本文要旨是，

根據到目前為止最大規模的前瞻性調查研究證實：

在停經後的女性，攝取高量的鉀離子（每天4700mg），與缺血性中風以及各種原因的死亡率呈現負相關，尤其是對於沒有高血壓的女性而言更是如此。

多攝取蔬菜、水果就很容易能攝取足量的鉀離子。例如馬鈴薯、香蕉、橘子汁、菠菜、鮭魚、杏子、白豆、優格就含有高量的鉀離子。

Higher potassium intake is associated with a lower risk for all stroke and ischemic stroke, as well as all-cause mortality in older women, according to new data from the Women's Health Initiative (WHI) study, the largest prospective study of older women with long-term follow-up.

This latest analysis from the WHI is published online in Stroke September 4, with Arjun Seth, BS, Albert Einstein College of Medicine, Bronx, New York, as first author.

The effect was particularly evident for ischemic stroke in women without hypertension, they report. "In the WHI study of older women aged 50-79, those without hypertension who had higher levels of potassium had a 27% reduced risk of stroke than women with low potassium levels," Seth told Medscape Medical News.

In the study, higher potassium intake was also associated with a lower risk for small-vessel stroke subtype but was not linked to any reduction in hemorrhagic stroke.

Below Recommended Intake

The researchers also found that in general, this population was well below the recommended daily allowance of potassium. In the United States, this is 4700 mg. The women in the WHI study had average intake of 2600 mg, which is very similar to average US intakes. Only 2.8% of women met or exceeded the 4700 mg recommended intake.

The World Health Organization recommends a potassium intake of more than 3510 mg per day, which may be easier to achieve, but still only 16% of women in this cohort met this requirement.

Senior author, Sylvia Wassertheil-Smoller, PhD, Albert Einstein College of Medicine, Bronx, New York, commented to Medscape Medical News. "In this study, women in the upper quartile had intake over 3200 mg and showed a benefit in terms of reduced stroke versus women with lower intakes. Very few actually achieved the recommended level of 4700 mg."

She pointed out that it is easily possible to get enough potassium in the diet just by increasing the consumption of fruit and vegetables. Good sources of potassium are potatoes, banana, orange juice, spinach, salmon, raisins, apricots, white beans, and yogurt. A baked potato contains 900 mg of potassium and a banana contains 420 mg.

"So have a banana and a cup of yogurt for breakfast and a meal of salmon, spinach, and a baked potato for dinner and you're fine," she said.

The WHI study population consisted of 90,137 postmenopausal women aged 50 to 79 years at enrollment, with no history of stroke. They were followed for an average of 11 years.

Potassium consumption was calculated from food-frequency questionnaires completed by participants at enrollment and at year 3 of follow-up. Stroke was initially identified through self-report at annual visits, and medical records were then requested and stroke was centrally adjudicated by a neurologist. More than 95% of WHI stroke classification was based on MRI or computed tomographic findings.

Results of the current analysis showed that after adjustment for multiple confounders there were significant reductions in stroke and all-cause mortality in women in the highest quartile of potassium intake (>3193.6 mg) compared with those in the lowest (<1925.5 mg="" span="">