Zinc supplementation could prevent type 2 diabetes in obese patients

The findings, published in Obesity Research & Clinical Practice, suggest that zinc supplementation could be a viable adjunct therapy to reduce the risk of diabetes development in obese/overweight individuals.

Over 40% of the global population is reported to be affected by obesity and overweight, and their growing prevalence is of concern. Some studies have shown that overweight and obese people have a higher risk of type 2 diabetes (T2D) incidence than normal-weight individuals.

Several studies have shown that zinc plays a critical role in the pathophysiology of glycemic metabolism and affects insulin homeostasis. Still, the efficacy of zinc supplementation in blood sugar control among overweight and obese people remains unknown. Hao-Yu Yang, Kaohsiung Veterans General Hospital, Kaohsiung City, Taiwan, and colleagues aimed to evaluate the effectiveness of zinc supplementation for blood sugar control among overweight and obese individuals in a meta-analysis. They hypothesized that zinc supplementation would improve the blood sugar parameters of this population.

For this purpose, the researchers searched the online databases from inception until May 2022 for RCTs (randomized controlled trials) investigating the effects of zinc supplementation among overweight/obese people without language restriction. It is a random-effect meta-analysis that analyzed the effect of zinc supplementation on fasting glucose (primary outcome) and other variables, including homeostasis model assessment-insulin resistance index (HOMA-IR), fasting insulin (FI), 2-hour postprandial glucose (2 h- PG), high-sensitivity C-reactive protein (hs-CRP), and glycated haemoglobin (HbA1c).

The study led to the following findings:

• Analysis of 12 eligible RCTs comprising 651 overweight/obese participants showed that zinc supplementation significantly improves FG (weighted mean difference [WMD]: −8.57 mg/dL), HOMA-IR (WMD: −0.54), HbA1c (WMD: −0.25%), and two h-PG (WMD: −18.42 mg/dL) compared to those in the control group.
• After conducting subgroup analyses, the authors found that the primary outcome, fasting glucose, showed more significant results in the subgroups with Asia, Zinc supplementation alone, higher dose (≥30 mg) and patients with diabetes.

"Our meta-analysis revealed that zinc supplementation benefits insulin resistance and blood sugar control in overweight/obese populations, significantly reducing two h-PG, HbA1c, HOMA-IR, and FG," the researchers wrote.

Based on the findings, they suggested that zinc supplementation could be a viable adjunct therapy to reduce the risk of diabetes in this population.

"Contrary to prior meta-analyses, subgroup analyses revealed that zinc supplementation alone and at higher dosages resulted in reduced FG and HOMA-IR," they wrote. The team indicate the need for further large RCTs to strengthen the evidence base for optimal zinc dosage.

Reference:

Yang, H., Hung, K., Chuang, M., Chang, R., Chen, R., Wang, F., Wu, J., & Chen, J. (2023). Effect of zinc supplementation on blood sugar control in the overweight and obese population: A systematic review and meta-analysis of randomized controlled trials. Obesity Research & Clinical Practice. https://doi.org/10.1016/j.orcp.2023.06.003