July 1, 2003British Journal Of Nutrition67 citationsOpen Access

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

Structured PICO

Does low-dose potassium supplementation (24 mmol/d) reduce blood pressure in apparently healthy volunteers?

Population

59 apparently healthy volunteers (aged 25-65 years) who completed the study, recruited from academic and postgraduate research staff. Mean age 44.5 (K group) and 41.7 (placebo group), predominantly European (83%). Key exclusion criteria: diabetes, cardiovascular diseases, renal diseases, use of anti-hypertensive drugs.

Intervention

Potassium chloride (KCl) 24 mmol/day, administered orally as one slow-release tablet containing 8 mmol KCl three times daily with meals for 6 weeks.

Comparator

Matching placebo (containing sorbitol and fructose) administered three times daily with meals for 6 weeks.

Outcome

Change in mean arterial pressure (MAP) after 6 weeks of supplementation.surrogate

A low daily dietary supplement of potassium (24 mmol/d) induced a substantial reduction in blood pressure in apparently healthy volunteers, comparable to the effect of single-drug therapy for hypertension.

Abstract

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.

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