Dietary Potassium Attenuates the Effects of Dietary Sodium on Vascular Function in Salt-Resistant Adults

Abstract

The influence of dietary sodium and potassium on blood pressure (BP) has been extensively studied, however their impact on endothelial function, particularly any interactive effects, has received less attention. The purpose of this study was to determine if dietary potassium can offset the deleterious effect of high dietary sodium on endothelial function independent of BP. Thirty-three adults with salt-resistant BP (16 M and 17 F; 27 ± 1 year) completed seven days each of the following diets in a random order: a moderate potassium/low sodium diet (65 mmol potassium/50 mmol sodium; MK/LS), a moderate potassium/high sodium diet (65mmol potassium/300 mmol sodium; MK/HS) and a high potassium/high sodium (120 mmol potassium/300 mmol sodium; HK/HS). On day seven of each diet, 24-h ambulatory BP and a urine collection were performed. Brachial artery flow-mediated dilation (FMD) was measured in response to reactive hyperemia. Between diets, 24-h BP was unchanged confirming salt resistance (p > 0.05). Sodium excretion increased on both HS diets compared to MK/LS (p < 0.05) and potassium excretion was increased on the HK diet compared to MK/LS and MK/HS (p < 0.05) confirming diet compliance. FMD was lower in MK/HS (5.4 ± 0.5%) compared to MK/LS (6.7 ± 0.5%; p < 0.05) and HK/HS (6.4 ± 0.5%), while there was no difference between the MK/LS and HK/HS diets (p > 0.05). These data suggest that dietary potassium provides vascular protection against the deleterious effects of high dietary sodium by restoring conduit artery function.

Mechanisms of Dietary Sodium-Induced Impairments in Endothelial Function and Potential Countermeasures

“…Sundhir and colleagues also observed a protective effect of potassium supplementation (2.1% potassium chloride or 2.1% potassium bicarbonate) against the vascular insult of sodium in Dahl rats; however, these findings appeared to be related to a direct effect of potassium on systolic BP [108]. Notably, in young, salt-resistant humans, a high-potassium diet (4700 mg/day) abolished the reduction in brachial artery FMD caused by a seven-day high-sodium diet with moderate potassium intake (2500 mg/day), despite no change in either laboratory-measured or 24-hr ambulatory BP [38]. Furthermore, added dietary potassium counteracts an acute sodium insult without changing BP, as the postprandial reduction in FMD following a single high-sodium meal containing only 117 mg of potassium was completely abolished when the high-sodium meal contained 1482 mg of potassium [43].…”

“…In a subset of subjects, nitroglycerin induced similar dilation of the brachial artery across both diets, providing evidence that the impairment occurred at the endothelium [37] and not the VSM cells. High dietary sodium-induced reductions in FMD have been found in multiple [30,38] but not all [27] studies. There is some evidence that the impact of a high-sodium diet on FMD is greater in men than women [39].…”

Association between Dietary Calcium and Potassium and Diabetic Retinopathy: A Cross-Sectional Retrospective Study

“…In addition, potassium was suggested to have an anti-inflammatory function by suppressing T-cell proliferation and inducing Foxp3+ cells expression [40]. Evidence supports the view point that dietary potassium has a protective effect on the endothelium, which may prevent vascular injury against oxidative stress [41,42].…”

Role of no table salt on hypertension and stroke based on large sample size from National Health and Nutrition Examination Survey database

“…2 ). Previous studies have revealed that potassium is an essential nutrient and the addition of a high potassium diet could reduce the blood pressure in people [ 30 , 31 ]. Also, some randomized controlled trials indicated that higher potassium intake could lower the blood pressure in those with hypertension [ 32 ].…”