Is a potassium-rich diet tied to lower stroke risk?

Potass­ium helps balanc­e effect­s of sodium, keepin­g blood pressu­re down.

Reuters August 18, 2011

NEW YORK: People who eat plenty of high-potassium fruits, vegetables and dairy products may be less likely to suffer a stroke than those who get little of the mineral, a new study suggests.

The findings, reported in the journal Stroke, come from an analysis of 10 international studies involving more than 200,000 middle-aged and older adults.

Researchers found that across those studies, stroke risk dipped as people's reported potassium intake went up. For each 1,000-milligram (mg) increase in daily potassium, the odds of suffering a stroke in the next five to 14 years declined by 11 per cent.

That would translate into a modest benefit for any one person, the researchers say. And the findings do not prove that potassium, itself, is what produces the positive effect.

Since high-potassium foods are generally healthy ones -- including beans, a variety of fruits and vegetables, and low-fat dairy -- the findings offer one more reason for people to eat more of them, Larsson told Reuters Health in an email.

Potassium is an electrolyte needed for maintaining the body's fluid balance. It's also involved in nerve and muscle control and blood pressure regulation. A number of studies have suggested that diets high in potassium help maintain a healthy blood pressure and possibly protect against heart disease and stroke.

Potassium was specifically linked to reduced risk of ischemic strokes -- those caused by a blockage in an artery feeding the brain. They account for about 80 per cent of strokes.

The mineral was not, however, linked to a lower risk of hemorrhagic stroke, which occurs when there is bleeding in the brain.

It's not clear why that is, according to Larsson, who noted that only a few of the studies actually broke strokes down into subtypes.

If potassium protects against ischemic stroke only, that would suggest there are reasons other than better blood pressure control, the researchers say.

Potassium helps balance the effects of sodium, keeping blood pressure down and helping the body excrete excess fluids. So the combination of too much sodium and too little potassium may be especially harmful.

But experts say that imbalance is common in the U.S. diet, with about 90 percent of Americans getting more sodium than is recommended -- often from processed foods.

As for potassium, the CDC advises adults to get 4,700 mg a day from food.

There are some people, though, who need to be careful about potassium. They include people with kidney disease, which can hinder the body's ability to clear potassium, and those on certain blood pressure drugs.

Too much potassium in the blood can lead to a condition called hyperkalemia, which may cause dangerous heart-rhythm disturbances.


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