Potassium depletion as a risk factor for stroke

Paleoanthropologic studies show that prehistoric humans consumed a K⁺-rich diet of unprocessed foods,1 with estimated intakes of K⁺ ranging from 150 to 270 mEq/day. In comparison, with the processed foods in the modern Western diet, average K⁺ intake is now only a fraction of the hunter–gatherer diet: 70 mEq K⁺ for whites and 32 mEq for Southern blacks. The lowest K⁺ intake in America is in parts of the stroke belt (Mississippi, Alabama, and Georgia),2 where death rates from stroke are the highest. Recent epidemiologic studies show an association between dietary K⁺ and stroke.

In NHANES I (National Health and Nutrition Examination Survey), a prospective study of 9,800 subjects, low dietary K⁺ was associated with greater stroke mortality.3 The association was strongest for African-American men: a fourfold risk of death among those with the lowest K⁺ intake vs those with the highest dietary intake. Similar findings between dietary K⁺ and risk of stroke were also seen in a follow-up of 43,738 health professionals.4 Like NHANES I, the association was strongest in hypertensive men. The Nurses’ Health Study of 85,764 women also found an increased risk of stroke with low dietary K⁺.5

Adding to epidemiologic data, basic physiologic studies6 support …