Maintaining cognitive health as we age is a growing concern, and research increasingly points to the significant role of diet. A new study published in JAMA Neurology suggests that adhering to several healthy dietary patterns—particularly the Dietary Approaches to Stop Hypertension (DASH) diet—is associated with better cognitive function and a reduced risk of cognitive decline. This research builds upon existing evidence indicating that specific eating habits can positively influence brain health and promote healthy aging.
While the connection between diet and cognitive well-being isn’t fully understood, the latest findings offer valuable insights. Researchers acknowledge that discrepancies in previous studies may stem from variations in study design, participant demographics, and how dietary intake and cognitive function are measured. The extended preclinical phase of dementia, which can influence behavior and memory, also presents challenges in accurately assessing dietary impact.
The study, conducted by Hui Chen, PhD, from the department of nutrition at Harvard T.H. Chan School of Public Health, and colleagues, analyzed data collected between 1986 and 2017 from three large-scale studies: the Nurses’ Health Study, Nurses’ Health Study II, and Health Professionals Follow-Up Study. This comprehensive dataset allowed researchers to evaluate the impact of six distinct dietary patterns on both subjective cognitive decline (SCD) and objective cognitive function. The six diets examined included the DASH-style diet, the Healthful Plant-Based Diet Index (hPDI), the Alternate Healthy Eating Index 2010 (AHEI-2010), the Planetary Health Diet Index (PHDI), and two reversed empirical dietary indices focusing on hyperinsulinemia (rEDIH) and inflammatory patterns (rEDIP).
Researchers assessed SCD through self-reported questionnaires focusing on perceived changes in memory and attention. Objective cognitive function was measured using telephone-based assessments within the Nurses’ Health Study. The study cohort comprised 159,347 individuals, with a mean age of 44 years and a predominantly female representation (82.6%).
The results indicated that greater adherence to all six dietary patterns was linked to a decreased risk of SCD. Notably, the DASH-style diet demonstrated the most substantial effect, reducing the risk by 41% (RR = 0.59; 95% CI, 0.57-0.62). Following the DASH diet, the hPDI (RR = 0.76; 95% CI, 0.65-0.85), rEDIH (RR = 0.76; 95% CI, 0.73-0.8), PHDI (RR = 0.8; 95% CI, 0.75-0.86), AHEI-2010 (RR = 0.84; 95% CI, 0.8-0.89), and rEDIP (RR = 0.89; 95% CI, 0.85-0.93) also showed protective associations.
The DASH-style diet also exhibited the strongest correlation with improved cognitive function, showing a mean z score difference of 0.05 (95% CI, 0.02-0.09). Specific food groups were identified as particularly beneficial, including leafy green vegetables, yellow and other vegetables, fruits, fish, wine, salad dressing, and tea. Conversely, higher consumption of fried potatoes, red and processed meats, sugary drinks, eggs, nuts, and seeds was associated with poorer cognitive outcomes.
The researchers suggest that the benefits of the DASH diet may be linked to its impact on blood pressure control, aligning with previous research highlighting the cognitive advantages of maintaining healthy blood pressure. They also noted that the associations observed with other diets, such as rEDIH and rEDIP, likely reflect the roles of insulin and inflammatory pathways in cognitive health.
The study authors acknowledge certain limitations, including the reliance on self-reported SCD data, which may be subject to individual perceptions and reporting biases. The study population was primarily composed of white, highly educated health professionals, potentially limiting the generalizability of the findings to more diverse populations. Despite these limitations, the data strongly support the importance of prioritizing healthy eating as a proactive strategy for maintaining brain health throughout midlife.
This research underscores the potential for dietary interventions to mitigate the risk of cognitive decline. Further investigation is needed to fully elucidate the underlying mechanisms and to develop targeted nutritional strategies for promoting optimal brain health. Future studies should also focus on diverse populations to confirm these findings and ensure their broad applicability.
Source: Chen H, et al. JAMA Neurol. 2026;doi:10.1001/jamaneurol.2026.0062.
Disclaimer: This article is for informational purposes only and should not be considered medical advice. Please consult with a qualified healthcare professional for personalized guidance on diet and cognitive health.
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