• Magnesium Chloride, Magnesium Citrate, Magnesium Fumarate, Magnesium Gluconate, Magnesium Malate, Magnesium Orotate, Magnesium Oxide, Magnesium Sulfate
• ]]>Diabetes]]>, ]]>Hypertension]]>, ]]>Kidney Stones]]>, ]]>Migraine Headaches]]>, Noise-related ]]>Hearing Loss]]>
• ]]>Angina]]>, ]]>Asthma]]>, ]]>Atherosclerosis]]>, ]]>Autism]]>, ]]>Congestive Heart Failure]]>, Coronary Artery Disease, ]]>Fatigue]]>, ]]>Fibromyalgia]]>, ]]>Glaucoma]]>, Low HDL ("Good") Cholesterol, ]]>Mitral Valve Prolapse]]>, ]]>Osteoporosis]]>, ]]>Dysmenorrhea]]> (Painful Menstruation) , ]]>Premenstrual Syndrome]]> (PMS) , ]]>Preeclampsia]]>, ]]>Pregnancy-induced Leg Cramps]]>, ]]>Restless Legs Syndrome]]>, ]]>Stroke]]>
• Following a ]]>Heart Attack]]>
Magnesium is an essential nutrient, meaning that your body needs it for healthy functioning. It is found in significant quantities throughout the body and used for numerous purposes, including muscle relaxation, blood clotting, and the manufacture of ATP (adenosine triphosphate, the body's main energy molecule).
It has been called nature's calcium channel blocker. The idea refers to magnesium's ability to block calcium from entering muscle and heart cells. A group of prescription heart medications work in a similar way, although much more powerfully. This may be the basis for some of magnesium's effects when it is taken as a supplement in fairly high doses.
Requirements for magnesium increase as we grow and age. The official US and Canadian recommendations for daily intake are as follows:
- 0-6 months: 30 mg
- 7-12 months: 75 mg
- 1-3 years: 80 mg
- 4-8 years: 130 mg
- 9-13 years: 240 mg
- 14-18 years: 410 mg
- 19-30 years: 400 mg
- 31 years and older: 420 mg
- 9-13 years: 240 mg
- 14-18 years: 360 mg
- 19-30 years: 310 mg
- 31 years and older: 320 mg
- Pregnant Women
- 18 years and younger: 400 mg
- 19-30 years: 350 mg
- 31-50 years: 360 mg
- Nursing Women
- 18 years and younger: 360 mg
- 19-30 years: 310 mg
- 31-50 years: 320 mg
Note : These recommendations refer to total intake from food plus supplements. The average diet provides a daily intake of magnesium very close to these amounts.
In the United States, the average dietary intake of magnesium is lower than the recommended daily allowance; however, it is unclear whether this truly indicates deficiency, or if the recommended allowance is too high. 1,2]]>]]>Alcohol abuse]]> , ]]>surgery]]> , ]]>diabetes]]> , ]]>zinc]]> supplements, certain types of diuretics ( ]]>thiazide]]> and ]]>loop diuretics]]> , but not ]]>potassium-sparing diuretics]]> ), ]]>estrogen]]> and ]]>oral contraceptives]]> , and the medications cisplatin and ]]>cyclosporin]]> have been reported to reduce the body's level of magnesium or increase magnesium requirements. ]]>3,4,5,88-92]]> If you are taking ]]>potassium]]> supplements, you may receive greater benefit from them if you take extra magnesium as well.
]]>Kelp]]> is very high in magnesium, as are wheat bran, wheat germ, almonds, and cashews. Other good sources include blackstrap molasses, brewer's yeast (not to be confused with nutritional yeast), buckwheat, nuts, and whole grains. You can also get appreciable amounts of magnesium from collard greens, dandelion greens, avocado, sweet corn, cheddar cheese, sunflower seeds, shrimp, dried fruit (figs, apricots, and prunes), and many other common fruits and vegetables.
A typical supplemental dosage of magnesium ranges from the nutritional needs described above to as high as 600 mg daily. For premenstrual syndrome (PMS) and dysmenorrhea (painful menstruation), an alternative approach is to start taking 500 to 1,000 mg daily, beginning on day 15 of the menstrual cycle and continuing until menstruation begins.
Magnesium citrate may be slightly more absorbable than other forms of magnesium. 100]]>
Preliminary double-blind studies suggest that regular use of magnesium supplements may help prevent migraine headaches]]> , ]]>10-12,101]]> hearing loss caused by exposure to loud noises, ]]>13]]> and ]]>kidney stones]]> , ]]>14]]> and help treat ]]>high blood pressure]]> , ]]>15-18]]>]]>angina]]> , ]]>19,97,115]]>]]>dysmenorrhea]]> (menstrual cramps), ]]>21,22]]>]]>pregnancy-induced leg cramps]]> , ]]>41]]> and ]]>premenstrual syndrome (PMS)]]> (including menstrual migraines). ]]>23,24]]>
People with ]]>diabetes]]> are often deficient in magnesium, ]]>27-29]]> and according to some (but not all) studies, magnesium supplementation may enhance blood sugar control and insulin sensitivity in people with diabetes or prediabetic conditions. ]]>98,102-109,118]]>
Magnesium supplements do not appear to be very helpful, if at all, for preventing ]]>preeclampsia]]> . ]]>6,7,52,53,110]]> (Magnesium, taken by injection rather than orally, however, is probably helpful for treating preeclampsia that already exists. ]]>69,76,77]]> )
Magnesium is sometimes said to decrease symptoms of ]]>restless legs syndrome]]> , but the evidence that it works consists solely of ]]>open]]> trials without a placebo group, and such studies are not trustworthy. ]]>25,26]]> (For information on why this is so, see ]]>Why Does This Database Rely on Double-blind Studies?]]> ) Very weak evidence hints at possible benefits for ]]>insomnia]]> . ]]>111]]>
Magnesium has also been suggested as a treatment for ]]>Alzheimer's disease]]> , ]]>attention deficit disorder]]> , ]]>fatigue]]> , ]]>fibromyalgia]]> , low HDL ("good") ]]>cholesterol]]> , ]]>periodontal disease]]> , ]]>rheumatoid arthritis]]> , and ]]>stroke]]> . However, there is virtually no evidence at all that it is helpful for any of these conditions.
Magnesium is sometimes advocated for stabilizing the heart after a ]]>heart attack]]> , but one study actually found that use of magnesium slighltly increased risk of sudden death, repeat heart attack, or need for bypass surgery in the year following the initial heart attack. ]]>78]]> However, magnesium may be helpful in ]]>congestive heart failure]]> . ]]>112]]> In a well-designed trial involving 79 patients with severe congestive heart failure, magnesium (as magnesium orotate) significantly improved survival and clinical symptoms after one year compared to a placebo. ]]>121]]>
Alternative medical literature frequently mentions magnesium as a treatment for ]]>asthma]]> . However, this idea seems to be based primarily on the use of intravenous magnesium as an emergency treatment for asthma. When you take something by mouth, it's a very different matter from having it injected into your veins. Studies of oral magnesium for asthma have shown more negative than positive results. ]]>42,113,116]]> Inhaled, aerosolized magnesium, however, has shown some promise. ]]>117]]>
Although magnesium is sometimes mentioned as a treatment to help keep the heart beating normally, a 6-month, double-blind trial of 170 people did not find it effective for preventing a particular ]]>heart rhythm]]> abnormality called atrial fibrillation. ]]>43]]> However, a small double-blind, placebo-controlled trial found that magnesium supplements reduced episodes of arrhythmia in individuals with ]]>congestive heart failure (CHF)]]> . ]]>82]]> One possible explanation: People with congestive heart failure often take drugs ( ]]>loop diuretics]]> ) that deplete magnesium. The combination of magnesium deficiency with ]]>digoxin]]> (another drug given for CHF) may cause arrhythmias. ]]>4,93-95]]> Thus, it is possible that the benefits seen here were caused by correction of that depletion.
What Is the Scientific Evidence for Magnesium?
A double-blind study found that regular use of magnesium helps prevent migraine headaches]]> . In this 12-week trial, 81 people with recurrent migraines were given either 600 mg of magnesium daily or placebo. ]]>54]]> By the last 3 weeks of the study, the treated group's migraines had been reduced by 41.6%, compared to a reduction of 15.8% in the placebo group. The only side effects observed were diarrhea (in about one-fifth of the participants) and, less often, digestive irritation.
Similar results have been seen in other smaller double-blind studies. ]]>55,56,114]]> One study found no benefit, ]]>57]]> but it has been criticized on many significant points, including using an excessively strict definition of what constituted benefit. ]]>58]]>
Noise-related Hearing Loss
Magnesium inhibits the growth of calcium oxalate stones in the test tube ]]>60]]> and decreases stone formation in rats. ]]>61]]> However, human studies have had mixed results. In one 2-year open study, 56 people taking magnesium hydroxide had fewer recurrences of ]]>kidney stones]]> than 34 people not given magnesium. ]]>62]]> In contrast, a double-blind (and, hence, more reliable) study of 124 people found that magnesium hydroxide was essentially no more effective than placebo. ]]>63]]>
Magnesium works with calcium and potassium to regulate ]]>blood pressure]]> . Several studies suggest that magnesium supplements can reduce blood pressure in people with hypertension, ]]>64-67]]> although some have not.
In a double-blind, placebo-controlled trial of 187 people with ]]>angina]]> , 6 months of treatment with magnesium at a dose of 730 mg daily improved exercise tolerance and enhanced overall quality of life. ]]>97]]> Benefits were also seen in a similar, smaller double-blind trial. ]]>68]]>
After a Heart Attack
In a 1-year, double-blind, placebo-controlled trial of 468 individuals who had just experienced a ]]>heart attack]]> , use of a magnesium supplement at a dose of 360 mg daily failed to prevent heart-related events (defined as heart attack, sudden cardiac death, or need for cardiac bypass), and actually may have increased the risk slightly. ]]>78]]>
A 6-month, double-blind, placebo-controlled study of 50 women with ]]>menstrual pain]]> found that treatment with magnesium significantly improved symptoms. ]]>70]]> The researchers reported evidence of reduced levels of prostaglandin F 2 alpha, a hormone-like substance involved in pain and inflammation.
Similarly positive results were seen in a double-blind, placebo-controlled study of 21 women. ]]>71]]>
Premenstrual Syndrome Symptoms
A double-blind, placebo-controlled study of 32 women found that magnesium taken from day 15 of the menstrual cycle to the onset of menstrual flow could significantly improve ]]>PMS]]> symptoms, specifically mood changes. ]]>72]]>
Another small double-blind preliminary study found that regular use of magnesium could reduce symptoms of PMS-related fluid retention. ]]>73]]> In this study, 38 women were given magnesium or placebo for 2 months. The results showed no effect after one cycle, but by the end of two cycles, magnesium significantly reduced weight gain, swelling of extremities, breast tenderness, and abdominal bloating.
In addition, one small double-blind study (20 participants) found that magnesium supplementation can help prevent menstrual migraines. ]]>74]]>
The US government has set the following upper limits for use of magnesium supplements:
- 1-3 years: 65 mg
- 4-8 years: 110 mg
- Adults : 350 mg
- Pregnant or Nursing Women : 350 mg
In general, magnesium appears to be quite safe when taken at or below recommended dosages. The most common complaint is loose stools. However, people with severe kidney or heart disease should not take magnesium (or any other supplement) except on the advice of a physician. Maximum safe dosages have not been established for young children. There has been one case of death caused by excessive use of magnesium supplements in a developmentally and physically disabled child. 84]]> Pregnant or nursing women should not exceed the nutritional dosages presented under ]]>Requirements/Sources]]> .
If taken at the same time, magnesium can interfere with the absorption of antibiotics in the ]]>tetracycline]]> family, ]]>85]]> and, possibly, the drug ]]>nitrofurantoin]]> . ]]>96]]> Also, when combined with ]]>oral diabetes]]> drugs in the sulfonylurea family, magnesium may cause blood sugar levels to fall more than expected. ]]>86]]>
Interactions You Should Know About
If you are taking:
- Potassium supplements]]> , ]]>manganese]]> , ]]>loop]]> and ]]>thiazide diuretics]]> , ]]>oral contraceptives]]> , ]]>estrogen-replacement therapy]]> , cisplatin, ]]>digoxin]]> , or medications that reduce stomach acid: You may need extra magnesium.
- ]]>Antibiotics in the tetracycline family]]> or ]]>nitrofurantoin]]> (Macrodantin): You should separate your magnesium dose from doses of these medications by at least 2 hours to avoid absorption problems.
- ]]>Oral diabetes medications]]> in the sulfonylurea family (Tolinase, Micronase, Orinase, Glucotrol, Diabinese, DiaBeta): Work closely with your physician when taking magnesium to avoid hypoglycemia.
- ]]>Amiloride]]> : Do not take magnesium supplements except on medical advice. ]]>77]]>
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43. Frick M, Darpo B, Ostergren J, et al. The effect of oral magnesium, alone or as an adjuvant to sotalol, after cardioversion in patients with persistent atrial fibrillation. Eur Heart J . 2000;21:1177-1185.
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54. Peikert A, Wilimzig C, Kohne-Volland R. Prophylaxis of migraine with oral magnesium: results from a prospective, multi-center, placebo-controlled and double-blind randomized study. Cephalalgia . 1996;16:257-263.
67. Henderson DG, Schierup J, Schodt T. Effect of magnesium supplementation on blood pressure and electrolyte concentrations in hypertensive patients receiving long term diuretic treatment. Br Med J (Clin Res Ed) . 1986;293:664-665.
75. De Souza MC, Walker AF, Robinson PA, et al. A synergistic effect of a daily supplement for 1 month of 200 mg magnesium plus 50 mg vitamin B 6 for the relief of anxiety-related premenstrual symptoms: a randomized, double-blind, crossover study. J Womens Health Gend Based Med. 2000;9:131-139.
76. The Magpie Trial Collaborative Group. Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial: a randomised placebo-controlled trial. Lancet . 2002;359:1877-1890.
77. Rudnicki M, Frolich A, Rasmussen WF, et al. The effect of magnesium on maternal blood pressure in pregnancy-induced hypertension. A randomized double-blind placebo-controlled trial. Acta Obstet Gynecol Scand . 1991;70:445-450.
81. Findling RL, Maxwell K, Scotese-Wojtila L, et al. High-dose pyridoxine and magnesium administration in children with autistic disorder: an absence of salutary effects in a double-blind, placebo-controlled study. J Autism Dev Disord . 1997;27:467-478.
82. Bashir Y, Sneddon JF, Staunton A, et al. Effects of long-term oral magnesium chloride replacement in congestive heart failure secondary to coronary artery disease. Am J Cardiol . 1993;72:1156-1162.
97. Shechter M, Bairey Merz CN, Stuehlinger HG, et al. Effects of oral magnesium therapy on exercise tolerance, exercise-induced chest pain, and quality of life in patients with coronary artery disease. Am J Cardiol . 2003;91:517-521.
98. Rodriguez-Moran M, Guerrero-Romero F. Oral magnesium supplementation improves insulin sensitivity and metabolic control in type 2 diabetic subjects: a randomized double-blind controlled trial. Diabetes Care . 2003;26:1147-1152.
101. Wang F, Van Den Eeden SK, Ackerson LM, et al. Oral magnesium oxide prophylaxis of frequent migrainous headache in children: a randomized, double-blind, placebo-controlled trial. Headache . 2003;43:601-10.
102. Guerrero-Romero F, Tamez-Perez H, Gonzalez-Gonzalez G, et al. Oral magnesium supplementation improves insulin sensitivity in non-diabetic subjects with insulin resistance. A double-blind placebo-controlled randomized trial. Diabetes Metab. 2004;30:253-258.
112. Branea I, Gaita D, Dragulescu I, et al. Assessment of treatment with orotate magnesium in early postoperative period of patients with cardiac insufficiency and coronary artery by-pass grafts (ATOMIC). Rom J Intern Med. 2004;37:287-296.
114. Wang F, Van Den Eeden SK, Ackerson LM, et al. Oral magnesium oxide prophylaxis of frequent migrainous headache in children: a randomized, double-blind, placebo-controlled trial. Headache . 2003;43:601-610.
115. Pokan R, Hofmann P, von Duvillard SP, et al. Oral magnesium therapy, exercise heart rate, exercise tolerance, and myocardial function in coronary artery disease patients. Br J Sports Med. 2006 Jul 6. [Epub ahead of print].
116. Gontijo-Amaral C, Ribeiro MA, Gontijo LS, et al. Oral magnesium supplementation in asthmatic children: a double-blind randomized placebo-controlled trial. Eur J Clin Nutr. 2006 Jun 21. [Epub ahead of print]
117. Hughes R, Goldkorn A, Masoli M, et al. Use of isotonic nebulised magnesium sulphate as an adjuvant to salbutamol in treatment of severe asthma in adults: randomised placebo-controlled trial. Lancet . 2003;361:2114-2117.
118. Song Y, He K, Levitan EB, et al. Effects of oral magnesium supplementation on glycaemic control in Type 2 diabetes: a meta-analysis of randomized double-blind controlled trials. Diabet Med . 2006;23:1050-1056.
119. Carpenter TO, Delucia MC, Zhang JH, et al. A randomized controlled study of effects of dietary magnesium oxide supplementation on bone mineral content in healthy girls. J Clin Endocrinol Metab . 2006 Oct 3. [Epub ahead of print]
120. Whelan AM, Jurgens TM, Bowles SK. Natural health products in the prevention and treatment of osteoporosis: systematic review of randomized controlled trials. Ann Pharmacother. 2006;40:836-849. Epub 2006 May 2.
Last reviewed April 2009 by EBSCO CAM Review Board]]>
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