Zinc supplementation does not alter sensitive biomarkers of copper status in healthy boys.

The tolerable upper intake levels (UL) for zinc for children were based on limited data and there is concern that the UL may be set too low. The first effect of excessive zinc intake is a reduction in copper status. The primary objective of this study was to examine the effect of zinc supplementation on copper status in children. Healthy, 6- to 8-y-old boys from Ontario, Canada were assigned to take a placebo (n = 10) or 5 mg (n = 10), 10 mg (n = 9), or 15 mg (n = 8) of zinc supplement daily for 4 mo in a double-blinded, placebo-controlled, randomized trial. Biochemical measures were evaluated at baseline and after 2 and 4 mo of supplementation. Food records were completed near the baseline and 4-mo visits. Age and anthropometric measurements did not differ (P > 0.05) between treatment groups at baseline. Mean zinc intakes from food alone (10.9-14.8 mg zinc/d) approached or exceeded the UL of 12 mg/d. Compared with the placebo group, the zinc groups had a greater change in the urine zinc:creatinine ratio at 4 mo (P = 0.02). Traditional (plasma copper and ceruloplasmin activity) and more sensitive biomarkers of copper status, including erythrocyte SOD1 activity and the erythrocyte CCS:SOD1 protein ratio, were unchanged in zinc-supplemented boys, demonstrating that copper status was not depressed. Serum lipid measures and hemoglobin concentrations were also unaffected and gastrointestinal symptoms were not reported. These data provide evidence in support of the need for reexamining the current UL for zinc for children.

Effect of the transition from high school to university on anthropometric and lifestyle variables in males.

The obesity epidemic in North America has focused attention on the health risks of excess weight gain. The transition from high school to university is a critical period for weight gain, commonly referred to as the Freshman 15. The purpose of this study was to investigate the effect of the transition from high school to university on anthropometrics and physical and sedentary activities in males. A total of 108 males completed 3 study visits: the summer prior to first year university, and the ends of the first and second semesters. Outcome measures were body mass, height, body mass index (BMI), body fat, waist circumference, hip circumference, waist:hip ratio, dietary intake, and participation in physical and sedentary activities. Between the summer prior to and the end of first year university, male students experienced a significant weight gain, of 3.0 kg, with significant increases in BMI, body fat, waist circumference, hip circumference, and waist:hip ratio. Energy and nutrient intake did not change. Final body mass was significantly predicted by intention for body mass to stay the same, relative to weight loss intention. Fast aerobic physical activity significantly decreased between the summer prior to and the end of first year university, while slow aerobic physical activity, strength training, and flexibility training did not change. Computer and studying time significantly increased, while television time and hours of nightly sleep significantly decreased between the summer prior to and the end of first year university. Weekly alcoholic drinks and binge drinking frequency significantly increased over this time period. In conclusion, between the summer prior to and the end of first year university, male students gained an average of 3.0 kg, with increases in related anthropometrics. These changes may be due to body mass change intention and (or) the observed decreased physical and increased sedentary activities, but appear to be unrelated to dietary intake.