FOGELHOLM, M., T. RANKINEN, M. ISOKÄÄNTÄ, U. KUJALA, and M. UUSITUPA. Growth, dietary intake, and trace element status in pubescent athletes and schoolchildren. Med. Sci. Sports Exerc., Vol. 32, No. 4, pp. 738–746, 2000.
Purpose: To examine interactions between club-level sports training, dietary intake, and nutritional status during puberty.
Methods: A 2-yr prospective study was undertaken with 64 boys (40 ice hockey players, 24 controls) and 71 girls (28 gymnasts, figure skaters, and runners, 43 controls). The boys’ age in the beginning of the study was 12–13 yr, whereas the girls were 11–12 yr. The following variables were measured in the beginning, and after 1 and 2 yr: physical activity level (record), dietary intake (record), blood hemoglobin concentration, serum ferritin, zinc and copper concentration, anthropometric indices (height, weight, skinfolds, upper arm muscle girth), and biological maturation (self-report).
Results and Conclusions: The changes in the anthropometric variables throughout the study period were not different between the athletes and controls (P ≥ 0.09). The athlete boys had higher mean energy, iron and zinc intakes, and higher mean serum zinc concentration than the controls (P ≤ 0.003). The athlete and control girls’ dietary intakes and biochemical indices of trace element status were not different from each other (P ≥ 0.13). Moreover, sports participation was not associated with the longitudinal changes in trace element status (P ≥ 0.08). These data suggest that club-level sports training does not affect growth, maturation or nutritional status during puberty.
Puberty is characterized by rapid growth and changes in the fat and fat-free body weight (19). The requirements for daily intake of energy and protein are increased in order to ensure energy for tissue growth, basal metabolism, and physical-activity related thermogenesis (33). In addition to the energy-yielding nutrients, certain micronutrients are also needed to ensure normal growth. An adequate intake of especially trace elements iron, zinc, and copper is important during puberty (2,18,19).
Active participation in sports may have positive effects on nutritional status during puberty by stimulating growth of fat-free tissue and by increasing the daily intake of energy and micronutrients (19). In contrast, if the increased energy needs are covered by food of poor nutritional value, or if food intake is restricted to control body weight (5), dietary intake might be inadequate to support normal growth (21).
To obtain a deeper insight on the interactions between club-level sports training, dietary intake, and nutritional status during a period of rapid growth, a 2-yr prospective study was undertaken with 64 boys (40 athletes, 24 controls) and 71 girls (28 athletes, 43 controls). These data will increase our knowledge on nutritional advantages and disadvantages involved in sports training during puberty and give suggestions for nutritional counseling. The baseline results on pubertal development stage, dietary intake, and trace element status have been reported earlier (26).