Assessing exchangeable zinc pools may be a useful approach to evaluating zinc status and is positively related to dietary zinc intake, daily-absorbed zinc, and excretion of zinc. The aim of this randomized, double-blind, placebo-controlled study conducted in France was to evaluate the effects of zinc supplementation on zinc status in healthy middle-aged men. Men (16 per group) were supplemented daily for 6 months
with 15 mg or 30 mg of zinc (as zinc gluconate) or a placebo. Kinetic studies to estimate the distribution and excretion of zinc were performed. After six-months of supplementation, zinc concentrations were measured in plasma, red blood cells, and urine at various time points over a 10-day period. Compared with the control group, the supplemented groups increased exchangeable zinc pool mass regardless of the approach used to estimate these levels. However, the changes in exchangeable zinc pool mass were smaller than the changes in plasma zinc concentration, suggesting that exchangeable zinc pool mass may not be as sensitive as plasma zinc concentrations in assessing zinc status. Based on these findings, the authors concluded that zinc intakes by French men were inadequate and needed to be increased to levels recommended in the United States (11 mg/day). In addition, these data suggest that zinc supplementation is an efficient way of improving zinc status in late-middle-aged men.
Funding: European Commission.
C Feillet-Coudray, N Meunier, M Rambeau, M Brandolini-Bunlon, JC Tressol, M Andriollo, A Mazur, KD Cashman, and C Coudray. American Journal of Clinical Nutrition (Am J Clin Nutr) 2005 82:103-110.