The role of habitual potassium and sodium intake on vascular function in healthy adults
Date
2016
Authors
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Publisher
University of Delaware
Abstract
Cardiovascular disease (CVD) is the number one killer in U.S. Endothelial dysfunction is considered an underlying non-traditional risk factor for CVD. High sodium intake has been linked with incidents of hypertension and CVD while high potassium intake has been linked with lower incidence. Independent of blood pressure (BP), a high sodium intake has shown to cause endothelial dysfunction however this association has been predominantly under controlled conditions. Assessment of vascular function on a habitual diet remains to be investigated. Therefore, the aim of this study was to determine the relationship between habitual sodium and potassium intake on vascular function in healthy adults. We hypothesized that high potassium/low sodium diets would result in greater endothelial-dependent dilation as determined by brachial artery flow mediated dilation (FMD) and nitric oxide (NO)-mediated cutaneous vasodilation in response to local heating in healthy adults and second that low potassium/high sodium diets would have an improvement in cutaneous vasodilation in response to infusion of antioxidants compared to subjects with a higher potassium/lower sodium diet. Nine healthy subjects aged 28.8 ± 4 years completed the assessment of vascular function that included brachial artery FMD and cutaneous microvascular function while consuming their habitual diet. Subjects underwent 24-hr BP monitoring and collected their urine for 24 hours for analysis of sodium and potassium concentrations. Three-day diet records were used to assess habitual intake and a 24-hour recall was given the day of the study visit to compare to urinary sodium excretion. The 24-hour recall of sodium and potassium did not significantly correlate with 24-hour urinary excretion. Twenty-four BP monitoring revealed that all subjects were normotensive. The average brachial artery FMD was 6.24 ± 1.26%. However, there was no correlation between habitual sodium, potassium, or the ratio of sodium to potassium with FMD. In regards to microvascular function, there were no baseline or NO-mediated plateau differences between sites. However, there was a relationship between the NO plateau for the ascorbic acid site with sodium intake (R = 0.7650; P <0.05) suggesting that those individuals with a higher sodium intake were more responsive to ascorbic acid. However, no other relationship between sodium and potassium intake with vascular function was found. In conclusion, this study found that administration of ascorbic acid improved the NO-mediated plateau in those with a higher sodium intake suggesting a role for oxidative stress. However, no other relationship between sodium and potassium intake with vascular function was found.