Saturday, December 18, 2010

Magnesium and Sudden Cardiac Death

Increased intakes of magnesium-rich foods have been reported to be associated with a reduced risk of sudden cardiac death.

A new study reports a protective effect against the risk of sudden cardiac death in women who consume higher levels of dietary magnesium.

Researchers under the direction of Stephanie Chiuve of the Harvard Medical School evaluated data from more than 88,000 women (1).

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. The apparent protective effects of magnesium are strongest when the researchers focused their attention on blood levels, with every 0.25 milligram per deciliter increase there was a 41 percent reduction in the risk of sudden cardiac death.

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.

Magnesium: What is it?

Magnesium is the fourth most abundant mineral in the body and is essential to good health. About 50 percent of total body magnesium is found in bone. The other half is found predominantly inside cells of body tissues and organs. Only 1% of magnesium is found in blood, but the body works very hard to keep blood levels of magnesium constant.

Magnesium plays a role in more than 300 biochemical reactions in the body (2). These include:

  1. Normal Muscle and Nerve Function
  2. Steady Heart Rhythm
  3. Healthy Immune System
  4. Keeping Bones Strong.
  5. Healthy Blood Sugar Levels,
  6. Promoting Normal Blood Pressure
  7. Energy metabolism and Protein Synthesis.

Magnesium deficiency can trigger a number of health conditions and problems (3), such as:

  • Anxiety
  • Depression
  • Diabetes
  • Migraines
  • Heart disease
  • Hypertension

What foods provide magnesium?

Green vegetables such as spinach are good sources of magnesium because the center of the chlorophyll molecule (which gives green vegetables their color) contains magnesium. Some legumes (beans and peas), nuts and seeds, and whole, unrefined grains are also good sources of magnesium. Refined grains are generally low in magnesium. When white flour is refined and processed, the magnesium-rich germ and bran are removed. Bread made from whole grain wheat flour provides more magnesium than bread made from white refined flour. Tap water can be a source of magnesium, but the amount varies according to the water supply. Water that naturally contains more minerals is described as "hard". "Hard" water contains more magnesium than "soft" water.

Eating a wide variety of legumes, nuts, whole grains, and vegetables will help you meet your daily dietary need for magnesium. CLICK HERE for selected food sources of magnesium.

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).

Dietary magnesium is absorbed in the small intestines. Magnesium is excreted through the kidneys.


  1. Chiuve SE, Korngold EC, Januzzi JL Jr, Gantzer ML, Albert CM. Plasma and dietary magnesium and risk of sudden cardiac death in women. American Journal of Clinical Nutrition 2010 Nov 24.
  2. Office of Dietary Supplements, National Institutes of Health, USA
  3. Guerrera MP, Volpe SL, Mao JJ. Therapeutic uses of magnesium. American Family Physician. 2009 Jul 15;80(2):157-62. FULL TEXT
  4. Picture Credit

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