Published in:
01-06-2020 | Original Article
High dietary sodium augments vascular tone and attenuates low-flow mediated constriction in salt-resistant adults
Published in: European Journal of Applied Physiology | Issue 6/2020
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Introduction
Low-flow mediated constriction (L-FMC) has emerged as a valuable and complementary measure of flow-mediated dilation (FMD) for assessing endothelial function non-invasively. High dietary sodium has been shown to impair FMD independent of changes in blood pressure (BP), but its effects on L-FMC are unknown.
Purpose
To test the hypothesis that high dietary sodium would attenuate brachial artery L-FMC in salt-resistant adults.
Methods
Fifteen healthy, normotensive adults (29 ± 6 years) participated in a controlled feeding study. Following a run-in diet, participants completed a 7-day low sodium (LS; 20 mmol sodium/day) and 7-day high sodium (HS; 300 mmol sodium/day) diet in randomized order. On the last day of each diet, 24 h urine was collected and assessments of 24 h ambulatory BP and L-FMC were performed. Salt-resistance was defined as a change in 24 h ambulatory mean arterial pressure (MAP) between the LS and HS diets of ≤ 5 mmHg. Resting vascular tone and L-FMC were calculated from ultrasound-derived arterial diameters.
Results
High dietary sodium increased serum sodium and urinary sodium excretion (p < 0.001 for both), but 24 h MAP was unchanged (p = 0.16) by design. High dietary sodium augmented vascular tone (LS: 91 ± 23%, HS: 125 ± 56%, p = 0.01) and attenuated L-FMC (LS: − 0.58 ± 0.99%, HS: 0.17 ± 1.23%, p = 0.008).
Conclusion
These findings in salt-resistant adults provide additional evidence that dietary sodium has adverse vascular effects independent of changes in BP.