Magnesium

Magnesium is an essential dietary mineral and the second most prevalent intracellular cation in the body. It also serves as a cofactor for over 600 enzymes. Most notably, magnesium is required for energy production, carbohydrate metabolism, and DNA and protein synthesis.

Magnesium is also an antagonist of calcium in the body and is required for vitamin D synthesis and activation. As such, magnesium deficiency can inhibit the potential benefits of vitamin D supplementation.^[1]

Magnesium is abundant in green leafy vegetables, nuts, seeds, legumes, and whole grains. Inadequate magnesium intake is common in developed countries, as Western diets tend to contain a very low content of the aforementioned foods and are rich in refined grains and processed foods, which are poor sources of magnesium.

Magnesium deficiency increases blood pressure, reduces insulin sensitivity, and causes neural excitation. Consequently, low serum magnesium levels are associated with a wide variety of conditions, including obesity, type 2 diabetes, cardiovascular disease, metabolic syndrome, and osteoporosis.^[2]

Magnesium supplementation is not very effective at reducing fat mass or muscle cramps.^[3] Further evidence is needed to determine whether magnesium supplementation can improve sleep parameters.^[4]

Magnesium supplementation modestly reduces (a) systolic and diastolic blood pressure (by about −2 mmHg each),^[5][6][7] (b) fasting blood glucose in people with type 2 diabetes or at an increased risk of type 2 diabetes,^[8][9] and (c) C-reactive protein levels.^[10] The magnitude of improvement is larger in people with magnesium deficiency.

Magnesium supplementation can also reduce the frequency and intensity of migraine.^[11][7]

There aren’t many side effects associated with magnesium supplementation because, in healthy people, the body will only absorb as much as it needs. With that said, high doses of some magnesium salts (e.g. hydroxide, oxide, and citrate) are used as laxatives; therefore, excessive doses may cause gastrointestinal distress and diarrhea.

Many of magnesium’s beneficial effects are related to (a) its role as an antagonist of calcium in the body and (b) its role in regulating inflammation and oxidative stress,^[12] which are intimately involved in the development of chronic diseases (e.g., type 2 diabetes, hypertension).

Magnesium regulates the insulin signaling pathway and affects insulin secretion from pancreatic beta cells.^[13] In the case of magnesium deficiency, insulin secretion is dysfunctional.^[14] Magnesium deficiency can also reduce glucose tolerance because many of the enzymes involved in carbohydrate metabolism require magnesium.^[15]

Magnesium affects blood pressure mainly by modulating calcium concentrations and therefore affecting vascular tone.^[16] Additionally, it supports vasodilation by stimulating the production of nitric oxide.^[16] These properties are also pivotal to magnesium’s effects on migraine.^[17]

Lastly, magnesium blocks NMDA receptors, whose activation is associated with migraine. With magnesium deficiency, NMDA receptors allow an increased influx of calcium, triggering the release of glutamate, which binds to and activates NMDA receptors.^[17]