Among 14,163 US adults with self-reported hypertension drawn from NHANES cycles 2003–2018, adherence to the DASH diet declined significantly — from 22.1% in 2003–2010 to 18.6% in 2011–2018 (adjusted OR 0.78; 95% CI 0.67–0.91). Mean DASH scores also fell (2.98 to 2.85). Sodium and total fat threshold attainment both worsened. Non-Hispanic Black adults, those with BMI ≥30, and adults with prior stroke showed the steepest adherence gaps.
The DASH diet has one of the strongest evidence bases for lowering blood pressure — typically reducing systolic BP by 8–14 mmHg — and is recommended by virtually every major cardiovascular guideline. The finding that adherence is deteriorating, not improving, despite decades of public-health messaging and refined dietary guidance is both striking and discouraging. It suggests that awareness campaigns alone are insufficient; structural barriers including food cost, access, and cultural acceptability likely dominate. The disparity among Black adults is particularly concerning given their disproportionate burden of hypertension-related stroke and kidney disease. Obesity further compounding non-adherence creates a compounding cardiovascular risk spiral. Limitations include reliance on self-reported dietary recall (subject to underreporting), self-reported hypertension status, and the observational design precluding causal inference. As a preprint posted on medRxiv and not yet peer-reviewed, these findings should be interpreted cautiously — methodological scrutiny may refine the estimates. Still, the trajectory is a clear signal that implementation science, not more evidence generation, is now the critical gap.