Associations of Dietary Vitamin C and E Intake With Depression. A Meta-Analysis of Observational Studies

Associations between antioxidant vitamin intake and mental health in Swedish adolescents: a cross-sectional study

PURPOSE

Mental health problems are increasingly prevalent during adolescence. Nutritional factors, particularly antioxidants, are of interest due to their potential to reduce oxidative stress and inflammation linked to mental health issues. However, the relationship between dietary antioxidants and adolescent mental health remains unclear. This study aimed to investigate this association in Swedish adolescents and explore potential gender differences.

METHODS

Cross-sectional data were gathered among Swedish boys and girls aged 13-14 years (n = 1139). Participants reported their dietary intake using a detailed web-based method and mental health outcomes, including anxiety, psychosomatic symptoms, and health-related quality of life (HRQoL) using self-report scales. Multiple linear regression analysis, adjusted for confounders, was used to investigate the associations between mental health outcomes and tertiles of dietary intake of vitamin C, E and β-carotene.

RESULTS

Adolescents in the highest tertile of β-carotene intake reported lower anxiety (β=-1.23, 95% CI=-2.34, -0.12), fewer psychosomatic symptoms (β=-0.91, 95% CI=-1.69, -0.13), and better HRQoL (β = 0.89, 95% CI = 0.11, 1.68). Similarly, higher vitamin C intake was associated with fewer psychosomatic problems (β=-1.00, 95% CI=-1.79, -0.21). Vitamin E intake showed no associations. Significant gender interactions were observed on the multiplicative scale analysis and limited to the middle tertiles of β-carotene and vitamin C for anxiety and psychosomatic symptoms, respectively.

CONCLUSION

Our findings underscore the potential role of dietary antioxidants, particularly β-carotene and vitamin C, in adolescent mental health. Further research including diverse populations and employing prospective designs could deepen the understanding and inform public health interventions.

The association of vitamin deficiency with depression risk in late-life depression: a review

Late-life depression (LLD), a growing public health challenge in aging societies, profoundly impacts physical and mental health by exacerbating cognitive decline, functional disability, and comorbid chronic diseases. Emerging research highlights vitamin supplementation as a promising adjunctive therapy for LLD, targeting its multifactorial pathogenesis involving mitochondrial dysfunction, neuroinflammation, and oxidative stress. Specific vitamins, including B-complex vitamins (B1, B6, B9, B12), vitamin D, and antioxidants (C, E), demonstrate therapeutic potential through mechanisms ranging from neurotransmitter regulation to mitochondrial function enhancement. For instance, vitamin D modulates serotonin synthesis and calcium signaling, while B vitamins mitigate homocysteine-mediated neurotoxicity and support energy metabolism. Antioxidants counteract neural oxidative damage linked to depressive severity. Clinical studies reveal that vitamin D deficiency (<20 ng/mL) correlates with elevated depression risk, and combined B-vitamin supplementation shows symptom alleviation in nutritionally deficient subgroups. However, evidence remains heterogeneous due to variability in dosing protocols, bioavailability, and population-specific factors like comorbidities. Despite growing evidence, critical gaps persist regarding optimal dosages, bioavailability variations, and long-term outcomes in elderly populations. This review synthesizes current evidence on vitamin-mediated cellular pathways in LLD management, evaluates clinical efficacy across interventions, and proposes personalized nutritional strategies to optimize therapeutic outcomes. By integrating mechanistic insights with clinical data, this analysis aims to guide evidence-based vitamin supplementation protocols for LLD within geriatric care frameworks.

Factors influencing mental health outcomes among university students: a cross-sectional study in Bangladesh

INTRODUCTION

Mental health issues, particularly anxiety and depression, are on the rise among university students globally, including in Bangladesh. However, comprehensive data on the factors influencing mental health outcomes in this group remain limited, hindering the development of effective programmes and interventions.

OBJECTIVES

This study aims to assess the mental health status of university students in Bangladesh and examine the key factors influencing mental health outcomes.

DESIGN

A cross-sectional online survey was conducted in Bangladesh from December 2022 to March 2023.

SETTING

Universities in Bangladesh.

PARTICIPANTS

University students aged 18 and older.

OUTCOME MEASURES

Data were collected through a structured survey that assessed depression and anxiety using the Patient Health Questionnaire and the Generalized Anxiety Disorder scale, as well as dietary diversity through the Individual Dietary Diversity Score.

RESULTS

The results showed that while female students exhibited greater dietary diversity, they also had higher obesity rates, whereas male students reported more physical activity. Mental health assessments revealed that 36.1% of participants experienced mild anxiety, 11.5% severe anxiety, 39.8% mild depression and 8.3% severe depression. Binary logistic regression analysis identified significant predictors of anxiety and depression, including gender, personal income, body mass index and screen time. Females were less likely to experience anxiety (crude odds ratios (COR): 0.531, p =0.034) and depression (COR: 0.591, p =0.023) compared with males. Furthermore, low intake of wheat, rice (COR: 2.123, p=0.050) and pulses (COR: 1.519, p=0.050), as well as high consumption of fats, oils (COR: 2.231, p=0.024) and sugary foods (COR: 2.277, p=0.001), were associated with anxiety, while inadequate intake of vitamin A- and C-rich fruits (COR: 1.435, p =0.018) was linked to depression. Overweight students were found to be more susceptible to depression.

CONCLUSION

The findings of the study emphasise the necessity for targeted interventions that promote healthier lifestyles to enhance mental health outcomes among university students in Bangladesh.

Inverse association of oxidative balance score with depression and specific depressive symptoms among cancer population: Insights from the NHANES (2005-2020)

BACKGROUND

The rising prevalence of depression among cancer patients is alarming. This study examines the relationship between the Oxidative Balance Score (OBS)-a composite measure of dietary and lifestyle factors-and depression, including specific depressive symptoms in this population.

METHODS

Data were analyzed from 3,280 adult cancer patients collected in NHANES from 2005-2020. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), where a score of 10 or above indicated depression. Symptoms experienced frequently were classified as specific depressive symptoms. Weighted logistic regression models were utilized to explore the correlation between OBS and depression, along with distinctive depressive symptoms.

RESULTS

There was a negative correlation between OBS and depression. The highest quartile of OBS (OR 0.313, 95% CI: 0.161-0.609), along with dietary OBS (OR 0.429, 95% CI: 0.234-0.786) and the third quartile of lifestyle OBS (OR 0.404, 95% CI: 0.226-0.722), was associated with reduced depression risk. OBS was correlated with lower risks of all four somatic depressive symptoms and one cognitive symptom. Dietary OBS was associated with fewer risks of three somatic symptoms and one cognitive symptom. Lifestyle OBS showed a negative correlation with two somatic symptoms. Stratified analyses indicated that the inverse relationship between OBS and depression risk was consistent across subgroups, including females and individuals under 65. a nonlinear association was observed between OBS (p = 0.024), dietary OBS (p<0.001), lifestyle OBS (p = 0.021), and depression.

CONCLUSIONS

OBS is inversely related to depression and specific depressive symptoms in cancer patients. Encouraging a diet and lifestyle rich in antioxidants may help reduce the risk of depression in this group.

Dietary Factors Associated with Depressive Symptoms in Midlife Women 40-50 Years of Age Living in the United States

Purpose

Women in the decade before menopause are at risk for depression. This study describes dietary factors associated with depression risk in late premenopausal women that could be modifiable with targeted interventions.

Methods

Descriptive cross-sectional study comparing a community-based sample of 342 healthy premenopausal women categorized as low-risk and high-risk for depression in a secondary analysis of dietary variables. Depression risk was estimated with the Center for Epidemiological Studies-Depression (CES-D) scale. Dietary variables were based on three random 24-hour diet recalls during a 1-week period that included an in-person visit with measures of potential covariates such as blood pressure, height, and weight for body mass index (BMI), a urine sample for follicle-stimulating hormone, demographic factors, exercise and sleep. Independent t-tests were used initially to compare groups, followed by logistic regression to adjust for covariates. Statistical significance was set at p ≤ 0.05.

Results

Depression risk (CES-D ≥ 16) was present in 30% of participants. Compared with the low-risk group, the high-risk group had significantly higher intake of polyunsaturated fat, omega-6 linoleic acid and sucrose, and lower intake of galactose, vitamin C, and omega-3 eicosapentaenoic acid. After adjusting for energy intake and significant covariates (income adequacy, education, race/ethnicity, marital status, BMI, exercise and sleep duration), only polyunsaturated fat, omega-6, and sucrose remained significant.

Conclusion

Depression prior to menopause is common and multifactorial. Findings support the importance of assessing saturated fats, omega-6 fatty acids, and sucrose. Attention to diet in addition to exercise and sleep may improve intervention outcomes for mental health in midlife women.

The association between neutrophil percentage-to-albumin ratio (NPAR) and depression among US adults: a cross-sectional study

Inflammation plays an important role in depression, and the neutrophil-to-albumin ratio (NPAR) is a cost-effective and readily available novel biomarker of inflammation. The association between NPAR and depression is unclear; therefore, to assess the relationship between NPAR and depression, we conducted a cross-sectional study of 33,768 participants ≥ 18 years of age from the 2005-2018 NHANES database. NPAR was calculated as Neutrophil percentage (in total WBC count) (%) × 100/Albumin (g/dL). Multivariate logistic regression models were used to test the independent association between NPAR and depression, adjusting for demographic factors, education, smoking status, alcohol consumption, hypertension, diabetes mellitus, body mass index, the ratio of income to poverty, and history of cardiovascular disease. Results showed that NPAR was significantly and positively associated with depression. When NPAR were analyzed as a categorical variable, there was a 20% increase in the prevalence of depression in the quartile with the highest NPAR compared to the quartile with the lowest NPAR (OR 1.20[95% CI 1.06, 1.36]). Smoothed curve fitting and threshold effect analyses also showed a positive association between NPAR and depression, with an inflection point for threshold and saturation effects of 12.65. NPAR was positively associated with the likelihood of developing depression when NPAR > 12.65 (OR 1.06[95% CI 1.04, 1.09]). The results of subgroup analyses and interaction tests indicated that smoking status had a significant effect on the relationship between NPAR and depression (P < 0.05). Our study reveals a positive association between NPAR levels and depression, suggesting that higher NPAR levels are associated with an increased likelihood of developing depression.

Association between dietary total antioxidant capacity and sleep problems and depressive symptoms among U.S. adults

Background

In this study, we aim to examine the impact of dietary total antioxidant capacity (TAC) on sleep problems and depressive symptoms (DS); besides, we seek to elucidate the potential mediating effect of dietary TAC on the relationships between sleep problems and DS.

Methods

Weighted Kruskal-Wallis tests for continuous variables and Chi-square tests for categorical variables were employed to discriminate between DS and non-DS participants. Multivariable logistic regression and restricted cubic spline analysis were applied to evaluate the associations of TAC with DS and sleep problems.

Results

Among the 21,805 participants, 1,947 participants suffered from DS. Weighted multivariable logistical regression indicated that shorter sleep hours were linked to an increased likelihood of risk of DS even after complete adjustments. Restricted cubic spline cure displayed that TAC was almost non-linearly correlated with DS and sleep problems. Mediation analysis indicated that sleep duration slightly mediated the association between TAC and DS (proportion of mediation: 3.12%, p < 0.001).

Conclusion

This study illustrated the inverse association between TAC value and sleep problems and DS. Furthermore, TAC slightly mediated the effect of sleep duration on the DS, and there was a nearly non-linear relationship between TAC and DS, and TAC and sleep problems.

The association between vitamin C and depressive risk based on the National Health and Nutrition Examination Survey of 2017-2018 and Mendelian randomization study

OBJECTIVES

There is some debate about the link between vitamin C and depressive risk. This study utilized data from the National Health and Nutrition Examination Survey (NHANES) and Mendelian randomization (MR) methodology to investigate the association between the two.

METHODS

We obtained serum vitamin C levels through laboratory data and determined the intake of vitamin C through a 24-hour dietary recall method on the first day from NHANES 2017 to 2018. Assessment of depressive risk was employed by the 9-item Patient Health Questionnaire (PHQ-9). The association between serum vitamin C levels and depressive risk was examined using logistic regression. Furthermore, the research utilized a two-sample MR methodology to investigate the potential causal connection between vitamin C and depressive risk.

RESULTS

Three thousand four hundred and thirty-four participants aged 20+ with serum vitamin C levels and depressive risk data was included. Among the participants, 18.7% had low serum vitamin C levels and 25.2% had self-reported depressive risk. Serum vitamin C levels were associated with depressive risk [OR 1.64, (95% CI: 1.36-1.97), P < 0.01], which remained significant [OR 1.32, (95% CI: 1.08-1.61), P < 0.01] after adjustments. Distinct genetic SNPs were identified for serum vitamin C levels and depressive risk, allowing detailed analysis. No additional influences were observed between genetic variations. IVW and MR Egger analysis showed a non-causal association between vitamin C levels and depressive risk (All P > 0.05).

CONCLUSIONS

Our findings of the nationally representative survey revealed a strong correlation between serum levels, intake as a supplement or medication of vitamin C and depressive risk, however, without a unidirectional causal association.

The Dietary Inflammatory Index and Its Associations with Biomarkers of Nutrients with Antioxidant Potential, a Biomarker of Inflammation and Multiple Long-Term Conditions

We aimed to validate the Dietary Inflammatory Index (DII®) and assess the cross-sectional associations between the DII® and multiple long-term conditions (MLTCs) and biomarker concentrations and MLTCs using data from the European Prospective Investigation into Cancer (EPIC-Norfolk) study (11,113 men and 13,408 women). The development of MLTCs is associated with low-grade chronic inflammation, and ten self-reported conditions were selected for our MLTC score. Data from a validated FFQ were used to calculate energy-adjusted DII® scores. High-sensitivity C-reactive protein (hs-CRP) and circulating vitamins A, C, E, β-carotene and magnesium were available. Micronutrient biomarker concentrations were significantly lower as the diet became more pro-inflammatory (p-trend < 0.001), and hs-CRP concentrations were significantly higher in men (p-trend = 0.006). A lower DII® (anti-inflammatory) score was associated with 12-40% higher odds of MLTCs. Lower concentrations of vitamin C and higher concentrations of hs-CRP were associated with higher odds of MLTCs. The majority of the associations in our study between MLTCs, nutritional biomarkers, hs-CRP and the DII® were as expected, indicating that the DII® score has criterion validity. Despite this, a more anti-inflammatory diet was associated with higher odds of MLTCs, which was unexpected. Future studies are required to better understand the associations between MLTCs and the DII®.

Oxidative status: A general but overlooked indicator of welfare across animal species?

Because of their ubiquity, plasticity, and direct effects on the nervous system, markers of oxidative status may be of great value to assess animal welfare across species and conditions in the wild. However, welfare biologists have not yet seized this opportunity, possibly because the validity of these markers as welfare indicators remains questionable. A validation process was, therefore, performed here using a meta-analytical approach considering three conditions assumed to impair the welfare of animals. With very few exceptions, two of the four considered markers consistently varied across these negatively-valenced conditions. By highlighting the current underrepresentation of markers of oxidative status in animal welfare studies, and by concretely illustrating that some of these markers can consistently reflect negative affective states, this article aims to encourage biologists to include these physiological markers in their toolbox to better measure, monitor, and perhaps also improve the welfare of animals in their natural habitat.

Assessing the role of antioxidant and pro-oxidant balance in mediating the relationship between vitamin K intake and depressive symptoms in adults

Background

Growing evidence suggests a link between vitamin K (VK) intake and depression, although the underlying mechanisms remain unclear. We aimed to investigate whether oxidative balance scores (OBS) mediate the association between VK intake and depression in participants from the National Health and Nutrition Examination Survey (NHANES) 2007-2018.

Methods

We analyzed data from 30,408 individuals. Dietary VK intake served as the independent variable, depression symptoms as the outcome variable, and OBS as the mediator. Multivariable logistic regression and restricted cubic splines assessed the associations. Mediation analysis was conducted to evaluate the potential mediating role of OBS.

Results

Higher dietary VK intake was associated with lower depression risk in the multivariate model. Compared to the lowest log2 VK quartile, those in the higher quartiles had significantly lower depression odds (Q3: OR 0.66, 95% CI 0.55-0.78; Q4: OR 0.64, 95% CI 0.52-0.78). Additionally, a 1-unit increase in log2 VK intake was associated with a 15% decrease in depression odds (OR 0.85, 95% CI 0.81-0.90). Restricted cubic splines revealed a non-linear relationship between log2 VK and depression (p for non-linearity <0.001). Notably, OBS mediated 26.09% (p < 0.001) of the association between log2 VK and depression.

Conclusion

Higher VK intake is associated with reduced depression risk, potentially mediated by oxidative balance. Further research is warranted to confirm causality and elucidate the underlying mechanisms.

Association between Dietary Antioxidant Capacity in Midlife and Depressive Symptoms in Late Life: The Singapore Chinese Health Study

Preclinical and limited epidemiological studies suggest that oxidative stress may be implicated in geriatric depression. Our study investigated the association between midlife dietary total antioxidant capacity (TAC) and depressive symptoms in late life among 13,712 participants in a population-based cohort of Chinese in Singapore. At baseline (1993-1998), intake of antioxidants from diet and supplements at a mean age of 52.4 years was estimated using a validated food frequency questionnaire to derive two dietary TAC indices from vitamins C and E, carotenoids and flavonoids: the Comprehensive Dietary Antioxidant Index (CDAI) and Vitamin C Equivalent Antioxidant Capacity (VCEAC). At follow-up 3 (2014-2016), when participants were at a mean age of 72.5 years, depressive symptoms were assessed using the Geriatric Depression Scale, and depression, defined as having ≥5 symptoms, was presented in 3173 (23.1%) participants. Both CDAI and VCEAC indices were inversely associated with odds of depressive symptoms in a stepwise manner: the OR (95% CI) comparing the extreme quartiles was 0.73 (0.64-0.83; Ptrend < 0.01) for the CDAI and 0.77 (0.68-0.87; Ptrend < 0.01) for the VCEAC. Specifically, higher intakes of vitamin C, carotenoids, and flavonoids were associated with a lower likelihood of depressive symptoms. Our findings support the recommendation of an antioxidant-rich diet for the prevention of depression.

Association of composite dietary antioxidant index with depression and all-cause mortality in middle-aged and elderly population

Current research has shown an increasing acceptance of interventions for depression through dietary modifications. However, whether composite dietary antioxidant index (CDAI) is associated with depression and all-cause mortality in middle-aged and elderly population remains unknown. This study aimed to explore those associations in American middle-aged and elderly population. Weighted logistic regression models and weighted Cox proportional hazard regression models were used to assess the association of CDAI, covariates, depression, and all-cause mortality, respectively. The stability of the results was also determined by a linear trend test based on CDAI quintiles. Restricted cubic spline curves were employed to test for non-linear relationships. In the model adjusted for all covariates, significant associations were found with the ORs (95% CI) for CDAI and depression [0.77 (0.67, 0.89)] and the HRs (95% CI) for CDAI with all-cause mortality[0.91 (0.83, 1.00)]. Upon conducting restricted cubic spline curves, we found that the association between CDAI and depression was linear, whereas the association between CDAI and all-cause mortality was non-linear with an inflection point of -0.19. Statistical significance was only found before the inflection point. In this study of middle-aged and elderly Americans, CDAI was linearly negatively associated with depression and non-linearly negatively associated with all-cause mortality.

Association between vitamin C in serum and trouble sleeping based on NHANES 2017-2018

Vitamin C is an important micronutrient for human. Association between vitamin C and trouble sleeping was less studied. Therefore, the purpose of this study was to investigate the possible link between vitamin C in serum and trouble sleeping. The cross-sectional data was derived from the National Health and Nutrition Examination Survey (NHANES, 2017-2018). Trouble sleeping was measured by asking participants: "Have you ever told doctor had trouble sleeping". Responses to this question was "yes" or "no". vitamin C in serum was obtained by measuring the serum samples. We used multivariable binary logistic regressions to examine the possible link between vitamin C in serum and trouble sleeping, and then a subgroup analysis was performed. Moreover, the non-linear relationship between vitamin C in serum and trouble sleeping was further detected using a restricted cubic spline (RCS) model. A total of 3227 participants were included in the study. After adjusting all potential confounders, the results of multivariable logistic regression showed the significant negative association between vitamin C in serum and trouble sleeping(OR = 0.816; 95% CI:0.669 ~ 0.995). The significant inverse association was also found in female(OR = 0.713; 95% CI:0.546 ~ 0.931), age ≤ 65 years(OR = 0.773; 95% CI:0.600 ~ 0.996), and in participants with high cholesterol level(OR = 0.738; 95% CI:0.548 ~ 0.994). In addition, the RCS model demonstrated the significant non-linear relationship between vitamin C in serum and trouble sleeping (P value of nonlinear = 0.010). Our study demonstrates the significant negative association between vitamin C in serum and trouble sleeping.

Age and Sex Differences in the Association between Serum Vitamin E Levels and Depressive Symptoms: Korea National Health and Nutrition Examination Survey

Studies have reported inconsistent results regarding the relationship between serum vitamin E levels and depressive symptoms. Furthermore, the potential modulating role of age and sex has been underexplored. We conduct an age- and sex-stratified investigation of the association between serological vitamin E status and depressive symptoms in a large nationwide sample. Data from the Korean National Health and Nutrition Examination Survey were analyzed (n = 4448). The participants were stratified into four groups according to age (<65 vs. ≥65 years) and sex. Each group was divided into tertiles of vitamin E/total lipid ratio, and Patient Health Questionnaire-9 (PHQ-9) scores were compared among the tertiles via multivariable linear regression analyses. The relationship between dietary supplement use and the proportions of tertiles was assessed in each group. With the middle tertile as the reference group, the low tertile of vitamin E/total lipid ratio was associated with increased PHQ-9 scores in younger females and older males after adjusting for all covariates, while the high tertile showed no significant associations with PHQ-9 scores in any group. The low tertile was associated with increased adjusted mean PHQ-9 scores by 0.53 and 1.02 compared to the middle tertile in younger females and older males, respectively. Dietary supplement use was related to higher vitamin E/total lipid ratio in all four groups. In conclusion, younger females and older males with a low vitamin E status showed worse depressive symptoms. These individuals may benefit from dietary interventions to prevent depressive symptoms.

Appropriate Macronutrients or Mineral Elements Are Beneficial to Improve Depression and Reduce the Risk of Depression

Depression is a common mental disorder that seriously affects the quality of life and leads to an increasing global suicide rate. Macro, micro, and trace elements are the main components that maintain normal physiological functions of the brain. Depression is manifested in abnormal brain functions, which are considered to be tightly related to the imbalance of elements. Elements associated with depression include glucose, fatty acids, amino acids, and mineral elements such as lithium, zinc, magnesium, copper, iron, and selenium. To explore the relationship between these elements and depression, the main literature in the last decade was mainly searched and summarized on PubMed, Google Scholar, Scopus, Web of Science, and other electronic databases with the keywords "depression, sugar, fat, protein, lithium, zinc, magnesium, copper, iron, and selenium". These elements aggravate or alleviate depression by regulating a series of physiological processes, including the transmission of neural signals, inflammation, oxidative stress, neurogenesis, and synaptic plasticity, which thus affect the expression or activity of physiological components such as neurotransmitters, neurotrophic factors, receptors, cytokines, and ion-binding proteins in the body. For example, excessive fat intake can lead to depression, with possible mechanisms including inflammation, increased oxidative stress, reduced synaptic plasticity, and decreased expression of 5-Hydroxytryptamine (5-HT), Brain Derived Neurotrophic Factor (BDNF), Postsynaptic density protein 95(PSD-95), etc. Supplementing mineral elements, such as selenium, zinc, magnesium, or lithium as a psychotropic medication is mostly used as an auxiliary method to improve depression with other antidepressants. In general, appropriate nutritional elements are essential to treat depression and prevent the risk of depression.

Inflammation mediated the effect of dietary fiber on depressive symptoms

BACKGROUND AND AIMS

Previous 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.

METHODS

A 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.

RESULTS

Factor 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 (β_indirect = -0.0025, 95% CI: -0.0038 to -0.0013), and the mediated proportion was 10.5%.

CONCLUSION

In 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.