Magnesium and potassium supplementation may ease insomnia severity in people with diabetes. Digest
Sleep problems are common among people with diabetes and place an additional burden on daily life. Because minerals play important roles in sleep regulation and disrupted mineral levels are common in diabetes, researchers examined whether magnesium and potassium could improve sleep in people with diabetes and insomnia.
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In this study, 320 participants were assigned to placebo tablets, magnesium gluconate tablets (2 x 250 mg), potassium chloride tablets (2 x 250 mg), or one magnesium plus one potassium tablet for 2 months. Researchers assessed insomnia using the Insomnia Severity Index, a questionnaire that classifies insomnia symptoms by severity, and measured blood levels of cortisol (a stress-related hormone) and melatonin (a hormone involved in sleep timing) before and after the trial.
- After 2 months, none of the participants in the supplement groups were still classified as having severe clinical insomnia, compared with about 40% of those in the placebo group. Before treatment, severe clinical insomnia affected about 11% to 27% of participants in the supplement groups and 34% in the placebo group.
- 41% of participants taking magnesium plus potassium were below the questionnaire threshold for clinically significant insomnia by the end of the trial, compared with 31% in the magnesium group and 32% in the potassium group, while none of the placebo participants were in that category. Before treatment, these rates were about 6%, 1%, 1%, and 0%, respectively.
- Morning cortisol levels fell in all supplement groups, with the largest drop in the magnesium plus potassium group, from about 42 to 23 micrograms/dL after 2 months. In the placebo group, levels stayed roughly the same.
- Melatonin had the largest increase in the magnesium plus potassium group, increasing from about 6 pg/mL before the trial to 15 pg/mL after 2 months, while levels only changed slightly in the other groups.
Magnesium may support sleep by calming overactive nerve activity and balancing stimulating and relaxing signals in the brain. Potassium may contribute by allowing nerve and muscle cells to maintain stable electrical activity, which supports normal relaxation and sleep regulation. Together, these minerals could plausibly shift physiology away from heightened arousal and toward a more sleep-ready state.
The study has several important limitations. Because the trial was only single-blind, treatment assignments were not hidden from all study personnel during the trial, which can subtly affect how participants are treated and potentially influence the results. The study also did not objectively measure sleep with wearable monitors or overnight sleep-lab recordings, so it cannot show whether participants actually slept longer, woke up less often, or had deeper sleep. Nevertheless, if confirmed in studies with stronger methodology, magnesium and potassium supplementation could become a simple add-on strategy for improving sleep in people with diabetes. In this clip, I discuss how sleep loss affects glucose metabolism and how vigorous-intensity exercise can help counteract these effects.