Acute dietary salt loading impairs endothelial‐dependent dilation in normotensive‐salt resistant adults

Abstract

In humans, the effects of salt consumption on endothelial function have not been separated from the effects on blood pressure (BP). We sought to determine whether acute salt loading adversely affects endothelial function in normotensive salt‐resistant individuals. We hypothesized that brachial artery flow‐mediated dilation (FMD) would be impaired during a high salt diet in the absence of a change in BP. Fourteen healthy adults with salt‐resistant BP were studied (9M,5F; age 33±2.4 years). After a control run‐in diet, subjects were randomized to a 7 day high salt (HS) (350 mmol/day) and a 7 day low salt (LS) (20 mmol/day) diet (controlled feeding study). Salt‐resistant BP was defined as a change in 24 hour mean BP of ≤ 5 mmHg from the LS to the HS diet. FMD was measured in each subject on the last day of each diet. 24 hour mean BP was unchanged between the LS and the HS diet (LS: 85±1, HS: 85±2 mmHg). Sodium excretion significantly increased during the HS diet (LS: 29±9, HS: 231±16 mmol/24hr, p < 0.05). FMD was significantly impaired on the HS diet (LS: 10.3±0.9, HS: 7.3±0.7%, p < 0.05). These data suggest that in normotensive salt‐resistant adults, a high salt diet impairs endothelial‐dependent dilation independent of changes in arterial BP.Supported by 2 P20 RR016472‐11 and HL104106.