Background: Accumulating evidence suggests that dietary factors are associated with Alzheimer's disease, cognition, and brain health in older adults. It is however unclear whether inflammation explains this association.
Objective: To examine whether an inflammation-related nutrient pattern (INP) was associated with neuroimaging and cognitive measures of brain health.
Method: The current cross-sectional study included 330 non-demented elderly (mean age 79 years at MRI scan) participants in a multi-ethnic, community-based cohort study who had information on nutritional intake (estimated from food frequency questionnaire), circulating C-reactive protein and interleukin- 6 (measured by ELISA), MRI scans, and cognition. Diet and blood samples were collected approximately 5.3 years prior to the MRI and cognitive test visit. We used a reduced rank regression model to derive an INP based on 24 nutrients' relationship with CRP and interleukin-6. We examined the association of the INP with brain and cognitive measures using regression models adjusted for age, sex, race/ethnicity, education, caloric intake, APOE genotype, body mass index, and vascular burden, as well as intracranial volume for the brain MRI measures.
Results: The INP was characterized by low intake (effect loading <-0.15) of calcium, vitamins (D, E, A, B1, B2, B3, B5, B6), folate, Ω-3 poly-unsaturated fatty acids, and high intake (>0.15) of cholesterol. As designed, this INP was positively correlated with CRP (Pearson's r=0.25 p=0.005) and interleukin-6 (r=0.30, p<0.0001). Each unit increase in INP was associated with 36.8 cm3 (p=0.023) smaller total brain volume and 0.21 (p=0.038) lower visuospatial z-score. Mediation analysis showed that TGMV (b=0.002, p=0.003) was associated with visuospatial cognitive function, and there was a significant mediation effect by TGMV (indirect effect: -0.049, 95% CI: -0.1121 ~ -0.0131) for the association between INP and visuospatial cognitive score.
Conclusions: Among older adults, a diet with high inflammatory potential is associated with less favorable brain and cognitive health.