuels interest in measures of assessment of mineral element nutritional status of physically active people.1,2 Selection of an appropriate assessment tool is complicated by theoretical and practical limitations. The ideal marker should be specific and sensitive, and should distinguish adequate from deficient nutritional status. Among vigorous individuals, however, subclinical or marginal nutritional, compared to overt or clinical, deficiency is more likely to occur and thus requires one or more biomarkers for characterization. Biochemical indicators of subclinical deficiency should be practical, convenient, and cost effective, and reflect cellular mineral content and the function of specific cells. Because no single method achieves all of these criteria, a compromise is needed to achieve a valid and realistic indicator to routinely identify subclinical mineral nutritional status in humans.3 This chapter details some useful approaches to assess human mineral nutritional status with an emphasis on biochemical methods and indicators. The focus is on mineral elements that are either acknowledged to have key roles in promoting physical performance or are used as performance-enhancing supplements; they include calcium, chromium, copper, iron, magnesium, phosphorus, and zinc. The chapter describes traditional and new biochemical measures of mineral element nutriture, presents values in

11.6 Magnesium ................................................................................................. 326 11.6.1 Methods for Assessment of Magnesium Status ........................... 326

11.6.1.1 Serum and Plasma Magnesium .................................. 327 11.6.1.2 Ionized Magnesium .................................................... 327 11.6.1.3 Muscle Magnesium ..................................................... 327 11.6.1.4 Blood Cells ................................................................. 327 11.6.1.5 Magnesium Load Test ................................................. 328 11.6.1.6 Magnesium Reference Intervals and Data from

Athletes ....................................................................... 328 11.7 Phosphorus ................................................................................................. 328

11.7.1 Methods for Assessment of Phosphorus Status ........................... 329 11.7.1.1 Phosphorus Reference Intervals and Data from

Phosphate Supplementation Trials .............................. 329 11.8 Zinc............................................................................................................. 330

11.8.1 Methods for Assessment of Zinc Status....................................... 330 11.8.1.1 Plasma and Serum Zinc .............................................. 330 11.8.1.2 Zinc-Containing Enzymes .......................................... 330 11.8.1.3 Zinc Reference Intervals and Data from Athletes ...... 331

11.9 Inflammation and Mineral Status .............................................................. 331 11.10 Future Research Needs ............................................................................... 332 11.11 Conclusions ................................................................................................ 333 Note.... .................................................................................................................... 333 References .............................................................................................................. 334

diverse groups of physically active persons, and identifies alterations in physiological functions and performance linked with altered mineral nutritional status.