The influence of zinc supplementation on glucose homeostasis in NIDDM

Decreased serum zinc levels and hyperzincuria occur in some non-insulin dependent diabetic subjects (NIDDM). Zinc deficiency was demonstrated in various tissues of animal models for NIDDM. Serum zinc and 24-hr urine zinc of subjects with NIDDM were compared with that of age- and sex-matched healthy volunteers. Zincuria was significantly increased in the diabetic group. Thirteen diabetic subjects with hyperzincuria and hypozincemia were supplemented with zinc sulfate 220 mg x 3/day for 7-8 weeks. At the end of the study, glucose disposal (evaluated by kg) decreased significantly from 0.562 +/- 0.03 to 0.414 +/- 0.05 (p less than 0.05) and fasting glucose and fructosamine were significantly increased from 177 +/- 10 mg/dl to 207 +/- 15 mg/dl (p less than 0.05) and from 2.7 +/- 0.2% to 3.2 +/- 0.28% (p less than 0.05), respectively. T-lymphocyte response to phytohemagglutinin was increased significantly. We conclude that zinc supplementation to NIDD patients with hypozincemia and hyperzincemia might aggravate their glucose intolerance. More accurate methods to assess zinc deficiency in NIDD patients is needed to justify the supplementation of zinc in these patients.