The relationship between habitual sodium and potassium intake on vascular function in healthy, older adults
Date
2013
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Publisher
University of Delaware
Abstract
Hypertension (HTN) is a significant Public Health problem and the risk of an elevated blood pressure increases greatly with advancing age. Vascular dysfunction may precede HTN, characterized by an increase in inflammation, thrombosis, coagulation, proliferation, and constriction of the vasculature. Dietary factors can influence the development of HTN and the effects of a high sodium/low potassium diet on increasing blood pressure are well known. While these two minerals have been studied extensively in relation to HTN, it is becoming clearer that they may impact the vasculature prior to a change in blood pressure. Recently, the sodium:potassium excretion ratio has been used as a marker of cardiovascular health. The purpose of this study was to cross-sectionally examine the relationship between sodium and potassium intake and vascular function in a healthy, aged population free of hypertension. Thirty subjects (16 M, 14 F) with an average age of 62 ±1 years were recruited for this study. Subjects recorded their dietary intake for three days and collected their urine for 24 hours on the final day. Following the last day of self-collection, subjects came to the lab for a vascular assessment, including measurements of pulse wave analysis (PWA), pulse wave velocity (PWV), and brachial artery flow-mediated dilation (FMD). Urinary levels of sodium and potassium were determined. Dietary analysis revealed that subjects consumed a higher level of sodium (3,187 ±169 mg) and a lower level of potassium (3,120 ±177 mg) than recommended. The primary variable, the sodium:potassium excretion ratio did not correlate with any of the vascular measurements, nor did sodium or potassium intake, or sodium or potassium excretion. However, a higher sodium excretion was associated with higher systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP). When comparing men to women, there was a significant difference in augmentation index (AIx) that was to be expected given height differences. In conclusion, in this sample of healthy, aged adults, the sodium:potassium excretion ratio and thereby sodium and potassium intake, does not appear to have an effect on vascular function. However, as supported by previous literature, sodium excretion related to blood pressure. Therefore, because of the small sample size, more extensive research needs to be performed to examine the relationship between the sodium:potassium excretion ratio and vascular health measurements in a larger population with a greater range of sodium and potassium intakes.
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Keywords
Sodium, Potassium, Vascular function, Aging