The highest dietary intakes of the mineral were associated with a 37 percent reduction in the risk of sudden cardiac death, compared with the lowest average intakes, according to new findings published in the American Journal of Clinical Nutrition.
The apparent protective effects of magnesium were strongest when the researchers focused their attention on blood levels, with every 0.25 milligram per deciliter increase associated with a 41 percent reduction in the risk of sudden cardiac death.
Sudden cardiac death, according to the British Journal of Sports Medicine (1997, Vol. ), is defined as: “An event that is non-traumatic, non-violent, unexpected, and resulting from sudden cardiac arrest within six hours of previously witnessed normal health”.
Magnesium in the diet
Dietary sources of magnesium include green, leafy vegetables, meats, starches, grains and nuts, and milk. Earlier dietary surveys show that a large portion of adults does not meet the RDA for magnesium (320 mg per day for women and 420 mg per day for men).
Interest in magnesium and its potential health benefits have increased recently. Indeed, a report from The Freedonia Group reported that global demand for nutrients and minerals will reach $12.6bn by 2013; a 6.4 per cent increase on last year’s level.
The report, World Nutraceutical Ingredients, highlighted magnesium as one of the minerals with fastest growth, along with calcium. Other fact growing ingredients included soy proteins and isoflavones, psyllium and resistant maltodextrin fibres, omega-3 fatty acids, probiotics, and carotenoids.
Potential cardiovascular benefits of the mineral were highlighted in a review in the Journal of the American Academy of Nurse Practitioners (2009, Vol. 21, pp. 651-657), which found that increased intakes of magnesium may reduce the risk of coronary heart disease (CHD) in men, but the evidence is lacking for women.
Reviewers Tavia Mathers and Renea Beckstrand from Brigham Young University concluded that, with the mineral being implicated in more than 300 biochemical reactions in the body, and toxicity issues being rare, “oral magnesium supplementation is recommended”.
The new study adds to this body of evidence by indicating a protective role in women from sudden cardiac death. The Boston-based researchers, led by Stephanie Chiuve, analyzed data from 88,375 women participating in the Nurses' Health Study.
During an impressive 26 years of follow-up, a total of 505 cases of sudden or arrhythmic death were documented by the researchers. Subsequent analysis of the role of magnesium was performed data from 99 cases of sudden cardiac death and 291 women who did not die.
After adjusting the data for a range of factors that could potentially affect the result, like smoking, age, and presence of cardiovascular disease, the researchers noted that the highest intakes and the highest blood level of magnesium were associated with significant decreases in the risk of sudden cardiac death, compared with the lowest average intakes and blood levels.
“In this prospective cohort of women, higher plasma concentrations and dietary magnesium intakes were associated with lower risks of sudden cardiac death. If the observed association is causal, interventions directed at increasing dietary or plasma magnesium might lower the risk of sudden cardiac death,” concluded the researchers.
The study was supported by Siemens Healthcare Diagnostics and the American Heart Association.
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.3945/ajcn.110.002253
“Plasma and dietary magnesium and risk of sudden cardiac death in women”
Authors: S.E. Chiuve, E.C. Korngold, J.L. Januzzi Jr, M.L. Gantzer, C.M. Albert