Project Summary
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resubmission in response to PAR-22-093. Prevention strategies, such as healthy sustainable
diets are critical and ase-related dementia (AD/ADRD) to have a population-wide
impact on reducing the risk of AD/ADRD for the growing aging population. Healthy diets are associated with slower
cognitive decline, reduced less AD pathology, and better cognitive resilience but the underlying
mechanisms of their protective effects are unknown. These diets are rich in antioxidant nutrients, flavonoids, and essential
fatty acids. Animal studies indicate the brain health benefits of these dietary factors via inflammatory and oxidative
pathways. Yet, our knowledge of how these dietary factors (diets, nutrients, and flavonoids) are related to mechanisms such
as neuroinflammation and brain oxidative stress, two important aspects of AD/ADRD pathogenesis and progression in
humans remains incomplete. Moreover, the diet association with emerging plasma AD and neurodegenerative biomarkers
is also not fully understood. This relationship can be studied to reflect the marker of AD pathology, degeneration, and brain-
reactive astrocytes among living persons. Disparities in AD are seen across race and sex and since relatively little is known
about diet and brain health in diverse populations, the link between diet and these biomarkers could be especially informative
in the underrepresented groups where autopsy rates are lower. The goal of this study is to examine the relationship between
diet, neuroinflammation, brain oxidative stress, and plasma neurodegenerative biomarkers in a diverse population, to
elucidate the link between diet and AD/ADRD. We will collect new data and leverage existing data capitalizing on four
harmonized, well-characterized, longitudinal community cohorts that enroll participants without dementia with high follow-
up rates, annual clinical evaluations, plasma collection, and brain tissue collection for those who come to autopsy. In the
first aim using autopsied brains, we will examine the relationship of diet over follow-up years with hippocampal and mid-
frontal activated microglia. Activated microglia is an early effect of neuroinflammation which enhances the risk of AD. In
the second aim, leveraging the data we assess the association of diet with oxidized lipids in the brain, which reflects oxidative
stress, another potential pathway for diet and AD. In the third aim, we examine the association of plasma phosphorylated-
glial fibrillary acidic protein (GFAP) with diet in our diverse sample
and also investigate race and sex differences to inform us if group-specific dietary approaches may impact these AD/ADRD
outcomes. Additionally, we examine if these plasma biomarkers are associated with activated microglia and/or oxidized
brain lipids. These data will advance the understanding of potential mechanisms linking diet with cognition and AD risk.
This study will also inform designs of population-specific diet interventions and insight into personalized nutrition
approaches in AD using brain health biomarkers.