New Delhi: Greater adherence to healthy diets during midlife—particularly the Dietary Approaches to Stop Hypertension—may help reduce the risk of cognitive decline and support better brain function in later years, according to a new study.

The findings, published in JAMA Neurology, indicate that the benefits of a healthy diet are most pronounced when followed between the ages of 45 and 54.

The DASH diet, widely regarded as heart-healthy, emphasises fruits, vegetables, whole grains and low-fat dairy products, while encouraging fish and poultry and limiting salt and red meat.

Researchers from Harvard University and Zhejiang University analysed data from over 1.5 lakh participants drawn from long-term studies including the Nurses' Health Study and the Health Professionals Follow-Up Study.

The study examined six dietary patterns, including the Healthful Plant-Based Diet Index (hPDI) and the Planetary Health Diet Index (PHDI).

The results showed that higher adherence to healthy diets was associated with a lower risk of subjective cognitive decline and improved cognitive performance. Among the diets studied, the DASH diet showed the strongest association, followed by hPDI and other indices linked to lower insulin levels and reduced inflammation.

Hyperinsulinemia—characterised by high insulin levels in the blood and often linked to type 2 diabetes—was identified as a factor influencing cognitive health.

The study also highlighted that diets rich in vegetables and fish, along with reduced consumption of red and processed meats, were associated with better cognitive outcomes.

Researchers noted that adopting healthy eating habits in midlife could play a key role in preserving cognitive health and reducing the risk of decline in later years.