Measuring magnesium's impact on stroke

To study the potential connections between dietary magnesium and stroke risk, researchers used meta-analysis to combine and analyze data from seven previous observational studies on three types of stroke:

• Ischemic stroke, which occurs when a blood vessel supplying blood to the brain becomes blocked
• Intracerebral hemorrhage, which occurs when there is bleeding within the brain tissue
• Subarachnoid hemorrhage, which occurs when there is bleeding within the skull, but not within the brain tissue itself

The study authors found that for every 100 mg per day increase in magnesium intake, the risk of ischemic stroke, a common type of stroke, decreased by 9%. The risk of the other stroke types--intracerebral hemorrhage and subarachnoid hemorrhage--was not related to dietary magnesium levels.

Mastering magnesium

The meta-analysis approach allows for larger numbers of people to be studied together, and typically, more study subjects makes for a stronger study. However, this type of study is observational, so it cannot prove cause and effect. Still, the results suggest a high-magnesium diet may protect against ischemic stroke.

Here are some steps you can take to reduce your stroke risk:

• Focus on food. The magnesium master list includes whole grains, especially buckwheat, bulgur wheat, oats and oat bran, whole wheat, barley, and corn meal; nuts and seeds, including pumpkin seeds, Brazil nuts, cashews, and almonds; all beans and peas; and vegetables, especially spinach, canned tomatoes, beet greens, and okra.
• Address high blood pressure. Given that magnesium plays a role in keeping blood pressure in the healthy range, and that high blood pressure is a major risk factor for ischemic stroke, it makes sense that this mineral may protect against stroke. Keep tabs on your blood pressure and talk to your doctor about how best to manage it if your numbers creep up.
• Have a healthy heart. The same things that can lead to clogged vessels around the heart--and subsequent heart disease--also lead to clogged vessels around the brain. If you focus on heart-healthy habits, you'll get the added bonus of stroke prevention.
• Heed heart tips. To keep your ticker, and your brain, healthy, eat less saturated fat, which is found in red meat, high fat dairy products, baked goods, and fast food; avoid trans fat, found in processed food, baked goods, and fast food; avoid sodium-loaded chips, crackers, canned soups, and other high-sodium processed foods; exercise at least 30 minutes most days of the week; do not smoke; and use alcohol only in moderation, if at all.

(Am J Clin Nutr 2012;95:362-6)