Afibbers are magnesium-deficient
HARTFORD, CONNECTICUT. Magnesium (Mg) is an enormously important mineral being a cofactor in over 300 enzymatic reactions continuously taking place in the body. Magnesium is also a vital component of the skeletal structure and about 65% of the body�s magnesium stores are found in bone, another 34% is found in transcellular fluids, and the remaining 1% is found in extracellular fluids such as blood. It is thus clear that measuring magnesium in blood serum is not likely to be a very accurate measure of the body�s overall magnesium status. There is increasing evidence that magnesium plays a crucial role in preventing and terminating cardiac arrhythmias. A group of cardiologists and pharmacologists at the Hartford Hospital reasoned that a pre-procedure infusion of magnesium might help prevent the acute development of atrial fibrillation following a radiofrequency ablation for this disorder. As a first step in proving or disproving this hypothesis, they decided to do a trial in which half the participants would have saline solution (0.9% sodium chloride) with 4 grams of magnesium sulfate (800 mg elemental magnesium) infused over a 15-minute period just prior to accessing the left atrium in a standard PVI procedure, while the other half would just have a saline solution infusion. The trial involved 22 patients with paroxysmal or persistent afib. Samples of venous blood (for determination of extracellular Mg concentration) and buccal scrapings (scrapings from inside the cheek) were collected before the start of the procedure, 15 minutes after the completion of the infusion, at the end of the ablation procedure, and at 6 hours after the infusion. The blood samples (serum) were analyzed for extracellular magnesium concentration and the buccal scrapings were analyzed (using the EXAtest) for intracellular magnesium concentration as well as for concentrations of calcium, potassium, sodium, chloride, and phosphate. At least one study has shown that there is an excellent correlation between the magnesium (intracellular) content of buccal scrapings and that of myocytes (heart cells). The major findings are as follows:

• None of the study participants were deficient in Mg at baseline when considering blood serum values only. The average serum Mg concentration was 2.08 mg/dL versus the normal lower limit of 1.6 mg/dL.
• The majority (89%) of participants were magnesium-deficient at baseline when considering intracellular (EXAtest) values only. The average intracellular Mg concentration was 32.2 mEq/IU versus a normal lower limit of 33.9 mEq/IU. NOTE: The unit is defined as x-ray intensity (peak divided by background) divided by unit cell volume.
• There was no correlation whatsoever between serum magnesium and intracellular magnesium concentrations.
• Serum levels of Mg rose rapidly in the magnesium infusion group 15 minutes post-infusion and, although declining over the 6-hour observation period, remained considerably higher than the level in the placebo group (saline infusion only).
• Intracellular level of Mg increased rapidly in the magnesium infusion group 15 minutes post infusion and continued to rise throughout the 6-hour observation period. Somewhat surprisingly, the intracellular Mg level also increased somewhat (over baseline) in the placebo group over the 6-hour period. The Hartford researchers speculate that the ablation procedure itself, most likely the anaesthesia, facilitates the transfer of magnesium from serum to intracellular space.
• The intracellular calcium concentration increased significantly in the Mg infusion group post infusion, but gradually reverted to baseline over the 6-hour period.
• The intracellular potassium concentration increased by about 50% from baseline to the end of the PVI procedure and then began to drop off at the 6-hour mark.

The authors of the report conclude that future studies are needed to evaluate the electrophysiologic benefits of magnesium repletion and the effects of routine procedures and anaesthesia on intracellular electrolytes.
Shah, SA, et al. The impact of magnesium sulfate on serum magnesium concentrations and intracellular electrolyte concentrations among patients undergoing radio frequency catheter ablation. Connecticut Medicine, Vol. 72, May 2008, pp. 261-65

Magnesium infusions in AF control
TORONTO, CANADA. Magnesium is effective in prolonging the atrial and atrioventricular nodal refractory periods. As afib cannot be initiated during refractory periods, this is clearly a good thing and may explain why many afibbers have experienced substantial benefit from magnesium supplementation. Unfortunately, several studies have shown that 50% or more of patients with atrial fibrillation suffer from hypomagnesemia � that is, a lower than normal blood serum magnesium concentration (less than about 0.8 mmol/L). Serum magnesium concentration is a fairly poor indicator of magnesium status since only about 2% of the body�s total magnesium stores are found in the blood. It is thus likely that substantially more than 50% of afibbers are magnesium deficient if intracellular levels are measured.

Researchers at the University of Toronto have just released the results of a meta-analysis of 8 clinical trials involving patients presenting with rapid atrial fibrillation. The trials compared the effect of magnesium infusions with placebo controls and patients given intravenous diltiazem or amiodarone. In the trials 1,200 to 10,000 mg of magnesium (as magnesium sulfate) was infused over a period of 1 to 30 minutes. In four of the studies magnesium infusion was continued for an additional 2 to 6 hours. Adequate rate control (ventricular rate below 100 bpm) was achieved in 61% of patients with magnesium as compared to 35% among controls. Magnesium was found to be as effective as diltiazem and amiodarone in achieving adequate rate control during the first hour. Magnesium was also found to be twice as effective as diltiazem or placebo in restoring sinus rhythm. Overall, the average time to conversion to sinus rhythm was 4 hours for magnesium as compared to 15 hours for placebo. The researchers conclude that magnesium infusions are safe and effective in achieving both rate and rhythm control in patients presenting with rapid atrial fibrillation.
Onalan, O, et al. Meta-analysis of magnesium therapy for the acute management of rapid atrial fibrillation. American Journal of Cardiology, Vol. 99, June 15, 2007, pp. 1726-32

Magnesium helps control afib
Canadian researchers have done a meta-analysis of studies dealing with the benefits of intravenous administration of magnesium in the acute treatment of atrial fibrillation. They found that effective rate control (reduction in heart rate to below 100 bpm) and/or conversion to normal sinus rhythm was achieved in 84% of patients given magnesium as compared to 53% given a placebo. Seven trials used calcium channel blockers or placebo as controls. In these trials 69% of patients in the magnesium group experienced relief as compared to 53% in the control group. The researchers conclude that intravenous magnesium is an effective and safe strategy for the acute treatment of afib.
PACE, Vol. 29, April 2006, Suppl 1, Abstract #36, p. S19 (European Cardiac Arrhythmia Society, 2nd Annual Congress)

Magnesium sulfate for rate control in AF
ADELAIDE, AUSTRALIA. At least seven published clinical trials have concluded that infusions of magnesium sulfate are effective in reducing heart rate (ventricular response rate) in patients with supraventricular arrhythmias including atrial fibrillation. Emergency department physicians at the Royal Adelaide Hospital have now put these findings into practice in a major evaluation. Their study included 199 patients between the ages of 60 and 80 years who were admitted with rapid AF (heart rate above 120 bpm, average of 142 bpm). The patients were randomly assigned to receive intravenous infusions of magnesium sulfate (102 patients) or placebo. The magnesium infusion consisted of 40 mEq (5 g, 20 mmol) of magnesium sulfate in 100 mL of a 5% dextrose solution. Half the solution was infused over a 20-minute period followed by the other half being infused over the following 2 hours. The placebo solution (5% dextrose) was infused in a similar manner. In addition to the magnesium infusion most patients also received a rate-reduction drug such as digoxin (79%), beta-blocker (10%), or verapamil (3%). NOTE: The reason for the predominant use of digoxin is that beta- and calcium channel blockers may cause complications in patients with poor left ventricular function. In most cases, emergency physicians do not know the underlying cardiac status of the patients, so they err on the side of caution by using digoxin, which is safe for patients with low left ventricular ejection fraction. The authors of the study observed that 65% of the patients given magnesium sulfate experienced a reduction in heart rate to below 100 bpm, while only 34% of placebo patients did so. It was also noted that 27% of the magnesium-treated patients reverted spontaneously to sinus rhythm during the infusion, while only 12% of those in the placebo group did so. Several adverse side effects were, however, observed during magnesium treatment. Five patients experienced hypotension (systolic blood pressure below 100 mm Hg), two experienced bradycardia, while six complained of a flushing sensation. The researchers conclude that an infusion of magnesium sulfate helps reduce heart rate and increases the likelihood of spontaneous conversion in patients with rapid afib. They caution that treating physicians should watch for hypotension and bradycardia.
Davey, MJ and Teubner, D. A randomized controlled trial of magnesium sulfate in addition to usual care, for rate control in atrial fibrillation. Annals of Emergency Medicine, Vol. 45, April 2005, pp. 347-53

Magnesium and Cardiovascular Disease

Magnesium benefits heart patients
LOS ANGELES, CALIFORNIA. The health of the lining (endothelium) of the blood vessels is crucial to cardiovascular health. There is considerable evidence that a dysfunction of the endothelium can lead to atherosclerosis and subsequent coronary artery disease (CAD). Researchers at the Cedars-Sinai Medical Center now report that oral magnesium supplementation can substantially reduce endothelial dysfunction and improve exercise tolerance in CAD patients. The randomized, prospective, double blind, placebo- controlled trial involved 50 patients (41 men and 9 women with a mean age of 67 years) who had been diagnosed with CAD either by angiography or after having had a heart attack. Initial evaluation of the patients showed that 72 per cent of them had a lower than normal tissue magnesium level. The tissue magnesium level was measured in sublingual epithelial cells scraped from under the tongue or from between the gums and the upper or lower lips. Magnesium levels measured in sublingual cells have been found to correlate well with levels found in heart tissue.
The patients were randomized to receive either a placebo or 365 mg of elemental magnesium (in the form of oxide and carbonate) daily. After six months tissue magnesium concentration was measured again, a treadmill test was performed, and endothelial function was evaluated using ultrasound. Patients in the magnesium group increased their intracellular magnesium level by about 10 per cent to reach the lower limit of the normal range. Endothelial function (flow-mediated vasodilation measured at the brachial artery) improved by 25 per cent in the magnesium group as compared to a 4.5 per cent decline in the placebo group over the six-month period. The magnesium supplemented group also performed significantly better on the treadmill test than did the placebo group. Not only did they improve their exercise duration as compared to baseline and the placebo group, but it was also highly significant that none of them experienced an arrhythmia during the test whereas four patients in the placebo group did.
The researchers suggest that magnesium may protect the heart against the detrimental effects of a calcium overload and may improve intracellular ATP production and glucose use. They conclude that oral magnesium supplementation improves exercise tolerance and endothelial function in coronary artery disease patients. NOTE: This study was partially funded by Asta Medica Company, Inc. (Vienna, Austria) the manufacturer of the magnesium supplement.
Shechter, Michael, et al. Oral magnesium therapy improves endothelial function in patients with coronary artery disease. Circulation, Vol. 102, November 7, 2000, pp. 2353-58

Magnesium and heart surgery in children
CHARLESTON, SOUTH CAROLINA. Administration of magnesium has been shown to reduce the incidence of heart surgery related arrhythmias in adults. It has also been observed that the magnesium level in the right atrial tissue is lower in adult patients with postoperative cardiac arrhythmias compared to patients without arrhythmias after heart surgery. Researchers at the Department of Pediatric Cardiology at the Medical University of South Carolina now report that children undergoing surgery for congenital heart defects develop a severe magnesium deficiency immediately after surgery. This deficiency is associated with a greater incidence of a serious arrhythmia (junctional ectopic tachycardia) and can be prevented by an infusion of magnesium sulfate immediately after completion of the surgery.
The study involved 28 pediatric patients (average age of five years) who were scheduled to undergo heart surgery with cardiopulmonary bypass (CPB). The patients were randomly assigned to receive an infusion of magnesium (30 mg/kg body weight of a five per cent saline solution administered over a period of 10 minutes) or an infusion of saline solution immediately after cessation of CPB. Blood levels of magnesium were measured in all patients before surgery, before CPB, after CPB, upon arrival in the intensive care unit (ICU), and then every four hours for 24 hours. Each patient was also monitored for arrhythmias for 24 hours with a Holter monitor.
Comparison of the results for the two treatment groups revealed that the magnesium level was significantly below normal in patients who had received saline solution (placebo) when they arrived in the ICU and for the following 20 hours. Patients who had received the magnesium infusion, on the other hand, had magnesium levels that were well within the normal range (1.6 to 2.3 mg/dL) when tested in the ICU and for the following 20 hours. There were no incidences of junctional ectopic tachycardia in the magnesium group, but four (27 per cent) of the patients in the placebo group experienced this serious arrhythmia. It stopped after a magnesium infusion. The researchers "recommend routine measurement of magnesium levels after CPB in children undergoing heart surgery, with timely magnesium supplementation in the postoperative period." [49 references]
Dorman, B. Hugh, et al. Magnesium supplementation in the prevention of arrhythmias in pediatric patients undergoing surgery for congenital heart defects. American Heart Journal, Vol. 139, No. 3, 2000, pp. 522- 28

Lack of magnesium and heart disease
ATLANTA, GEORGIA. Researchers at the Centers for Disease Control and Prevention have just released the results of a study which shows a clear association between low blood serum levels of magnesium and the risk of dying from heart disease and other causes. The study involved 12,000 participants who were enrolled between 1971 and 1975 and followed for 19 years. At the end of the study 4282 of the participants had died, 1005 of them from ischemic heart disease. Compared with participants having a magnesium level of 0.80 mmol/L or less the risk of dying from heart disease was 21 per cent lower among participants with magnesium concentrations between 0.80 and 0.84 mmol/L and 31 to 34 per cent lower among participants with concentrations higher than 0.84 mmol/L. This correlation held true even after adjusting for other major variables such as age, sex, race, education, smoking status, systolic blood pressure, use of anti- hypertensive medications, body mass index, history of diabetes, alcohol use, and the level of physical activity. The researchers estimate that about 11 per cent of the almost 500,000 deaths from coronary heart disease which occurred in 1993 in the United States can be attributed to low magnesium levels. They also point out that a recent study (NHANES I) found that about 23 per cent of the people evaluated had magnesium levels below 0.80 mmol/L. Other studies have shown that a large proportion of the American population does not consume the recommended daily allowance of magnesium (350 mg/day for men and 280 mg/day for women).
Ford, Earl S. Serum magnesium and ischaemic heart disease: findings from a national sample of US adults. International Journal of Epidemiology, Vol. 28, August 1999, pp. 645-51

Magnesium supplementation helps heart patients
LOS ANGELES, CALIFORNIA. Clinical trials have shown that a magnesium injection can reduce the risk of dying during a heart attack. Whether orally administered magnesium is of benefit to heart patients is unclear. Now researchers at the Cedars-Sinai Medical Center report that daily oral magnesium supplementation may help prevent the formation of blood clots in patients suffering from coronary artery disease (CAD). Their experiment involved 42 CAD patients who were randomized to receive either magnesium oxide tablets (800-1200 mg/day) or a placebo for a three-month period followed by a four-week washout period, and then the alternative treatment for three months. All patients were taking aspirin as well as their other regular medications throughout the study. Before and after each phase the researchers measured a range of blood chemistry variables among them platelet-dependent thrombosis (PDT) which is a measure of the blood's tendency to form clots. The average (median) PDT was found to be 35 per cent lower in patients taking magnesium than in patients taking the placebo. It is interesting that the researchers found no significant differences in blood serum magnesium levels even after three months of supplementation. This confirms that blood serum is a very poor indicator of magnesium status in the body. This is perhaps not surprising as 99 per cent of the body's magnesium content is found in bones and cells rather than in the blood. The researchers conclude that oral magnesium supplementation may benefit CAD patients. NOTE: This study was partly funded by Blaine Company Inc. (supplier of magnesium oxide), Erlanger, KY and Nutrition 21, San Diego, CA.
Shechter, Michael, et al. Oral magnesium supplementation inhibits platelet-dependent thrombosis in patients with coronary artery disease. American Journal of Cardiology, Vol. 84, July 15, 1999, pp. 152- 56

Magnesium combats mitral valve prolapse syndrome
WARSAW, POLAND. Mitral valve prolapse syndrome (MVP) is a fairly frequent disorder and is particularly prevalent among women of childbearing age. It usually manifests itself through symptoms such as chest pain, palpitations, anxiety, headaches, and a low level of vital energy. It can be clinically confirmed through an echocardiogram. The cause of MVP is not clear and there is no effective conventional treatment. Researchers at the Grochowski Hospital in Warsaw now report that MVP is related to a magnesium deficiency and can be successfully treated with oral administration of magnesium supplements. Their study involved 141 patients (124 women and 17 men aged 16 to 57 years) whose diagnosis of MVP had been confirmed by echocardiography. The researchers measured the serum (blood) level of magnesium in the 141 patients and in 40 matched, healthy controls. They found that 60 per cent of the MVP patients had an abnormally low magnesium level (<0.7 mmol/L) while only five per cent of the controls had a low level. Seventy of the patients (64 women and 6 men) were then randomized to receive either oral magnesium supplementation or a placebo for a five-week period. The magnesium group received 1800 mg/day of magnesium carbonate (510 mg of elementary magnesium) for the first week and than 1200 mg/day of magnesium carbonate (340 mg of elementary magnesium) for the remaining weeks. At the end of the test period all participants were evaluated for MVP symptoms, anxiety level, serum magnesium level, and urine content of adrenaline and noradrenaline. The average number of MVP symptoms in the patients treated with magnesium decreased from 10.4 to 5.6 after treatment. There was no significant change among the patients in the placebo group. The number of patients reporting a high level of anxiety decreased from 32 (54 per cent) to 9 (15 per cent) after supplementation with no change observed in the placebo group. The level of noradrenaline excreted in the urine also declined markedly after magnesium supplementation (from 42 micrograms/gram/24 hours to 26.8 micrograms/gram/24 hours), but increased in the placebo group. The researchers conclude that MVP symptoms are linked to a magnesium deficiency and believe that this deficiency may be caused by an increased release of adrenaline and noradrenaline in MVP patients. They also conclude that magnesium supplementation is effective in combatting MVP symptoms particularly anxiety. They speculate that this beneficial effect could be due to magnesium's ability to inhibit the toxic effects of an excessive release of catecholamines (adrenaline and noradrenaline).
Lichodziejewska, Barbara, et al. Clinical symptoms of mitral valve prolapse are related to hypomagnesemia and attenuated by magnesium supplementation. American Journal of Cardiology, Vol. 79, March 15, 1997, pp. 768-72

Magnesium in drinking water prevents heart attacks
GOTHENBURG, SWEDEN. Previous studies have shown that there is a significant correlation between mortality from cardiovascular disease and drinking water hardness. Now Swedish researchers report that men who live in areas where the drinking water has a high content of magnesium are much less likely to suffer a heart attack than are men who live in areas with a low content. Their study involved 854 men who had died from a heart attack between ages 50 and 69 years and 989 age-matched controls who died from cancer during the seven-year study period. All the men lived within a well defined study area in which the drinking water was supplied by 17 different municipal water works. The magnesium content of the water supply varied significantly between the municipalities, but had not changed over a 10-year period. The researchers found that the incidence of fatal heart attacks was 35 per cent lower in areas where the magnesium content of the drinking water was 9.8 mg/liter or more than in areas where the content was 3.5 mg/liter or less. The calcium content of the water was not significantly associated with the incidence of fatal heart attacks. The researchers believe that magnesium protects against fatal heart attacks through its ability to prevent arrhythmias and artery spasms. They also point out that many people are magnesium deficient and that drinking water with a high magnesium content may just be enough to help prevent heart attacks. Magnesium in water is more easily absorbed than magnesium in food. The absorption of magnesium is significantly affected by the simultaneous intake of other nutrients such as sugar, phytates, saturated fats, proteins, calcium, and phosphates.
Rubenowitz, Eva, et al. Magnesium in drinking water and death from acute myocardial infarction. American Journal of Epidemiology, Vol. 143, No. 5, March 1, 1996, pp. 456-62

Magnesium prevents death from heart attack
LEICESTER, ENGLAND. Medical doctors at the Leicester Royal Infirmary report that the previously found reduction in mortality among heart attack patients injected with magnesium sulfate is long term in nature. The doctors' original study involved 2316 randomly selected heart attack victims. Half of the patients were given 8 mmol of magnesium sulfate injected intravenously over five minutes within three hours or less of the first symptoms of the attack; this was followed by a total of 65 mmol of magnesium sulfate supplied by constant infusion over a 24-hour period. The placebo group received the same amount of saline solution. After 28 days, 24 per cent fewer patients in the magnesium group had died than in the placebo group. The doctors followed up on all the patients for an average of 2.7 years (1.0 - 5.5 years) and now report that the longer term mortality rate from ischaemic heart disease was reduced by 21 per cent and the all-cause mortality rate by 16 per cent in the magnesium-treated patients. The researchers point out that it is important that the magnesium be administered quickly (within three hours of onset of symptoms) and before the start of thrombolytic therapy.
Woods, Kent L. and Fletcher, Susan. Long-term outcome after intravenous magnesium sulphate in suspected acute myocardial infarction: the second Leicester Intravenous Magnesium Intervention Trial (LIMIT-2). The Lancet, Vol. 343, April 2, 1994, pp. 816-19

Magnesium helps patients with heart failure
CHAPEL HILL, NORTH CAROLINA. Researchers at the University of North Carolina have found that magnesium injections lower the frequency and severity of ventricular arrhythmias in patients with heart failure. Twenty-one men and nine women aged 49 +9.6 years participated in the double-blind, placebo- controlled crossover experiment. The active treatment consisted of one injection of 0.3 mEq/kg magnesium chloride in 5 per cent dextrose in water followed by continuous infusion of a dextrose/water magnesium chloride solution (0.08 mEq/kg per hour) over 24 hours. The placebo treatment was similar except that the magnesium chloride was omitted from the dextrose/water solution. The number of PVCs (premature ventricular contractions) per hour was reduced by 53 per cent in the magnesium group as compared to the placebo group; the number of episodes of ventricular tachycardia was reduced by 69 per cent and in the patients who did have such episodes the heart rate was significantly lower than during placebo treatment (143 beats/minute vs. 179 beats/minute). The researchers recommend that a larger study be undertaken to determine if oral administration of magnesium would have similar benefits.
Sueta, Carla A., et al. Effect of acute magnesium administration on the frequency of ventricular arrhythmia in patients with heart failure. Circulation, Vol. 89, No. 2, February 1994, pp. 660-66

Magnesium saves lives
LEICESTER, ENGLAND. Reports of the beneficial effects of the use of magnesium in the treatment of heart attack patients date back to the 1960s. More recent studies show a possible 25% reduction in mortality among patients injected with magnesium. Now a large study carried out at the Leicester Royal Infirmary in England confirms the beneficial effects. The experiment involved 2316 randomly selected heart attack victims. Half of the patients were given an injection of 8 mmol of magnesium sulfate injected intravenously over 5 minutes followed by a total of 65 mmol supplied by constant infusion over a 24-hour period. The placebo group received the same amount of saline solution. After 28 days, 90 of the 1150 patients treated with magnesium had died as compared to 118 of the 1150 patients in the placebo group. This corresponds to a 24% reduction in mortality. Researchers involved in the studies conclude that magnesium injection is a safe, effective, and inexpensive therapy in the management of myocardial infarction (heart attack).
Yusuf, Salim, et al. Intravenous magnesium in acute myocardial infarction. Circulation, Vol. 87, No. 6, June 1993, pp. 2043-46

Magnesium helps recovery after bypass surgery
BALTIMORE, MARYLAND. Patients having undergone coronary bypass surgery often suffer from ventricular dysrhythmias and decreased stroke volume immediately after the operation. Medical doctors at the Sinai Hospital of Baltimore have now found that supplementation with magnesium markedly decreases the frequency of these serious complications. One hundred patients were studied over a 6-month period; 50 were given an intravenous infusion of magnesium chloride (2 grams) immediately after the operation while the other 50 were given a placebo. The magnesium treated patients suffered significantly fewer ventricular dysrhythmias (16% vs. 34%) than did the untreated patients.
Journal of the American Medical Association, November 4, 1992, pp. 2395-2402

Magnesium deficiency and heart disease go together
TUCSON, ARIZONA. Researchers at the University Medical Center in Tucson have confirmed that magnesium deficiency is closely associated with cardiovascular disease. Lowered serum magnesium concentrations have been found in heart attack patients and administration of magnesium has proven beneficial in treating ventricular arrhythmias, particularly those caused by digoxin toxicity.
American Heart Journal, October 1992, pp. 1113-18

Magnesium may prevent fatal heart attacks
SAN FRANCISCO, CALIFORNIA. Sudden fatal heart attacks claim over 300,000 victims each year in the U.S. alone. Fatal heart attacks are more common in areas where the water supply is magnesium deficient. Dr. Eisenberg at the University of California now suggests that there is a definite link between magnesium deficiency and sudden fatal heart attacks. He points out that the average human body contains about 24 grams of magnesium and requires a daily intake of 200-400 milligrams. The actual average intake through food and drinking water is often significantly less than the requirement particularly in areas having a supply of soft drinking water. The doctor recommends large scale studies to evaluate the potential benefits of oral magnesium supplementation.
American Heart Journal, August 1992, pp. 544-49

Magnesium and Bone Mass

Magnesium benefits bone health
MEMPHIS, TENNESSEE. Magnesium could be as important to bone health as calcium, new research suggests. A team from the University of Tennessee investigated the links between magnesium intake and bone mineral density (BMD) by studying data on 2,038 black and white men and women aged between 70 and 79 years. The participants were enrolled in the Health, Aging and Body Composition Study (Health ABC) initiated in 1996 by the Geriatric Epidemiology Section of the National Institute on Aging. Participants were given tests to measure their BMD, and the results were compared with data from questionnaires covering food and supplement intake of magnesium. Analysis showed that magnesium intake was significantly linked to higher BMD throughout the whole body, but only in the white men and women. The effect was stronger in women than men - BMD was higher by 0.04g per square centimeter in women and 0.02g/cm2 higher in men in the top fifth for magnesium intake compared with the bottom fifth. This effect was independent of several other factors including age, osteoporosis or bone fractures, calorie intake, calcium and vitamin D intake, BMI, smoking, alcohol and exercise.

The researchers believe that magnesium's role is similar to that of calcium. They calculate that for every 100 milligram per day increase in magnesium intake, there is a one per cent increase in BMD. They report that although this one per cent increase seems small, across a population it may have large impact, and explain that most older adults get far less than the recommended daily allowance of magnesium (320 mg/day for women and 420/mg day for men). They add that black people might process vitamin D and other calcium regulating hormones slightly differently to whites, but magnesium may still have an association with BMD. Previous observational and clinical studies have suggested an association between low magnesium status and increased risk of cardiovascular diseases, hypertension, osteoporosis, diabetes, and other chronic diseases.
Ryder, K.M. et al. Magnesium Intake from Food and Supplements Is Associated with Bone Mineral Density in Healthy Older White Subjects. The Journal of the American Geriatrics Society, Vol. 53, November 2005, pp. 1875-80

Magnesium improves bone strength
MEMPHIS, TENNESSEE. Many atrial fibrillation patients have found magnesium supplementation highly beneficial in preventing ectopic beats (PACs and PVCs) and even afib episodes. Now there is evidence that an adequate daily magnesium intake also materially improves the density of skeletal bone and helps prevent osteoporosis and hip fractures. Researchers at the University of Tennessee measured bone mineral density (BMD) in a group of older men and women (black and white between the ages of 70-79 years). The 2038 participants were enrolled in the Health, Aging and Body Composition Study initiated in 1997. The researchers also determined the participants� daily intake of magnesium, calcium, potassium, vitamin D, and vitamin C. Less than 26% of the study group met the Recommended Daily Allowance (RDA) for magnesium (320 mg/day for women and 420 mg/day for men over the age of 70 years). Twenty-five per cent took a magnesium supplement providing an average of 83 mg/day of elemental magnesium. Black men and women had a significantly higher BMD than did white persons and did not benefit from higher magnesium intake.

White women with the highest magnesium intake had a significantly higher BMD than women with lower intakes with an increase in daily intake from 220 mg/day to 320 mg/day corresponding to an increase of 0.020 g/cm2 in whole body BMD (after adjusting for other relevant variables). For white men, an increase from 320 mg/day to 420 mg/day corresponded to an increase of 0.010 g/cm2 in whole body BMD. These increases are roughly equivalent to those that would result from increasing daily calcium intake by about 400 mg. The researchers speculate that the beneficial effects of an increased magnesium intake on bone density may be due to one or more of the following factors:

• Improved synthesis of vitamin D with subsequent suppression of parathyroid hormone function.
• Increased alkalinity of a diet high in magnesium and lower net acid production.
• Substitution of calcium with magnesium in the formulation of bone hydroxyapatite, resulting in greater structural strength. NOTE: Strontium may have a similar effect.

Magnesium supplementation reduces bone loss
LOMA LINDA, CALIFORNIA. It is generally assumed that an adequate calcium intake is essential in promoting the achievement of peak bone mass in growing children and young adults. Now researchers at the University of Graz Medical School in Austria and the Loma Linda University in California suggest that an adequate magnesium intake may be equally important. About half the body's reservoir of magnesium is found in soft tissue while the other half is found in bone. Excess magnesium is excreted in the urine. The researchers recently completed an experiment in which 12 healthy, young men received 350 mg of magnesium as a daily oral supplement for a 30-day period. A comparison of the level of biomarkers for bone turnover in the supplemented group and in an age-matched control group showed a statistically significant decrease in the level of these biomarkers in the supplemented group. Neither the supplement group nor the control group were deficient in magnesium and had a dietary intake of about 300 mg/day (RDA is 300-350 mg/day). The researchers conclude that magnesium supplementation (over and above the current RDA) may suppress bone turnover in young adults and speculate that it may also help prevent age- related osteoporosis.
Dimai, H.P., et al. Daily oral magnesium supplementation suppresses bone turnover in young adult males. Journal of Clinical Endocrinology and Metabolism, Vol. 83, August 1998, pp. 2742-48

Magnesium effective in treatment of osteoporosis
ADELAIDE, AUSTRALIA. Dr. Ivor Dreosti of the Commonwealth Scientific and Industrial Research Organization has just released a major report detailing the current knowledge of the importance of magnesium in human nutrition. Magnesium is involved in the functioning of more than 200 enzymes and is a key player in the body's energy (ATP) cycle. The recommended dietary intake is 300-400 mg/day (in the U.S.A.), an amount which many scientists now feel may be insufficient. It is also clear that many people do not even get the recommended intake and that this can lead to problems with muscle spasms and idiopathic mitral valve prolapse. Dr. Dreosti points out that the body's requirement is increased markedly by both stress and vigorous exercise. Recent tests have also shown that exercise capacity can be significantly increased by the use of magnesium supplements. Many researchers are now also reporting that magnesium deficiency plays a significant role in the development of osteoporosis. Studies have shown that women suffering from osteoporosis tend to have a lower magnesium intake than normal and also have lower levels of magnesium in their bones. It is also clear that recommendations to postmenopausal women to increase calcium intake can lead to an unfavourable Ca:Mg ratio unless the magnesium intake is increased accordingly; the optimum ratio of Ca:Mg is believed to be 2:1. A magnesium deficiency can also affect the production of the biologically active form of vitamin D and thereby further promoting osteoporosis. Some very recent research shows that magnesium supplementation is effective in treating osteoporosis. A trial in Israel showed that postmenopausal women suffering from osteoporosis could stop further bone loss by supplementing with 250-750 mg/day of magnesium for two years. Some (8 per cent) of the treated women even experienced a significant increase in trabecular bone density. Untreated controls lost bone mass at the rate of 1 per cent per year. Another experiment in Czechoslovakia found that 65 per cent of women who supplemented with 1500 to 3000 mg of magnesium lactate daily for two years completely got rid of their pain and stopped further development of deformities of the vertebrae. Other studies have shown that magnesium is helpful in the treatment of cardiac arrhythmias and that an adequate intake may help prevent atherosclerosis.
Dreosti, Ivor E. Magnesium status and health. Nutrition Reviews, Vol. 53, No. 9, September 1995, pp. S23- S27

Magnesium and Muscle Health

Muscle strength linked to magnesium in older adults
PALERMO, ITALY. Magnesium is central to human health as it plays a role in a wide range of activities on the cellular level. A deficiency can lead to muscle weakness, fatigue and insomnia. This nutrient may therefore be essential for maintaining muscle strength throughout life. Evidence from athletes supports a role for magnesium in avoiding damage to muscle cells. Muscle mass and function can be compromised in older age, a condition known as sarcopenia. Researchers from the University of Palermo investigated the relationship between sarcopenia and magnesium status. They analyzed data from the Italian InCHIANTI (aging in the Chianti area) study. Data on muscle performance and serum magnesium, gathered at the same time, were available for 1,138 healthy men and women. Mean age was 67 years and the participants were considered representative of the general population. Magnesium status was found to be significantly related to each of the measures of muscle strength - grip strength, lower-leg muscle power, knee rotation, and ankle strength. The link, found in both men and women, remained "highly significant" once the results were adjusted for factors including age, sex, body mass index, and levels of several other nutrients. In case the link was due to magnesium deficiency among certain participants, the analysis was repeated excluding individuals identified as deficient and a highly significant relationship was still observed. The researchers suggest that the explanation may lie in the importance of magnesium to metabolism, or the increased free radical production and proinflammatory effects of low magnesium. They conclude that serum magnesium is significantly, independently, and strongly linked to muscle performance in older people. Measurement of serum magnesium should be part of routine physical check-ups, they believe, but they add that it is not fully clear whether magnesium supplementation improves muscle function. Magnesium is found in green vegetables such as spinach, nuts (especially almonds), seeds, and some whole grains. Excessive intake can interfere with calcium absorption.
Dominguez, L. J. et al. Magnesium and muscle performance in older persons: the InCHIANTI study. The American Journal of Clinical Nutrition, Vol. 84, August 2006, pp. 419-26

Muscle cramps cured with magnesium
ST. JOHN'S, CANADA. Canadian doctors report on two cases of severe muscle cramps which were relieved by the intravenous infusion of magnesium sulfate. The first case involved a 17-year-old soldier who had been exercising too strenuously and developed muscle spasms so severe that he was immobilized. The soldier was hospitalized and underwent a battery of tests. The only abnormality found was a low concentration of magnesium in the blood serum (0.54 mmol/L vs. a normal range of 0.7 to 1.5 mmol/L). The soldier was given two intravenous infusions of magnesium sulfate in a saline solution. His pain lessened significantly within 48 hours and was gone after four days. The second case involved an 81-year-old woman who was hospitalized with abdominal cramps so severe that even injections of Demerol and morphine could not subdue the pain. Laboratory tests showed a significant magnesium deficiency (serum level was 0.50 mmol/L). The patient was given a slow intravenous infusion of five grams of magnesium sulfate in a 2000 ml N saline solution over a 24-hour period. She was completely pain-free by the third day and was discharged after another week "never feeling better for years". The doctors conclude that diuretic therapy (with furosemide) was almost certainly the cause of this latter case of muscle cramps. They also recommend that physicians do a magnesium level check whenever patients complain of muscle cramps, muscle weakness or neuromuscular dysfunction. Oral supplements have also been found effective in treating muscle cramps with the preferred form being magnesium glucoheptonate or magnesium gluconate.
Bilbey, Douglas L.J. and Prabhakaran, Victor M. Muscle cramps and magnesium deficiency: case reports. Canadian Family Physician, Vol. 42, July 1996, pp. 1348-51

Magnesium and Diabetes

Magnesium deficiency linked to diabetes
BALTIMORE, MARYLAND. A link between low body levels of magnesium and type 2 diabetes has long been suspected, but there has been no agreement as to whether low magnesium levels cause diabetes or the presence of diabetes results in low magnesium levels. A team of researchers from the Johns Hopkins University School of Medicine and three other medical schools have just released a major report which clearly supports the idea that low magnesium levels are an important risk factor for diabetes. Their study involved 12,128 middle-aged white and black Americans who were non-diabetic at the start of the study. Six years later 367 of the black participants (14 per cent) and 739 (8 per cent) of the white participants had developed diabetes. A comparison of baseline blood serum levels and the incidence of diabetes showed that among white participants those with high magnesium levels (greater than 0.95 mmol/L) had a 50 per cent lower incidence of diabetes than participants with low levels (0.25-0.70 mmol/L). Total incidence was 11.1 cases per 1000 person-years at the high level and 22.8 cases at the low level. No significant correlation between serum magnesium levels and diabetes was found among the black participants. Surprisingly, the researchers also did not find any association between dietary intake of magnesium and the incidence of diabetes. Other studies have, however, found such a correlation. The researchers suggest that increased magnesium consumption along with modification of other risk factors for type 2 diabetes (obesity and lack of exercise) might represent a novel means to prevent type 2 diabetes.
Kao, W.H. Linda, et al. Serum and dietary magnesium and the risk of type 2 diabetes mellitus. Archives of Internal Medicine, Vol. 159, October 11, 1999, pp. 2151-59
Orchard, Trevor J. Magnesium and type 2 diabetes mellitus. Archives of Internal Medicine, Vol. 159, October 11, 1999, pp. 2119-20 (editorial)

Magnesium deficiency linked to diabetes
NEW YORK, NY. Researchers at Columbia University report that as many as one in three diabetics may lack magnesium. Magnesium deficiencies have also been implicated in cardiac arrhythmias, vasospasms, and seizures. It is believed that a lack of magnesium leads to increased insulin resistance, ie. a faulty metabolism of carbohydrates that causes unoxidized sugar to accumulate in the blood and urine (diabetes mellitus). Although the increase in insulin resistance caused by magnesium deficiency is most pronounced in diabetics it can also occur in non-diabetics. Furthermore, it is now clear that magnesium absorption is impaired in diabetics thus setting up a vicious cycle of magnesium deficiency and insulin resistance. The researchers believe that insulin-dependent diabetics can benefit substantially from oral supplementation with magnesium (hydroxide or chloride). They also point out that magnesium supplementation (six weeks of magnesium chloride, 384 mg/day) has been found to lower systolic blood pressure in type II diabetics (by about 7 mm Hg). The recommended magnesium intake for adults is 300-400 mg/day, but significantly higher intakes may be required to correct severe depletion. Supplementation is not recommended for patients with kidney disease.
Tosiello, Lorraine. Hypomagnesemia and diabetes mellitus. Archives of Internal Medicine, Vol. 156, June 10, 1996, pp. 1143-48

Magnesium and Hypertension

Natural mineral salt lowers blood pressure
ROTTERDAM, NETHERLANDS. Medical researchers at the Erasmus University Medical School have discovered a natural mineral salt which significantly lowers blood pressure in people suffering from mild to moderate hypertension. The salt, "SagaSalt" (Akzo Nobel, Netherlands) occurs naturally in Iceland and contains 41 per cent sodium chloride, 41 per cent potassium chloride, 17 per cent magnesium salts and 1 per cent trace minerals. The researchers tested the salt in a randomized double blind placebo controlled trial involving 100 men and women aged 55 to 75 years. The participants had systolic blood pressures between 140 and 200 mm Hg or diastolic pressures between 85 and 100 mm Hg. Half the group used the mineral salt in food preparation and at the table while the other half used common table salt (sodium chloride). Blood pressures were measured at the start of the experiment and after 8, 16 and 24 weeks. After eight weeks the average blood pressure in the mineral salt group had fallen significantly. The systolic blood pressure (mean of measurement at weeks 8, 16 and 24) fell by 7.6 mm Hg and the diastolic pressure by 3.3 mm Hg in the mineral salt group as compared with the control group. After 24 weeks all participants went back to using common table salt and at week 25 there was no longer any difference in blood pressures between the two groups. The researchers conclude that replacing common table salt with a low sodium, high potassium, high magnesium mineral salt is an effective way of lowering blood pressure in older people suffering from mild to moderate hypertension. NOTE: Systolic pressure is the first (highest) reading given in a blood pressure measurement, diastolic is the second (lowest) reading, i.e. 120/80.
Geleijnse, J.M., et al. Reduction in blood pressure with a low sodium, high potassium, high magnesium salt in older subjects with mild to moderate hypertension. British Medical Journal, Vol. 309, August 13, 1994, pp. 436-40

Magnesium supplement lowers blood pressure
ROTTERDAM, THE NETHERLANDS. A double-blind controlled trial was recently carried out by Dutch and Belgian researchers in order to determine if oral supplementation with magnesium is an effective way of lowering blood pressure in women suffering from mild to moderate hypertension. Their experiment involved 91 women between 35 and 77 years of age who did not take anti-hypertensive medication. All the women had a systolic blood pressure between 140 and 185 mm Hg and a diastolic pressure between 90 and 105 mm Hg. After a two-week period where all subjects received a placebo, the participants were randomly assigned to two groups. One group continued to receive the placebo while the other group received 485 mg per day of magnesium aspartate-HCl. Both the placebo and the magnesium supplement were supplied in the form of four packets of water-soluble powder per day to be taken with meals. At the end of the six- month trial period the systolic blood pressure in the magnesium supplementation group had decreased by 2.7 mm Hg and the diastolic pressure by 3.4 mm Hg when compared to the placebo group. The researchers conclude that oral supplementation with magnesium aspartate-HCl may be effective in lowering blood pressure in people suffering from mild to moderate hypertension who are not taking anti-hypertensive drugs.
Witteman, Jacqueline C.M., et al. Reduction of blood pressure with oral magnesium supplementation in women with mild to moderate hypertension. American Journal of Clinical Nutrition, Vol. 60, July 1994, pp. 129-35

Dietary fiber and magnesium prevent hypertension
BOSTON, MASSACHUSETTS. Doctors at the Harvard School of Public Health have completed a study to determine the relationship between diet and hypertension (high blood pressure). The study involved over 30,000 male health professionals 40 to 75 years old. The baseline mean systolic blood pressure for the men was 125.5 mm at age 40-44 and 133.7 mm at age 70-75. The diastolic blood pressure at 79.3 to 80.4 mm was relatively unchanged with age. During four years of follow-up 1248 of the men developed hypertension. An analysis showed that participants consuming less than 250 mg per day of magnesium had a 50% greater chance of developing hypertension than had men who consumed 400 mg/day or more. Similarly, an intake of less than 2.4 g/day of potassium increased the risk of hypertension by 50% as compared to an intake of 3.6 g/day or more. The most striking effect was found in the case of dietary fiber where an intake of 24 grams/day or more was found to provide significant protection. A higher intake of dietary fiber, magnesium, and potassium was also found to be associated with lower blood pressure in healthy men. The results of this study confirm the findings of an earlier study involving 58,000 nurses. The authors point out that although diet is important in preventing hypertension, its effect is overshadowed by the risk imposed by obesity and excessive alcohol intake.
Circulation, November 1992, pp. 1475-84

Magnesium: Odds and Ends

Supplement recommendations for chronic fatigue syndrome
BERKELEY, CALIFORNIA. Dr. Melvyn Werbach, MD of the UCLA School of Medicine has just published a thorough review of nutritional deficiencies involved in chronic fatigue syndrome (CFS). These include deficiencies in vitamin C, coenzyme Q10, magnesium, zinc, sodium, l-tryptophan, l-carnitine, essential fatty acids, and various B vitamins. He points out that there is some evidence that the deficiencies are caused by the disease itself rather than by an inadequate diet. He suggests that the deficiencies not only contribute to the symptoms of CFS but also impair the healing process. Although the results of supplementation trials involving CFS patients have been inconclusive so far Dr. Werbach nevertheless recommends that CFS patients be given large doses of certain supplements for at least a trial period to see if their symptoms improve. His recommendations are:

• Folic acid: 1-10 mg/day for 3 months
• Vitamin B12: 6-70 mg (intramuscular injection) per week for 3 weeks
• Vitamin C: 10-15 grams/day
• Magnesium: 600 mg/day + 2400 mg/day of malic acid for 8 weeks
• Zinc: 135 mg/day for 15 days
• 5-hydroxytryptophan: 100 mg three times daily for 3 months (if fibromyalgia is present)
• L-carnitine: 1-2 grams three times daily for 3 months
• Coenzyme Q10: 100 mg/day for 3 months
• Essential fatty acids: 280 mg GLA and 135 mg EPA daily for 3 months

The supplements should be administered with medical supervision and accompanied by a high-potency vitamin/mineral supplement for the duration of the trial. [95 references]
Werbach, Melvyn R. Nutritional strategies for treating chronic fatigue syndrome. Alternative Medicine Review, Vol. 5, No. 2 April 2000, pp. 93-108

Sports drinks lack magnesium
HONOLULU, HAWAII. Dr. Robert Whang MD, Professor of Medicine at the University of Hawaii, believes that commonly available sports drinks like Gatorade, Allsport and Powerade are less than optimum for rehydration purposes because they contain no magnesium. Dr. Whang points out that adequate levels of intracellular potassium and magnesium are important in ensuring sufficient blood flow to the muscles and internal organs, in maintaining normal acid-base balance, and in controlling the level of excitation of the nerves, particularly in the heart. Magnesium is a vital component in the synthesis of ATP (the body's main energy source), DNA, RNA and protein, and is required for proper nerve conduction, muscle contraction, cell division, and transport across cell membranes. Magnesium losses during strenuous exercise can be quite considerable and are accompanied by significant losses of potassium as well. There is also some evidence that a magnesium deficiency can interfere with the reuptake of potassium after dehydration. The United States Army has recently developed a new rehydration beverage specifically designed for troops operating in desert and tropical environments. The new drink, Army CE 1, contains 128 mg of sodium, 96 mg of potassium, and 16 mg of magnesium per 240 ml. In comparison the popular sports drink Gatorade contains 110 mg of sodium, 30 mg of potassium, and no magnesium. Dr. Whang concludes that consideration should be given to adding magnesium to sports drinks. He points out that the American diet is usually deficient in magnesium and suggests that people engaged in strenuous sports activities supplement with the RDA (Recommended Daily Allowance) for magnesium (350 mg/day for men and 280 mg/day for women in the USA) provided they do not suffer from kidney failure.
Whang, Robert. Electrolyte and water metabolism in sports activities. Comprehensive Therapy, Vol. 24, January 1998, pp. 5-8

Magnesium reduces cerebral palsy risk
ATLANTA, GEORGIA. Cerebral palsy is a serious muscle disorder caused by brain anomalies which affects babies even before they are born. It is particularly prevalent among very low-birth-weight babies (weight less than 1500 g at birth). These babies are also at much greater risk of being mentally retarded. Researchers at the Centers for Disease Control and Prevention now report that administration of magnesium sulfate to pregnant women prior to giving birth reduces dramatically the incidence of cerebral palsy and mental retardation among very low-birth-weight infants. Their study involved over 1000 very low- birth-weight infants born live in the Atlanta region between April 1986 and March 1988. The researchers found that babies born to mothers who had been given magnesium sulfate for pregnancy complications were 10 times less likely to be born with cerebral palsy and more than three times less likely to be born with mental retardation than were babies born to mothers who had not been given magnesium sulfate prior to giving birth. The researchers conclude that giving magnesium sulfate to all mothers in danger of delivering a very low-birth-weight infant might prevent 63 per cent of all cases of cerebral palsy and 49 per cent of all cases of mental retardation in low-birth-weight babies. They caution though that some women may have contraindications to magnesium sulfate therapy.
Schendel, Diana E., et al. Prenatal magnesium sulfate exposure and the risk for cerebral palsy or mental retardation among very low-birth-weight children aged 3 to 5 years. Journal of the American Medical Association, Vol. 276, No. 22, December 11, 1996, pp. 1805-10
Nelson, Karin B. Magnesium sulfate and risk of cerebral palsy in very low-birth-weight infants. Journal of the American Medical Association, Vol. 276, No. 22, December 11, 1996, pp. 1843-44 (editorial)

Magnesium deficiency: A risk factor for asthma?
NOTTINGHAM, ENGLAND. Researchers at the University of Nottingham have concluded that a high intake of magnesium is associated with a better lung function and a reduced risk of airway hyper-reactivity and wheezing. Their study involved 2633 adults aged 18 to 70 years whose average daily magnesium intake was 380 mg as estimated via a diet questionnaire. The actual magnesium intake varied widely from 182 to 654 mg/day in men and from 160 to 527 mg/day for women. The researchers estimate that the daily steady state requirement may be as high as 420 mg/day and conclude that a substantial proportion of adults in the U.K. are deficient in their magnesium intake. They also conclude from their experiment that the lung capacity (forced expiratory volume) of participants who had a 100 mg/day higher than average intake of magnesium was significantly better than among participants with a lower intake. Participants who consumed more magnesium also reported less wheezing within the preceding 12 months and showed less reactivity when challenged with a methacholine spray. The researchers conclude that a magnesium deficiency may be implicated in the development of asthma and other chronic obstructive airways diseases.
Britton, John, et al. Dietary magnesium, lung function, wheezing, and airway hyper-reactivity in a random adult population sample. The Lancet, Vol. 344, August 6, 1994, pp. 357-62