Beth Greenfield, Senior Writer
Yahoo, Sep 5, 2014

You can’t really eat too many bananas — especially if you’re a woman over the age of 50, according to the findings of a new study regarding potassium intake and stroke prevention. Published on Thursday in the journal Stroke, researchers discovered that women in that age group who ate high-potassium foods were 12 percent less likely to suffer from a stroke in general and 16 percent less likely to suffer from an ischemic stroke (one caused by a blood clot) than women who didn’t. Finally, the high-potassium women were 10 percent less likely to die — from any cause — than those who ate low amounts of the healthy mineral.

“Potassium has long been associated with lower blood pressure,” said Sylvia Wassertheil-Smoller, lead researcher and principal investigator at the Women’s Health Initiative of Yeshiva University’s Albert Einstein College of Medicine in New York. But, she told Yahoo Health, “We think it goes above and beyond that, to a cellular level. Potassium is used in cellular function, and could be positively affecting the cells that line blood vessels.”

One unexpected finding in the study, Wassertheil-Smoller noted, was that the relationship between potassium intake and stroke prevention was the strongest in women without hypertension. “That was surprising and really interesting,” she said. “So we think it’s good to up your potassium intake before hypertension has a chance to develop.”

The researcher said she could not leap to any conclusions about how a high potassium intake might protect men from strokes, since the research focused only on women. But, she said, “We think it does apply to men, as, in general and on average, men eat more potassium than women because they tend to consume more calories.” Also, the researchers only focused on dietary sources of potassium — which include foods such as bananas, spinach, dates, yogurt, potatoes, and salmon — and so could not comment on the impact of potassium supplements on stroke prevention.

For the study, researchers studied 90,137 postmenopausal women between the ages of 50 and 79 for an average of 11 years. The subjects consumed an average of 2,611 milligrams of potassium daily — well below the USDA recommended 4,700 mg and even the World Health Organization’s (WHO) 3,500 mg a day. Only three percent, in fact, actually exceeded the USDA recommendation. Based on the data, Wassertheil-Smoller suggests eating even more than that average. “We would say at least stick to the WHO recommendation — which equals 12 bananas a day,” she said with a laugh. But, she quickly added, “You don’t have to just eat bananas. A serving of spinach is probably twice that of a banana. Potassium is sort of everywhere, you just have to read labels to make sure.”