Healthy diets help maintain cognitive health

Adherence to healthy diets, such as the Dietary Approaches to Stop Hypertension (DASH) diet and those with lower hyperinsulinemia and inflammation potential, has been associated with a lower risk of subjective cognitive decline and better cognitive function in new research.

Researchers conducted a prospective cohort study based on the Nurses’ Health Study (NHS, 1986-2014), NHSII (1991-2017), and the Health Professionals Follow-Up Study (HPFS, 1986-2012). They identified a total of 159,347 adults (mean age 44.3 years, 82.6 percent female) with available data on diet and cognitive function.

Diet was evaluated using food frequency questionnaires completed every 4 years to capture habitual long-term dietary intake. Six dietary patterns were included, as follows: 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 the reversed empirical dietary indices for hyperinsulinemia (rEDIH) and inflammatory pattern (rEDIP).

The main outcome was subjective cognitive decline, assessed using seven questions on perceived cognitive changes. Cognitive function was objectively measured via telephone in the NHS.

In regression analyses, participants with greater adherence to all six dietary patterns had a reduced risk of subjective cognitive decline (SCD). The strongest association was observed for the DASH diet (90th vs 10th percentile of adherence: risk ratio [RR], 0.59, 95 percent confidence interval [CI], 0.57–0.62), followed by the hPDI (RR, 0.76, 95 percent CI, 0.65–0.85), rEDIH (RR, 0.76, 95 percent CI, 0.73–0.80), PHDI (RR, 0.80, 95 percent CI, 0.75–0.86), AHEI-2010 (RR, 0.84, 95 percent CI, 0.80–0.89), and rEDIP (RR, 0.89, 95 percent CI, 0.85–0.93). Higher DASH diet score at ages 45–54 years showed the strongest association with SCD.

Furthermore, Higher adherence to the DASH diet showed the most pronounced association with a higher objectively measured global cognition (90th vs 10th percentile of adherence: mean z score difference, 0.05, 95 percent CI, 0.02–0.09).

Among key food groups, higher intake of vegetable and fish and lower intake of red and processed meats intake were associated with better cognitive function.