Background: The aim of this study was to assess the acute and chronic effects of vigorous physical activity, with and without zinc supplementation, on distribution of elements in young amateur boxers.
Methods: The 8 week intervention trial experiment was designed with 32 healthy adolescent males in three parts: part 1, a 1 hour boxing training program; part 2, 4 weeks of regular boxing training without any supplementation; part 3, 4 weeks of regular boxing training with supplementation of pills containing 50 mg oral zinc. Plasma calcium, phosphorus, zinc, iron, copper, and magnesium levels of all participants were measured before and after each part of the study.
Results: After acute exercise serum calcium, zinc, copper levels decreased (p < 0.001; 0.001 and 0.017, respectively) and phosphorus increased (p < 0.001); iron and magnesium levels did not differ (p > 0.05). However, after 4 weeks of regular boxing training there was a decrease in zinc (93.92 ± 9.03 μg/dL vs. 85.86 ± 10.32 μg/dL, p < 0.001) and an increase in calcium concentrations (9.62 ± 0.34 μg/dL vs. 9.90 ± 0.26 μg/dL, p < 0.001). Zinc supplementation increased plasma calcium, phosphorus, and iron and decreased copper and magnesium (p < 0.001).
Conclusions: The body element distribution of children in pubertal age changes with physical activities. Zinc supplementation
can negatively affect their magnesium and copper concentrations.