Zinc supplementation for improving glucose handling in pre-diabetes: A double blind randomized placebo controlled pilot study

Aims: There are a number of studies showing that zinc supplementation may improve glucose handling in people with established diabetes. We sought to investigate whether this zinc-dependent improvement in glucose handling could potentially be harnessed to prevent the progression of pre-diabetes to diabetes. In this double-blind randomized placebo-controlled trial, we determined participants' fasting blood glucose levels, (FBG) and Homeostasis Model Assessment (HOMA) parameters (beta cell function, insulin sensitivity and insulin resistance) at baseline and after 6 months of zinc supplementation. Methods: The Bangladesh Institute of Health Sciences Hospital (BIHS) (Mirpur, Dhaka, Bangladesh) database was used to identify 224 patients with prediabetes, of whom 55 met the inclusion criteria and agreed to participate. The participants were randomized either to the intervention or control group using block randomization. The groups received either 30 mg zinc sulphate dispersible tablet or placebo, once daily for six months. Results: After six months, the intervention group significantly improved their FBG concentration compared to the placebo group (5.37 +/- 0.20 mmol/L vs 5.69 +/- 0.26, p < 0.001) as well as compared to their own baseline (5.37 +/- 0.20 mmol/L vs 5.8 +/- 0.09, p < 0.001). Beta cell function, insulin sensitivity and insulin resistance all showed a statistically significant improvement as well. Conclusion: To our knowledge this is the first trial to show an improvement in glucose handling using HOMA parameters in participants with prediabetes. Larger randomized controlled trials are warranted to confirm these findings and to explore clinical endpoints. (C) 2016 Elsevier Ireland Ltd. All rights reserved.