Abstract Body: Introduction
Evidence is limited on the cognitive benefits of the Mediterranean-DASH Intervention for Neurodegenerative Delay(MIND) diet and biological mechanism for middle-age adults. We examined the longitudinal association of MIND diet with cognitive change over time and whether the association was mediated by reduced inflammation.
Hypothesis
A higher MIND diet score, indicating better adherence to the dietary pattern, was associated with slower cognitive decline, and inflammation—measured by circulating inflammatory biomarkers—mediated the association.
Methods
This study included data from 3,515 participants of the 2013 Health Care and Nutrition Survey (HCNS), a subsample of the Health and Retirement Study, who were over 50 years of age, were without probable dementia at the baseline in 2012, and had self-reported cognitive measures between 2012 and 2020, MIND diet score, and key demographics. Inflammatory biomarkers included C-reactive protein (CRP), tumor necrosis factor receptor (TNFR1), and Insulin-like growth factor 1 (IGF-1). Change in cognition were estimated using linear mixed effects models. All models were adjusted for age, sex, race/ethnicity, educational attainment, household income, and presence of APOE e4 allele.
Results
Over half of the respondents were aged 65 years and older (51.7%) and female (54.7%). At baseline, compared to the low tertile, higher adherence to MIND diet was associated with better cognitive score [middle tertile: β(SE)=0.41(0.12); high tertile: β(SE)=0.66 (0.16), p<0.001], lower levels of CRP (p<0.001) and TNFR1 (p<0.001), and higher level of IGF1 (p<0.001); higher TNFR1 was associated with worse cognitive scores [β(SE)=-0.038(.17), p<0.029]. TNFR1 mediated 16.02% of the total effect of the MIND diet on cognitive function (indirect β = 0.11, 95% CI [0.08, 0.15]). During the 8-year follow-up, participants in the higher tertile of MIND diet had a slower rate of cognitive decline over time compared to those in the low tertile [low: β(SE)=-0.24(0.023); middle: β(SE)=-0.19(0.023); high: β(SE)=-0.11 (0.028)], p<0.001. The association between MIND diet and cognitive change was attenuated—7.90% for the high tertile—after including TNFR1.
Conclusions
Following a healthy MIND dietary pattern at middle-age can help slow down cognitive decline, which occurs at least partially through mitigating the TNFR1-related inflammation pathway.