Zinc supplementation improves glucose disposal in patients with cirrhosis

Abstract

Zinc deficiency is common in cirrhosis, and was proved to affect nitrogen metabolism. In experimental animals, zinc status may also affect glucose disposal, and acute zinc supplementation improves glucose tolerance in healthy subjects. This study was aimed at measuring the effects of long-term oral zinc supplements on glucose tolerance in cirrhosis. The time courses of glucose, insulin, and C-peptide in response to an intravenous (i.v.) glucose load were analyzed by the minimal-model technique before and after long-term oral zinc supplements (200 mg three times per day for 60 days) in 10 subjects with advanced cirrhosis and impaired glucose tolerance or diabetes. The test was performed using a simplified procedure, based on 20 blood samples collected within 4 hours from the glucose load. Normal values were obtained in 25 age-matched healthy subjects. Zinc levels were low to normal or reduced before treatment, and were normalized by oral zinc. Glucose disappearance improved by greater than 30% in response to treatment. There were no changes in pancreatic insulin secretion and systemic delivery, or in the hepatic extraction of insulin. Insulin sensitivity (SI), which was reduced by 80% before treatment, did not change. Glucose effectiveness (SG) was nearly halved in cirrhosis before treatment (0.013 [SD 0.007] min(-1) v. 0.028 [SD 0.009] in controls; P < .001), and increased to 0.017 (SD 0.009) after zinc (P < .05 v. baseline). The return to normal of plasma zinc levels after long-term zinc treatment in advanced cirrhosis improves glucose tolerance via an increase of the effects of glucose per se on glucose metabolism. Poor zinc status may contribute to the impaired glucose tolerance and diabetes of cirrhosis.

Zinc, pancreatic islet cell function and diabetes: new insights into an old story

“…Indeed, in another study on type 2 diabetes patients suffering neuropathy supplemented with comparable dose and duration (660 mg zinc sulfate/d; 6 weeks) a better glycaemic control was observed, along with an improvement in peripheral neuropathy (114) . Approximately the same dosage (200 mg three times per d) for 2 months was used by Marchesini et al (115) , who could thus show in patients with cirrhosis that long-term oral Zn supplementation normalised plasma Zn levels and improved glucose tolerance (115) . In additional studies with slightly higher than normal daily requirements, supplemental Zn in diabetics both restored serum Zn levels and significantly decreased the mean value for HbA1c percentage at the end of the 3 months of follow up, while no significant changes were found in the control group (116) .…”

Correlation Between Serum Zinc and Glycosylated Hemoglobin Levels in Type Ii Diabetes Mellitus.

“…The findings of the present study are consistent with Reefat et al, [28] who showed negative correlation between serum zinc concentration and baseline HbA1c% value in cases. Marchesini et al, [29] explained hypozincemia in diabetic population due to the low gastrointestinal absorption and high urinary excretion of zinc.…”

A 12-week Double-blind Randomized Clinical Trial Of Vitamin D3 Supplementation On Body Fat Mass In Healthy Overweight And Obese Women

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