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Calcium Reduces Women's Risk of Stroke
What the Study Showed
According to a 1999 Harvard study, an increase in calcium intake can cut the risk of stroke in middle-aged women.

How It Was Done
As part on the ongoing Nurses' Health Study, 85,764 women, ages 35 to 59, completed questionnaires detailing their medical history, lifestyle, and diet. The women were then followed over the course of 14 years.

Why It's Important
Study researchers are not clear about exactly how calcium protects against stroke. However, this mineral was indeed associated with a 32% lower risk of stroke among those with the highest intake when compared with those with the lowest intake.

Previous studies have found that calcium may slightly reduce blood pressure, but the authors of this study believe such an effect would be small and not likely to explain the amount of stroke reduction shown here.

Additional Findings
The women taking at least 400 mg of calcium a day in supplement form had a 12% lower risk of ischemic stroke (the type caused by plaque buildup in blood vessel walls) than did those women who took no calcium supplements at all.

On the other hand, calcium intakes greater than 600 mg a day didn't significantly boost protection against stroke. Dietary calcium was also found to be protective, especially calcium from dairy foods.

The study also showed dietary potassium was linked with a reduced stroke risk.

Source: Iso H, et al. Prospective study of calcium, potassium, and magnesium intake and risk of stroke in women. Stroke 1999;30:1772-1779

Date Published: 02/20/2001
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