Association of Healthy Eating Index-2015 total and component scores with measures of inflammation and immune activation in healthy adults

Authors: Stephensen, Charles; Jiang, Xiaowen; Gale, Barbara; PEERSON, JANET - University Of California, Davis

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/3/2025
Publication Date: 1/7/2025
Citation: Stephensen, C.B., Jiang, X., Gale, B., Peerson, J.M. 2025. Association of Healthy Eating Index-2015 total and component scores with measures of inflammation and immune activation in healthy adults. Journal of Nutrition. 155(3):994-1004. https://doi.org/10.1016/j.tjnut.2025.01.005.
DOI: https://doi.org/10.1016/j.tjnut.2025.01.005

Interpretive Summary: The Healthy Eating Index (HEI)-2015 is an index of overall diet quality developed to assess an individual’s compliance with the US Dietary Guidelines for Americans for 2015-2020. People with higher scores on HEI-2015 are at lower risk of death from chronic disease. Healthy diets may reduce the risk of chronic disease in many ways, including by affecting an individual’s immune system to decrease chronic inflammation that increases risk of some diseases, such as cardiovascular disease and some cancers. For the present study we hypothesized that the overall HEI-2015, as well as its 14 component scores (including Total Vegetables, Total Fruit, Whole Grains, and other indicators of specific types of foods) would be associated with lower inflammation and immune activation in healthy adults. For the present study, we examined the association of HEI-2015 scores with 88 immune markers in 346 healthy men and women using regression analysis to adjust for other factors, including age, sex, abdominal fat accumulation (using the visceral fat mass index, VFMI) that might also affect the levels of these immune markers. In this study, negative associations were seen for HEI-2015 with immune markers including plasma C-reactive protein (CRP), total leukocyte, lymphocyte, and neutrophil concentrations but these associations were attenuated by adjustment for VFMI. After adjustment, significant associations were not seen between total HEI score and immune variables, but significant negative associations were seen between several HEI-2015 component scores (Total Vegetables, Greens and Beans, Whole Grains, Fatty Acids and Refined Grains) and immune markers including total lymphocyte, expression of the activation marker CD11b on leukocytes, production of IL-10 by lymphocytes, production of IL-1' by mononuclear leukocytes, and Natural Killer T-lymphocytes. A positive association was also seen between the Total Dairy component score cytokine production by mononuclear cells. In conclusion, the associations of HEI-2015 component scores suggest that higher intake of vegetables, beans, whole grains, monounsaturated and polyunsaturated fatty acids, and lower intake of refined grains may dampen immune activation. Higher dairy food intake was not associated with inflammation but was associated with higher responsiveness of mononuclear leukocytes to stimulation with bacterial LPS.

Technical Abstract: Background: The Healthy Eating Index (HEI)-2015 is an index of overall diet quality that is associated with a lower risk of death from chronic disease. Objective: Healthy diets may reduce the risk of chronic disease by multiple mechanisms, including decreasing chronic inflammation. We hypothesized that the HEI-2015 and its component scores would be associated with lower inflammation and immune activation in healthy adults. Methods: The association of HEI-2015 total and component scores with 88 innate and adaptive immune markers was examined in 346 men and women without diagnosed chronic disease with a wide age (18 – 66 y) and BMI range (18.5 – 44 kg/m2) using multiple, linear regression analysis to adjust for covariates, including visceral fat mass index (VFMI). Results: Negative associations were seen for HEI-2015 with plasma CRP, total leukocyte, lymphocyte, and neutrophil concentrations but these associations were attenuated by adjustment for VFMI. After adjustment, significant associations were not seen between total HEI score and immune variables, but significant negative associations were seen between several HEI-2015 component scores (total vegetables, greens and beans, whole grains, fatty acids and refined grains) and immune markers including total lymphocyte, expression of the activation marker CD11b on monocytes and neutrophils, production of IL-10 by T-cells, production of IL-1' by mononuclear cells stimulated with bacterial lipopolysaccharide (LPS), and percent natural killer (NK) T-cells. A positive association was also seen between the total dairy component score and LPS-stimulated cytokine production by mononuclear cells. Conclusions: In this population of healthy adults, the associations of HEI-2015 component scores suggest that higher intake of vegetables, beans, whole grains, monounsaturated and polyunsaturated fatty acids, and lower intake of refined grains may dampen immune activation. Higher dairy food intake was not associated with inflammation but was associated with higher responsiveness of mononuclear leukocytes to stimulation with bacterial LPS.