28 November 2023

In people with type 2 diabetes, insulin secretion is progressively lost and insufficient to compensate for insulin resistance. This leads to an elevated blood glucose concentration, associated with an increased risk for cardiovascular complications. Up to 48% of people with type 2 diabetes have low serum magnesium levels, which has been suggested to worsen insulin resistance and type 2 diabetes management. 

Drenthen and colleagues investigated whether magnesium supplementation improved insulin resistance and overall glucose control and reduced the need for glucose-lowering drugs in people with type 2 diabetes. The research group, led by Bastiaan de Galan and Cees Tack, in collaboration with the department of Medical BioSciences, published the results in Diabetologia on 3 November.

The study had a randomised, placebo-controlled, two-period, cross-over study design. The study included 14 people with insulin-treated type 2 diabetes, since it was expected that people on insulin would benefit the most from improvements in insulin resistance. All participants underwent two treatment periods consisting of 6 weeks of treatment with magnesium gluconate or a matched placebo. Using the gold standard for measuring insulin sensitivity (i.e. the hyperinsulinaemic euglycaemic clamp), they found no difference in insulin sensitivity between treatment with magnesium or placebo. Also, during the 6-week treatment periods, magnesium supplementation did not improve glucose control, lipids, blood pressure or symptoms, such as muscle cramps, which are often mentioned to be related to low magnesium levels.

The findings of their study do not support a role for magnesium supplementation in people with insulin-treated type 2 diabetes. However, type 2 diabetes is associated with a chronic low-grade inflammatory state and low magnesium levels are associated with increased levels of pro-inflammatory molecules. At the moment, they are studying whether magnesium supplementation decreases this low-grade inflammation in people with type 2 diabetes, the results of which they hope to publish soon.

Read the study here

Drenthen LCA, de Baaij JHF, Rodwell L, van Herwaarden AE, Tack CJ, de Galan BE. Oral magnesium supplementation does not affect insulin sensitivity in people with insulin-treated type 2 diabetes and a low serum magnesium: a randomised controlled trial. Diabetologia. Nov 3, 2023; doi:10.1007/s00125-023-06029-9

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