Magnesium may help lower risk for cerebral infarction, a type of stroke, in male smokers, says a new study.
This kind of stroke occurs when blood flow to the brain is blocked.
The study, led by Susanna C. Larsson, Ph.D., of the Karolinska Institutet, Stockholm, Sweden, based its findings on the analysis of the diets of 26,556 Finnish male smokers age 50 to 69 years who had not previously had strokes.
In addition to the types of food they ate, the men in the study reported other characteristics including medical, smoking and physical activity histories. Their height, weight and blood pressure were recorded, and a blood sample was taken.
During an average of 13.6 years of follow-up, 2,702 of the men had cerebral infarctions; 383 had intracerebral hemorrhages, which involve bleeding into the brain tissue; 196 had subarachnoid hemorrhages, or bleeding between the brain and the thin tissues that cover it; and 84 had unspecified types of strokes.
After adjusting for age and cardiovascular risk factors, such as diabetes and cholesterol level, men who consumed the most magnesium had a 15 percent lower risk for cerebral infarction than those who consumed the least.
The association was stronger in men younger than 60 years. Magnesium intake was not associated with a lower risk of intracerebral or subarachnoid hemorrhage, and calcium, potassium and sodium intake were not associated with risk for any type of stroke.
"An inverse association between magnesium intake and cerebral infarction is biologically plausible," the authors said.
In addition to lowering blood pressure, magnesium may influence cholesterol concentrations 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 results "suggest that a high consumption of magnesium-rich foods, such as whole-grain cereals, may play a role in the prevention of cerebral infarction," the researchers said.
"Whether magnesium supplementation lowers the risk of cerebral infarction needs to be assessed in large, long-term randomized trials," they added.
The study is published in the Archives of Internal Medicine, one of the JAMA/Archives journals.