Effect of Dietary Sodium Intake on Blood Pressure Variability

Abstract

PurposeStudies in rodents have demonstrated that increased dietary sodium intake elevates blood pressure variability (BPV), independent of changes in resting blood pressure. Clinical studies have shown that increased BPV independently contributes to target organ damage and cardiovascular events. However, the effects of high dietary sodium intake on BPV in young, normotensive adults remains unknown. Therefore, the purpose of this study was to test the hypothesis that increased dietary sodium intake alters BPV in young, healthy adults.MethodsFourteen healthy, normotensive adults (7M/7W; age: 25±4 yrs; BMI: 24.7±0.9 kg/m2, Mean‐±SEM) participated in a controlled feeding study that consisted of 10 days of either low‐(LS:1 g sodium/day), medium‐ (MS: 2.3 g sodium/day), or high‐sodium (HS: 7 g sodium/day) diets, in randomized order. The diets were separated by at least a month. Urinary sodium excretion was determined to ensure compliance on diets. Resting beat‐to‐beat BPV was assessed in the laboratory in the supine position for ten minutes. BPV was also derived from 24‐hour ambulatory blood pressure monitoring (ABPM) to assess BPV under free‐living conditions. BPV was calculated as the average real variability index (ARV; the average of the absolute differences between consecutive blood pressure measurements) and as standard deviation (SD).ResultsTwenty‐four‐hour urinary sodium excretion increased in a step‐wise manner from low, to the medium, to the high sodium diets (LS: 34±6 mmol/24 hours, MS: 93±9 mmol/24, HS:275±29 mmol/24 hours, p<0.05). Dietary sodium did not alter laboratory beat‐to‐beat systolic ARV (LS=2.2±0.2 mmHg, MS= 2.0±0.2 mmHg, HS= 2.1±0.2 mmHg, p>0.05) or 24h ABPM systolic ARV (LS=9.4±0.5 mmHg, MS= 9.9±0.4 mmHg, HS=10.3±0.7 mmHg, p>0.05). Dietary sodium also did not alter laboratory beat‐to‐beat systolic SD (LS= 5.4±0.5 mmHg, MS=5.1±0.3 mmHg, HS=5.8±0.6 mmHg, p>0.05) or 24h ABPM systolic SD (LS= 12.1±0.9 mmHg, MS= 13.9±0.7 mmHg, HS= 13.1±0.9 mmHg, p>0.05).ConclusionThese preliminary data suggest that 10 days of high dietary sodium intake does not alter systolic BPV in young, healthy adults.Support or Funding InformationNIH Grant 1RO1HL128388This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.