Effects of Diet and Sodium Reduction on Cardiac Injury, Strain, and Inflammation: The DASH-Sodium Trial.

backgroundThe DASH (Dietary Approaches to Stop Hypertension) diet has been determined to have beneficial effects on cardiac biomarkers. The effects of sodium reduction on cardiac biomarkers, alone or combined with the DASH diet, are unknown.

objectivesThe purpose of this study was to determine the effects of sodium reduction and the DASH diet, alone or combined, on biomarkers of cardiac injury, strain, and inflammation.

methodsDASH-Sodium was a controlled feeding study in adults with systolic blood pressure (BP) 120 to 159 mm Hg and diastolic BP 80 to 95 mm Hg, randomly assigned to the DASH diet or a control diet. On their assigned diet, participants consumed each of three sodium levels for 4 weeks. Body weight was kept constant. At the 2,100 kcal level, the 3 sodium levels were low (50 mmol/day), medium (100 mmol/day), and high (150 mmol/day). Outcomes were 3 cardiac biomarkers: high-sensitivity cardiac troponin I (hs-cTnI) (measure of cardiac injury), N-terminal pro-B-type natriuretic peptide (NT-proBNP) (measure of strain), and high-sensitivity C-reactive protein (hs-CRP) (measure of inflammation), collected at baseline and at the end of each feeding period.

resultsOf the original 412 participants, the mean age was 48 years; 56% were women, and 56% were Black. Mean baseline systolic/diastolic BP was 135/86 mm Hg. DASH (vs. control) reduced hs-cTnI by 18% (95% confidence interval [CI]: -27% to -7%) and hs-CRP by 13% (95% CI: -24% to -1%), but not NT-proBNP. In contrast, lowering sodium from high to low levels reduced NT-proBNP independently of diet (19%; 95% CI: -24% to -14%), but did not alter hs-cTnI and mildly increased hs-CRP (9%; 95% CI: 0.4% to 18%). Combining DASH with sodium reduction lowered hs-cTnI by 20% (95% CI: -31% to -7%) and NT-proBNP by 23% (95% CI: -32% to -12%), whereas hs-CRP was not significantly changed (-7%; 95% CI: -22% to 9%) compared with the high sodium-control diet.

conclusionsCombining a DASH dietary pattern with sodium reduction can lower 2 distinct mechanisms of subclinical cardiac damage: injury and strain, whereas DASH alone reduced inflammation. (Dietary Patterns, Sodium Intake and Blood Pressure [DASH - Sodium]; NCT00000608).