Researchers have suspected for a long time that the dietary intake of minerals other than sodium can affect the blood pressure, but conclusive evidence has been lacking. This study reviews all the published articles examining the relationship between the intake of magnesium, (evaluated from people's descriptions of their diets) and blood pressure. It evaluated 30 reports from 12 different countries. The general finding was that people whose diets contain more magnesium have slightly lower blood pressure than those with less magnesium. However, the authors of the analysis concluded that it was not possible to say exactly how big is the effect of magnesium on blood pressure from the existing data.
Other studies have suggested that insufficient intake of magnesium may be one of the many factors that lead to heart disease. As this analysis shows, it could also raise the blood pressure. But studies in which people have been given extra magnesium have not shown consistent effects on blood pressure. Most of the magnesium in our diets comes from leafy vegetables, beans, nuts and grains, and about 25% from drinking water. Americans have an average daily magnesium intake of about 250 milligrams - less than the recommended daily intake (350 milligrams for men and 280 for women).
Where it was published
Mizushima S and colleagues. Dietary magnesium intake and blood pressure; a qualitative overview of the observational studies. Journal of Human Hypertension1998;12:447-53