Abstract P202: The Effects of Sodium (Na) Reduction and the Dash Diet on Ambulatory Blood Pressure in Black and Non-Black Individuals: Results From the DASH-Na Trial

Abstract

Background: Black individuals compared to White individuals tend to have higher nighttime BP. It has been hypothesized that lifestyle changes will reduce and potentially eliminate this disparity. Objectives: To determine the effect of reduced Na and the DASH diet, alone and combined, on ambulatory blood pressure (ABP) in Blacks (B) and Non-Blacks (NB, mostly white). Methods: Participants (n=335, 58% B) were randomly assigned to eat a control diet or the DASH diet. On their assigned diet, each participant had three, randomly ordered, 30d feeding periods with different Na levels (low, medium, and high). ABP was measured at the end of each period. Results: Before feeding, mean office SBP was similar in B and NB (135.5 and 134.5 mmHg, respectively). On the reference diet (control diet with high Na), daytime and nighttime SBP were higher in B than NB adults (Table). Compared to the ref diet, reducing Na and consuming the DASH diet, alone and combined, substantially lowered daytime and nighttime systolic ABP in Black and Non-Black individuals. The DASH diet combined with low Na reduced daytime SBP in B and NB with no significant B-NB difference, i.e. no racial disparity in daytime SBP; otherwise, B-NB differences were present in daytime SBP for Na reduction alone and DASH diet alone. For nighttime SBP, there was a consistent pattern such that Na reduction alone, DASH diet alone, and the DASH diet with low Na reduced nighttime SBP in B and NB, but in each case, B had significantly higher nighttime SBP levels than NB. For DBP, Na reduction alone, DASH diet alone, and combined DASH with low Na reduced daytime and nighttime BP in B and NB, but significant B-NB differences persisted (data not shown). Conclusions: Reducing dietary Na and consuming the DASH diet, alone and combined, substantially lowered ABP in Black and Non-Black individuals. However, racial disparities in ABP mostly persisted. These results highlight the importance of implementing both the DASH diet and Na reduction as a means to reduce BP throughout the day, regardless of racial background.