Zinc supplementation improves glycemic control for diabetes prevention and management: a systematic review and meta-analysis of randomized controlled trials (original) (raw)

ABSTRACT

Background

Although many studies have shown that low zinc status is associated with diabetes, the putative effects of zinc supplementation on glycemic control are inconclusive.

Objectives

The aim of this meta-analysis of randomized controlled trials was to assess the effects of zinc supplementation in preventing and managing diabetes.

Methods

PubMed, Embase, and the Cochrane Library were searched for articles that were published through February 10, 2019 and contained estimates for the outcomes of interest. The pooled results were then analyzed with the use of a random-effects model.

Results

Thirty-two placebo-controlled interventions were extracted from 36 publications, involving a total of 1700 participants in 14 countries. Overall, compared with their respective control groups, the subjects in the zinc-supplementation group had a statistically significant reduction in fasting glucose [FG, weighted mean difference (WMD): −14.15 mg/dL; 95% CI: −17.36, −10.93 mg/dL], 2-h postprandial glucose (WMD: −36.85 mg/dL; 95% CI: −62.05, −11.65 mg/dL), fasting insulin (WMD: −1.82 mU/L; 95% CI: −3.10, −0.54 mU/L), homeostasis model assessment for insulin resistance (WMD: −0.73; 95% CI: −1.22, −0.24), glycated hemoglobin (WMD: −0.55%; 95% CI: −0.84, −0.27%), and high-sensitivity C-reactive protein (WMD: −1.31 mg/L; 95% CI: −2.05, −0.56 mg/L) concentrations. Moreover, subgroup analyses revealed that the effects of zinc supplementation on FG are significantly influenced by diabetic status and the formulation of the zinc supplement.

Conclusions

Our analysis revealed that several key glycemic indicators are significantly reduced by zinc supplementation, particularly the FG in subjects with diabetes and in subjects who received an inorganic zinc supplement. Together, these findings support the notion that zinc supplementation may have clinical potential as an adjunct therapy for preventing or managing diabetes. This trial was registered at PROSPERO as CRD42018111838.

Keywords:

zinc supplementation

glycemic control

type 2 diabetes

prediabetes

obesity

meta-analysis

Abbreviations used:

hs-CRP

high-sensitivity C-reactive protein

WMD

weighted mean difference

2h-PG

2-hour postprandial glucose.

Cited by (0)

This study was supported by research grants from the National Natural Science Foundation of China (31600953 to XW, 31530034 to FW, 31570791 and 91542205 to JM), the National Key R&D Program of China (2018YFA0507801 to JM and 2018YFA0507802 to FW), and the Zhejiang Provincial Natural Science Foundation of China (LQ15C110002 to XW).

Supplemental Table 1 and Supplemental Figures 1 and 2 are available from the “Supplementary data” link in the online posting of the article and from the same link in the online table of contents at https://academic.oup.com/ajcn/.

XW and WW contributed equally to this work.