Posted on 29 July 2020
Magnesium is an essential dietary mineral, and the second most prevalent electrolyte in the human body. Magnesium deficiency, which is common in developed countries, increases blood pressure and impairs control of blood sugar.
Magnesium deficiency is common in developed countries because important sources of magnesium such as nuts are not consumed often enough. Dietary changes or supplementation can address magnesium deficiency, but further supplementation may still be beneficial in some circumstances.
As we age, sleep quality and duration tend to decrease, a phenomenon that has been linked to increased risk of dementia. Magnesium can normalise age-related sleep patterns and may therefore be neuroprotective. Magnesium can also lower high blood pressure and high blood sugar, both of which increase the risk of chronic diseases of ageing such as heart disease and diabetes.
A small randomised, placebo-controlled trial of 12 elderly subjects suggested that magnesium supplementation partially reverses nocturnal EEG and neuroendocrine changes that occur during ageing. A larger study with 100 participants with poor sleep quality over the age of 51 suggested that that 320mg magnesium supplementation per day improved sleep. However, part of this association may be explained by the finding that sleep deprivation lowers magnesium in the blood. Consequently, placebo-induced improvements in sleep quality may have boosted magnesium and confused results. It is currently unknown whether magnesium is beneficial in those with normal sleep quality.
A meta-analysis of 22 trials involving 1173 participants concluded that magnesium supplementation achieved a small but clinically significant reduction in blood pressure. Studies suggest that significant reductions appear to occur when the subject is either magnesium deficient or has an elevated blood pressure (140/90 or above).
There is also evidence from meta-analyses that magnesium supplementation can improve insulin sensitivity and reduce blood sugar in those with or at risk of diabetes, though the blood sugar reduction is not always reliable.
Magnesium supplementation may therefore be beneficial in those who are deficient, and seems to also benefit hypertensives and diabetics/prediabetics. There is also emerging evidence that magnesium reverses age-related sleep decline.
Examine.com: Magnesium: https://examine.com/supplements/magnesium/
Sleep and aging: 1. Sleep disorders commonly found in older people:: https://doi.org/10.1503/cmaj.060792
Oral Mg(2+) supplementation reverses age-related neuroendocrine and sleep EEG changes in humans: DOI: 10.1055/s-2002-33195
Magnesium supplementation improves indicators of low magnesium status and inflammatory stress in adults older than 51 years with poor quality sleep: DOI: 10.1684/mrh.2010.0220
Effects of oral magnesium supplementation on insulin sensitivity and blood pressure in normo-magnesemic nondiabetic overweight Korean adults: DOI: 10.1016/j.numecd.2009.01.002
Effect of magnesium supplementation on blood pressure: a meta-analysis: DOI: 10.1038/ejcn.2012.4
Effect of magnesium supplementation on glucose metabolism in people with or at risk of diabetes: a systematic review and meta-analysis of double-blind randomized controlled trials: DOI: 10.1038/ejcn.2016.154
Higher Magnesium Intake Is Associated with Lower Fasting Glucose and Insulin, with No Evidence of Interaction with Select Genetic Loci, in a Meta-Analysis of 15 CHARGE Consortium Studies1,2,3,4: doi: 10.3945/jn.112.172049
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