HONOLULU, HAWAII. Several studies have observed that low potassium levels are associated with a greater mortality from stroke. Now American researchers report that the incidence of stroke also increases with low potassium levels. Their study involved 5600 men and women over the age of 65 years who were free of stroke at enrollment in 1990-93. All participants underwent a thorough medical examination at baseline, completed a food frequency questionnaire and had blood serum potassium level determined.
After 4 to 8 years of follow-up a total of 473 strokes (404 ischemic) had occurred in the group. The
researchers found that participants on diuretics had a 2.5 times increased risk of stroke if their serum level of
potassium was below 4.1 mEq/L. The highest number of potassium-deficient individuals (71.9 per cent) was
found among those taking thiazide diuretics. Using potassium-sparing diuretics lowered the risk slightly
while taking potassium supplements with the diuretic brought it down to 1.4 times the risk of diuretic users
with a serum potassium level above 4.0 mEq/L. Participants who were not taking diuretics were found to
have a 50 per cent (1.5 times) increased risk of stroke if their dietary potassium intake was less than 2340
mg/day. Participants who were on diuretics and also had low potassium levels and atrial fibrillation had a 10
times greater risk of stroke than did diuretic users in normal sinus rhythm whose potassium levels were
above 4.0 mEq/L.
Editor's comment: This study clearly shows that an adequate potassium intake is a vital ingredient in stroke protection, especially for users of diuretics. Potassium is best obtained from the diet - tomato paste, beet greens, raisins, prunes, bananas, and sockeye salmon are all good sources.