Dietary Inflammatory Index and Cognitive Function: Findings from a Cross-Sectional Study in Obese Chinese Township Population from 45 to 75 Years

Abstract

Background and Objective

Cognitive dysfunction is highly prevalent in obese people, and food is a key factor in obesity, and dietary inflammatory index (DII) can reflect whether diet has anti-inflammatory or pro-inflammatory potential. In addition, dietary fatty acid consumption is linked to inflammation, obesity, and cognitive impairment. Erythrocyte membrane fatty acids can reflect dietary fatty acid intake. Our hypothesis was that erythrocyte membrane fatty acids might have a significant impact on the relationship between DII and cognition in obese individuals, and we designed experiments to test the hypothesis.

Methods

In three villages in Beijing, we collected 579 respondents from individuals 45 to 75 years old and categorized them by body mass index. The Montreal Cognitive Assessment (MoCA) score and DII score was calculated and gas chromatography was used to measure the proportion of erythrocyte membrane fatty acids. The relationship between the DII score and cognition was examined using multiple linear regression and binary logistic regression. Mediation analysis can help to understand the causal chain between variables, deeply explore the internal relationship and mechanism of action between variables. So a multiple chain mediation model was developed to investigate the mediating factors between the DII score and cognitive association.

Results

According to adjusted linear regression, higher DII scores were linked to lower MoCA scores in the obese group. The negative correlation between DII score and cognitive function score remains in binary linear regression. We discovered through mediation analysis that erythrocyte membrane fatty acids mediate the detrimental link between DII and cognitive function in obese individuals.

Conclusion

We propose that higher DII scores in obese people are associated with a decline in cognitive function. In addition, this effect might be mediated via the fatty acids in the erythrocyte membrane.

Keywords:

• mild cognitive impairment
• dietary inflammatory index
• obesity
• fatty acids
• chain mediation effect

Abbreviations

DII, dietary inflammatory index; E-DII, energy-adjusted dietary inflammatory index; MCI, mild cognitive impairment; AD, Alzheimer’s diseases; MoCA, Montreal cognitive assessment; DSST, digit symbol substitution test; AF, animal fluency; OB, obese group; NM, normal weight group; BMI, body mass index; WHR, waist-hip ratios; C15:0, pentadecanoic acid; C16:0, palmitic acid; C23:0, 1-tricosanoic acid; C24:0, lignoceric acid; SFA, saturated fatty acids; OCFAs, odd-chain saturated fatty acids; ECFAs, even-chain saturated fatty acids; C15:1, ginkgolic acid; MUFA, monounsaturated fatty acids; n-6, omega-6 fatty acids; n-3, omega-3 fatty acids C20:4 n-6, arachidonic acid; PUFA, polyunsaturated fatty acids; TC, total cholesterol; TG, total triglyceride; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; FBG, fasting blood glucose; ApoE, apolipoprotein E; 5-HT, serotonin; TLR4, toll-like receptor 4; LPS, lipopolysaccharide; IL-6, interleukin-6; IFN-γ, interferon gamma; CRP, C-reactive protein; FFQ, food frequency questionnaire; NOX, NADPH oxidase; ORs, odds ratio; 95% CI, 95% confidence intervals; Mg, magnesium; Fe, ferrum; Zn, zinc; Se, selenium.

Data Sharing Statement

The research article data used to support the findings of this study are available from the corresponding author upon request.

Ethics Approval

The study was conducted in accordance with the Declaration of Helsinki, and approved by the Ethics Review Board of Capital Medical University (Z2019SY011).

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work. All authors have read and approved the final submitted manuscript.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

This research was funded by the National Natural Science Foundation of China, grant number (81773406 and 82373556).