Zinc status among low-fat and moderate-fat male triathletes and controls

The purpose of this research was to evaluate serum zinc status among low-fat triathletes, moderate-fat triathletes, and male controls. Based on % body fat, 33 male triathletes were separated into tertiles. The lower tertile, low-fat triathletes (n = 11) and upper tertile, moderately fat triathletes (n = 11) were 7.4 ± 1.4 and 15.4 ± 2.8% body fat, respectively. Male controls (n = 10) were 13.5 ± 4.1% body fat and participated in less than 30 minutes of aerobic activity 3 x/wk. Mean training distances for low-fat triathletes and moderate-fat triathletes were similar. Using the mean intake from a 7-day food record, energy intake (kcal/day) was significantly higher for low-fat triathletes (3,208 ± 832; P < .05) than moderately fat triathletes (2,204 ± 751) and male controls (2,318 ± 310). Dietary zinc intake (mg/day) was significantly higher for low-fat triathletes (16.7 ± 3.6; P < .05) as compared to moderately fat triathletes (12.0 ± 3.6). Serum zinc, determined by atomic absorption spectrophotometry, was significantly lower (P < .01) for low-fat triathletes (82 ± 11 μg%) and moderately fat triathletes (75 ± 9 μg%) than for male controls (99 ± 14 μg%). Nine of the 11 moderately fat triathletes (81%) and five of the 11 low-fat triathletes (45%) had marginal serum zinc levels of less than 80 μg%. Triathletes who restrict calorie intake in order to reduce body fat may be at an increased risk of developing marginal zinc status.