DASH vs. Mediterranean diet on a salt restriction background in adults with high normal blood pressure or grade 1 hypertension: A randomized controlled trial

Background & aims: Non-pharmacological measures are recommended as the first-line treatment for individuals with high-normal blood pressure (BP) or mild hypertension. Studies directly comparing the BP effects of the Dietary Approaches to Stop Hypertension (DASH) vs. the Mediterranean diet (MedDiet) on a salt restriction background are currently lacking. Thus, our purpose was to assess the BP effects of a 3-month intensive dietary intervention implementing salt restriction either alone or in the context of the DASH, and the MedDiet compared to no/minimal intervention in adults with high normal BP or grade 1 hypertension. Methods: We randomly assigned never drug-treated individuals to a control group (CG, n = 60), a salt restriction group (SRG, n = 60), a DASH diet with salt restriction group (DDG, n = 60), or a MedDiet with salt restriction group (MDG, n = 60). The primary outcome was the attained office systolic BP difference among the randomized arms during follow-up. Results: A total of 240 patients were enrolled, while 204 (85%) completed the study. According to the intention-to-treat analysis, compared to the CG, office and 24 h ambulatory systolic and diastolic BP were reduced in all intervention groups. A greater reduction in the mean office systolic BP was observed in the MDG compared to all other study groups (MDG vs. CG: mean difference = -15.1 mmHg; MDG vs. SRG: mean difference = -7.5 mmHg, and MDG vs. DDG: mean difference = -3.2 mmHg, all P-values <0.001). The DDG and the MDG did not differ concerning the office diastolic BP and the 24 h ambulatory systolic and diastolic BP; however, both diets were more efficient in BP-lowering compared to the SRG. Conclusions: On a background of salt restriction, the MedDiet was superior in office systolic BP-lowering, but the DASH and MedDiet reduced BP to an extent higher than salt restriction alone. (c) 2023 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.