If you are concerned about your respiratory health, read about compelling research related to magnesium for asthma and lungs. Many studies show that the respiratory system depends on sufficient quantities of this essential mineral.
Magnesium is Well Documented for Asthma and Lung Health
Magnesium, an essential macro-mineral, is well documented to facilitate a host of processes that support lung health. One way this happens is that Magnesium is involved with DNA repair and stabilizing its structure by binding the DNA’s negative charge, reducing its density.  Many studies have reported that magnesium may help to protect the body against oxidative stress and systematic inflammation.  Conversely, low magnesium levels affect immune function, which may contribute to asthma.  Magnesium is also a co-factor in enzyme activation reactions that require adenine triphosphate (ATP).  And, since ATP is the form of energy used by all cells in the body, all lung functions require ATP in order to run properly.
Because air pollution and asthma are such severe issues in China, this article sites multiple sources and studies specifically related to that region, but the health needs are universal around the world.
Magnesium for Asthma
Asthma is characterized by smooth-muscle spasms in the lung, edema or swelling, inflammation, and over-secretion of mucous into the airways. According to the China Journal of Pediatrics, asthma rates among children rose 64 percent to a prevalence of 1.97% between 1990 and 2000, with some cities having as high as 4.63 percent of their children under 14 with asthma. Many specialists have estimated that there has been a 40% increase of asthma even within the last five years in China. 
Low magnesium intake levels play a role in the development of asthma, with many studies finding that magnesium may even protect against the development of asthma and chronic airway obstruction. [4,14] For instance, those who had higher magnesium in their diets had better forced expiratory volume and were less likely to report wheezing in the past 12 months.  In one study done with 2,566 children in southern California, researchers found that low magnesium intakes were associated with lower lung function, with some children functioning as low as 25 percent below normal lung capacities.  Simultaneously, a magnesium deficiency can affect the activity of white blood cells called neutrophils and this may actually make asthma attacks worse than they otherwise would be. In another study, researchers found that asthma patients had lower magnesium levels than their healthy cohorts. 
Magnesium Prevents Calcium Imbalance and Promotes Smooth Muscle Function
Magnesium also functions as an antagonist of calcium’s entry into the lung cells by regulating the amount of calcium in our blood. In recent years, calcium intake has increased due to diet and supplementation, while magnesium levels in the general population have declined. This has led to a calcium/magnesium ratio imbalance. Too much calcium in our blood can cause muscle contractions or cramps since magnesium is critical for the electrical conduction across cell membranes.  Adequate magnesium in the diet helps regulate bronchial activity by keeping the smooth muscles relaxed. This helps to explain why reduced magnesium intake is associated with decreased lung function and health. [7,12]
Magnesium also calms the nervous system. If you are magnesium deficient, your body will have a hard time switching from the sympathetic state (flight or fight) to the parasympathetic state (rest and recover).  This is why increasing magnesium relaxes the smooth muscles in the lungs and reduces hyper-excitability .
Magnesium depresses the central nervous system and causes a calming effect on the lung tissue itself (antihistamine effect on the mast cells).  Indeed, when there is too much calcium in the system, calcium actually blocks the magnesium from being available in the lungs. This leads the mast cells of the lung to secrete more chemical mediators such as histamine and acetylcholine, which leads to the contraction of the smooth muscles in the respiratory system .
Low Magnesium Leads to Lower Lung Function
Studies have found that low intakes of magnesium in the diet are associated with lower lung function as shown through airway flow rates, airway hyper-reactivity, and increased risk of wheezing.  Thus, it is important that the body receives adequate levels of magnesium for asthma and lung health.
In addition, magnesium has also been shown to inhibit cholinergic neuromuscular transmission, stabilize mast cells and t-lymphocytes, and stimulate the generation of nitric oxide and prostacyclin. This means low magnesium in the diet may be a serious risk factor for lung diseases. 
Magnesium is a known mild bronchodilator of smooth muscles in the airway, which helps to increase airflow to the lungs.  As a result, increases in the intakes of magnesium in the diet have been proven to be beneficial for lung function responsiveness and decreased wheezing. Furthermore, increasing magnesium in the diet has also led to a higher, forced expiratory volume. 
The Correlation Between Lung Cancer and Low Magnesium
Research has shown that low intake of magnesium in the diet leads to systematic inflammation and that this condition is associated with increased lung cancer risk . In a study measuring newly diagnosed lung cancer patients against healthy controls, there was an inverse association between the dietary intake of magnesium and the risk of lung cancer. They found that increasing magnesium decreased lung cancer risk by between 17 and 53 percent. In addition, the authors of this study believed that magnesium was able to achieve this effect because it helps maintain genetic stability, regulates cell proliferation, is a protector against inflammations and helps to protect against oxidative stress, all to maintain healthy lung function. 
How Much Magnesium to Take?
The World Health Organization recommends that magnesium be taken in the amounts indicated in the following chart: 
Pollution is becoming more of a problem throughout the world. As the air worsens, we are seeing an increasing number of ill effects on the lungs. Poor air quality causes oxidative stress and can lead to the development of infections, lung cancer, and chronic lung diseases such as asthma, emphysema, and chronic obstructive pulmonary disease. [1,15] While many governments are working to reduce pollution levels, it is still imperative for individuals to take the necessary precautions in order to protect their own health.
Air pollution directly influences respiratory infections and lung cancer.  Urban air pollution is estimated to contribute to 1.3 million deaths worldwide per year.  The World Health Organization (WHO) recommends in its Air Quality Guidelines that populations target reducing particulate matter pollution from 70 to 20 micrograms per cubic meter. By doing so, the WHO estimates a reduction in air quality related deaths by 15 percent.  A recent study found that in China, where total suspended particulates can often be over 500 micrograms per cubic meter, that life expectancy was 5.5 years lower. This can mostly be attributed to the increases in cardiorespiratory deaths. 
Supplementing Magnesium for Asthma and Healthy Lung Function
Healthy lung function depends on an adequate supply of magnesium in your diet. Consuming sufficient amounts of magnesium will help to protect your lungs from asthma and the effects of pollution. Extensive research shows that most people around the world do not get adequate magnesium, which means supplementation is crucial.
1. American Lung Association. 2014. Indoor Air Quality.April 2. www.lung.org/associations/charters/mid-atlantic/air-qualit/indoor-air-quality.html.
2. Anastassopoulou, J., and T. Theophanides. 2002. “Magnesium–DNA Interactions and the Possible Relation of Magnesium to Carcinogenesis. Irradiation and Free Radicals.” Critical Reviews in Oncology/Hematology10 (0): 79-91. doi:https://doi.org/10.1016/S1040-8428(02)00006-9.
3. Baker, J, W Tunnicliffe, R Duncanson, and J Ayres. 1999. “Dietary Antioxidants and Magnesium in Type 1 Brittle Asthma: a Case Control Study.” Thorax54 (2): 115-118. doi:10.1136/thx.54.2.115.
4. Baker, J.C, and J.G Ayres. 2000. “Diet and Asthma.” Respiratory Medicine94 (10): 925-934. doi:https://doi.org/10.1053/rmed.2000.0873.
5. Britton, J, I Pavord, K Richards, A Wisniewski, A Knox, and S Lewis. 1994. “Dietary Magnesium, Lung Function, Wheezing, and Airway Hyperactivity in a Random Adult Population Sample.” The Lancet344 (8919): 357-362. doi:https://doi.org/10.1016/S0140-6736(94)91399-4.
6. Chen, Yuyu, Avraham Ebenstein, Michael Greenstone, and Hongbin Li. 2013. “Evidence on the Impact of Sustained Exposure to Air Pollution on Life Expectancy from China’s Huai River Policy.” PNAS110 (32): 12936=12941. doi:10.1073/pnas.1300018110.
7. Gilliland, Frank D., Kiros T. Berthane, Yu-Fen Li, Deborah H. Kim, and Helene G. Margolis. 2002. “Dietary Magnesium, Potassium, Sodium, and Children’s Lung Function.” American Journal of Epidemiology155 (2): 125-131. doi:https://doi.org/10.1093/aje/155.2.125.
8. King, DE, AG 3rd Mainous, ME Geesey, and RF Woolson. 2005. “Dietary Magnesium and C-Reactive Protein Levels.” J Am Coll Nutr.24 (3): 166-171. doi:10.1080/07315724.2005.10719461.
9. Landon, Rose A. 1993. “Role of Magnesium in Regulation of Lung Function.” Journal of the Academy of Nutrition and Dietetics93 (6): 674-677. doi: https://doi.org/10.1016/0002-8223(93)91675-G.
10. Mahabir, Somdat, Qingyi Wei, Stephanie L. Barrera, Yong Quan Dong, Carol J. Etzel, Margaret R. Spitz, and Michele R. Forman. 2008. “Dietary Magnesium and DNA Repair Capacity as Risk Factors for Lung Cancer.” Carcinogenesis29 (5): 949-956. doi:10.1093/carcin/bgn043.
11. Neilsen, Forrest H, LuAnn K Johnson, and Huawei Zeng. 2010. “Magnesium Supplementation Improves Indicators of Low Magnesium Status and Inflammatory Stress in Adults Older Than 51 Years with Poor Quality Sleep.” Magnesium Research23 (4): 158-68. doi:10.1684/mrh.2010.0220.
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14. Rolla, G., C. Bucca, M. Bugiani, W. Arossa, and S Spinaci. 1987. “Reduction of Histamine-Induced Bronchoconstriction by Magnesium in Asthmatic Subjects.” Allergy42 (3): 186-188. doi:https://doi.org/10.1111/j.1398-9995.1987.tb02198.x.
15. Romieu, I. 2005. “Nutrition and Lung Health.” International Journal of Tuberculosis and Lung Disease9 (4): 362-374. Accessed April 2, 2014.
16. Shivakumar, K., and B. Prakash Kumar. 1997. “Magnesium Deficiency Enhances Oxidative Stress and Collagen Synthesis In Vivo in the Aorta of Rats.” The International Journal of Biochemistry & Cell Biology29 (11): 1273-1278. doi:https://doi.org/10.1016/S1357-2725(97)00068-X.
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19. World Health Organization. 2001. “Ch. 14: Magnesium.” In Human Vitamin andMineral Requirements, by Food and Agriculture Organizationof the United Nations, 223-233. https://www.fao.org/tempref/docrep/fao/004/y2809e/y2809e00.pdf.
Marysa Cardwell is a Registered Dietitian Nutritionist, who works with clients and organizations on a variety of nutrition topics including eating disorders, intuitive eating, weight management, diabetes, food allergies, healthy eating, meal planning, and other nutrition topics. She LOVES being an “Eating Coach” (or eating cheerleader) at her business: https://allofnutrition.com/