Association of Healthy Eating Index-2015 Total and Component Scores with Measures of Inflammation and Immune Activation in Healthy Adults.

Background: The Healthy Eating Index (HEI)-2015 measures diet quality and is associated with a lower risk of death from chronic disease. Dietary components may affect health via multiple mechanisms, including decreasing inflammation and affecting immune activation.

Objective: We hypothesized that the overall HEI-2015 score, or individual component scores, would be associated with altered inflammation and immune activation in healthy adults.

Methods: The association of HEI-2015 scores with 88 inflammation and immune activation markers was examined in 346 adults without diagnosed disease using general linear models to adjust for covariates, including visceral fat mass index (VFMI).

Results: The overall HEI-2015 score was inversely associated with plasma C-reactive protein (CRP) and leukocyte concentrations, which are markers of inflammation, but these associations lost statistical significance with adjustment for VFMI. However, even with VFMI adjustment, the total vegetable score was inversely associated with total lymphocyte concentration (β = -0.157 ± 0.052, P = 0.019) and with monocyte and neutrophil activation (e.g., classic monocyte CD11b β = -0.153 ± 0.055, P = 0.030; neutrophil CD11b β = -0.122 ± 0.051, P = 0.049). The refined grain score was inversely associated with percent NK-T cells (β =-0.171 ± 0.058, P = 0.037), IL-10 production by T cells (β = -0.204 ± 0.057, P = 0.0039), and positively associated with plasma soluble CD14 (β = 0.220 ± 0.059, P = 0.0041). The total dairy score was positively associated with production of multiple cytokines by lipopolysaccharide-stimulated peripheral blood mononuclear cells [e.g., interleukin (IL)-1β β = 0.182 ± 0.054, P = 0.0066].

Conclusions: Adjustment for VFMI decreased the association of HEI-2015 with inflammation, consistent with the known role of adiposity in mediating effects of poor diet on inflammation. This study also identified component scores associated with various aspects of immune activation that bear further study to clarify possible health benefits. This trial was registered at clinicaltrials.gov as NCT02367287.