Effects of a low-salt diet on flow-mediated dilatation in humans

• Published in: The American journal of clinical nutrition Vol. 89; no. 2; pp. 485 - 490
• Main Authors: Dickinson, Kacie M, Keogh, Jennifer B, Clifton, Peter M
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Clinical Nutrition 01.02.2009; American Society for Nutrition; American Society for Clinical Nutrition, Inc
• Subjects: administration & dosage; Adult; adults; Biological and medical sciences; blood; Blood Flow Velocity; Blood Flow Velocity - physiology; Blood Pressure; Blood Pressure - drug effects; Blood Pressure - physiology; Brachial Artery; Brachial Artery - diagnostic imaging; Brachial Artery - drug effects; Brachial Artery - physiopathology; cardioprotective effect; cardiovascular diseases; Cardiovascular Diseases - blood; Cardiovascular Diseases - prevention & control; cardiovascular system; Cross-Over Studies; Diet; diet therapy; Diet, Sodium-Restricted; disease prevention; drug effects; Endothelium, Vascular; Endothelium, Vascular - drug effects; Endothelium, Vascular - physiology; Feeding. Feeding behavior; Female; Food; food choices; food intake; Fundamental and applied biological sciences. Psychology; heart rate; human nutrition; Humans; low sodium diet; Male; mathematical models; metabolism; Middle Aged; Nutrition; Nutrition research; obesity; overweight; physiology; physiopathology; prevention & control; Pulsatile Flow; risk factors; Salt; Sodium; Sodium - metabolism; Sodium - urine; Sodium Chloride, Dietary; Sodium Chloride, Dietary - administration & dosage; Systole; systolic blood pressure; Ultrasonography; urine; Vasodilation; Vasodilation - drug effects; Vasodilation - physiology; Veins & arteries; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Human; Salt; Diet; Low; Feeding
• ISSN: 0002-9165; 1938-3207; 1938-3207
• DOI: 10.3945/ajcn.2008.26856

BACKGROUND: The effect of salt reduction on vascular function, assessed by brachial artery flow-mediated dilatation (FMD), is unknown. OBJECTIVE: Our aim was to compare the effects of a low-salt (LS; 50 mmol Na/d) diet with those of a usual-salt (US; 150 mmol Na/d) diet on FMD. DESIGN: This was a randomized crossover design in which 29 overweight and obese normotensive men and women followed an LS diet and a US diet for 2 wk. Both diets had similar potassium and saturated fat contents and were designed to ensure weight stability. After each intervention, FMD, pulse wave velocity, augmentation index, and blood pressure were measured. RESULTS: FMD was significantly greater (P = 0.001) with the LS diet (4.89 ± 2.42%) than with the US diet (3.37 ± 2.10%), systolic blood pressure was significantly (P = 0.02) lower with the LS diet (112 ± 11 mm Hg) than with the US diet (117 ± 13 mm Hg), and 24-h sodium excretion was significantly lower (P = 0.0001) with the LS diet (64.1 ± 41.3 mmol) than with the US diet (156.3 ± 56.7 mmol). There was no correlation between change in FMD and change in 24-h sodium excretion or change in blood pressure. No significant changes in augmentation index or pulse wave velocity were observed. CONCLUSIONS: Salt reduction improves endothelium-dependant vasodilation in normotensive subjects independently of the changes in measured resting clinic blood pressure. These findings suggest additional cardioprotective effects of salt reduction beyond blood pressure reduction. The trial is registered with the Australian and New Zealand Clinical Trials Registry (unique identifier: ANZCTR12607000381482; http://www.anzctr.org.au/trial_view.aspx?ID=82159).