Effects of oral zinc supplementation on serum leptin levels in Ache males of eastern Paraguay

Significant population variation has been demonstrated in serum leptin levels, independent of adiposity. Included within these populations, Ache males have significantly lower leptin levels compared to American subjects with comparable adiposity. The underlying causes of these differences are not understood but zinc has been shown to be an important regulator of leptin in humans and rodents. Zinc deficiency is associated with somatic wasting and significant declines in circulating leptin levels. Zinc deficiency is common in underdeveloped regions and may therefore contribute to low leptin levels among Ache men. To ascertain the potential role of zinc on Ache male leptin profiles, zinc supplementation was conducted to observe leptin responsiveness. Ache males were given daily oral zinc supplementation (50 mg zinc gluconate) (n = 8) or placebo (n = 6) for 10 days. Serum leptin levels were measured on the first and last days of the treatment/placebo period. Despite supplementation exceeding triple the USDA recommended daily requirements, serum leptin levels did not change in the zinc-supplemented group (P = 0.61) and were not significantly different from males receiving placebo (P = 0.72). It is concluded that zinc is not likely to be a contributing factor in male Ache leptin profiles and that other sources of variation such as chronic energetic stresses affecting leptin production and perhaps receptor number or sensitivity should be considered. (C) 2003 Wiley-Liss, Inc.