Thirty-nine healthy men and women supplemented their usual diet with 60 mmol of potassium chloride (about 2.3 g of potassium) per 70 kg of body weight per day for 3 days, while 35 others maintained their usual potassium intake. Potassium supplementation significantly decreased platelet reactivity, as determined by an increase in the concentration of ADP needed to produce 50% of the maximal initial rate of platelet aggregation.

Comment: High potassium intake has been shown to reduce blood pressure in people with hypertension. In addition, observational studies have found that increasing potassium intake is associated with lower risk of stroke, even after adjustment for blood pressure. Thus, potassium may help prevent stroke both by lowering blood pressure and by another, as yet unidentified, mechanism. Drugs that inhibit platelet aggregation, such as aspirin and clopidogrel bisulfate (Plavix) are known to reduce the risk of stroke, so it is possible that inhibition of platelet aggregation is the other mechanism by which potassium prevent strokes. Good food sources of potassium include fruits (particularly bananas and oranges), vegetables, legumes, and potatoes (with the skin).

Kimura M, et al. Potassium chloride supplementation diminishes platelet reactivity in humans. Hypertension 2004;44:969-973.