Zinc as a potential coadjuvant in therapy for type 2 diabetes.

BACKGROUND Type 2 diabetes is highly prevalent in populations having high rates of overweight and obesity. It is a chronic condition responsible for long-term severe dysfunction of several organs, including the kidneys, heart, blood vessels, and eyes. Although there are a number of pharmacologic products in the market to treat insulin resistance and impaired insulin secretion--the most prominent features of this disease--interventions directed at preserving the integrity and function of beta-cells in the long term are less available. The use of some nutrients with important cellular protective roles that may lead to a preservation of beta-cells has not been fully tested; among these, zinc may be an interesting candidate. OBJECTIVE To assess the potential of zinc supplementation as coadjuvant to diabetes therapy. METHODS This article reviews the available information on the use of zinc as part of diabetes therapy. RESULTS Cellular and animal models provide information on the insulin mimetic action of zinc, as well as its role as a regulator of oxidative stress, inflammation, apoptosis, and insulin secretion. Zinc supplementation studies in humans are limited, although some positive effects have been reported; mainly, a modest but significant reduction in fasting glucose and a trend to decreased glycated hemoglobin (HbA1c). CONCLUSIONS Zinc supplementation may have beneficial effects on glycemic control. Nevertheless, among the studies considered, the vast majority lasted for 6 months or less, suggesting the importance of conducting long-duration studies given the characteristics of type 2 diabetes as a chronic disease.