title: Increased potassium intake from fruit and vegetables or supplements does not lower blood pressure or improve vascular function in UK men and women with early hypertension: a randomised controlled trial.
abstract: K-rich fruit and vegetables may lower blood pressure (BP) and improve vascular function. A randomised controlled trial (ISRCTN50011192) with a cross-over design was conducted in free-living participants with early stages of hypertension (diastolic BP>80 and < 100 mmHg, not receiving BP-lowering medication) to test this hypothesis. Following a 3-week run-in period on a control diet, each subject completed four dietary 6-week dietary interventions (control+placebo capsules, an additional 20 or 40 mmol K(+)/d from fruit and vegetables or 40 mmol potassium citrate capsules/d) using a Latin square design with a washout period ≥ 5 weeks between the treatment periods. Out of fifty-seven subjects who were randomised, twenty-three male and twenty-five female participants completed the study; compliance to the intervention was corroborated by food intake records and increased urinary K(+) excretion; plasma lipids, vitamin C, folate and homocysteine concentrations, urinary Na excretion, and body weight remained were unchanged. On the control diet, mean ambulatory 24 h systolic/diastolic BP were 132·3 (sd 12·0)/81·9 ((SD) 7·9) mmHg, and changes (Bonferroni's adjusted 95 % CI) compared with the control on the diets providing 20 and 40 mmol K(+)/d as fruit and vegetables were 0·8 (- 3·5, 5·3)/0·8 (- 1·9, 3·5) and 1·7 (- 3·0, 5·3)/1·5 (- 1·5, 4·4), respectively, and were 1·8 (- 2·1, 5·8)/1·4 (- 1·6, 4·4) mmHg on the 40 mmol potassium citrate supplement, and were not statistically significant. Arterial stiffness, endothelial function, and urinary and plasma isoprostane and C-reactive protein (CRP) concentrations did not differ significantly between the diets. The present study provides no evidence to support dietary advice to increase K intake above usual UK intakes in the subjects with early stages of hypertension.
authors.affiliation: King's College London, UK.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Berry
authors.forename: Umme Z
authors.initials: UZ
authors.lastname: Mulla
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Chowienczyk
authors.forename: Thomas A B
authors.initials: TA
authors.lastname: Sanders
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000032:analysis / Q000494:pharmacology; D002318:Cardiovascular Diseases / Q000517:prevention & control; D018592:Cross-Over Studies; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D005638:Fruit / Q000737:chemistry*; D006801:Humans; D006973:Hypertension / Q000178:diet therapy* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000032:analysis / Q000494:pharmacology*; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology; D014675:Vegetables / Q000737:chemistry*; D055815:Young Adult
chemical_list: D000959:Antihypertensive Agents; D011188:Potassium