Low magnesium levels may increase stroke risk

Study suggests that increasing levels of magnesium could decrease the risk of stroke by 25% through beneficial effects on blood pressure and diabetes.

The study included over 14,000 men and women aged between 45 and 64. During the course of 15 years of follow-up, the researchers documented 577 cases of ischemic stroke (1). The incidence of stroke was highest amongst diabetics and people with hypertension, added the researchers. High blood levels of magnesium were associated with a lower risk of stroke, but after the results were adjusted for hypertension and diabetes, the researchers found that the links became non-significant.

The researchers concluded that low serum magnesium levels could be partly associated with increased risk of ischemic stroke via the beneficial effects of magnesium on hypertension and diabetes.

In 2007, a meta-analysis of prospective cohort studies reported that for every 100 milligram increase in magnesium intake, the risk of developing type-2 diabetes decreased by 15% (2). The researchers concluded that while it is too early to recommend magnesium supplements for type-2 diabetes prevention, increased consumption of magnesium-rich food seems prudent.

Diet is known to have an impact on a person's risk of having a stroke, and in particular a connection has been made between intake of sodium and hypertension. Conversely, more magnesium, potassium and calcium have been linked to risk reduction for hypertension in some observational studies.

The new study supports the potential of magnesium to reduce the risk of stroke, possibly via an anti-hypertensive mechanism, suggest the researchers.

Dietary sources of magnesium include green, leafy vegetables, meats, starches, grains and nuts, and milk. Earlier dietary surveys show that many adults do not meet the recommended dietary allowances for magnesium (320 mg per day for women and 420 mg per day for men).

1. Ohira T. et al. Serum and Dietary Magnesium and Risk of Ischemic Stroke - The Atherosclerosis Risk in Communities Study. American Journal of Epidemiology, 2009; 169(12):1437–1444.
2. Larsson S., Wolk A. Magnesium intake and risk of type 2 diabetes: a meta-analysis. Journal of Internal Medicine, 2007; 262(2):208–214.