Magnesium May Protect Women Against Sudden Cardiac Death
Women need to pay more attention to their magnesium intake if they want to protect their heart against sudden cardiac death. That is the gist of a new study from Brigham and Women’s Hospital and Harvard Medical School, which found that the mineral is associated with a reduced risk of this lethal condition in women.
Women can reduce their risk for sudden cardiac death
According to invasive cardiologist John Kennedy, MD, sudden cardiac death strikes more than 400,000 people per year in the US, and of these, 120,000 of those affected are women. Sudden cardiac death (also known as sudden arrest) occurs when there is a sudden loss of heart function (cardiac arrest). Victims may or may not have diagnosed heart disease.
In 90 percent of adults who die suddenly from cardiac arrest, the underlying reason is coronary heart disease, which is characterized by accumulation of plaque in the arteries that supply the heart muscle. Among young adults, heart abnormalities are often involved, and the sudden cardiac death may be triggered by intense physical or athletic activity. Use of some heart medications and other drugs, including illegal ones, can cause abnormal heart rhythms that result in sudden death.
In the new study, researchers under the direction of Stephanie Chiuve evaluated data from 88,375 women who had participated in the Nurses’ Health Study. During 26 years of follow-up, the investigators documented 505 cases of sudden or arrhythmic death and also analyzed magnesium levels in 99 women who had died of sudden cardiac death and 291 women who did not die.
After allowing for factors such as smoking, age, and the presence of cardiovascular disease, the researchers observed that the highest intakes of magnesium were associated with a 37 percent reduced risk of sudden cardiac death compared with the lowest intakes. A comparison of blood levels revealed an even greater advantage: with every 0.25 mg/dL increase in magnesium, there was a 41 percent reduction in the risk of sudden cardiac death.
About 50 percent of the magnesium in the body is located in the tissues, while only 1 percent is found in the blood stream. Magnesium is necessary for more than 300 biochemical reactions, including maintaining heart rhythm and promoting normal blood pressure and nerve function. Good dietary sources of magnesium include green leafy vegetables, unrefined grains, nuts, and legumes. The Recommended Daily Allowance for women is 320 mg, but many women do not reach that goal.
This new study suggests women should strive to get sufficient magnesium to protect their heart. “Higher plasma concentrations and dietary magnesium intakes were associated with lower risks of sudden cardiac death,” note the authors. “Interventions directed at increasing dietary or plasma magnesium might lower the risk of sudden cardiac death.”
American Heart Association
Chiuve SE et al. American Journal of Clinical Nutrition 2010 Nov 24; doi: 10.3945/ajcn.110.002253