Effects of Zinc Supplementation in Patients with Type 1 Diabetes

Abstract

The purpose of this study was to identify the effect of oral zinc supplementation in patients with type 1 diabetes (T1DM) on metabolic control and zinc blood concentrations. The sample consisted of 20 patients with T1DM and a control group (n=17). Metabolic control was evaluated by glycemia at fast, 24 h glycosuria, and HbA1c. Zinc concentrations were measured in plasma and erythrocytes. After the first collection of biological material, oral zinc supplementation was initiated and continued for 4 mo in T1MD patients (T1). Daily dosages were established based on Dietary Recommended Intakes (DRIs), considering zinc intake based on data from other studies previously performed with this population. All analyses were repeated after supplementation (T2). Metabolic control was unsatisfactory, with an HbA1c increase at T2. There was no difference in zinc concentrations in plasma and erythrocytes between patients with T1DM and control. Zinc concentrations in plasma were within the normal range in T1MD before and after supplementation and the control. Zinc concentrations in erythrocyte presented lower than normal values for all groups. A zinc increase in erythrocyte after supplementation was observed in T1DM patients, although without statistical significance. More studies are needed to confirm oral zinc supplementation as nutritional management in diabetes.

Zinc and diabetes — clinical links and molecular mechanisms

“…However, the zinc dose administered has to be determined individually and the zinc status should be controlled in order to prevent adverse effects based on inappropriately high zinc dosage [69,112].…”

“…Studies of zinc supplementation conducted in humans showed that zinc supplementation was less favorable in type 1 diabetes [69,112] than in type 2 diabetes, where zinc supplementation led to a decrease of the insulin resistance index (homeostasis model assessment-estimated insulin resistance), a reduction of the typically elevated insulin concentration [49] and a reduction of HbA 1C [50]. Few studies failed to demonstrate a positive effect of zinc on type 2 diabetes [113] or its prevention [114], being possibly due to an inadequately high zinc dose in the first case [24,115].…”

“…Few studies failed to demonstrate a positive effect of zinc on type 2 diabetes [113] or its prevention [114], being possibly due to an inadequately high zinc dose in the first case [24,115]. In contrast, zinc supplementation in type 1 diabetes might even have negative effects on the HbA 1C level [69,112]. Taken together, these studies indicate some beneficial effects of zinc on the diabetic state, in humans especially concerning type 2 diabetes, but they also emphasize the necessity to carefully consider the risk factors and to tightly control glycemic parameters and zinc status when supplementing zinc.…”

Modulating the immune response by oral zinc supplementation: a single approach for multiple diseases

“…One study found a positive effect on oxidative stress, measured by an increase in selenium-glutathione peroxidase activity, and a decrease in plasma thiobarbituric acid reactive substances, which are an indicator for lipid peroxidation [39]. On the other hand, two other studies detected an increase in the glycosylated form of hemoglobin, HbA1c, indicating a further deterioration of metabolic control [25,29]. Taken together, it seems that zinc supplementation can be helpful against oxidative stress, but its effect on glucose metabolism may limit its usefulness in diabetic patients.…”

The Role of Complementary and Alternative Therapies in Pediatric Diabetes

“…66 In a prospective, nonrandomized study, 20 Brazilian children aged 4 to 16 years with type 1 diabetes received daily zinc supplementation 1.5 to 1.8 times the recommended dietary allowances for 4 months. 68 The study found an increase in HbA 1c after zinc supplementation, attributing this to poor metabolic control. Increased appetite and weight were side effects reported by participants, and agreed with findings of increased HbA 1c in 7 young adults with type 1 diabetes after a month of zinc supplementation.…”