For ASTHMA, higher tissue levels of the mineral magnesium correlate with better lung function and reduced asthma symptoms. Research since 1912 has repeatedly confirmed that magnesium relaxes smooth muscle in the bronchial passages so that airways remain more open, and breathing is easier. Magnesium is a classic smooth muscle relaxant used to prevent exacerbations of asthma and COPD, and also to help sleep. Intravenous magnesium is used in emergency medicine to halt acute exacerbations of asthma and COPD, and its good effects can last longer than rescue inhalers. In contrast, a low level of magnesium, an important mineral involved in nerve cell function, exacerbates spasms of the air passages and is linked with worsened asthma risk and more symptoms.

How does magnesium work in the lungs?

Bronchi are made up of cartilage and smooth muscle, and they are lined by mucous membranes. Cartilage provides structural strength, and the smooth muscle controls airway dimensions during respiration. Muscle tissue relies on sufficient magnesium levels to relax after a contraction; whereas calcium is required to initiate and maintain muscle contraction. Magnesium then stimulates the re-uptake of the calcium by muscle cells and competes for its binding sites, allowing muscle fibers to relax. If the body’s magnesium levels are depleted, muscles are less able to relax, and spasms will remain.

Magnesium deficiency is very common in the U.S. population: Research shows that the magnesium content of food sources is declining, although magnesium is found in many foods like seeds, nuts, dark leafy greens, legumes, whole grains, and dark chocolate. Studies estimate that 75% of Americans do not meet the recommended dietary allowance of magnesium.¹ Magnesium depletion may result from low dietary intake or poor absorption, or loss of magnesium due to excessive calcium intake, alcohol, diuretic drugs, oral contraceptives, or kidney or liver disorders.

Magnesium is the second-most ubiquitous mineral within cells of the body, after potassium. Its many health benefits also arise from its role in activating a wide variety of enzymes, for numerous metabolic processes. Magnesium is especially concentrated in the brain, heart, liver, and kidneys, where it has a critical role in energy production.

Magnesium is a classic clinical asthma remedy

Magnesium is a standard medical treatment for acute asthma attacks. Magnesium is a recognized smooth muscle relaxant used to prevent exacerbations of asthma and COPD. Used daily for chronic or allergic asthma, magnesium can significantly reduce wheezing, tight chest, and shortness of breath, and the doses needed of medications.

The science behind magnesium and asthma

Magnesium has several different actions in the lungs:

• It relaxes and opens the airways.
• Magnesium exerts an anti-inflammatory effect on the airways through several mechanisms, including:
  • preventing the release of oxygen free radicals, unstable molecules that contain highly reactive abnormal oxygen variants,
  • stabilization of T-cells and mast cells,
  • and facilitating the release of endogenous nitric oxide and prostacyclins (an effective vasodilator in the body).
• Magnesium is a calcium channel blocker and blocks chemicals that cause muscle spasms.

There is growing evidence that magnesium has a role in managing chronic asthma through its dual effect as an anti-inflammatory and bronchodilation agent. A notable randomized, placebo-controlled experiment followed 55 subjects with mild to moderate asthma to determine if long-term treatment (6.5 months) with oral magnesium would improve their asthma. Those receiving magnesium had significantly increased forced expiratory volume and peak expiratory flow rate, meaning they could breathe out more freely and with less restriction; and they had less bronchial reactivity. Additionally, these subjects reported significant improvement in their asthma quality of life and control questionnaires.²

We prefer magnesium citrate for our patients, and a randomized, double-blind, placebo-controlled clinical trial performed on 112 patients with mild and moderate persistent asthma confirmed its use. After 2 months of taking magnesium citrate, patients had significantly increased forced vital capacity (FVC) and forced exhalation volume in one second (FEV1), meaning that their air flow was improved, and the FEV1/FVC ratio value decreased significantly. This provides evidence that magnesium citrate can improve lung function in patients with mild and moderate asthma.³

Another magnesium study added to these findings by measuring interleukin-17 (IL-17), a noninvasive marker of airway inflammation made in the bodies of patients with asthma. IL-17 plays important roles in allergic responses including allergic airway inflammation and delayed or contact hypersensitivity. The IL-17 pathway promotes inflammation by inducing various proinflammatory cytokines and chemokines, recruiting neutrophils, enhancing antibody production, and activating T cells. Researchers observed a significant difference in those receiving magnesium versus placebo subjects in asthma control, although the data is still under review for IL-17 concentrations.⁴

How is magnesium measured in the body?

Because magnesium is found predominantly within cells rather than in serum, the only meaningful measurement is to test levels in the interior of cells. Red blood cells (RBCs) are an easy source to obtain a good indication of magnesium levels inside cells throughout the body. The Food and Nutrition Board at the Institute of Medicine established the average daily intake of magnesium that is sufficient to meet the nutrient requirements of nearly all healthy individuals, but a person may need more to achieve a healthy blood level. In general, men ages 19 to 30 need an average of 400 mg, with an increase to 420 mg of magnesium daily after the age of 31. Women ages 19 to 30 require 310 mg, with an increase to 320 mg of magnesium per day after the age of 31. Any patient may need higher doses to reach the target RBC magnesium blood level.

Our target for RBC magnesium is 4 to 6.4 mg/dL. For patients who begin with low RBC magnesium levels, we recheck this after 4 to 8 weeks of taking magnesium. We have found that magnesium citrate in an organic form is particularly well-recognized by body tissues including the lungs for superior absorption. Common dosing can range from 150 mg to 450 mg of magnesium daily. Depending on the form of magnesium used, large doses over 500 mg may cause loose stools, which is harmless but easily avoided. Incidentally, magnesium is actually used as a treatment for constipation.

Recommendation: 150 to 450 mg of magnesium citrate or chelate daily, taken with or between meals, or as directed by your healthcare provider.

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