Effect of Dietary Approaches to Stop Hypertension (DASH) diet on blood pressure indices and urinary metabolites in children with overweight and obesity: an 8-week triple-blind randomized controlled trial.

Background: This study aimed to evaluate the effects of the Dietary Approaches to Stop Hypertension (DASH) diet on blood pressure (BP) indices and urinary metabolites in overweight and obese children over an 8-week period. Methods: In this triple-blind randomized controlled trial, 60 children (8-12 years) were assigned to a DASH or control group for 8-week. Urinary sodium (UNa), potassium (UK), creatinine, UNa-UK ratio, systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), mid-BP (MBP), mean proportional arterial pressure (MPAP), and pulse pressure were measured before and after the intervention. Twenty-four-hour UNa excretion and salt intake were estimated using the INTERSALT equation. Outcomes were analyzed using analysis of variance on an intention-to-treat basis. Results: The mean age and body mass index of participants were 11.8 ± 0.8 years (69% girls) and 25.9 ± 3.52 kg/m2, respectively. Fifty-eight children completed the study (29 per group). After 8-week, the DASH group showed significantly lower UNa (110 vs. 123 mmol/L), UNa-UK ratio (1.84 vs. 1.99 mmol/L), SBP (97.7 vs. 105 mmHg), DBP (68.9 vs. 64.6 mmHg), MBP (88.1 vs. 81.2 mmHg), MAP (81.6 vs. 75.6 mmHg), and MPAP (92.3 vs. 84.7 mmHg) compared with controls (P for all < 0.05). The mean change percent in UNa, UNa-UK ratio, SBP, MBP, MAP, and MPAP was significantly greater in the control group than in the DASH group (P for all < 0.05). Salt intake increased in the control group, but decreased in the DASH group (8.32 vs. -2.88 gr/day; P-value = 0.001). Conclusions: The DASH diet improved BP indices and urinary metabolites in overweight and obese children, suggesting its potential as a non-pharmacological intervention for hypertension management in pediatric populations. Trial Registration: Iranian Registry of Clinical Trials Identifier: IRCT20240623062229N1.