The purpose of this investigation is to evaluate the impact of zinc supplementation on
fasting glucose levels, hemoglobin A1c (HbA1c), and other indices of glucose homeostasis in
individuals with prediabetes. We hypothesize that prediabetic subjects receiving zinc will
demonstrate a greater decrease in HbA1c and blood glucose compared to prediabetic subjects
receiving placebo.
Specific Aim: Conduct a prospective, double-blind randomized clinical trial comparing the
effects of 12 months of zinc supplementation (zinc acetate 25 mg/day) versus placebo on
glucose homeostasis. Based upon expected effect size and power calculations, and anticipating
a 20% drop-out rate, we will study 200 prediabetic subjects (100 per group) using a 1:1
randomization design. HbA1c, fasting plasma glucose, and other measures will be obtained at
0, 6, and 12 months and will be compared between zinc supplementation and placebo groups.