Inflammation mediated the effect of dietary fiber on depressive symptoms

Abstract

Background and aimsPrevious studies showed that inflammation affects depressive symptoms. Dietary fiber may be associated with inflammation and depressive symptoms. We aimed to investigate the relationship between inflammation and depressive symptoms at different levels of dietary fiber intake and to explore whether dietary fiber affects depression through inflammation.MethodsA total of 8,430 National Health and Nutrition Examination Survey (NHANES) samples were collected between 2015 and 2018. Factor analysis was used to determine dietary patterns. Linear regression and logistic regression analysis were used to explore the relationship between nutrients, inflammation, and depressive symptoms, and the mediation analysis was conducted using the bootstrap method.ResultsFactor 3 (dietary fiber and vitamins) was inversely associated with depressive symptoms and inflammation. The upper quartile scores of the dietary inflammatory index (DII) and C-reactive protein (CRP) were associated with depressive symptoms compared with controls (DII: OR = 1.851, 95% CI: 1.267–2.705; CRP: OR = 1.737, 95% CI: 1.136–2.656). The DII score and CRP were associated with depressive symptoms in the group with low dietary fiber intake (DII: OR = 2.736, 95% CI: 1.628–4.598; CRP: OR = 2.092, 95% CI: 1.196–3.658) but not in the high dietary fiber intake group. Mediating analysis showed that CRP partially mediated the effect of dietary fiber intake on depressive symptoms (βindirect = −0.0025, 95% CI: −0.0038 to −0.0013), and the mediated proportion was 10.5%.ConclusionIn this study, we found that DII scores and CRP were not associated with depressive symptoms in participants with high dietary fiber intake, and inflammation partially mediates the effect of dietary fiber on depressive symptoms.

Exploring Depression and Nutritional Covariates Amongst US Adults using Shapely Additive Explanations

“…The visualizations completed for the top four continuous covariates were concordant with current literature: there is strong epidemiological evidence that good diet is associated with decreased risk of depression 22 . Many authors have noted statistically significant associations between Vitamin B6, Dietary Fiber, Potassium Intake, Vitamin E, Low Fat and Low Cholesterol Diet, Copper, Caffeine, Lutein Zeaxanthin, Phosphorous, Food Folate, Folate, Vitamin K, Iron, Theobromine, Total Choline, Magnesium, Sodium, Grams of Protein, Vitamin B12, Fiber, and Zinc similarly to our study 38–43 . Since visualizations for risk factors match literature relationships, we have increased confidence that the machine learning model is able to capture the actual physiological relationships of these covariates 44–51 .…”

Association between hs-CRP and depressive symptoms: a cross-sectional study

“…The components and quality of the diet can also impact the inflammatory state. Research has shown that diets with higher scores on the Dietary Inflammatory Index (DII) are associated with a greater likelihood of depression occurrence ( 28 ). There are also reports indicating that the Systemic Inflammation Index (SII) might contribute to the development of depression ( 29 ).…”

Nourishing the Mind: How Food Security Influences Mental Wellbeing

“…Consuming a fiber-rich diet promotes the growth of gut bacteria that produce butyrate [ 47 , 48 , 49 ], consequently lowering stress levels and depression [ 50 ]. Zhang et al’s 2023 study observed that in individuals with high dietary fiber intake, there was no association between symptoms of depression and dietary inflammatory index (DII), a sociodemographic characteristic representing dietary inflammation and C-reactive protein (CRP) [ 51 ]. A previous study by Caspani et al, 2019 explored the mechanism used by the gut microbiota in modulating metabolites that influenced mood changes in major depressive disorder (MDD) through actions in the gut–brain axis [ 52 ].…”