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Magnesium

Also known as: Magnesium oxide, Magnesium hydroxide, Magnesium citrate, Magnesium aspartate, Magnesium glycinate, Magnesium orotate, Magnesium L-threonate, Magnesium chloride, Magnesium lactate, Magnesium malate, Magnesium sulfate, Magnesium taurate, Magnesium carbonate

Overview

Magnesium is an essential dietary mineral that is involved in energy production, nervous system function, blood pressure regulation, and blood glucose control. A lack of magnesium in the diet — which is common in modern societies — is associated with an increased risk of diabetes, cardiovascular disease, and other health conditions.

Benefits

Many observations related to magnesium’s effect on reducing disease risk are likely due to correction of a deficiency. In other words, it may not be the case that supplemental magnesium is beneficial per se; instead, magnesium deficiency may lead to several health problems, many of which may be related to chronic low-grade inflammation. There is also the possibility of reverse causation because many modern diseases (i.e., obesity and diabetes) may lead to a magnesium deficiency. Nonetheless, there are well-documented mechanisms that explain why magnesium may benefit health. For one, magnesium plays a role in beta-cell activity in the pancreas, influencing insulin secretion and, therefore, our ability to regulate blood glucose. Magnesium deficiency can lead to impaired insulin secretion, impaired glucose utilization, and insulin resistance — all of which contribute to the development of type 2 diabetes. In the cardiovascular system, magnesium regulates calcium concentrations, which enhances vascular relaxation and inhibits vasoconstriction, leading to healthy vascular tone and protecting against high blood pressure (hypertension). Magnesium also improves endothelial function by directly stimulating the release of nitric oxide (NO). In the brain, magnesium binds to and blocks the actions of NMDA receptors, thereby preventing glutamate-dependent transmission of cortical spreading depression — one mechanism involved in the pathogenesis of migraine headache. Magnesium is also a GABA agonist. Magnesium affects the function of serotonin receptors, influences platelet aggregation, and regulates the synthesis and release of several neurotransmitters. These mechanisms explain magnesium’s benefit for migraine, as well as the potential for magnesium to improve sleep and other aspects of neurological health.

How it works

Low magnesium levels are associated with a higher risk of diabetes, and supplementation with magnesium has been shown to reduce blood glucose and improve insulin sensitivity, especially in people who are insulin resistant and/or magnesium deficient and/or in women with gestational diabetes. Supplemental magnesium also appears to lower blood pressure in people who are deficient in magnesium and in those who have elevated blood pressure (hypertension). The average reduction in blood pressure after magnesium supplementation is 2–4 mmHg for systolic blood pressure and 2 mmHg for diastolic blood pressure, though the reductions may be greater for individuals with type 2 diabetes (6–8 mmHg and 2–3 mmHg for systolic and diastolic blood pressure, respectively). There is some indication that magnesium supplementation may reduce the frequency and intensity of migraine headache and attenuate premenstrual symptoms in women.

Side effects

The recommended dietary allowance (RDA) of magnesium for adults is 410–420 mg/day for men and 320–360 mg/day for women. This includes magnesium from all sources such as food, beverages, supplements, and medications. The tolerable upper intake level (UL) for magnesium for adults is 350 mg; this value only includes magnesium obtained from dietary supplements and medications.

Dosage

Magnesium supplementation that is not excessive is well tolerated and probably won’t cause side effects, and it’s difficult to ingest too much magnesium from food sources alone. Excess magnesium in the body is eliminated by the kidneys, so the risk of magnesium toxicity from food is quite low for healthy people. Supplementing with high doses and certain magnesium salts (i.e., magnesium carbonate, magnesium chloride, magnesium gluconate, magnesium hydroxide, and magnesium oxide) can have a laxative effect — though some people choose to take certain forms of magnesium for this reason. Unabsorbed magnesium salts have an osmotic effect in the intestinal tract and can increase gastric motility. Nausea, diarrhea, and abdominal cramping are also occasional side effects reported from supplemental magnesium. Magnesium supplements can also interfere with the absorption of certain medications, including bisphosphonates (used for treating osteoporosis) and antibiotics — to avoid these interactions, individuals who are taking these types of medications should talk to their healthcare provider about how to space out and time their supplemental magnesium.

FAQs

What is magnesium?

Magnesium is an essential dietary nutrient and is one of the most abundant minerals in the body. Magnesium acts as an electrolyte and is a cofactor for more than 300 enzymes. Magnesium is required for energy (ATP) production, glucose metabolism, DNA and protein synthesis, nerve conduction, bone health, and cardiovascular regulation, among other functions. It also plays a crucial role in the synthesis and activation of vitamin D.

What are the different types of magnesium?

Magnesium supplements generally come in the form of magnesium salts bound to another element or amino acid. Some of the main forms of magnesium include magnesium oxide, magnesium hydroxide (the commercial product Milk of Magnesia), magnesium citrate, magnesium lactate, magnesium gluconate, magnesium aspartate, magnesium glycinate, magnesium orotate, magnesium threonate, and magnesium sulfate (Epsom salt).

What foods are highest in magnesium?

A variety of plant and animal foods are good sources of magnesium, including the following: Dark leafy green vegetables: kale, spinach, collard greens, turnip greens, mustard greens; Nuts and seeds: cashews, almonds, pumpkin seeds, chia seeds, flaxseed.

Does magnesium help with sleep?

Due to its actions as an N-methyl-D-aspartate (NMDA) antagonist and a gamma-aminobutyric acid (GABA) agonist, magnesium is hypothesized to help regulate the sleep/wake cycle and thereby promote healthy sleep. For this reason, magnesium is often promoted as a sleep-enhancing supplement, and some people use magnesium to treat insomnia and improve sleep quality and/or sleep duration. However, there is surprisingly little evidence to support its use.

Can you take magnesium during pregnancy?

Supplementation with magnesium during pregnancy can have health benefits for both mother and baby; however, the quality of evidence is mixed, and large, well‐designed randomized controlled trials are needed to draw firm conclusions. Importantly, adverse effects of magnesium are rare, and supplementation with magnesium before or during pregnancy appears to be safe for mother and baby.

Does magnesium help with anxiety?

Observational studies have found that serum magnesium concentrations are not different between people with and without generalized anxiety disorder and that serum magnesium concentrations are not correlated with self-reported levels of anxiety. Some observational studies have found an association between a greater dietary magnesium intake and lower odds of anxiety, but other studies do not confirm that finding.

Does magnesium help with constipation?

Some people take Milk of Magnesia, which contains magnesium hydroxide, to alleviate constipation. While some studies find a benefit, its overall efficacy is unclear due to a lack of high-quality research. Other studies have found that magnesium oxide might also improve constipation; similarly, however, further high-quality research is needed to draw firm conclusions concerning its efficacy.

Does magnesium help with blood pressure?

Large cross-sectional studies have shown that a higher systolic blood pressure in adults who experience hypertensive crises (sudden and severe rises in blood pressure) is associated with a higher serum magnesium concentration. However, in healthy children and adults without hypertensive crises, higher blood pressure is associated with a lower serum magnesium concentration.