In 892 older Singaporean adults tracked across 32 years (1993–2025), higher adherence to the DASH diet during midlife (ages 44–55) and early elderhood (ages 61–73) was independently associated with better verbal memory in late life (ages 68–82). Midlife DASH adherence linked to greater white matter volume in association tracts, while later-life adherence linked to lower white matter hyperintensity burden in the basal ganglia and periventricular regions, and lower cortical free-water signal — markers of reduced neurovascular and inflammatory damage. Mediation analyses showed white matter volume explained 12.3% of the midlife diet–memory association; cortical free water explained 12.5% of the later-life association. Critically, adults who improved their diet quality between midlife and elderhood showed better brain integrity than those with persistently poor diets.
This preprint, not yet peer-reviewed, offers unusually long diet-tracking data for a cognitive neuroscience study, lending it above-average credibility compared with shorter observational work. The finding that late-life dietary improvement still confers measurable brain benefit is practically significant — it challenges the assumption that the window for diet-driven neuroprotection closes at midlife. The DASH diet is already clinically recommended for blood pressure; this adds cognitive resilience to its evidence base. Limitations include the observational design (causality unproven), a single ethnicity (Singapore Chinese), and reliance on self-reported dietary recall. Effect sizes from mediation are modest, suggesting diet is one of many contributors. Nonetheless, the life-course design and multimodal MRI endpoints make this a substantive contribution to longevity-relevant nutrition research.