Higher Potassium Means Lower Risk of Stroke for Older Women
Postmenopausal women who ate foods higher in potassium had a lower risk of stroke and death compared to those who had less potassium in their diet, according to a new study in the journal Stroke.
“Women, ages 50-79, who had a dietary intake of 3200mg of potassium per day or more had significantly lower risk of stroke and all-cause mortality than women who had intakes of 125mg or less,” says senior study author Sylvia Wassertheil-Smoller, PhD, of the Albert Einstein College of Medicine, Bronx, NY.
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Overall, compared to women who ate the least potassium, women who ate the most potassium were:
• 10% less likely to die.
• 12% less likely to suffer a stroke, in general.
• 16% less likely to suffer an ischemic stroke.
There appeared to be no association between dietary potassium intake and hemorrhagic stroke.
“Potassium has a beneficial effect on endothelial function so the effects on blood vessels may be one reason for our findings,” says first author Arjun Seth, a medical student at the Albert Einstein College of Medicine. “Also, potassium has been shown to lower blood pressure, which is a major risk factor for stroke. However, in our study, there was no association of potassium with lower blood pressure, so we think the potassium effects are beyond the effects on blood pressure.”
Wassertheil-Smoller, Seth, and colleagues examined 90,137 postmenopausal women, ages 50 to 79, who were stroke-free at the start of their study. They followed them for an average of 11 years—documenting how much potassium they consumed, if they had strokes (ischemic or hemorrhagic), or if they died during the study period.
Women who had normal blood pressure and were not taking any medications for high blood pressure seemed to show more benefits than their counterparts who were hypertensive.
“Among women who were not hypertensive, those who had high intakes of potassium had a 27% lower risk of ischemic stroke and 21% reduced risk for all stroke types than those with low intakes,” Seth says.
On the other hand, women with hypertension who ate the most potassium had a lower risk of death, but potassium intake didn’t lower their stroke risk. The researchers suggest that higher dietary potassium intake may be more beneficial before high blood pressure develops.
While the Institute of Medicine and the US Department of Agriculture recommend 4700mg of potassium daily and the World Health Organization suggests a goal of 3500mg per day, most study participants were far from either target.
“Americans, on average, consume 2640mg of potassium daily—in our study, the average intake was 2611mg, which falls considerably below the recommendations,” Wassertheil-Smoller says. “In our study, only about 3% of the women consumed 4700mg or more, and only about 17% met the WHO goals.”
These results would suggest that older women need to increase their potassium intake. Patients in this study showed these benefits from consuming dietary potassium, not potassium supplements.
Eating more fruits and vegetables, in general, can help patients to build more potassium into their diet. Foods particularly rich in potassium include: bananas, baked potatoes, orange juice, spinach, yogurt, salmon, and unprocessed meats.
While getting more dietary potassium is likely beneficial for most older women, the researchers warn it can be dangerous for certain patients who have too much potassium in their blood. They recommend that patients consult with their health care provider before increasing their potassium intake.
—Colleen Mullarkey
Reference
Seth A, Mossavar-Rahmani Y, Kamensky V, Silver B, Lakshminarayan K, Prentice R, et al. Potassium intake and risk of stroke in women with hypertension and nonhypertension in the Women’s Health Initiative. Stroke. 4 September 2014. [Epub ahead of print].