高钾食物可降低年长女性的中风死亡危险

Postmenopausal women who eat foods higher in potassium are less likely to have strokes and die than women who eat less potassium-rich foods, according to new research in the American Heart Association's journal Stroke. "Previous studies have shown that potassium consumption may lower blood pressure. But whether potassium intake could prevent stroke or death wasn't clear," said Sylvia Wassertheil-Smoller, Ph.D., study senior author and distinguished university professor emerita, department of epidemiology and population health at Albert Einstein College of Medicine, Bronx, NY.

"Our findings give women another reason to eat their fruits and vegetables. Fruits and vegetables are good sources of potassium, and potassium not only lowers postmenopausal women's risk of stroke, but also death."

Researchers studied 90,137 postmenopausal women, ages 50 to 79, for an average 11 years. They looked at how much potassium the women consumed, as well as if they had strokes, including ischemic and hemorrhagic strokes, or died during the study period. Women in the study were stroke-free at the start and their average dietary potassium intake was 2,611 mg/day. Results of this study are based on potassium from food, not supplements.

The researchers found: Women who ate the most potassium were 12 percent less likely to suffer stroke in general and 16 percent less likely to suffer an ischemic stroke than women who ate the least. Women who ate the most potassium were 10 percent less likely to die than those who ate the least. Among women who did not have hypertension (whose blood pressure was normal and they were not on any medications for high blood pressure), those who ate the most potassium had a 27 percent lower ischemic stroke risk and 21 percent reduced risk for all stroke types, compared to women who ate the least potassium in their daily diets. Among women with hypertension (whose blood pressure was high or they were taking drugs for high blood pressure), those who ate the most potassium had a lower risk of death, but potassium intake did not lower their stroke risk.

Researchers suggested that higher dietary potassium intake may be more beneficial before high blood pressure develops. They also said there was no evidence of any association between potassium intake and hemorrhagic stroke, which could be related to the low number of hemorrhagic strokes in the study.

The U.S. Department of Agriculture recommends that women eat at least 4,700 mg of potassium daily. "Only 2.8 percent of women in our study met or exceeded this level. The World Health Organization's daily potassium recommendation for women is lower, at 3,510 mg or more. Still, only 16.6 percent of women we studied met or exceeded that," said Wassertheil-Smoller.

"Our findings suggest that women need to eat more potassium-rich foods. You won't find high potassium in junk food. Some foods high in potassium include white and sweet potatoes, bananas and white beans."

While increasing potassium intake is probably a good idea for most older women, there are some people who have too much potassium in their blood, which can be dangerous to the heart. "People should check with their doctor about how much potassium they should eat," she said.

The study was observational and included only postmenopausal women. Researchers also did not take sodium intake into consideration, so the potential importance of a balance between sodium and potassium is not among the findings. Researchers said more studies are needed to determine whether potassium has the same effects on men and younger people.