Lessons from Observational Studies Evaluating Magnesium Intakes: Can They Predict Outcomes for Clinical Interventions?

W.H. Linda Kao, Ph.D


Type 2 diabetes mellitus imposes a substantial public health burden in the United States. It affects approximately 15 million Americans and leads to an excess risk of blindness, renal failure, lower extremity amputation, and cardiovascular disease. Several lines of evidence suggest a possible, novel risk factor for type 2 diabetes S magnesium deficiency. First, several large observational studies have demonstrated strong cross-sectional associations between low serum magnesium and type 2 diabetes. Second, in vitro studies have shown an effect of magnesium on the secretion of insulin by the pancreas and on the responsiveness to insulin by peripheral tissues. Third, magnesium supplementation prevents the development of diabetes in a rat model of spontaneous type 2 diabetes. Finally, clinical intervention studies demonstrated that daily magnesium supplementation can improve short-term insulin response and glucose handling in diabetic individuals. Results from large, prospective, observational studies of the associations between serum magnesium and magnesium intake and the risk of developing type 2 diabetes will be reviewed. Although results from these studies support the notion that low serum magnesium levels and low dietary magnesium intake may be important in the development of type 2 diabetes, whether pharmacologic doses of magnesium used as dietary supplement can reduce the long-term risk for type 2 diabetes remains to be investigated.

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