Increasing Magnesium in Diet Lowers Heart Disease Risk

Healthnotes Newswire (December 4, 2003)—Increasing the amount of magnesium one consumes in the diet may reduce the risk of developing coronary heart disease, according to a new study in The American Journal of Cardiology (2003;92:665–9). Eating foods high in magnesium may lower the likelihood of having a heart attack or stroke.

Heart disease is the number one killer of Americans and affects more than 58 million adults in the United States. More than 1 million people die from heart disease every year. Coronary heart disease, an obstruction in the arteries of the heart that closes off its blood supply, often goes undetected until the arteries become completely blocked. The plaque that builds up on the inner wall (called atherosclerosis) can also break off and become lodged in smaller arteries, leading to a stroke. Studies show that eating a low-saturated-fat diet and exercising regularly reduce the risk of heart disease. The current findings suggest that eating foods high in magnesium may also contribute to lowering risk.

In the study, 7,172 men of Japanese ancestry between the ages of 45 and 68 years enrolled as part of the Honolulu Heart Program from 1965 to 1968 to evaluate the effects of nutrition on heart disease. Data on dietary and supplemental intake of magnesium were collected initially and up to 30 years afterward. Intake of magnesium was broken down into quintiles, from one (lowest) to five (highest). Those in the highest quintile of magnesium intake consumed between 340 mg and 1,138 mg of magnesium per day. Those in the lowest quintile ate less than 186 mg of magnesium per day. The number of heart disease-related events was recorded during the 30-year follow-up period.

The incidence of coronary heart disease decreased consistently with the increasing intake of magnesium. Men in the lowest quintile were almost twice as likely to have heart disease as those in the highest quintile. The average amount of magnesium consumed each day by the participants in this study was 268 mg. High magnesium consumers were also found to eat higher amounts of fiber, calcium, and protein, so it is possible that the high magnesium consumption reflects better overall dietary habits. The incidence of heart disease was similar in all groups consuming less than 340 mg per day compared with those with higher intake amounts.

Magnesium deficiency may lead to serious adverse effects, such as high blood pressure, diabetes, arrhythmia, atherosclerosis, and heart attack. Blood levels of magnesium do not necessarily reflect amounts found in tissues and organs. Some physicians believe that measuring red blood cell magnesium levels provides a more accurate assessment of magnesium status, although published research does not necessarily support that point of view.

Some studies indicate that most Americans do not get adequate amounts of magnesium in their diets. Foods that contain significant amounts of magnesium include nuts, whole grains, beans, dark green vegetables, fish, and meat.