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

• Published in: British journal of nutrition Vol. 104; no. 12; pp. 1839 - 1847
• Main Authors: Berry, Sarah E., Mulla, Umme Z., Chowienczyk, Philip J., Sanders, Thomas A. B.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 28.12.2010
• Subjects: Adult; Aged; Antihypertensive Agents - analysis; Antihypertensive Agents - pharmacology; antihypertensive effect; Arterial stiffness; arteries; Biological and medical sciences; Blood pressure; Body weight; C-reactive protein; Cardiovascular Diseases - prevention & control; Circulatory system; Clinical outcomes; Clinical trials; Cross-Over Studies; Diet; diet-related diseases; dietary mineral supplements; dietary minerals; Dietary Supplements; Endothelial function; endothelium; Excretion; experimental diets; Feeding. Feeding behavior; Female; food intake; Fruit - chemistry; Fruit and vegetables; Fruits; fruits (food); Fundamental and applied biological sciences. Psychology; hemodynamics; Human and Clinical Nutrition; human diseases; Humans; Hypertension; Hypertension - diet therapy; Hypertension - epidemiology; isoprostane; Isoprostanes; Lipids; Male; men; Middle Aged; nutrient intake; Nutrition research; nutritional intervention; Potassium; Potassium - analysis; Potassium - pharmacology; randomized clinical trials; Risk Factors; United Kingdom - epidemiology; Vegetables; Vegetables - chemistry; Vertebrates: anatomy and physiology, studies on body, several organs or systems; women; Young Adult; United Kingdom; Isoprostanes; Fruit and vegetables; Blood pressure; Endothelial function; Arterial stiffness; Potassium; Human; Hypertension; Vegetables; Fruit; Cardiovascular disease; Endothelium; Isoprostane; Vertebrata; Mammalia; Female; Early; Hemodynamics
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1017/S0007114510002904

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.