A high magnesium intake may reduce the risk for primary ischemic stroke among male smokers, a new study suggests.

Investigators at the Karolinska Institutet in Stockholm, Sweden, found that male smokers with the highest magnesium intake had a 15% lower risk for cerebral infarction vs counterparts with the lowest intake of magnesium.

"An inverse association between magnesium intake and cerebral infarction is biologically plausible. In addition to lowering blood pressure, magnesium may influence cholesterol concentration or the body's use of insulin to turn glucose into energy. Either of these mechanisms would affect the risk for cerebral infarction but not hemorrhage," the study authors write.

Led by Susanna C. Larsson, PhD, the study is published in the March 10 issue of the Archives of Internal Medicine.

According to the study authors, some previous observational studies have linked magnesium, calcium, and potassium intake to lower blood pressure and a reduced risk for hypertension. Furthermore, the authors point out that some, though not all, randomized controlled trials have shown that supplementation with these minerals, alone or in combination, can reduce blood pressure.

However, they note that "the question of whether magnesium, calcium, potassium and sodium intake is associated with risk of stroke remains controversial."

Stroke is an important cause of morbidity and mortality in developed countries. Because hypertension is a strong risk factor for stroke, dietary factors that influence blood pressure levels may affect the risk for stroke. A high intake of magnesium, calcium, and potassium and a low intake of sodium have been hypothesized to reduce the risk for stroke by affecting blood pressure. However, prospective data relating intake of these minerals to the risk for stroke are inconsistent. 

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