Associations between dietary patterns and subclinical cardiac injury: An observational analysis from the DASH trial

Background: The DASH diet has been found to lower blood pressure (BP) and low-density lipoprotein cholesterol levels. Objective: To compare diets rich in fruits and vegetables with a typical American diet in their effects on cardiovascular injury in middle-aged adults without known preexisting cardiovascular disease (CVD). Design: Observational study based on a 3-group, parallel-design, randomized trial conducted in the United States from 1994 to 1996. (ClinicalTrials.gov: NCT00000544) Setting: 3 of the 4 original clinical trial centers. Participants: 326 of the original 459 trial participants with available stored specimens. Intervention: Participants were randomly assigned to 8 weeks of monitored feeding with a control diet typical of what many Americans eat; a diet rich in fruits and vegetables but otherwise similar to the control diet; or the DASH diet, which is rich in fruits, vegetables, low-fat dairy, and fiber and has low levels of saturated fat and cholesterol. Weight was kept constant throughout feeding. Measurements: Biomarkers collected at baseline and 8 weeks: high-sensitivity cardiac troponin I (hs-cTnI), N-terminal pro–B-type natriuretic peptide (NT-proBNP), and high-sensitivity C-reactive protein (hs-CRP). Results: The mean age of participants was 45.2 years, 48% were women, 49% were black, and mean baseline BP was 131/85 mm Hg. Compared with the control diet, the fruit-and-vegetable diet reduced hs-cTnI levels by 0.5 ng/L (95% CI, -0.9 to -0.2 ng/L) and NT-proBNP levels by 0.3 pg/mL (CI,-0.5 to -0.1 pg/mL). Compared with the control diet, the DASH diet reduced hs-cTnI levels by 0.5 ng/L (CI, -0.9 to -0.1 ng/L) and NT-proBNP levels by 0.3 pg/mL (CI, -0.5 to -0.04 pg/mL). Levels of hs-CRP did not differ among diets. None of the markers differed between the fruit-and-vegetable and DASH diets. Limitation: Short duration, missing specimens, and an inability to isolate the effects of specific foods or micronutrients. Conclusion: Diets rich in fruits and vegetables given over 8 weeks were associated with lower levels of markers for subclinical cardiac damage and strain in adults without preexisting CVD.