In type 2 diabetes, magnesium deficiency worsens insulin resistance.10Then, as blood glucose levels rise, urinary excretion of magnesium increases,10creating a vicious cycle. 

A retrospective review involving 286,668 persons and 10,912 cases of type 2 diabetes uncovered a statistically significant, linear association between magnesium and the incidence of type 2 diabetes.11

In asthma, magnesium is often used as an abortive agent in acute bronchospasm due to its bronchodilatory action. In addition, one study showed that a 100mg/day higher intake of magnesium yielded a forced expiratory volume in 1 second (FEV1) that was 27.7mL higher.12

Finally, magnesium supplementation is garnering interest in the treatment of refractory depression. The element acts as a key neurotransmitter that strengthens synaptic function.13In vivo studies of patients with known refractory depression have shown a reduction in (intracellular) magnesium.14

Safety, How Supplied, Cost

Those who need to enhance their dietary intake of magnesium (almonds and spinach are particularly good sources)15might turn to supplements. 

Magnesium supplementation is generally safe (the recommended maximum supplemental dose for a healthy adult is 30mg/day15), but toxicity can occur.

Supplemental magnesium is supplied as a pill or capsule, and in multiple forms. Magnesium oxide, hydroxide, chloride, carbonate, and sulfate are common, but magnesium gluconate or lactate is better absorbed. A month’s supply costs about $20.

Dose, Interaction

Because magnesium and calcium are antagonistic, supplements combining the two should be avoided. Those that are used should contain a 2:1 ratio of calcium to magnesium.16 

Long-term use of antacids, some antibiotics, and diuretics reduce gastric absorption and increase excretion. Esomeprazole magnesium and lansoprazole are among the prescription proton pump inhibitors that can cause hypomagnesemia.15

Magnesium can form insoluble complexes with some tetracycline and quinolone antibiotics.15Some diuretics, such as furosemide, can increase the loss of magnesium in urine, leading to magnesium depletion, whereas others—for example, spironolactone—can reduce magnesium excretion.15 

Magnesium can decrease the absorption of alendronate and other oral bisphosphonates.

Sherril Sego, FNP-C, DNP, is a staff clinician at the VA Hospital in Kansas City, Mo., where she practices adult medicine and women’s health. She also teaches at the nursing schools of the University of Missouri and the University of Kansas.


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This article originally appeared on Clinical Advisor