Magnesium

Magnesium and the brain

An observational study of more than 6,000 people aged 40 to 73 found that a high dietary magnesium intake, approximately 550 milligrams daily, was correlated with greater gray matter and hippocampal volumes compared with the average intake of about 350 milligrams daily, with a difference equivalent to roughly one year less of brain aging, especially in women; although observational correlations have limitations, the fact that lower magnesium levels are consistently linked to the development and progression of multiple age-related brain disorders adds credibility to the relationship.

In a study that followed more than 1,000 middle-aged adults for 17 years, those who consumed more magnesium daily, at least 196 milligrams, were 37 percent less likely to develop dementia in later life compared with those who consumed less than 174 milligrams, and in a study of adults over 60 without dementia, a higher magnesium intake, at least 434 milligrams daily, reduced the risk of developing mild cognitive impairment by 7 percent; a person with adequate magnesium intake is not immune to brain aging, but does appear to age with a measurable advantage.

Magnesium and stress: a vicious circle

Chronic stress depletes magnesium stores through multiple mechanisms: cortisol signals the kidneys to increase magnesium excretion, and other stress mediators promote lower intestinal absorption and greater renal excretion of the mineral; what makes this relationship especially pernicious is that many symptoms of magnesium deficiency, such as fatigue, irritability, and mild anxiety, are indistinguishable from the symptoms of stress itself, creating a vicious cycle in which stress produces deficiency and deficiency amplifies the stress response; correcting the deficit lowers cortisol levels, finally closing that cycle in the right direction.

Magnesium and athletic performance

Magnesium can improve athletic performance through its roles in energy production, muscle function, and electrolyte balance: male athletes who took 390 milligrams of magnesium daily for 25 days experienced an improvement in maximal oxygen uptake and in total work output, and adolescents who took 8 milligrams of magnesium per kilogram of body weight daily saw increases in endurance and reductions in oxygen consumption during submaximal exercise; sauna and intense exercise, two of the most powerful tools for health, are precisely the activities that deplete magnesium the most, which makes supplementation especially relevant for those who practice them regularly.

Forms of supplementation and what matters

Not all magnesium supplements are equivalent: magnesium glycinate and citrate have high bioavailability and are well tolerated, with glycinate especially recommended for improving sleep and reducing anxiety because of its weaker laxative effect; magnesium threonate has generated interest for its supposed ability to cross the blood-brain barrier and improve cognitive function, although human clinical studies are scarce, mostly industry-funded, and had results that were significant only in pooled analyses of multiple tests, not in individual tests; magnesium sulfate in Epsom salt baths, despite its popularity, lacks solid scientific evidence supporting its transdermal absorption in clinically relevant amounts.

References

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