Prebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trials

Fiber intake and fiber intervention in depression and anxiety: a systematic review and meta-analysis of observational studies and randomized controlled trials

CONTEXT

Dietary fibers hold potential to influence depressive and anxiety outcomes by modulating the microbiota-gut-brain axis, which is increasingly recognized as an underlying factor in mental health maintenance.

OBJECTIVE

Evidence for the effects of fibers on depressive and anxiety outcomes remains unclear. To this end, a systematic literature review and a meta-analysis were conducted that included observational studies and randomized controlled trials (RCTs).

DATA SOURCES

The PubMed, Embase, CENTRAL, CINAHL, and PsychINFO databases were searched for eligible studies.

DATA EXTRACTION

Study screening and risk-of-bias assessment were conducted by 2 independent reviewers.

DATA ANALYSIS

Meta-analyses via random effects models were performed to examine the (1) association between fiber intake and depressive and anxiety outcomes in observational studies, and (2) effect of fiber intervention on depressive and anxiety outcomes compared with placebo in RCTs. A total of 181 405 participants were included in 23 observational studies. In cross-sectional studies, an inverse association was observed between fiber intake and depressive (Cohen's d effect size [d]: -0.11; 95% confidence interval [CI]: -0.16, -0.05) and anxiety (d = -0.25; 95%CI, -0.38, -0.12) outcomes. In longitudinal studies, there was an inverse association between fiber intake and depressive outcomes (d = -0.07; 95%CI, -0.11, -0.04). In total, 740 participants were included in 10 RCTs, all of whom used fiber supplements. Of note, only 1 RCT included individuals with a clinical diagnosis of depression. No difference was found between fiber supplementation and placebo for depressive (d = -0.47; 95%CI, -1.26, 0.31) or anxiety (d = -0.30; 95%CI, -0.67, 0.07) outcomes.

CONCLUSION

Although observational data suggest a potential benefit for higher fiber intake for depressive and anxiety outcomes, evidence from current RCTs does not support fiber supplementation for improving depressive or anxiety outcomes. More research, including RCTs in clinical populations and using a broad range of fibers, is needed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021274898.

Depression and obesity: Focus on factors and mechanistic links

Major depressive disorder (MDD) is defined as mood disorder causing a persistent loss of interest and despair for two weeks or greater, with related symptoms. Depression can interfere with daily life and can cause those affected to not work, study, eat, sleep, and enjoy previously enjoyed hobbies and life events as they did previously. If untreated, it can become a serious health condition. Depression is multifactorial with a variety of factors influencing the condition. These factors include: (1) poor diet and exercise, (2) socioeconomic status, (3) gender, (4) biological clocks, (5) genetics and epigenetics, and (6) personal stressors. Treatment of depressive disorders is thus also multifactorial and utilizes the following therapies: (1) diet and exercise, (2) bright light therapy, (3) cognitive behavioral therapy, and (4) pharmaceutical therapy. Obesity is defined as body mass index over 30 and above, is believed to be causally linked to MDD through both psychological and molecular means. Atypical depression, a common form of MDD, is most strongly correlated with a high proclivity for obesity. Obesity and depression have a bidirectional relationship, a patient experiencing either condition singularly is more likely to develop the other due to the neural links between the two, including emotional lability, physical health of the brain, hormones, cytokine secretion, appetite, diet and feeding habits, inflammatory state. In individuals consuming a high fat diet (HFD) commonly ingested by those with obesity, the gut-microbiome is altered leading to systemic inflammation and the dysregulation of mood and the HPA axis impacting their neural health. The purpose of this paper is to examine the interplay of potential molecular, psychological, societal, and environmental causal factors of depressive disorders and how obesity perpetuates depression. A secondary aim of this paper is to examine current interventions that may help improve those affected by both conditions.

Review article: The role of the gut-brain axis in inflammatory bowel disease and its therapeutic implications

BACKGROUND

Treatments targeting the gut-brain axis (GBA) are effective at reducing symptom burden in irritable bowel syndrome (IBS). The prevalence of common mental disorders and IBS-type symptom reporting is significantly higher in inflammatory bowel disease (IBD) than would be expected, suggesting potential GBA effects in this setting. Manipulation of the GBA may offer novel treatment strategies in selected patients with IBD. We present a narrative review of the bi-directional effects of the GBA in IBD and explore the potential for GBA-targeted therapies in this setting.

METHODS

We searched MEDLINE, EMBASE, EMBASE Classic, PsychINFO, and the Cochrane Central Register of Controlled Trials for relevant articles published by March 2024.

RESULTS

The bi-directional relationship between psychological well-being and adverse longitudinal disease activity outcomes, and the high prevalence of IBS-type symptom reporting highlight the presence of GBA-mediated effects in IBD. Treatments targeting gut-brain interactions including brain-gut behavioural treatments, neuromodulators, and dietary interventions appear to be useful adjunctive treatments in a subset of patients.

CONCLUSIONS

Psychological morbidity is prevalent in patients with IBD. The relationship between longitudinal disease activity outcomes, IBS-type symptom reporting, and poor psychological health is mediated via the GBA. Proactive management of psychological health should be integrated into routine care. Further clinical trials of GBA-targeted therapies, conducted in selected groups of patients with co-existent common mental disorders, or those who report IBS-type symptoms, are required to inform effective integrated models of care in the future.

Effectiveness and safety study of formula containing probiotics, prebiotics, synbiotics on fullterm infants' growth - a systematic review and meta-analysis of randomized controlled study

BACKGROUND AND OBJECTIVE

Probiotics, prebiotics, and synbiotics, are hot topics of research and have been shown to improve the body's disease state and promote health. Analysis of whether infant formula containing probiotcs, prebiotics, synbiotics is beneficial to infant and child growth.

METHODS

We systematically searched multiple electronic databases (PubMed, Web of Science, The Cochrane Library, Embase) to identify eligible studies published from 1966 to December 25, 2022. Included studies were randomized controlled trials (RCTs) studying the influence of milk powder containing probiotcs, prebiotics, synbiotics on infants and children's growth. RevMan 5.4 was used to analyze the data.

RESULTS

A total of 55 RCTs with a total sample size of 8868 participants met the inclusion criteria. Milk powder with probiotics, prebiotics, synbiotics does not significantly improve the growth of infants and children (Weight, height, BMI, and Head Circumference); The incidence of minor adverse events (OR 0.88, 95% CI 0.70-1.11 P = 0.28) and serious adverse events (OR 0.92, 95% CI 0.62-1.36 P = 0.67) was also comparable to the control group; The intestinal microbial diversity of infants consuming probiotcs, prebiotics, synbiotics supplemented formula was lower than that of infants consuming formula without probiotcs, prebiotics, synbiotics (SMD -0.88, 95% CI -1.66- -0.1 P = 0.03), but the abundance of individual beneficial flora was increased. (SMD 1.62, 95%CI 0.61-2.62 P = 0.002). In particular, the abundance of Lactobacillus (SMD 1.62, 95% CI 0.61-2.62 P = 0.002). For metabolites, synbiotics increased fecal antibody concentrations (SMD 0.47, 95% CI 0.08-0.86 P = 0.02), but fecal short-chain fatty acid concentrations remained balanced in both groups (SMD 0.05 95% CI -0.17-0.28 P = 0.64). Compared to the control group, infants who consumed formula with prebiotics had softer stools (SMD -1.47, 95% CI -2.23 to -0.7 P = 0.002) and lower stool pH (SMD -0.82, 95% CI -1.15- -0.5 P < 0.00001), there is also more frequency of bowel movements (SMD 0.27, 95% CI 0.09-0.44 P = 0.002).

CONCLUSIONS

Probiotcs, prebiotics, synbiotics supplemented formulas significantly increased abundance of individual probiotics, alter intestinal antibody secretion, and improve bowel movements. Incidence of adverse reactions did not differ between the two groups. So we can choose formula-supplemented probiotcs, prebiotics, synbiotics to maintain the intestinal health of infants.

Addressing Mental Health in Rural Settings: A Narrative Review of Blueberry Supplementation as a Natural Intervention

Depression and anxiety are major public health issues; however, there is an unmet need for novel, effective, and accessible treatments, particularly in rural communities. Blueberries are an unexplored nutraceutical for these conditions due to their excellent nutritional profile, with particularly high levels of polyphenols and anthocyanins and benefits on mood, cognition, and health. Here, we present a narrative review of the literature concerning the etiology and treatments of major depressive disorder (MDD) and generalized anxiety disorder (GAD). In both animal and human studies, blueberry supplementation can ameliorate behavioral symptoms of both anxiety and depression. The mechanistic underpinnings of these behavioral improvements are not fully defined, but likely involve biochemical alterations in the gut-brain axis, including to inflammatory cytokines, reactive oxygen species, and growth factors. We also review the limitations of traditional therapies in rural settings. Finally, we assess the potential benefit of nutraceutical interventions, particularly blueberries, as novel therapeutics for these distinct, yet related mental health issues.

Pharmacists' Knowledge, Perception, and Prescribing Practice of Probiotics in the UAE: A Cross-Sectional Study

BACKGROUND

The human body is a complex and interconnected system where trillions of microorganisms, collectively known as the gut microbiota, coexist with these cells. Besides maintaining digestive health, this relationship also impacts well-being, including immune function, metabolism, and mental health. As frontline healthcare providers, pharmacists are pivotal in promoting the benefits of probiotics for immune support. This study explored pharmacists' knowledge, perception, and practice behavior in the UAE towards the implication of probiotic application beyond digestive health, such as cardiovascular and mental health impacts and their diverse dosage forms.

METHOD

An online self-administered survey was distributed among pharmacists in the UAE. Data were collected through personal visits to pharmacies, where pharmacists were approached and asked to complete the questionnaire. The sample size included 407 pharmacists, determined using the formula for proportions with a 95% confidence level and a 5% margin of error. Statistical analysis was performed using SPSS version 29. Descriptive statistics were used to summarize demographic characteristics and survey responses. The knowledge levels were categorized into poor, moderate, and good. Chi-square analysis was employed to investigate associations between demographic factors and knowledge levels, with a significance level set at p < 0.05, enhancing the robustness of the study's findings.

RESULTS

This study included 407 completed eligible responses. About 63.56% of participants were female, with 52.1% employed in pharmacy chains. While 91.2% of pharmacists recognized probiotics' role in immune support, only 30% were aware of their cardiovascular benefits. Moreover, chewing gum was the least known dosage form of probiotics, recognized by only 16.7% of respondents. Additionally, only 57% of the participants recognized liposomes as a dosage form. In practice, most pharmacists recommended storing probiotics at room temperature, accounting for 66.6%. The most prevalent misconception encountered in the pharmacy setting was the belief that probiotics are primarily intended for gastrointestinal tract problems, at 79.1% of the respondents. Regarding perception, the agreement was observed regarding the safety of probiotics for all ages. Perceived barriers included the high cost of probiotics, with the majority (86.5%) indicating this as a significant obstacle, while lack of demand was identified as the minor barrier by 64.6%. Additionally, an association was found at a significance level of p < 0.05 with knowledge, gender, educational level, type and location of pharmacy, and source of information.

CONCLUSIONS

The study highlights knowledge gaps in pharmacists' understanding of probiotic applications beyond digestive health, particularly cardiovascular health and depression. Targeted educational interventions are necessary to address these gaps. The findings underscore the importance of ongoing professional development for pharmacists, enhancing their role in patient education and the promotion of probiotics for overall health.

Effects of probiotic and vitamin D co-supplementation on clinical symptoms, mental health, and inflammation in adult patients with migraine headache: a randomized, triple-blinded, placebo-controlled trial

BACKGROUND

Migraine headache is a major public health problem. Routine medications for migraine treatment are not useful in treating all patients and may have some side effects. The present study aimed to investigate the effect of vitamin D and probiotic co-supplementation on clinical characteristics of migraine, daily functioning, mental health outcomes, and serum levels of high-sensitivity C-reactive protein (hs-CRP).

METHODS

In this randomized, triple-blinded, placebo-controlled trial, patients aged 18 to 55 years diagnosed with migraine based on the International Classification of Headache Disorders-3 (ICHD-3) were randomized to either vitamin D (50,000 IU every 2 weeks) plus probiotic (4.5 × 1011 CFU per day) or placebo for 12 weeks. The Headache Impact Test (HIT-6) and Depression, Anxiety, and Stress Scale (DASS) questionnaires were administered to patients at baseline and after 12 weeks. In addition, the frequency, duration, and severity of migraine headaches per month were assessed using a self-administered 30-day headache diary at baseline and the end of the intervention. Anthropometric indices, blood pressure, and serum levels of 25-hydroxy vitamin D and hs-CRP were also examined at first and the end of the study.

RESULTS

Seventy-two migraine patients with a mean age of 37.46 ± 8.32 years were included in this trial. Probiotic and vitamin D co-supplementation compared to placebo resulted in a significant increase in serum levels of vitamin D (+ 12.86 ± 1.64 vs. + 1.12 ± 0.80 ng/mL, P < 0.001). The between-group analysis in the adjusted model showed a significantly greater reduction in migraine headache frequency (- 3.17 ± 0.84 vs. - 1.25 ± 0.34; P = 0.031) and severity (- 1.55 ± 0.35 vs. + 0.67 ± 0.29; P = 0.017) in the probiotic and vitamin D group than the placebo group. No significant difference was found between the two arms of the intervention regarding the change in headache duration, hs-CRP, scores of DASS, and HIT-6 questionnaires (P > 0.05).

CONCLUSIONS

This trial showed that probiotic and vitamin D co-supplementation for 12 weeks has beneficial effects on migraine headache characteristics. Further research is needed to confirm this finding.

Efficacy of bifidobacterium-related preparations on depression: the first meta-analysis

Currently, depression-induced suicide has emerged as the primary contributor to the worldwide burden of disability. However, the prevailing drug treatment not only suffers from delayed effectiveness and limited efficacy, but also there are withdrawal symptoms and rebound phenomenon. Consequently, there is an imperative to investigate safer and more efficient treatments to ameliorate the clinical manifestations of depression. At present, there is increased evidence that probiotics can improve the symptoms of depression, but the existing studies use many and mixed types of probiotics, and it is impossible to determine the specific efficacy of bifidobacteria in the treatment of depression. This review will systematically review the effects of bifidobacteria on the treatment effect of depression, Meta-analysis showed that Bifidobacterium-related preparations effectively improved depressive symptoms in patients with depression. This study represents the initial meta-analysis conducted on the use of bifidobacteria-related agents for treating depression. The objective was to determine the effect of bifidobacteria-related preparations on improving depressive symptoms. We found that Bifidobacterium and its related agents can effectively reduce depression scale scores in patients with depression, suggesting the need for further research into this potential strategy for the prevention and treatment of depression.

Probiotics may be useful for drug-induced liver dysfunction in patients with depression - A secondary analysis of a randomized clinical trial

BACKGROUND & AIMS

There is a need to identify new treatment options for depression with its comorbidities. Depression often coexists with liver steatosis and the two may share a pathophysiological overlap, including inflammation and microbiota changes. Probiotics might represent a safe option as an adjunctive therapy in patients with depression and possible liver steatosis. The paper presents the secondary analysis of a clinical trial of the effect of probiotic supplementation on the levels of non-invasive markers of liver steatosis and fibrosis in adult patients with depressive disorders.

METHODS

The research had a two-arm, parallel-group, prospective, randomized, double-blind, controlled design on probiotics in depression. 116 participants received a probiotic preparation containing Lactobacillus helveticus Rosell®-52 and Bifidobacterium longum Rosell®-175 over 60 days. Here, data from 92 subjects was analyzed. The following were assessed: alanine aminotransferase (ALT), alanine aminotransferase/aspartate aminotransferase (ALT/AST) ratio, Hepatic Steatosis Index, Framingham Steatosis Index, as well as non-invasive biomarkers of liver fibrosis (AST to Platelet Ratio Index, Fibosis-4 Index), or baseline socio-demographic, clinical, and laboratory parameters.

RESULTS

The probiotics did not influence liver steatosis and fibrosis parameters compared with placebo (p = 0.940 for HSI). However, the subgroup analysis revealed significant differences in liver-related parameters when stratified by the main diagnosis group (better improvement in steatosis indices after probiotics in depressive episode than mixed depression and anxiety disorder patients) or psychotropic medications use (better improvement in ALT-based indices after probiotics in antidepressant-treated subjects than those non-antidepressant-treated). The interplay between probiotics, medications, clinical and metabolic profiles of depression, and the changes in liver-related parameters has been discussed.

CONCLUSIONS

Multiple factors may modulate the postulated hepatoprotective properties of probiotics efficacy in patients with depression. Further studies with larger sample sizes, different probiotic strains, and longer intervention period are necessary to assess the real significance of probiotics for liver health in this population.

CLINICALTRIALS

GOV IDENTIFIER

NCT04756544.

Importance of dietary fiber in children

Dietary fibers (DFs) are essential components of human nutrition and are principally defined as non-digestible carbohydrates (oligosaccharides and polysaccharides) usually classified by their physicochemical and physiological characteristics (water solubility, viscosity, fermentability, and bulking effect). Unfortunately, there is limited information on dietary fiber recommendations for children, and the evidence on their effect on health and symptom control is mainly available for the adult population. Therefore, this review aims to give a comprehensive overview of the characteristics and dietary sources of dietary fiber and their potential health benefits in healthy children but also their potential use in the treatment of sick children.

The Role of Inflammation in Depression and Beyond: A Primer for Clinicians

PURPOSE OF REVIEW

We evaluate available evidence for the role of inflammation in depression. We reappraise literature involving systemic inflammation, neuroinflammation and neurotransmission and their association with depression. We review the connection between depression, autoimmunity and infectious diseases. We revise anti-inflammatory treatments used in depression.

RECENT FINDINGS

Peripheral inflammatory markers are present in a subset of patients with depression and can alter common neurotransmitters in this population but there is no clear causality between depression and systemic inflammation. Infectious conditions and autoimmune illnesses do not have a clear correlation with depression. Certain medications have positive evidence as adjunctive treatments in depression but studies are heterogenic, hence they are sparsely used in clinical settings. The current evidence does not fully support inflammation, infections or autoimmunity as possible etiologies of depression. The available studies have numerous confounders that obscure the findings. Anti-inflammatory agents may have potential for treatment of depression, but further research is needed to clarify their usefulness in routine clinical practice.

Critical Windows: Exploring the Association Between Perinatal Trauma, Epigenetics, and Chronic Pain

Chronic pain is highly prevalent and burdensome, affecting millions of people worldwide. Although it emerges at any point in life, it often manifests in adolescence. Given that adolescence is a unique developmental period, additional strains associated with persistent and often idiopathic pain lead to significant long-term consequences. While there is no singular cause for the chronification of pain, epigenetic modifications that lead to neural reorganization may underpin central sensitization and subsequent manifestation of pain hypersensitivity. Epigenetic processes are particularly active during the prenatal and early postnatal years. We demonstrate how exposure to various traumas, such as intimate partner violence while in utero or adverse childhood experiences, can significantly influence epigenetic regulation within the brain and in turn modify pain-related processes. We provide compelling evidence that the burden of chronic pain is likely initiated early in life, often being transmitted from mother to offspring. We also highlight two promising prophylactic strategies, oxytocin administration and probiotic use, that have the potential to attenuate the epigenetic consequences of early adversity. Overall, we advance understanding of the causal relationship between trauma and adolescent chronic pain by highlighting epigenetic mechanisms that underlie this transmission of risk, ultimately informing how to prevent this rising epidemic.

New perspectives on microbiome-dependent gut-brain pathways for the treatment of depression with gastrointestinal symptoms: from bench to bedside

Patients with depression are more likely to have chronic gastrointestinal (GI) symptoms than the general population, but such symptoms are considered only somatic symptoms of depression and lack special attention. There is a chronic lack of appropriate diagnosis and effective treatment for patients with depression accompanied by GI symptoms, and studying the association between depression and GI disorders (GIDs) is extremely important for clinical management. There is growing evidence that depression is closely related to the microbiota present in the GI tract, and the microbiota-gut-brain axis (MGBA) is creating a new perspective on the association between depression and GIDs. Identifying and treating GIDs would provide a key opportunity to prevent episodes of depression and may also improve the outcome of refractory depression. Current studies on depression and the microbially related gut-brain axis (GBA) lack a focus on GI function. In this review, we combine preclinical and clinical evidence to summarize the roles of the microbially regulated GBA in emotions and GI function, and summarize potential therapeutic strategies to provide a reference for the study of the pathomechanism and treatment of depression in combination with GI symptoms.

Association between bowel movement disorders and depressive symptoms: a cross-sectional study

Objectives

This study aimed to explore the association between bowel movement disorders and depression in adults.

Method

A cross-sectional study was conducted using data from the National Health and Nutritional Examination Survey (NHANES), 2005-2010. Depression, constipation, diarrhea, and fecal incontinence were self-reported via questionnaires. Weighted logistic regression and subgroup analyses were performed to explore the association between bowel movement disorders and the risk of depression. Restricted cubic spline (RCS) was also conducted to investigate the association between bowel movements disorder and depression.

Results

A total of 13,820 participants were collected. Compared to the participants with normal bowel movements, the full-adjusted depression model ORs for constipation and diarrhea were 2.28 (95%CI,1.78-2.92), 1.75 (95%CI,1.31-2.31), respectively. Any kind of bowel leakage were associated with depression. The RCS showed the possible nonlinear association between bowel movement frequency/stool shape and depression.

Conclusions

Constipation, diarrhea, and bowel leakage are associated with an increased risk of depression.

Supplementation with Lactobacillus helveticus NS8 alleviated behavioral, neural, endocrine, and microbiota abnormalities in an endogenous rat model of depression

Introduction

Major depressive disorder is a condition involving microbiota-gut-brain axis dysfunction. Increasing research aims to improve depression through gut microbiota regulation, including interventions such as probiotics, prebiotics, and fecal microbiota transplants. However, most research focuses on exogenous depression induced by chronic stress or drugs, with less attention given to endogenous depression. Additionally, research on gut mycobiota in depression is significantly less than that on gut bacteria.

Methods

In the present study, Wistar-Kyoto rats were used as an endogenous depression and treatment-resistant depression model, while Wistar rats served as controls. Differences between the two rat strains in behavior, gut bacteria, gut mycobiota, nervous system, endocrine system, immune system, and gut barrier were evaluated. Additionally, the effects of Lactobacillus helveticus NS8 supplementation were investigated.

Results

Wistar-Kyoto rats demonstrated increased depressive-like behaviors in the forced swimming test, reduced sucrose preference in the sucrose preference test, and decreased locomotor activity in the open field test. They also exhibited abnormal gut bacteria and mycobiota, characterized by higher bacterial α-diversity but lower fungal α-diversity, along with increased butyrate, L-tyrosine, and L-phenylalanine biosynthesis from bacteria. Furthermore, these rats showed dysfunction in the microbiota-gut-brain axis, evidenced by a hypo-serotonergic system, hyper-noradrenergic system, defective hypothalamic-pituitary-adrenal axis, compromised gut barrier integrity, heightened serum inflammation, and diminished gut immunity. A 1-month L. helveticus NS8 intervention increased the fecal abundance of L. helveticus; reduced the abundance of Bilophila and Debaryomycetaceae; decreased immobility time but increased climbing time in the forced swimming test; reduced hippocampal corticotropin-releasing hormone levels; decreased hypothalamic norepinephrine levels; increased hippocampal glucocorticoid receptor, brain-derived neurotrophic factor dopamine, and 5-hydroxyindoleacetic acid content; and improved the gut microbiota, serotonergic, and noradrenergic system.

Conclusion

The depressive phenotype of Wistar-Kyoto rats is not only attributed to their genetic context but also closely related to their gut microbiota. Abnormal gut microbiota and a dysfunctional microbiota-gut-brain axis play important roles in endogenous depression, just as they do in exogenous depression. Supplementing with probiotics such as L. helveticus NS8 is likely a promising approach to improve endogenous depression and treatment-resistant depression.

Fluoxetine attenuates the anxiolytic effects of the probiotic VSL#3 in a stress-vulnerable genetic line of aves in the chick social-separation stress test, a dual screening assay

Anxiety disorders represent one of the most common and debilitating illnesses worldwide. However, the development of novel therapeutics for anxiety disorders has lagged compared to other mental illnesses. A growing body of research suggests the gut microbiota plays a role in the etiopathology of anxiety disorders and may, therefore, serve as a novel target for their treatment through the use of probiotics. The use of dietary supplements like probiotics is increasing and their interaction with pharmacotherapies is not well understood. Utilizing the chick social-separation stress test, the primary aim of this study was to evaluate the commercially-available multi-strain probiotic found in VSL#3 for potential anxiolytic-like and/or antidepressant-like effects in the stress-vulnerable Black Australorp genetic line. A secondary aim was to evaluate the interaction between probiotics and the SSRI fluoxetine. Animals were treated with either saline, probiotics, fluoxetine, or probiotics + fluoxetine for 8 days prior to exposure to a 90-min isolation stressor that produces both a panic-like (i.e., anxiety-like) state followed by a state of behavioral despair (i.e., depression-like). The 8-day probiotic regimen produced anxiolytic-like effects but did not attenuate behavioral despair. Fluoxetine failed to significantly alter behavior in either of the two phases. Moreover, the combination of fluoxetine with probiotics attenuated the anxiolytic-like effects of probiotics. The fluoxetine + probiotics combination had no effect on behavioral despair. The results of the current study align with other preclinical studies and some clinical trials suggesting probiotics may offer beneficial effects on anxiety. Investigations examining the anxiolytic-like mechanism of probiotics are needed before any conclusions can be made. Additionally, as the use of probiotics becomes more popular, research on the interactions between probiotic-microbiota and psychotropic medications is necessary.

Chronic constipation and gut microbiota: current research insights and therapeutic implications

Chronic constipation is a prevalent clinical condition. Its etiology and pathogenesis have not yet been fully understood. In recent years, mounting evidence suggests a close association between chronic constipation and intestinal dysbiosis, including alterations in the colony structure and metabolites, as well as the modulation of bowel movements via the brain-gut-microbiota axis. With the deepening of related research, probiotic-related therapies are expected to become a potential first-line treatment for chronic constipation in the future. In this review, we summarize the current research insights into the intricate relationships between chronic constipation and the gut microbiota and briefly discuss several different approaches for treating chronic constipation. The findings from this review may advance our understanding of the pathological mechanisms underlying chronic constipation and, ultimately, translate them into improvements in patient care.

Bacterial association with metals enables in vivo monitoring of urogenital microbiota using magnetic resonance imaging

Bacteria constitute a significant part of the biomass of the human microbiota, but their interactions are complex and difficult to replicate outside the host. Exploiting the superior resolution of magnetic resonance imaging (MRI) to examine signal parameters of selected human isolates may allow tracking of their dispersion throughout the body. Here we investigate longitudinal and transverse MRI relaxation rates and found significant differences between several bacterial strains. Common commensal strains of lactobacilli display notably high MRI relaxation rates, partially explained by elevated cellular manganese content, while other species contain more iron than manganese. Lactobacillus crispatus show particularly high values, 4-fold greater than any other species; up to 60-fold greater signal than relevant tissue background; and a linear relationship between relaxation rate and fraction of live cells. Different bacterial strains have detectable, repeatable MRI relaxation rates that in the future may enable monitoring of their persistence in the human body for enhanced molecular imaging.

"Inflamed" depression: A review of the interactions between depression and inflammation and current anti-inflammatory strategies for depression

Depression is a common mental disorder, the effective treatment of which remains a challenging issue worldwide. The clinical pathogenesis of depression has been deeply explored, leading to the formulation of various pathogenic hypotheses. Among these, the monoamine neurotransmitter hypothesis holds a prominent position, yet it has significant limitations as more than one-third of patients do not respond to conventional treatments targeting monoamine transmission disturbances. Over the past few decades, a growing body of research has highlighted the link between inflammation and depression as a potential key factor in the pathophysiology of depression. In this review, we first summarize the relationship between inflammation and depression, with a focus on the pathophysiological changes mediated by inflammation in depression. The mechanisms linking inflammation to depression as well as multiple anti-inflammatory strategies are also discussed, and their efficacy and safety are assessed. This review broadens the perspective on specific aspects of using anti-inflammatory strategies for treating depression, laying the groundwork for advancing precision medicine for individuals suffering from "inflamed" depression.

Therapeutic modulation of the kynurenine pathway in severe mental illness and comorbidities: A potential role for serotonergic psychedelics

Mounting evidence points towards a crucial role of the kynurenine pathway (KP) in the altered gut-brain axis (GBA) balance in severe mental illness (SMI, namely depression, bipolar disorder, and schizophrenia) and cardiometabolic comorbidities. Preliminary evidence shows that serotonergic psychedelics and their analogues may hold therapeutic potential in addressing the altered KP in the dysregulated GBA in SMI and comorbidities. In fact, aside from their effects on mood, psychedelics elicit therapeutic improvement in preclinical models of obesity, metabolic syndrome, and vascular inflammation, which are highly comorbid with SMI. Here, we review the literature on the therapeutic modulation of the KP in the dysregulated GBA in SMI and comorbidities, and the potential application of psychedelics to address the altered KP in the brain and systemic dysfunction underlying SMI and comorbidities. Psychedelics might therapeutically modulate the KP in the altered GBA in SMI and comorbidities either directly, via altering the metabolic pathway by influencing the rate-limiting enzymes of the KP and affecting the levels of available tryptophan, or indirectly, by affecting the gut microbiome, gut metabolome, metabolism, and the immune system. Despite promising preliminary evidence, the mechanisms and outcomes of the KP modulation with psychedelics in SMI and systemic comorbidities remain largely unknown and require further investigation. Several concerns are discussed surrounding the potential side effects of this approach in specific cohorts of individuals with SMI and systemic comorbidities.

The gut microbiota-brain axis in neurological disorders

Previous studies have shown a bidirectional communication between human gut microbiota and the brain, known as the microbiota-gut-brain axis (MGBA). The MGBA influences the host's nervous system development, emotional regulation, and cognitive function through neurotransmitters, immune modulation, and metabolic pathways. Factors like diet, lifestyle, genetics, and environment shape the gut microbiota composition together. Most research have explored how gut microbiota regulates host physiology and its potential in preventing and treating neurological disorders. However, the individual heterogeneity of gut microbiota, strains playing a dominant role in neurological diseases, and the interactions of these microbial metabolites with the central/peripheral nervous systems still need exploration. This review summarizes the potential role of gut microbiota in driving neurodevelopmental disorders (autism spectrum disorder and attention deficit/hyperactivity disorder), neurodegenerative diseases (Alzheimer's and Parkinson's disease), and mood disorders (anxiety and depression) in recent years and discusses the current clinical and preclinical gut microbe-based interventions, including dietary intervention, probiotics, prebiotics, and fecal microbiota transplantation. It also puts forward the current insufficient research on gut microbiota in neurological disorders and provides a framework for further research on neurological disorders.

Honey Added to Yogurt with Bifidobacterium animalis subsp. lactis DN-173 010/CNCM I-2494 Supports Probiotic Enrichment but Does Not Reduce Intestinal Transit Time in Healthy Adults: A Randomized, Controlled, Crossover Trial

BACKGROUND

Honey improves probiotic survival in vitro. However, if this effect translates to humans has not been investigated.

OBJECTIVES

We aimed to determine effects of honey plus yogurt containing the probiotic Bifidobacterium animalis subsp. lactis DN-173 010/CNCM I-2494 (B. animalis) on intestinal transit time, probiotic enrichment, digestive health, mood, and cognition in adults.

METHODS

Sixty-six healthy adults (34 female; 33.6 ± 9.8 y; 24.6 ± 3.0 kg/m2) in a crossover trial were randomly assigned to 2-wk yogurt conditions in a counterbalanced order with ≥4-wk washout: 1) Honey (HON): yogurt plus honey and 2) Negative Control (NC): heat-treated yogurt plus sugar. Of the participants, n = 62 completed the trial, and n = 37 (17 female; 32.0 ± 8.3 y; 25.0 ± 2.9 kg/m2) elected to enroll in a third condition (a nonrandomized study extension) after ≥4-wk washout with a reference Positive Control (PC): yogurt plus sugar. At baseline and end of each of the 3 conditions, intestinal transit time was measured with dye capsules; probiotic abundance with fecal DNA 16S sequencing; digestive health with symptom/function records, Bristol stool consistency, Gastrointestinal Tolerability, and Gastrointestinal Quality of Life Index; mood with Positive and Negative Affect Schedule-Short Form, Depression Anxiety Stress Scales-42, Patient-Reported Outcomes Measurement Information System questionnaires, and an emotional image task; and cognition with a spatial reconstruction task. Data were analyzed using linear mixed-effects models (LMMs) with significance at P ≤ 0.05. Baseline and end data were included in the LMM, with fixed effects being treatment, time, treatment by time interaction, and baseline covariate, and the random effect being the participant.

RESULTS

B. animalis was enriched in HON (d = 3.54; P = 0.0002) compared to controls with linear discriminant analysis effect size. Intestinal transit time, gastrointestinal health, mood, and cognition did not differ between conditions (LMM: Ps > 0.05).

CONCLUSIONS

Yogurt + honey enriched B. animalis but did not reduce intestinal transit time or have other functional gastrointestinal, mood, or cognitive effects in adults. This trial was registered at www.

CLINICALTRIALS

gov as NCT04187950 and NCT04901390.

Vitamin-mediated interaction between the gut microbiome and mitochondria in depression: A systematic review-based integrated perspective

Depression is one of the world's most prevalent mental disorders and its treatment remains suboptimal. Depression is a systemic disease with highly complex biological mechanisms. Emerging evidence points towards the involvement of mitochondria, microbiome and vitamins in its pathophysiology. Mitochondrial energy production was shown to be lowered in patients with depression. Mitochondrial energy production depends on vitamins, which are available from food, but are also synthesized by the gut microbiota. Several studies reported altered vitamin levels as well as changes in the gut microbiome composition and its vitamin metabolism in patients with depression. Therefore, the question of a connection between mitochondria and gut microbiome and vitamins influencing the mental health arises. This review aims to systematically investigate a combination of the topics - depression, mitochondria, microbiome, and vitamins - to generate an overview of a novel yet extremely complex and interconnected research field. A systematic literature search yielded 34 articles, and the results were summarized and bundled to develop this new integrative perspective on mitochondrial function mediated by the microbiome and microbiome-derived vitamins in depression. Furthermore, by discussing the research gaps this review aims to encourage innovative research approaches to better understand the biology of depression, which could result in optimized therapeutic approaches.

The effect of different sweeteners on the oral microbiome: a randomized clinical exploratory pilot study

Introduction

The aim of the study was to evaluate the modulating effects of five commonly used sweetener (glucose, inulin, isomaltulose, tagatose, trehalose) containing mouth rinses on the oral microbiome.

Methods

A single-centre, double-blind, parallel randomized clinical trial was performed with healthy, 18-55-year-old volunteers (N = 65), who rinsed thrice-daily for two weeks with a 10% solution of one of the allocated sweeteners. Microbiota composition of supragingival dental plaque and the tongue dorsum coating was analysed by 16S RNA gene amplicon sequencing of the V4 hypervariable region (Illumina MiSeq). As secondary outcomes, dental plaque red fluorescence and salivary pH were measured.

Results

Dental plaque microbiota changed significantly for two groups: inulin (F = 2.0239, p = 0.0006 PERMANOVA, Aitchison distance) and isomaltulose (F = 0.67, p = 0.0305). For the tongue microbiota, significant changes were observed for isomaltulose (F = 0.8382, p = 0.0452) and trehalose (F = 1.0119, p = 0.0098). In plaque, 13 species changed significantly for the inulin group, while for tongue coating, three species changed for the trehalose group (ALDEx2, p < 0.1). No significant changes were observed for the secondary outcomes.

Conclusion

The effects on the oral microbiota were sweetener dependant with the most pronounced effect on plaque microbiota. Inulin exhibited the strongest microbial modulating potential of the sweeteners tested. Further full-scale clinical studies are required.

Butyrate- and Beta-Hydroxybutyrate-Mediated Effects of Interventions with Pro- and Prebiotics, Fasting, and Caloric Restrictions on Depression: A Systematic Review and Meta-Analysis

To examine the butyrate- and beta-hydroxybutyrate (BHB)-modulated effects of pre- and probiotic interventions, fasting, and caloric restriction interventions, a systematic literature review was carried out with a subsequent meta-analysis. Three pre-and probiotic intervention randomized control trials (RCTs) were included in the meta-analysis. A significant increase in butyrate (standardized mean difference (SMD) [confidence interval (CI)] 0.34; [0.02-0.67]) and an improvement in depression scores (SMD [CI] 0.15, [-0.35-0.70]) through pre- and probiotic interventions were shown in the meta-analysis. The intervention duration of the included studies ranged from three days to four weeks, with the examined population being healthy adults. Butyrate was measured in either plasma or feces, and the depression score was obtained under the Swedish core affect scale, the hospital anxiety and depression scale (HADS), or the depression, anxiety, and stress scale-21 items (DASS-21). In addition to butyrate, the total SCFA concentration also seems to be positively associated with pre- and probiotic administration (SMD [CI] 0.55 [0.15-0.95]). Despite the significant short-chain fatty acid (SCFA) and butyrate concentration changes, no significant correlation between butyrate and depression or between SCFAs and depression could be shown through linear regression models. Nevertheless, the regression coefficient b1 = 1.57 (p = 0.17) for butyrate suggests a strong, positive connection between butyrate and depression. Additionally, three studies were qualitatively analyzed, examining fasting as an intervention and revealing a connection between fasting, BHB, and depression. The association between fasting, BHB, and depression or mood elevation appeared to be related to BHB concentrations, which may be due to the similar biochemical properties of BHB and butyrate. Furthermore, caloric restrictions as alternatives to fasting were proposed as potential long-term interventions.

Fecal Microbiota Transplantation for Sleep Disturbance in Post-acute COVID-19 Syndrome

BACKGROUND & AIMS

Post-acute COVID-19 syndrome (PACS) is associated with sleep disturbance, but treatment options are limited. The etiology of PACS may be secondary to alterations in the gut microbiome. Here, we report the efficacy of fecal microbiota transplantation (FMT) in alleviating post-COVID insomnia symptoms in a nonrandomized, open-label prospective interventional study.

METHODS

Between September 22, 2022, and May 22, 2023, we recruited 60 PACS patients with insomnia defined as Insomnia Severity Index (ISI) ≥8 and assigned them to the FMT group (FMT at weeks 0, 2, 4, and 8; n = 30) or the control group (n = 30). The primary outcome was clinical remission defined by an ISI of <8 at 12 weeks. Secondary outcomes included changes in the Pittsburgh Sleep Quality Index, Generalized Anxiety Disorder-7 scale, Epworth Sleepiness Scale, Multidimensional Fatigue Inventory, blood cortisol and melatonin, and gut microbiome analysis on metagenomic sequencing.

RESULTS

At week 12, more patients in the FMT than the control group had insomnia remission (37.9% vs 10.0%; P = .018). The FMT group showed a decrease in ISI score (P < .0001), Pittsburgh Sleep Quality Index (P < .0001), Generalized Anxiety Disorder-7 scale (P = .0019), Epworth Sleepiness Scale (P = .0057), and blood cortisol concentration (P = .035) from baseline to week 12, but there was no significant change in the control group. There was enrichment of bacteria such as Gemmiger formicilis and depletion of microbial pathways producing menaquinol derivatives after FMT. The gut microbiome profile resembled that of the donor in FMT responders but not in nonresponders at week 12. There was no serious adverse event.

CONCLUSIONS

This pilot study showed that FMT could be effective and safe in alleviating post-COVID insomnia, and further clinical trials are warranted.

CLINICALTRIALS

gov, Number: NCT05556733.

A healthy dietary pattern is associated with microbiota diversity in recently diagnosed bipolar patients: The Bipolar Netherlands Cohort (BINCO) study

BACKGROUND

Diet largely impacts the gut microbiota, and may affect mental and somatic health via the gut-brain axis. As such, the relationship between diet and the microbiota in Bipolar Disorder (BD) could be of importance, but has not been studied before. The aim was therefore to assess whether dietary quality is associated with the gut microbiota diversity in patients with recently diagnosed BD, and whether changes occur in dietary quality and microbiota diversity during their first year of treatment.

METHODS

Seventy recently (<1 year) diagnosed patients with BD were included in the "Bipolar Netherlands Cohort" (BINCO), and a total of 45 participants were assessed after one year. A 203-item Food Frequency Questionnaire (FFQ) data yielded the Dutch Healthy index (DHD-15), and the microbiota composition and diversity of fecal samples were characterized by 16S rRNA gene amplicon sequencing at baseline and 1-year follow-up. Associations and changes over time were analyzed using multivariate regression analyses and t-tests for paired samples.

RESULTS

Included patients had a mean age of 34.9 years (SD ± 11.2), and 58.6 % was female. Alpha diversity (Shannon diversity index), richness (Chao1 index) and evenness (Pielou's Evenness Index) were positively associated with the DHD-15 total score, after adjustment for sex, age and educational level (beta = 0.55; P < 0.001, beta = 0.39; P = 0.024, beta = 0.54; P = 0.001 respectively). The positive correlations were largely driven by the combined positive effect of fish, beans, fruits and nuts, and inverse correlations with alcohol and processed meats. No significant changes were found in DHD-15 total score, nor in microbiota diversity, richness and evenness indexes during one year follow-up and regular treatment.

CONCLUSION

A healthy and varied diet is associated with the diversity of the microbiota in BD patients. Its potential consequences for maintaining mood stability and overall health should be studied further.

Mixed probiotics reduce the severity of stress-induced depressive-like behaviors

In recent years, the gut microbiome has gained significant attention in the spheres of research and public health. As a result, studies have increasingly explored the potential of probiotic dietary supplements as treatment interventions for conditions such as anxiety and depression. The present study examined the effect of mixed probiotics (Lacticaseibacillus rhamnosus and Enterococcus faecium) on inflammation, microbiome composition, and depressive-like behaviors in a macaque monkey model. The mixed probiotics effectively reduced the severity of depressive-like behaviors in macaque monkeys. Further, treatment with mixed probiotics gradually increased the abundance of beneficial bacteria in the gut, improving the balance of the gut microbiota. Additionally, macaques treated with the mixed probiotics showed decreased serum levels of inflammatory factors (P < 0.05), an increased rate of L-tryptophan metabolism (P < 0.05), and the restoration of 5-HT and 5-HTP levels (P < 0.05). Correlation analysis confirmed that Lacticaseibacillus and other beneficial bacteria exhibited a negative correlation with inflammation in the body (P < 0.05), and a positive correlation with tryptophan metabolism (P < 0.05). In conclusion, the mixed probiotics effectively restored intestinal homeostasis in macaques and enhanced tryptophan metabolism, ultimately alleviating inflammation and depressive-like behaviors.

Evolution and the critical role of the microbiota in the reduced mental and physical health associated with low socioeconomic status (SES)

The evolution of the gut-microbiota-brain axis in animals reveals that microbial inputs influence metabolism, the regulation of inflammation and the development of organs, including the brain. Inflammatory, neurodegenerative and psychiatric disorders are more prevalent in people of low socioeconomic status (SES). Many aspects of low SES reduce exposure to the microbial inputs on which we are in a state of evolved dependence, whereas the lifestyle of wealthy citizens maintains these exposures. This partially explains the health deficit of low SES, so focussing on our evolutionary history and on environmental and lifestyle factors that distort microbial exposures might help to mitigate that deficit. But the human microbiota is complex and we have poor understanding of its functions at the microbial and mechanistic levels, and in the brain. Perhaps its composition is more flexible than the microbiota of animals that have restricted habitats and less diverse diets? These uncertainties are discussed in relation to the encouraging but frustrating results of attempts to treat psychiatric disorders by modulating the microbiota.

Explorative Characterization of GI Complaints, General Physical and Mental Wellbeing, and Gut Microbiota in Trained Recreative and Competitive Athletes with or without Self-Reported Gastrointestinal Symptoms

The current state of the literature lacks a clear characterization of gastrointestinal (GI) symptoms, gut microbiota composition, and general physical and mental wellbeing in well-trained athletes. Therefore, this study aimed to characterize differences in self-reported symptoms, gut microbiota composition, and wellbeing (i.e., sleep quality, mood, and physical (PHQ) and mental wellbeing) between athletes with and without GI symptoms. In addition, we assessed the potential impact of a 3-week multi-ingredient fermented whey supplement in the GI complaints group, without a control group, on the gut microbiota and self-reported GI symptoms and wellbeing. A total of 50 athletes (24.7 ± 4.5 years) with GI issues (GI group at baseline, GI-B) and 21 athletes (25.4 ± 5.3 years) without GI issues (non-GI group, NGI) were included. At baseline, there was a significant difference in the total gastrointestinal symptom rating scale (GSRS) score (24.1 ± 8.48 vs. 30.3 ± 8.82, p = 0.008) and a trend difference in PHQ (33.9 ± 10.7 vs. 30.3 ± 8.82, p = 0.081), but no differences (p > 0.05) were seen for other outcomes, including gut microbiota metrics, between groups. After 3-week supplementation, the GI group (GI-S) showed increased Bifidobacterium relative abundance (p < 0.05), reported a lower number of severe GI complaints (from 72% to 54%, p < 0.001), and PHQ declined (p = 0.010). In conclusion, well-trained athletes with GI complaints reported more severe GI symptoms than an athletic reference group, without showing clear differences in wellbeing or microbiota composition. Future controlled research should further investigate the impact of such multi-ingredient supplements on GI complaints and the associated changes in gut health-related markers.

Mood disturbance, but not overall diet quality, is associated with fecal microbiome diversity in free-living adults

OBJECTIVES

To investigate the gut-brain axis, we explored the relationships among mood disturbance (MD), diet quality (DQ), and fecal microbiota in free-living adults.

METHODS

A cross-sectional analysis was conducted with data from 75 healthy adults enrolled in two studies. Anthropometrics, 16s rRNA gene sequencing of fecal microbes, DQ as assessed by Healthy Eating Index-2015 (HEI), and MD determined by Profile of Mood States (POMS) were included. Alpha-diversity and DQ differences were explored between low (n = 37) and high MD (n = 38) groups. Spearman correlations were used to investigate relationships between alpha-diversity, DQ, and POMS subscales. Moderation analysis explored the effect of HEI score on the relationship between MD and alpha-diversity.

RESULTS

Participants were mostly white (67%), 54.5 years old (±11.8), and overweight (28.5 ± 6.5 kg/m2). Shannon and Simpson indices indicate higher alpha-diversity in participants with low MD compared to high MD (p = 0.004 and p = 0.008, respectively). Simpson and Shannon indices were correlated with subscale of anger (rho = -0.303, p = 0.011; rho = -0.265, p = 0.027, respectively)and total MD (rho = -0.404, p = 0.001; rho = -0.357, p = 0.002, respectively). Refined grains were associated with fatigue and tension subscales (rho = 0.428, p < 0.001; rho = 0.302, p = 0.014, respectively). DQ did not significantly moderate the relationship between alpha-diversity and mood disturbance (F(7, 53) = 2.00, p = 0.072, R2 = 0.209). Shannon index was a significant predictor of MD (b = -4.39, t(53) = -2.55, p = 0.014), but total HEI score and the interaction (Shannon index*HEI score) were not significant.

DISCUSSION

Greater bacterial diversity was associated with lower MD, and DQ was associated with various mood state subscales in this sample of adults.

Role of the microbiota-gut-heart axis between bile acids and cardiovascular disease

Bile acid (BA) receptors (e.g., farnesoid X-activated receptor, muscarinic receptor) are expressed in cardiomyocytes, endothelial cells, and vascular smooth muscle cells, indicating the relevance of BAs to cardiovascular disease (CVD). Hydrophobic BAs are cardiotoxic, while hydrophilic BAs are cardioprotective. For example, fetal cardiac insufficiency in maternal intrahepatic cholestasis during pregnancy, and the degree of fetal cardiac abnormality, is closely related to the level of hydrophobic BAs in maternal blood and infant blood. However, ursodeoxycholic acid (the most hydrophilic BA) can reverse/prevent these detrimental effects of increased levels of hydrophobic BAs on the heart. The gut microbiota (GM) and GM metabolites (especially secondary BAs) have crucial roles in hypertension, atherosclerosis, unstable angina, and heart failure. Herein, we describe the relationship between CVD and the GM at the BA level. We combine the concept of the "microbiota-gut-heart axis" (MGHA) and postulate the role and mechanism of BAs in CVD development. In addition, the strategies for treating CVD with BAs under the MGHA are proposed.

Nutraceuticals in Psychiatric Disorders: A Systematic Review

Correct nutrition and diet are directly correlated with mental health, functions of the immune system, and gut microbiota composition. Diets with a high content of some nutrients, such as fibers, phytochemicals, and short-chain fatty acids (omega-3 fatty acids), seem to have an anti-inflammatory and protective action on the nervous system. Among nutraceuticals, supplementation of probiotics and omega-3 fatty acids plays a role in improving symptoms of several mental disorders. In this review, we collect data on the efficacy of nutraceuticals in patients with schizophrenia, autism spectrum disorders, major depression, bipolar disorder, and personality disorders. This narrative review aims to provide an overview of recent evidence obtained on this topic, pointing out the direction for future research.

Distinguishing bipolar depression, bipolar mania, and major depressive disorder by gut microbial characteristics

BACKGROUND

Gut microbial disturbance has been widely confirmed in mood disorders. However, little is known about whether gut microbial characteristics can distinguish major depressive disorder (MDD), bipolar depression (BP-D), and bipolar mania (BP-M).

METHODS

This was a prospective case-control study. The composition of gut microbiota was profiled using 16S ribosomal RNA (rRNA) gene sequencing of fecal samples and compared between healthy controls (HC; n = 46), MDD (n = 51), BP-D (n = 44), and patients with BP-M (n = 45).

RESULTS

Gut microbial compositions were remarkably changed in the patients with MDD, BP-D, and BP-M. Compared to HC, distinct gut microbiome signatures were found in MDD, BP-D, and BP-M, and some gut microbial changes were overlapping between the three mood disorders. Furthermore, we identified a signature of 7 operational taxonomic units (OUT; Prevotellaceae-related OUT22, Prevotellaceae-related OUT31, Prevotellaceae-related OTU770, Ruminococcaceae-related OUT70, Bacteroidaceae-related OTU1536, Propionibacteriaceae-related OTU97, Acidaminococcaceae-related OTU34) that can distinguish patients with MDD from those with BP-D, BP-M, or HC, with area under the curve (AUC) values ranging from 0.910 to 0.996.

CONCLUSION

Our results provide the clinical rationale for the discriminative diagnosis of MDD, BP-D, and BP-M by characteristic gut microbial features.

Sleep deprivation-induced anxiety-like behaviors are associated with alterations in the gut microbiota and metabolites

The present study aimed to characterize the gut microbiota and serum metabolome changes associated with sleep deprivation (SD) as well as to explore the potential benefits of multi-probiotic supplementation in alleviating SD-related mental health disorders. Rats were subjected to 7 days of SD, followed by 14 days of multi-probiotics or saline administration. Open-field tests were conducted at baseline, end of SD (day 7), and after 14 days of saline or multi-probiotic gavage (day 21). Metagenomic sequencing was conducted on fecal samples, and serum metabolites were measured by untargeted liquid chromatography tandem-mass spectrometry. At day 7, anxiety-like behaviors, including significant decreases in total movement distance (P = 0.0002) and staying time in the central zone (P = 0.021), were observed. In addition, increased levels of lipopolysaccharide (LPS; P = 0.028) and decreased levels of uridine (P = 0.018) and tryptophan (P = 0.01) were detected in rats after 7 days of SD. After SD, the richness of the gut bacterial community increased, and the levels of Akkermansia muciniphila, Muribaculum intestinale, and Bacteroides caecimuris decreased. The changes in the host metabolism and gut microbiota composition were strongly associated with the anxiety-like behaviors caused by SD. In addition, multi-probiotic supplementation for 14 days modestly improved the anxiety-like behaviors in SD rats but significantly reduced the serum level of LPS (P = 0.045). In conclusion, SD induces changes in the gut microbiota and serum metabolites, which may contribute to the development of chronic inflammatory responses and affect the gut-brain axis, causing anxiety-like behaviors. Probiotic supplementation significantly reduces serum LPS, which may alleviate the influence of chronic inflammation.

IMPORTANCE

The disturbance in the gut microbiome and serum metabolome induced by SD may be involved in anxiety-like behaviors. Probiotic supplementation decreases serum levels of LPS, but this reduction may be insufficient for alleviating SD-induced anxiety-like behaviors.

Gut microbiota connects the brain and the heart: potential mechanisms and clinical implications

Nowadays, high morbidity and mortality of cardiovascular diseases (CVDs) and high comorbidity rate of neuropsychiatric disorders contribute to global burden of health and economics. Consequently, a discipline concerning abnormal connections between the brain and the heart and the resulting disease states, known as psychocardiology, has garnered interest among researchers. However, identifying a common pathway that physicians can modulate remains a challenge. Gut microbiota, a constituent part of the human intestinal ecosystem, is likely involved in mutual mechanism CVDs and neuropsychiatric disorder share, which could be a potential target of interventions in psychocardiology. This review aimed to discuss complex interactions from the perspectives of microbial and intestinal dysfunction, behavioral factors, and pathophysiological changes and to present possible approaches to regulating gut microbiota, both of which are future directions in psychocardiology.

Gut microbiota: A potential player in psychiatric symptoms during COVID-19

OBJECTIVES

This study aims to explore the potential interconnections among gut microbiota, COVID-19 infection, depression and anxiety disorder. Additionally, it tries to assess potential therapeutic interventions that may improve the dysbiosis of gut microbiota.

METHODS

To achieve these objectives, we reviewed existing literature, encompassing studies and critical reviews that intersect the domains of gut microbiota, COVID-19, depression and anxiety disorders.

RESULTS

The findings highlight a notable correlation between the dysbiosis of gut microbiota and psychiatric symptoms in the context of COVID-19. Specifically, there is a marked reduction in the populations of bacteria that generate anti-inflammatory short-chain fatty acids (SCFAs), alongside a rise in the prevalence of gut bacterial clusters linked to inflammatory processes. Furthermore, several potential treatment strategies were summarised for improving the dysbiosis.

CONCLUSIONS

Gut microbiota plays a significant role in psychiatric symptoms during COVID-19, which has significant implications for the study and prevention of psychiatric symptoms in major epidemic diseases.

Neurological and metabolic related pathophysiologies and treatment of comorbid diabetes with depression

BACKGROUND

The comorbidity between diabetes mellitus and depression was revealed, and diabetes mellitus increased the prevalence of depressive disorder, which ranked 13th in the leading causes of disability-adjusted life-years. Insulin resistance, which is common in diabetes mellitus, has increased the risk of depressive symptoms in both humans and animals. However, the mechanisms behind the comorbidity are multi-factorial and complicated. There is still no causal chain to explain the comorbidity exactly. Moreover, Selective serotonin reuptake inhibitors, insulin and metformin, which are recommended for treating diabetes mellitus-induced depression, were found to be a risk factor in some complications of diabetes.

AIMS

Given these problems, many researchers made remarkable efforts to analyze diabetes complicating depression from different aspects, including insulin resistance, stress and Hypothalamic-Pituitary-Adrenal axis, neurological system, oxidative stress, and inflammation. Drug therapy, such as Hydrogen Sulfide, Cannabidiol, Ascorbic Acid and Hesperidin, are conducive to alleviating diabetes mellitus and depression. Here, we reviewed the exact pathophysiology underlying the comorbidity between depressive disorder and diabetes mellitus and drug therapy.

METHODS

The review refers to the available literature in PubMed and Web of Science, searching critical terms related to diabetes mellitus, depression and drug therapy.

RESULTS

In this review, we found that brain structure and function, neurogenesis, brain-derived neurotrophic factor and glucose and lipid metabolism were involved in the pathophysiology of the comorbidity. Obesity might lead to diabetes mellitus and depression through reduced adiponectin and increased leptin and resistin. In addition, drug therapy displayed in this review could expand the region of potential therapy.

CONCLUSIONS

The review summarizes the mechanisms underlying the comorbidity. It also overviews drug therapy with anti-diabetic and anti-depressant effects.

Dietary habits, depression and obesity: an intricate relationship to explore in pediatric preventive strategies

Obesity and depression represent major health problems due to their high prevalence and morbidity rates. Numerous evidences elucidated the connections between dietary habits and the incidence or severity of depression. This overview aims to investigate the intricate relationship between dietary patterns and depression with the objective of elaborating preventive strategies for childhood obesity. Literature data recognized that there is a link between mood and food choices, with certain foods selected for their impact on the brain's reward centers. This behavior parallels the one observed in substance addiction, suggesting a specific neural mechanism for food addiction that contributes to overeating and obesity. It is important to note the significant correlation between obesity and depression, indicating a shared biological pathway influencing these conditions. Stress substantially affects also eating behaviors, often leading to increased consumption of pleasurable and rewarding foods. This can trigger a cycle of overeating, weight gain, and psychological distress, exacerbating mood disorders and obesity. In addition, consumption of certain types of foods, especially "comfort foods" high in fat and calories, may provide temporary relief from symptoms of depression, but can lead to long-term obesity and further mental health problems. Understanding these complex interactions is critical to developing preventive strategies focusing on dietary, emotional, and environmental factors, thereby reducing the risk of obesity and mood disorders.

SCFAs Supplementation Rescues Anxiety- and Depression-like Phenotypes Generated by Fecal Engraftment of Treatment-Resistant Depression Rats

Alteration of gut microbiota and microbial metabolites such as short-chain fatty acids (SCFAs) coexisted with stress-generated brain disorders, including depression. Herein, we investigated the effect of SCFAs in a treatment-resistant depression (TRD) model of rat. Rats were exposed to chronic-unpredictable mild stress (CUMS) and repeated adrenocorticotropic hormone (ACTH) injections to generate a TRD-like phenotype. The cecal contents of these animals were engrafted into healthy-recipient rats and allowed to colonize for 4 weeks (TRD-FMT group). Blood, brain, colon, fecal, and cecal samples were collected for molecular studies. Rats exposed to CUMS + ACTH showed TRD-like phenotypes in sucrose-preference (SPT), forced swim (FST), and elevated plus maze (EPM) tests. The TRD-FMT group also exhibited anxiety- and depression-like behaviors. Administration of SCFAs (acetate, propionate, and butyrate at 67.5, 25, and 40 mM, respectively) for 7 days exerted robust antidepressant and antianxiety effects by restoring the levels of SCFAs in plasma and fecal samples, and proinflammatory cytokines (TNF-α and IL-6), serotonin, GABA, norepinephrine, and dopamine in the hippocampus and/or frontal cortex of TRD and TRD-FMT animals. SCFAs treatment elevated the expression of free-fatty acid receptors 2/3, BDNF, doublecortin, and zonula-occludens, and reduced the elevated plasma levels of kynurenine and quinolinic acid and increased mucus-producing goblet cells in TRD and TRD-FMT animals. In 16S sequencing results, decreased microbial diversity in TRD rats corresponds with differences in the genus of Faecalibacterium, Anaerostipes, Allobaculum, Blautia, Peptococcus, Rombustia, Ruminococcaceae_UCG-014, Ruminococcaceae_UCG-002, Solobacterium, Subdolibacterium, and Eubacterium ventriosum. SCFAs may impart beneficial effects via modulation of tryptophan metabolism, inflammation, neurotransmitters, and microbiota-gut-brain axis in TRD rats.

Effect of prebiotic and probiotic supplementation on reduced pain in patients with fibromyalgia syndrome: a double-blind, placebo-controlled randomized clinical trial

It has recently been observed that microorganisms in the gut can regulate brain processes through the gut microbiota-brain axis, affecting pain, depression, and sleep quality. Consequently, prebiotics and probiotics may potentially improve physical, psychological, and cognitive states in those with fibromyalgia syndrome (FMS) who have an altered microbiota balance. In a randomised, double-blind, placebo-controlled clinical trial to determine the effects of probiotic and prebiotic treatments on pain, sleep, quality of life, and psychological distress (depression and anxiety) in FMS, 53 female participants with FMS were randomised to receive either: 1) 4 × 1010 CFUs per day for the 18 patients in the probiotics group; 2) 10 g dose inulin per day for the 17 patients in the prebiotic group; or 3) a placebo for 8 weeks for the 18 patients in this group. The mean ages of the groups were similar and there was no significant difference between the groups. The impact of FMS on pain, sleep quality, quality of life, anxiety, and depressive symptoms were measured at baseline, 4 weeks, and 8 weeks post-intervention. Probiotic supplementation significantly decreased the Beck Depression Index (BDI), Beck Anxiety Index (BAI), and Pittsburgh Sleep Quality Index (PSQI) scores compared to baseline, while prebiotic supplementation only significantly decreased PSQI scores. Moreover, participants who received probiotic treatment presented a significantly reduced Visual Analogue Scale (VAS) score compared with those who received placebo treatment, after the interventions. Probiotic supplementation significantly improved sleep quality, depression, anxiety, and pain scores compared to those at baseline in FMS patients, while prebiotic supplementation significantly improved pain scores and sleep quality. The potential benefits of using probiotics for treatment management in FMS patients is supported by the results of the current study and might provide an important strategy to combat FMS-associated diseases.

Probiotic, prebiotic, synbiotic and fermented food supplementation in psychiatric disorders: A systematic review of clinical trials

The use of probiotics, prebiotics, synbiotics or fermented foods can modulate the gut-brain axis and constitute a potentially therapeutic intervention in psychiatric disorders. This systematic review aims to identify current evidence regarding these interventions in the treatment of patients with DSM/ICD psychiatric diagnoses. Forty-seven articles from 42 studies met the inclusion criteria. Risk of bias was assessed in all included studies. Major depression was the most studied disorder (n = 19 studies). Studies frequently focused on schizophrenia (n = 11) and bipolar disorder (n = 5) and there were limited studies in anorexia nervosa (n = 4), ADHD (n = 3), Tourette (n = 1), insomnia (n = 1), PTSD (n = 1) and generalized anxiety disorder (n = 1). Except in MDD, current evidence does not clarify the role of probiotics and prebiotics in the treatment of mental illness. Several studies point to an improvement in the immune and inflammatory profile (e.g. CRP, IL6), which may be a relevant mechanism of action of the therapeutic response identified in these studies. Future research should consider lifestyle and dietary habits of patients as possible confounders that may influence inter-individual treatment response.

Probiotics and Prebiotics Affecting Mental and Gut Health

The effects of the gut microbiota on mental and intestinal health are an area of great interest. This study aimed to reveal the relationship between the intake of probiotic and prebiotic foods and mental and gut health. Data were obtained using an online survey from young adults (n = 538) enrolled at Afyonkarahisar Health Sciences University who agreed to participate in this study in the 2022-2023 academic year. This study included 538 participants, mostly (85.5%) females. Participants who never consumed yogurt had 7.614 times higher Gastrointestinal Symptom Rating Scale scores than those who consumed yogurt daily (p < 0.01). Similarly, the frequency of ayran consumption had a statistically significant effect on Bristol Stool Scale scores (p < 0.05). The ratio of normal defecation to constipation was 68.7% lower in participants who consumed ayran daily, whereas the ratio of diarrhea to constipation was 76.4% lower in participants who never consumed ayran. However, the frequency of prebiotic consumption did not have a significant effect on Bristol Stool Scale scores (p > 0.05). The consumption of probiotic and prebiotic foods exerted a significant effect on GSRS total scores and subfactors of the Depression Anxiety Stress Scale-42, namely depression, anxiety, and stress.

Effect of a multi-strain probiotic mixture consumption on anxiety and depression symptoms induced in adult mice by postnatal maternal separation

BACKGROUND

Intestinal microbial composition not only affects the health of the gut but also influences centrally mediated systems involved in mood, through the "gut-brain" axis, a bidirectional communication between gut microbiota and the brain. In this context, the modulation of intestinal microbiota and its metabolites through the administration of probiotics seems to represent a very promising approach in the treatment of the central nervous system alterations. Early postnatal life is a critical period during which the brain undergoes profound and essential modulations in terms of maturation and plasticity. Maternal separation (MS), i.e., the disruption of the mother-pup interaction, represents a pivotal paradigm in the study of stress-related mood disorders, by inducing persistent changes in the immune system, inflammatory processes, and emotional behavior in adult mammals.

RESULTS

We conducted experiments to investigate whether sustained consumption of a multi-strain probiotic formulation by adult male mice could mitigate the effects of maternal separation. Our data demonstrated that the treatment with probiotics was able to totally reverse the anxiety- and depressive-like behavior; normalize the neuro-inflammatory state, by restoring the resting state of microglia; and finally induce a proneurogenic effect. Mice subjected to maternal separation showed changes in microbiota composition compared to the control group that resulted in permissive colonization by the administered multi-strain probiotic product. As a consequence, the probiotic treatment also significantly affected the production of SCFA and in particular the level of butyrate.

CONCLUSION

Gut microbiota and its metabolites mediate the therapeutic action of the probiotic mix on MS-induced brain dysfunctions. Our findings extend the knowledge on the use of probiotics as a therapeutic tool in the presence of alterations of the emotional sphere that significantly impact on gut microbiota composition. Video Abstract.

Probiotics' Effects in the Treatment of Anxiety and Depression: A Comprehensive Review of 2014-2023 Clinical Trials

Changes in the gut microbiome can affect cognitive and psychological functions via the microbiota-gut-brain (MGB) axis. Probiotic supplements are thought to have largely positive effects on mental health when taken in sufficient amounts; however, despite extensive research having been conducted, there is a lack of consistent findings on the effects of probiotics on anxiety and depression and the associated microbiome alterations. The aim of our study is to systematically review the most recent literature of the last 10 years in order to clarify whether probiotics could actually improve depression and anxiety symptoms. Our results indicate that the majority of the most recent literature suggests a beneficial role of probiotics in the treatment of depression and anxiety, despite the existence of a substantial number of less positive findings. Given probiotics' potential to offer novel, personalized treatment options for mood disorders, further, better targeted research in psychiatric populations is needed to address concerns about the exact mechanisms of probiotics, dosing, timing of treatment, and possible differences in outcomes depending on the severity of anxiety and depression.

Effect of dietary living microbe intake on depression symptom in American adult: An opinion from NHANES study

BACKGROUND

Daily diet represents a potentially modifiable factor in the development of depression. However, to date, no studies have investigated the impact of dietary active microorganisms on depressive symptoms. The aim of this study is to explore the relationship between these two factors.

METHODS

Population data from NHANES 2005-2018 indicated that the exposure variable was dietary intake of active microbes, while the outcome variable was depression as defined by a 9-item Patient Health Questionnaire (PHQ-9) score. A multivariate logistic regression model was employed to assess the impact of dietary living microbe intake on depression symptoms.

RESULTS

A total of 19,169 American adults with a mean age of 46.89 years (SD = 16.97) were included in this cross-sectional analysis; among them, 53.84 % were male and 8.11 % (n = 1555) met the criteria for depression symptoms. In the fully adjusted model, patients with medium and high dietary living microbe intake exhibited a significant reduction in depression symptoms prevalence by 28 % (OR, 0.72; 95 % CI: 0.64-0.81) and 26 % (OR, 0.74; 95 % CI: 0.63-0.85), respectively, compared to those with low dietary living microbe intake. Subgroup analyse indicate that no significant interaction was observed between dietary living microbe intake group and subgroups.

CONCLUSION

Higher intake of active microbes in the diet was found to have a negative correlation with depression.

Determining the emotional regulation function of Bifidobacterium breve: the role of gut metabolite regulation over colonization capability

Psychobiotics that modulate the gut-brain axis have emerged as promising interventions for clinical mental disorders. Bifidobacterium breve CCFM1025 has demonstrated antidepressant effects in both mice and patients with major depression. Nevertheless, the precise mechanism of action of CCFM1025 in emotional regulation remains ambiguous. This study aimed to explore the colonization capacity of CCFM1025 and its dose-dependent effect on emotional regulation in mice exposed to chronic unpredictable mild stress (CUMS). Additionally, we examined its regulatory effects on intestinal and serum metabolites in mice. The results revealed that CCFM1025 did not exhibit a heightened gut retention capability compared to the conspecific control strain. Nevertheless, CCFM1025 exhibited dose-dependent mitigation of anxiety-like behavior and memory impairment induced by CUMS, while also restoring gut microbiota homeostasis. Notably, CCFM1025 demonstrated a robust ability to exert potent gut metabolite regulation, resulting in significant elevation of bile acid and tryptophan metabolites in the gut contents and serum of mice. These findings indicate that the impact of CCFM1025 on emotional regulation may be attributed to its regulation of gut metabolites rather than its gut retention capability. The potential of Bifidobacterium to modulate bile acid metabolism may serve as a valuable avenue for regulating the gut microbiota and successfully exert emotion regulation.

BDNF/CREB signaling pathway contribution in depression pathogenesis: A survey on the non-pharmacological therapeutic opportunities for gut microbiota dysbiosis

Emerging evidence supports the gut microbiota and the brain communication in general health. This axis may affect behavior through modulating neurotransmission, and thereby involve in the pathogenesis and/or progression of different neuropsychiatric disorders such as depression. Brain-derived neurotrophic factor and cAMP response element-binding protein known as CREB/BDNF pathway plays have critical functions in the pathogenesis of depression as the same of mechanisms related to antidepressants. However, the putative causal significance of the CREB/BDNF signaling cascade in the gut-brain axis in depression remains unknown. Also interventions such as probiotics supplementation and exercise can influence microbiome also improve bidirectional communication of gut and brain. In this review we aim to explain the BDNF/CREB signaling pathway and gut microbiota dysfunction and then evaluate the potential role of probiotics, prebiotics, and exercise as a therapeutic target in the gut microbiota dysfunction induced depression. The current narrative review will specifically focus on the impact of exercise and diet on the intestinal microbiota component, as well as the effect that these therapies may have on the microbiota to alleviate depressive symptoms. Finally, we look at how BDNF/CREB signaling pathway may exert distinct effects on depression and gut microbiota dysfunction.

Exploring the serotonin-probiotics-gut health axis: A review of current evidence and potential mechanisms

Modulatory effects of serotonin (5-Hydroxytryptamine [5-HT]) have been seen in hepatic, neurological/psychiatric, and gastrointestinal (GI) disorders. Probiotics are live microorganisms that confer health benefits to their host. Recent research has suggested that probiotics can promote serotonin signaling, a crucial pathway in the regulation of mood, cognition, and other physiological processes. Reviewing the literature, we find that peripheral serotonin increases nutrient uptake and storage, regulates the composition of the gut microbiota, and is involved in mediating neuronal disorders. This review explores the mechanisms underlying the probiotic-mediated increase in serotonin signaling, highlighting the role of gut microbiota in the regulation of serotonin production and the modulation of neurotransmitter receptors. Additionally, this review discusses the potential clinical implications of probiotics as a therapeutic strategy for disorders associated with altered serotonin signaling, such as GI and neurological disorders. Overall, this review demonstrates the potential of probiotics as a promising avenue for the treatment of serotonin-related disorders and signaling of serotonin.