Modified DASH Diet Lowers Blood Pressure via Sodium Reduction: DASH4D Trial

Adults with type 2 diabetes and hypertension have an increased risk for cardiovascular events because of chronic blood pressure elevation. Although lifestyle changes and pharmacologic therapy are the cornerstone of management, little evidence exists from feeding studies determining the effect of dietary changes alone, independent of weight loss, on blood pressure in these patients. The original DASH diet showed blood pressure benefit in the general population, but its effects had not been formally optimized or tested for individuals with type 2 diabetes—who tend to need individualized macronutrient needs and who are frequently on multiple medications.

The DASH4D trial was intended to bridge this gap by comparing a version of the DASH diet tailored for patients with type 2 diabetes lower in carbs, higher in monounsaturated fats, and containing less potassium with controlled sodium intake.

The DASH4D trial was a 4-period randomized crossover feeding trial at a community-based center from June 2021 through June 2024, with final data analysis in November 2024. The research recruited 102 type 2 diabetes adults, systolic blood pressure of 120–159 mm Hg, and diastolic blood pressure below 100 mm Hg. The subjects were supplied with all their meals, asked not to eat any food outside the research, and their weight kept constant during the research.Every subject was put on four different diets in a random sequence, each for five weeks: DASH4D diet low sodium, DASH4D diet high sodium, Comparison (typical US) diet with reduced sodium, Reference diet with increased sodium (used as comparison).

The main outcome was end-of-period systolic blood pressure, with secondary outcome diastolic blood pressure.

Key Findings

• 85 of the 102 enrolled participants (83.3%) completed all four diet phases.

• Participants' average age was 66 years, with 66% being women.

• Racial composition: 87% Black, 6% White, 6% Asian, 2% Hispanic.

• 66% of participants were on two or more antihypertensive medications.

• Baseline mean blood pressure was 135/75 mm Hg.

• The DASH4D low-sodium diet lowered systolic BP by 4.6 mm Hg (95% CI, 7.2 to 2.0; P < .001) in comparison with the US diet with high sodium.

• Diastolic BP decreased by 2.3 mm Hg (95% CI, 3.7 to 0.9) using the DASH4D low-sodium diet.

• The majority of the decreases in blood pressure took place during the initial 3 weeks of every dietary period.

• Sodium reduction was more potent on blood pressure compared to the DASH4D diet alone.

• Adverse events were uncommon during all periods of diet.

This trial establishes that sodium reduction with a DASH4D diet produces clinically significant blood pressure reductions in adults with type 2 diabetes, most of whom were receiving multiple antihypertensive medications. These results highlight the significance of dietary sodium restriction and endorse expanded use of formal dietary intervention as part of multidisciplinary hypertension treatment within diabetes care.

Reference:

Pilla SJ, Yeh H, Mitchell CM, et al. Dietary Patterns, Sodium Reduction, and Blood Pressure in Type 2 Diabetes: The DASH4D Randomized Clinical Trial. JAMA Intern Med. Published online June 09, 2025. doi:10.1001/jamainternmed.2025.1580