In this ambulatory-monitoring analysis of the DASH-Sodium feeding trial (335 participants, 58% Black), the DASH diet combined with low sodium lowered awake systolic pressure by 9.0 mmHg in Black and 7.5 mmHg in non-Black participants versus a control diet high in sodium. Asleep systolic fell 8.0 and 7.4 mmHg respectively. Both interventions worked alone and together, yet sleeping pressure stayed higher in Black participants (115.2 vs 112.5 mmHg on DASH with low sodium).
The effect sizes rival a first-line antihypertensive drug, delivered through food alone, and the benefit held during sleep, when nocturnal pressure predicts cardiovascular events better than clinic readings do. The finding that Black and non-Black adults responded similarly matters: it counters any suggestion that dietary approaches work less well in a group carrying a higher hypertension burden. The persistent nighttime gap suggests that diet is necessary but not sufficient to close disparities, pointing toward other contributors such as sleep quality, stress physiology, or social and environmental exposures. Caveats are real. These were controlled 30-day feeding periods with all food provided, so real-world adherence will deliver smaller effects, and the trial measured blood pressure rather than strokes or deaths. Race here is self-reported and a proxy for many unmeasured factors. Overall this is confirmatory rather than paradigm-shifting, but it strengthens the evidence that lowering sodium and eating a DASH-style pattern reduce 24-hour blood pressure, including overnight, in diverse adults.