Sorting strokes

To study the potential connections between dietary potassium and risk of stroke, researchers used meta-analysis to combine and analyze data from ten previous observational studies on this topic. The researchers considered 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 researchers found that for every 1,000 mg per day increase in potassium intake, the risk of ischemic stroke decreased by 11%. The risk of other stroke types, including intracerebral hemorrhage and subarachnoid hemorrhage, was not related to dietary potassium levels.

Parsing potassium

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, observational studies cannot completely control for all other factors that may influence results, so they cannot prove cause and effect. Still, taking the research limitations into account, the meta-analysis does suggest that something about a high-potassium diet may protect against ischemic stroke—the most common type of stroke in the US, accounting for approximately 87% of all strokes.

Increase your intake

It’s not surprising that a potassium-rich diet may protect against stroke. The foods that supply potassium—vegetables, fruit, beans, low-fat dairy, and fish—are the very same foods that offer other health benefits as well. Good potassium boosters include

• sweet potatoes and winter squash;
• low-sodium tomato juice;
• beet greens and other green leafy vegetables;
• white beans, soy beans, lima beans, and kidney beans;
• low-fat plain yogurt;
• halibut, tuna, rockfish, and cod;
• bananas, peaches, apricots, dried plums (prunes), cantaloupe, and honeydew melon;
• orange juice and oranges.

Hone your habits

Potassium may reduce stroke risk for another reason: The more potassium people consume, the lower their blood pressure tends to be, and high blood pressure is a major stroke risk factor. 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:

• Limit saturated fat, found in red meat, high fat dairy products, baked goods, and fast food.
• Avoid trans fat, which is found in processed food, baked goods, and fast food.
• Keep sodium (salt) intake low by limiting chips, crackers, canned soups, and other high-sodium processed foods.
• Exercise a minimum of 30 minutes most days of the week.
• Do not smoke, and use alcohol only in moderation, if at all.

(Stroke 2011, 42:00-00)