Zinc supplementation for the prevention of type 2 diabetes mellitus

Beletate V, El Dib R, Atallah ÁN

Published Online:

January 21, 2009

Currently no evidence to suggest the use of zinc for the primary prevention of type 2 diabetes. Diabetes mellitus is associated with long-term complications, especially eye, kidney, nerve, heart and blood vessel disease. Type 2 diabetes is mainly characterised by a reduced ability of the hormone insulin to stimulate glucose uptake in body fat and muscles (insulin resistance) and affects most people suffering from diabetes. Type 2 diabetes may not cause symptoms for some time and may remain undetected for many years. Zinc, an important mineral, plays a relevant role in the synthesis and action of insulin. The human body does not produce zinc on its own, so it must be obtained from outside sources. The mineral zinc can be found in both animal and plant food sources, but the richest source of zinc comes from animal food sources.
We assessed the effects of the zinc supplementation in the prevention of type 2 diabetes mellitus. Only one relevant study was detected. There were no significant differences favouring people receiving zinc supplementation compared to placebo concerning any outcome measured in the study. Thus, there is currently no evidence to suggest the use of zinc supplementation in the prevention of type 2 diabetes mellitus.

Abstract (click to read)

Background:

The chronic hyperglycaemia of diabetes is associated with long-term damage, dysfunction, and failure of various organs, especially the eyes, kidneys, nerves, heart, and blood vessels. The risk of developing type 2 diabetes increases with age, obesity, and lack of physical activity. Insulin resistance is a fundamental aspect of the aetiology of type 2 diabetes. Insulin resistance has been shown to be associated with atherosclerosis, hypertriglyceridaemia, glucose intolerance, dyslipidaemia, hyperuricaemia, hypertension and polycystic ovary syndrome. The mineral zinc plays a key role in the synthesis and action of insulin, both physiologically and in diabetes mellitus. Zinc seems to stimulate insulin action and insulin receptor tyrosine kinase activity.

Objectives:

To assess the effects of the zinc supplementation in the prevention of type 2 diabetes mellitus.

Search strategy:

Studies were obtained from computerised searches of MEDLINE, EMBASE, LILACS and The Cochrane Library.

Selection criteria:

Studies were included if they had a randomised or quasi-randomised design and if they investigated zinc supplementation in adults living in the community, 18 years or older with insulin resistance (compared to placebo or no intervention).

Data collection and analysis:

Two authors selected relevant trials, assessed methodological quality and extracted data.

Main results:

Only one study met the inclusion criteria of this review. There were 56 normal glucose tolerant obese women (aged 25 to 45 years, body mass index 36.2 ± 2.3 kg/m2). Follow-up was four weeks. The outcomes measured were decrease of insulin resistance, anthropometric and diet parameters, leptin and insulin concentration, zinc concentration in the plasma and urine, lipid metabolism and fasting plasma glucose. There were no statistically significant differences favouring participants receiving zinc supplementation compared to placebo concerning any outcome measured by the study.

Authors' conclusions:

There is currently no evidence to suggest the use of zinc supplementation in the prevention of type 2 diabetes mellitus. Future trials will have to standardise outcomes measures such as incidence of type 2 diabetes mellitus, decrease of the insulin resistance, quality of life, diabetic complications, all-cause mortality and costs.

This record should be cited as:

Beletate V, El Dib R, Atallah ÁN. Zinc supplementation for the prevention of type 2 diabetes mellitus. Cochrane Database of Systematic Reviews 2007, Issue 1. Art. No.: CD005525. DOI: 10.1002/14651858.CD005525.pub2

Assessed as up to date:

June 30, 2005

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Primary Review Group:

Metabolic and Endocrine Disorders Group

Health topics:

Endocrine & metabolic > Diabetes > Type 2

Complementary & alternative medicine > Endocrine & metabolic > Diabetes

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Zinc supplementation for the prevention of type 2 diabetes mellitus

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