DASH Diet Linked to Lower Subjective Cognitive Decline Risk
Key Clinical Summary
- In a prospective cohort of 159,347 US adults, higher adherence to 6 healthy dietary patterns was associated with lower risk of subjective cognitive decline (SCD).
- The Dietary Approaches to Stop Hypertension (DASH) diet showed the strongest association (RR, 0.59; 95% CI, 0.57–0.62; 90th vs 10th percentile).
- Greater DASH adherence was also linked to modestly higher objectively measured global cognition (mean z score difference, 0.05; 95% CI, 0.02–0.09).
A large prospective cohort study published in JAMA Neurology reports that greater adherence to several established healthy dietary patterns, particularly the Dietary Approaches to Stop Hypertension (DASH) diet, is associated with reduced subjective cognitive decline (SCD) and modestly better objective cognitive performance. The analysis included long-term data from 3 major US cohorts: the Nurses’ Health Study (NHS), NHSII, and the Health Professionals Follow-Up Study (HPFS).
Study Findings
Investigators evaluated 159,347 adults (mean [SD] age, 44.3 [9.3] years; 82.6% female) with available dietary and cognitive data. Six dietary pattern scores were examined: the Alternate Healthy Eating Index 2010 (AHEI-2010), the DASH diet score, the Healthful Plant-Based Diet Index (hPDI), the Planetary Health Diet Index (PHDI), and reversed empirical dietary indices for hyperinsulinemia (rEDIH) and inflammatory patterns (rEDIP).
Higher adherence to all 6 patterns was associated with lower SCD risk. The strongest association was observed for the DASH diet (risk ratio [RR], 0.59; 95% CI, 0.57–0.62; 90th vs 10th percentile), followed by hPDI (RR, 0.76; 95% CI, 0.65–0.85), rEDIH (RR, 0.76; 95% CI, 0.73–0.80), PHDI (RR, 0.80; 95% CI, 0.75–0.86), AHEI-2010 (RR, 0.84; 95% CI, 0.80–0.89), and rEDIP (RR, 0.89; 95% CI, 0.85–0.93).
Higher DASH adherence between ages 45 and 54 years showed the strongest association with later-life SCD in the HPFS and NHS. In the NHS, objective cognitive function measured by telephone demonstrated that greater DASH adherence was also correlated with higher global cognition scores (mean z score difference, 0.05; 95% CI, 0.02–0.09).
The study also found that higher vegetable and fish intake and lower red and processed meat intake were linked to better cognitive outcomes.
Clinical Implications
The data reinforce the potential cognitive benefits of dietary patterns already recommended for cardiometabolic health, particularly the DASH diet. The strong association with SCD—a patient-reported measure often considered an early marker of cognitive change—suggests that dietary modification during midlife, especially between ages 45 and 54 years, may be relevant for brain health. Although the observed improvement in objective global cognition was modest, it was directionally consistent with reduced SCD risk.
The findings underscore the potential importance of sustained adherence to healthy dietary patterns for maintaining long-term cognitive health, as reflected in both subjective and objective measures.
Expert Commentary
Because SCD is a self-reported measure, the findings “may be influenced by differences in health awareness or reporting tendencies, despite prior validation of this measure,” wrote Hui Chen, PhD, Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, and study coauthors. They also noted that the cohort consisted of predominantly White, highly educated health professionals, which may limit the study’s generalizability.
Still, the authors concluded that the results “support the importance of healthy eating as part of midlife brain-health strategies and motivate pragmatic and implementation research to translate these findings into scalable programs.”
