(PTFS08-05-25) The MIND Diet Association With Reduced Lower Microglial Inflammation in the Hippocampus: A Community-Based Neuropathologic Study

Objectives: Microglia are the innate immune cells of the brain. The reactive microglia is the first response to neuroinflammation, and potential risk for Alzheimer’s Disease (AD) and cognitive decline in aging. In animal studies, long-term exposure to a high-fat diet enhances reactive microglia and cognitive impairment. Healthy diets such as MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) are associated with slower cognitive decline among older persons. However, the link between diets with anti-inflammatory properties and microglial inflammation in human brains is unknown. This study examines the association of the MIND diet with microglia in the hippocampus.

Methods: Analyses included 237 autopsied participants (age at death = 91.2 ± 6.1 years, 72% females) of Rush Memory and Aging Project, a prospective clinical-neuropathological study enrolling persons without known dementia, with hippocampal microglia data and complete dietary data from an average of 7.2 (± 4.4) years. The microglia burden in the mid-hippocampus and anterior hippocampus was quantified using stereology. [Based on cellular morphology,] we counted the number of total microglia and reactive microglia (stages 2 and 3), which were defined as having hypertrophic/amoeboid morphology. The mean MIND diet score (range 0-15, higher score indicate better diet) was computed from multiple food frequency questionnaires obtained during follow-up.

Results: A higher MIND diet score during the follow-up before death was associated with fewer reactive microglia (i.e., less neuroinflammation) in the hippocampus when controlled for age at death, sex, education, calories, and AD pathology (β= -0.035, (SE=0.02, p = 0.045). MIND diet was not associated with total microglia (β= -4.88, (SE=3.08, p = 0.114)). No individual dietary component (green leafy vegetables, fish, other vegetables, berries, fried foods, pastries, and sweets) was associated with microglia.

Conclusions: The MIND diet may reduce microglial inflammation in the hippocampus. Further studies are needed to investigate if the diet’s role in lowering the overall neuroinflammatory response explains the association of diet and cognitive health in the older persons.

Funding Sources: National Institute on Aging, National Institutes of Health, grant numbers: R01AG085483, R01AG017917, K01AG075177, and R01AG067482.