Zinc, the pancreas, and diabetes: Insights from rodent studies and future directions

Molecular and cellular studies have demonstrated several roles for zinc (Zn) in insulin production and the consequent actions of insulin on metabolism. Clinical and epidemiological studies suggest that reduced Zn status is associated with diabetes. Investigations of Zn in rodent models of diabetes have provided a valuable link for understanding the molecular, cellular, clinical and epidemiological observations in the context of inter-organ metabolism and the metabolic disturbances of diabetes. This review highlights some of the current knowledge and future research directions for the role of Zn in the pancreas and diabetes based on rodent studies and experimental manipulations of Zn. Overall, Zn supplementation is effective for preventing or ameliorating diabetes in several rodent models of Type 1 and Type 2 diabetes. Studies with chemically-induced Type 1 diabetes indicate that the protective effects of Zn involve antioxidant mechanisms whether it is Zn alone (as an antioxidant), Zn induction of metallothionein or Zn inhibition of redox-sensitive transcription factors. Further studies are needed to identify the mechanism(s) for Zn protection in Type 2 diabetes, including pancreatic and peripheral effects. Experimental manipulations of Zn status in rodent models of diabetes provide a valuable approach to explore mechanisms for the protective effects of Zn; however, long term clinical studies establishing safety (lack of toxicity) and efficacy are required before any recommendations can be made for people with diabetes.