Volume 90, Issue 1, July (2003), pp. 53-60 © The Author 2003
doi:10.1079/BJN2003861

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The effect of low-dose potassium supplementation on blood pressure in apparently healthy volunteers

Donald J. Naismith¹, Alessandro Braschi^1
1Department of Nutrition and Dietetics, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 8WD, , UK

 (Received 18 July 2002–Revised 5 February 2003–Accepted 11 February 2003)

Epidemiological and clinical trials suggest an inverse relationship between dietary K intake and blood pressure (BP). Most trials however have been of short duration, the dose of K was high, and the results have been conflicting. The aim of the present study was to evaluate the effect on BP of a low-dose supplementation (24 mmol/d) for an extended period. A double-blind placebo-controlled trial was conducted on fifty-nine volunteers, randomly assigned to receive 24 mmol slow-release KCl/d (n 30) or a placebo (n 29). Measures of BP, anthropometric characteristics and urine analysis for electrolytes were recorded during a 1-week baseline period. Supplementation was for 6 weeks during which BP and changes in weight were assessed and a second 24 h urine collection made. The primary outcome was the change in mean arterial pressure (MAP); systolic BP (SBP) and diastolic BP (DBP) were secondary outcomes. After 6 weeks of supplementation MAP was reduced by 7·01 (95 % CI −9·12, −4·89; P<0·001) mmHg, SBP was reduced by 7·60 (95 % CI −10·46, −4·73; P<0·001) mmHg and DBP was reduced by 6·46 (95 % CI −8·74, −4·19; P<0·001) mmHg. The reduction in MAP was positively associated with baseline urinary Na:K (P<0·034). A low daily dietary supplement of K, equivalent to the content of five portions of fresh fruits and vegetables, induced a substantial reduction in MAP, similar in effect to single-drug therapy for hypertension.

Keywords:
Blood pressure, Potassium, Clinical trials, Diet

Abbreviations:
BP, blood pressure, DASH, Dietary Approaches to Stop Hypertension, DBP, diastolic blood pressure, MAP, mean arterial pressure, SBP, systolic blood pressure