Diet Quality Mediates the Relationship Between Chronic Stress and Inflammation in Patients With Metabolic Syndrome

Background Chronic stress is associated with promotion of inflammation and development of metabolic syndrome, as well as deterioration of diet quality. Inflammation can be modified by changes in dietary intake. Objective The aim of this study was to test the hypothesis that diet quality mediates the relationship of chronic stress with inflammation in patients with metabolic syndrome. Methods Participants with metabolic syndrome (n = 73, 62 ± 12 years old, 71% female) completed questionnaires on chronic stress (Perceived Stress Scale-10) and diet quality (Healthy Eating Index-2020). The Perceived Stress Scale-10 was dichotomized. The Healthy Eating Index-2020 score was used as a continuous variable, and higher scores indicate better diet quality. Inflammation was assessed using plasma high-sensitivity C-reactive protein (log-transformed). We used PROCESS in SPSS to test the hypothesis. Results Patients in the higher stress group had lower Healthy Eating Index-2020 scores (worse diet quality) than those in the lower stress group (57 ± 13 vs 64 ± 10, P =.01). Diet quality mediated the relationship between chronic stress and inflammation (indirect effect, 0.211; 95% bootstrap confidence interval, 0.006-0.496). Higher stress was associated with lower diet quality (effect, -7.152; 95% confidence interval, -13.168 to -1.137) that was associated with increased inflammation (effect, -0.030; 95% confidence interval, -0.052 to -0.007). Conclusions Our findings show the important role of diet quality in the relationship of chronic stress with inflammation in patients with metabolic syndrome. Healthcare providers should encourage patients with higher stress to improve diet quality, which can decrease inflammation.