Dietary fiber intake, depression, and anxiety: a systematic review and meta-analysis of epidemiologic studies

Effect of dietary fibre on cognitive function and mental health in children and adolescents: a systematic review and meta-analysis

Objective: The purpose of this study is to investigate the impact of dietary fibre on the mental health and cognitive function of children and adolescents. Methods: All interventional and observational studies that contained information on the relevant population (children and adolescents), intervention/exposures (high dietary fibre consumption) and outcomes (mental and cognitive parameters) were eligible. Eight electronic databases (Embase, Medline, Pubmed, Web of Science, Scopus, PsycINFO, Cochrane Library and ClinicalTrials.gov) were searched up to December 11, 2023. Results: A total of 15 studies (n = 4628) met inclusion criteria, consisting of 9 intervention trials and 6 observational studies. According to observational studies, higher dietary fibre consumption was associated with a 49% reduction in the odds of depression compared to lower intake (P < 0.0001; OR = 0.51; 95% CI: 0.38, 0.69; I2 = 0%). Furthermore, no significant correlations were found between dietary fibre consumption and intelligence or anxiety. Among intervention studies, no significant difference was observed between fibre supplementation and placebo in terms of anxiety (standardized mean difference (SMD): -0.23; 95% CI: -0.72, 0.27), stress (SMD: 0.03; 95% CI: -0.21, 0.28), memory (SMD: 0.46; 95% CI: -0.79, 1.71), or attention (SMD: -2.72; 95% CI: -6.30, 0.86). Conclusion: Evidence from observation studies demonstrated that higher dietary fibre consumption is associated with a decreased odds of depression symptoms, both in childhood and adolescence. However, the causal relationship between dietary fibre intake and mental and cognitive function in children and adolescents still requires further clarification through high-quality intervention studies in the future.

Association between different diet quality scores and depression risk: the REGICOR population-based cohort study

BACKGROUND

Our aim was to determine the association between diet quality and depression incidence in the population-based REGICOR cohort study, Catalonia, Spain.

METHODS

Prospective observational study using participants' baseline (2003-2006), follow-up (2007-2013) and clinical records data. Five diet quality scores were derived from a food frequency questionnaire (FFQ) at baseline: the relative Mediterranean Diet Score (rMED), the Modified Mediterranean Diet Score (ModMDS), a Dietary Approaches to Stop Hypertension (DASH) score, a Healthful Plant-based Diet Index (HPDI) and the World Health Organization Healthy Diet Indicator (WHO-HDI). Participants using pharmacological antidepressant treatment were excluded as a proxy for presence of depression at baseline. At follow-up, the Patient Health Questionnaire (PHQ-9) was applied to assess depressive symptoms (≥ 10 defining depressive disorder). A secondary outcome was depression diagnosis assessed through clinical records. Logistic regression and Cox proportional hazards models were used.

RESULTS

Main analysis included 3046 adults (50.3% women) with a mean age of 54.7 (SD = 11.6) years. After 6-years follow-up, 184 (6.04%) cases of depressive disorder were identified. There was 16% lower odds of depressive disorder per 1SD increase of rMED (OR = 0.84; 95%CI = 0.71-0.98). Secondary outcome analysis (n = 4789) identified 261 (5.45%) incident cases of clinical depression diagnosis over 12 years follow-up, and 19% lower risk of clinical depression was observed with the WHO-HDI (HR = 0.81; 95%CI = 0.70-0.93). Adjusting for BMI did not attenuate the findings.

CONCLUSIONS

A significant inverse association between diet quality and depression incidence was found in this population-based cohort study, independent of sociodemographic, health and lifestyle. Adherence to a healthy diet could be a complementary intervention for the prevention of depression.

Intestinal Barrier, Immunity and Microbiome: Partners in the Depression Crime

Depression is a highly prevalent disorder and a leading cause of disability worldwide. It has a major impact on the affected individual and on society as a whole. Regrettably, current available treatments for this condition are insufficient in many patients. In recent years, the gut microbiome has emerged as a promising alternative target for treating and preventing depressive disorders. However, the microbes that form this ecosystem do not act alone but are part of a complicated network connecting the gut and the brain that influences our mood. Host cells that are in intimate contact with gut microbes, such as the epithelial cells forming the gut barrier and the immune cells in their vicinity, play a key role in the process. These cells continuously shape immune responses to maintain healthy communication between gut microbes and the host. In this article, we review how the interplay among epithelial cells, the immune system, and gut microbes mediates gut-brain communication to influence mood. We also discuss how advances in our knowledge of the mechanisms underlying the gut-brain axis could contribute to addressing depression. SIGNIFICANCE STATEMENT: This review does not aim to systematically describe intestinal microbes that might be beneficial or detrimental for depression. We have adopted a novel point of view by focusing on potential mechanisms underlying the crosstalk between gut microbes and their intestinal environment to control mood. These pathways could be targeted by well defined and individually tailored dietary interventions, microbes, or microbial metabolites to ameliorate depression and decrease its important social and economic impact.

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.

Effect of Low-Fat Diet on Depression Score in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials

CONTEXT

Current evidence on the effect of a low-fat (LF) diet on depression scores has been inconsistent.

OBJECTIVE

To explore the effect of an LF diet on depression scores of adults by systematic review and meta-analysis of randomized controlled trials (RCTs).

DATA SOURCES

The PubMed, ISI Web of Science, Scopus, and CENTRAL databases were searched from inception to June 7, 2023, to identify trials investigating the effect of an LF diet (fat intake ≤30% of energy intake) on the depression score.

DATA EXTRACTION

Random-effects meta-analyses were used to estimate pooled summary effects of an LF diet on the depression score (as Hedges g).

DATA ANALYSIS

Finding from 10 trials with 50 846 participants indicated no significant change in depression score following LF diets in comparison with usual diet (Hedges g = -0.11; 95% CI, -0.25 to 0.03; P = 0.12; I2 = 70.7% [for I2, 95% CI, 44%, 85%]). However, a significant improvement was observed in both usual diet and LF diets when the content of protein was 15-20% of calorie intake (LF, normal protein diet: n = 5, Hedges g = -0.21, 95% CI, -0.24 to -0.01, P = 0.04, I2 = 0%; usual, normal protein diet: n = 3, Hedges g = -0.28, 95% CI, -0.51 to -0.05, P = 0.01, I2 = 0%). Sensitivity analysis also found the depression score improved following LF diet intervention in participants without baseline depression.

CONCLUSION

This study revealed that LF diet may have small beneficial effect on depression score in the studies enrolled mentally healthy participants. Moreover, achieving to adequate dietary protein is likely to be a better intervention than manipulating dietary fat to improve depression scores. However, it is not clear whether this effect will last in the long term. Conducting more studies may change the results due to the low-certainty of evidence.

SYSTEMATIC REVIEW REGISTRATION

CRD42023420978 (https://www.crd.york.ac.uk/PROSPERO).

Dietary fiber: Still alive

Dietary fiber (DF) was established as a key dietary constituent some decades ago, as were some of its mechanisms of action and health effects. Although there is consolidated evidence on many features regarding DF, at the same time there are still many aspects to be explored in the field, e.g., deeper explorations of the contribution of phenolic compounds linked to cell walls to the biological activities of DF, or of the relevance of the gut-brain axis. At the same time, increasing DF intake should be seen as a major public health problem since worldwide intakes are quite far from recommendations. The awareness of this fact by public bodies should lead, among others, to the assessment of effective strategies for promoting DF intake among general population or specific groups; and to consider potential regulatory modifications in order to clarify several aspects potentially misleading for consumers.

Dietary fiber intake is positively associated with health-related quality of life in patients with hypertension: The mediating role of anxiety in mental component summary

Few studies have focused on the exploration of the relationship between dietary fiber intake (DFI) and health-related quality of life (HRQoL) and its mediators in hypertensive patients. This study is a cross-sectional survey and the data were obtained from hypertensive patients from Suzhou, China. The DFI, office systolic blood pressure and diastolic blood pressure, anxiety and depression, and HRQoL were investigated. We hypothesized that blood pressure, anxiety, and depression mediated the association between DFI and HRQoL, and used Pearson correlations, linear regression, and bootstrap tests to validate this relationship. A total of 211 hypertensive patients aged 20 to 64 years were included in this study. The average DFI was 12.4 ± 5.2 g/d, and the scores of physical component summary and mental component summary (MCS) were 46.5 ± 6.1 and 46.4 ± 6.4, respectively. DFI was positively correlated with physical component summary (r = 0.17, p = 0.014) and MCS (r = 0.27, P < .001). After controlling for sociodemographic and clinical characteristics, neither systolic blood pressure nor diastolic blood pressure showed mediating effects in the mediated model of DFI on MCS, whereas anxiety (b = -0.30; 95% confidence interval, -0.41 to -0.18) fully mediated the improvement in MCS by DFI (F = 11.14, P < .001). Because the MCS of HRQoL encompassed the assessment of depression, we did not analyze the mediating effect of depression in this model in order to avoid variable duplication. The decreased DFI is a risk factor for lower HRQoL, and anxiety mediated the relationship between DFI and MCS. Further research should focus on increasing DFI and reducing anxiety levels in hypertensive patients to improve their quality of life.

Dietary Fibre Intake in Chile: 13 Years after the Last National Report

BACKGROUND

The objective is to provide updated data on the intake of total dietary fibre in the population residing in Chile and to identify food sources that contribute most to its intake, as well as its association with different sociodemographic and nutritional status-related determinants.

METHODS

In this descriptive cross-sectional study, a nationwide survey was applied to determine fibre intake using an instrument that has been previously validated in the resident population of Chile.

RESULTS

The sample consisted of a total of 1761 participants. Dietary fibre intake was 12.8 ± 7.1 g/day for the total population, and 90% of participants did not meet the recommendation, with no differences in consumption by sex, geographical area, and the urban/rural population. A lower consumption was found among participants with overweight and obesity. According to food groups, bread was the major contributor to fibre intake, providing 4.39 ± 3.05 g/day, followed by cereals (2.26 ± 2.80 g/day) and vegetables (1.85 ± 1.59 g/day).

CONCLUSIONS

90% of the population consume less fibre than recommended, and bread is the main food source; these data are critical for the development of strategies that are aimed at changing habits in order to improve diet quality.

Perspectives on Neuronutrition in Prevention and Treatment of Neurological Disorders

The term neuronutrition has been proposed as part of nutritional neuroscience, studying the effects of various dietary components on behavior and cognition. Other researchers underline that neuronutrition includes the use of various nutrients and diets to prevent and treat neurological disorders. The aim of this narrative review was to explore the current understanding of the term neuronutrition as the key concept for brain health, its potential molecular targets, and perspectives of its nutritional approach to the prevention and treatment of Alzheimer's and Parkinson's diseases, multiple sclerosis, anxiety, depressive disorders, migraine, and chronic pain. Neuronutrition can be defined as a part of neuroscience that studies the influence of various aspects of nutrition (nutrients, diet, eating behavior, food environment, etc.) on the development of nervous disorders and includes nutrition, clinical dietetics, and neurology. There is evidence that the neuronutritional approach can influence neuroepigenetic modifications, immunological regulation, metabolic control, and behavioral patterns. The main molecular targets in neuronutrition include neuroinflammation, oxidative/nitrosative stress and mitochondrial dysfunction, gut-brain axis disturbance, and neurotransmitter imbalance. To effectively apply neuronutrition for maintaining brain health, a personalized approach is needed, which includes the adaptation of the scientific findings to the genetic, biochemical, psycho-physiological, and environmental features of each individual.

Association between depression and oxidative balance score: National Health and Nutrition Examination Survey (NHANES) 2005-2018

BACKGROUND

Few studies have investigated the relationship between systemic oxidative stress status and depression. The oxidative balance score (OBS) was used to assess systemic oxidative stress status, with higher OBS scores implying exposure to more antioxidants. This study aimed to explore whether OBS is associated with depression.

METHODS

18,761 subjects from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018 were selected. Depression was diagnosed by the Patient Health Questionnaire (PHQ-9, score ≥ 10). OBS was scored by 20 dietary and lifestyle factors. Weighted logistic regression and restricted cubic splines (RCS) were used to assess the association between OBS and depression.

RESULTS

The prevalence of depression was 8.42 %. There was a significant negative nonlinear relationship between OBS, dietary OBS, lifestyle OBS and depression (p for nonlinear < 0.05). Compared to the lowest quartile of OBS, the adjusted ORs for the highest quartile of OBS, dietary OBS, and lifestyle OBS and depression were 0.290 (95 % CI: 0.193-0.434), 0.500(95 % CI: 0.380-0.658), 0.403(95 % CI: 0.299-0.545) respectively, and all P for trend < 0.001. In stratified analyses, three OBS were negatively associated with the odds of depression across sex groups (all P for trend < 0.05), and the OR was smaller in the female group than in the male group.

LIMITATIONS

Cross-sectional data and absence of drug considerations.

CONCLUSIONS

OBS was strongly negatively associated with depression, especially in females. The findings underline the significance of adhering to an antioxidant diet and lifestyle, which helps prevent depression and appears to be of greater benefit to women.

Dietary Nutrient Deficiencies and Risk of Depression (Review Article 2018-2023)

Depression is classified as one of the most common mental disorders. Its prevalence has recently increased, becoming a growing public health threat. This review focuses on clarifying the role and importance of individual nutrients in the diet and the impact of nutrient deficiencies on the risk of depression. Deficiencies in nutrients such as protein, B vitamins, vitamin D, magnesium, zinc, selenium, iron, calcium, and omega-3 fatty acids have a significant impact on brain and nervous system function, which can affect the appearance of depressive symptoms. However, it is important to remember that diet in itself is not the only factor influencing the risk of or helping to treat depression. There are many other aspects, such as physical activity, sleep, stress management, and social support, that also play an important role in maintaining mental health. The data review observed that most of the available analyses are based on cross-sectional studies. Further studies, including prospective cohort, case-control studies, are recommended to draw more reliable conclusions.

Serum short chain fatty acids mediate hippocampal BDNF and correlate with decreasing neuroinflammation following high pectin fiber diet in mice

Introduction

Dietary components, such as prebiotic fiber, are known to impact brain chemistry via the gut-brain axis. In particular, short chain fatty acids (SCFAs) generated from excessive soluble fiber consumption are thought to impact neuroimmune signaling and brain function through increased production of neurotropic factors. Given reports that high dietary fiber intake is associated with increased mental health and improved quality of life scores, we set out to identify whether changes in SCFA levels as a result of a high soluble fiber diet mediate hippocampal neuroinflammation and brain derived neurotrophic factor (BDNF) in mice.

Methods

Adult male and female C57BL/6 mice were fed a 1-month high pectin fiber or cellulose-based control diet. Following 1 month of excessive pectin consumption, serum SCFAs were measured using gas chromatography-mass spectrometry (GC-MS) and hippocampal cytokines and BDNF were assessed via multiplex magnetic bead immunoassay.

Results

Pectin-based fiber diet increased circulating acetic acid in both sexes, with no effect on propionic or butyric acid. In the hippocampus, a high fiber diet decreased TNFa, IL-1ß, IL-6, and IFNγ and increased BDNF levels. Furthermore, increased SCFA levels were inversely correlated with neuroinflammation in the hippocampus, with acetic acid revealed as a strong mediator of increased BDNF production.

Conclusion

Collectively, these findings highlight the beneficial effects of fiber-induced molecular changes in a brain region known to influence mood- and cognition-related behaviors. Dietary composition should be considered when developing mental health management plans for men and women with an emphasis on increasing soluble fiber intake.

Dietary intervention in depression - a review

Depression is a mental illness that affects the normal lives of over 300 million people. Unfortunately, about 30% to 40% of patients do not adequately respond to pharmacotherapy and other therapies. This review focuses on exploring the relationship between dietary nutrition and depression, aiming to find safer and efficient ingredients to alleviate depression. Diet can affect depression in numerous ways. These pathways include the regulation of tryptophan metabolism, inflammation, hypothalamic-pituitary-adrenal (HPA) axis, microbe-gut-brain axis, brain-derived neurotrophic factor (BDNF) and epigenetics. Furthermore, probiotics, micronutrients, and other active substances exhibit significant antidepressant effects by regulating the above pathways. These provide insights for developing antidepressant foods.

Anxiety, Insomnia, and Memory Impairment in Metabolic Syndrome Rats Are Alleviated by the Novel Functional Ingredients from Anacardium occidentale

Despite an increase in the coexistence of metabolic syndrome (MetS) and psychological disorders, together with their great impact on socio-economic burdens, no protective strategies that focus on these situations are available. Due to the role of oxidative stress in the pathophysiology of metabolic syndrome (MetS) and psychological disorders, we hypothesized that substances possessing antioxidant activity such as the novel functional ingredients from Anacardium occidentale (AO) could mitigate common psychological disorders in MetS rats. Male Wistar rats, weighing 200-250 g, were induced with MetS through a 12-week high-fat and high-cholesterol diet (HFHC). Then, they were given AO orally via a gastric gavage needle at doses of 1, 10 and 100 mg/kg BW for 14 days. Spatial memory, anxiety, depression, and sleep behaviors, together with changes in oxidative stress status and neurotransmitters, were assessed. All doses of AO significantly improved memory, anxiety, and sleep, together with the suppression of oxidative stress, AChE, and GABA-T in the cerebral cortex and hippocampus. These results suggest the protective effect of AO against anxiety, insomnia, and memory impairment that coexist with the MetS condition via an improvement in oxidative stress and the functions of the cholinergic and GABAergic systems. However, this benefit requires clinical confirmation.