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High-fiber diet ameliorates gut microbiota, serum metabolism and emotional mood in type 2 diabetes patients.
Chen, L, Liu, B, Ren, L, Du, H, Fei, C, Qian, C, Li, B, Zhang, R, Liu, H, Li, Z, et al
Frontiers in cellular and infection microbiology. 2023;13:1069954
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Accumulating studies have demonstrated that there are strong correlations between type 2 diabetes mellitus (T2DM) and gut microbiota. A nutritious diet composed of an adequate level of dietary fibres could provide enough carbohydrates for the gut microbiota to ferment, and the microbial metabolites could provide energy supply and regulate the immune function of the host. The aim of this study was to analyse the changes in gut microbiota, serum metabolism and emotional mood of patients with T2DM after consumption of a high-fibre diet. This study was a randomised, open-label, parallel-group clinical trial in T2DM patients with a 4-week treatment period. Seventeen patients clinically diagnosed with T2DM enrolled in the clinical trial and were randomly assigned into two groups: the control group (n = 8) or the intervention group (n = 9). Results showed that the high-fibre diet (compared to the control group): - improved glucose homeostasis and lipid metabolism of participants with T2DM; - decreased serum levels of inflammatory chemokines in participants with T2DM; - alleviated depression and anxiety symptoms, particularly by the uptake of more diverse carbohydrates in the diet in participants with T2DM; - enhanced the diversity of gut microbiota in the treatment group. Authors conclude that the dietary source of fibre demonstrated protective impacts on the gut ecosystem, and the alteration of the gut microbiota composition improved the glucose homeostasis in patients with T2DM.
Abstract
Previous studies have demonstrated that patients with type 2 diabetes mellitus (T2DM) often had the problems of fecal microbiota dysbiosis, and were usually accompanied with psychiatric comorbidities (such as depression and anxiety). Here, we conducted a randomized clinical study to analyze the changes in gut microbiota, serum metabolism and emotional mood of patients with T2DM after consumption of a high-fiber diet. The glucose homeostasis of participants with T2DM was improved by the high-fiber diet, and the serum metabolome, systemic inflammation and psychiatric comorbidities were also altered. The increased abundances of Lactobacillus, Bifidobacterium and Akkermansias revealed that the proportions of beneficial gut microbes were enriched by the high-fiber diet, while the abundances of Desulfovibrio, Klebsiella and other opportunistic pathogens were decreased. Therefore, the current study demonstrated that the intestinal microbiota alterations which were influenced by the high-fiber diet could improve the serum metabolism and emotional mood of patients with T2DM.
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Lactobacillus rhamnosus CNCM I-3690 decreases subjective academic stress in healthy adults: a randomized placebo-controlled trial.
Wauters, L, Van Oudenhove, L, Accarie, A, Geboers, K, Geysen, H, Toth, J, Luypaerts, A, Verbeke, K, Smokvina, T, Raes, J, et al
Gut microbes. 2022;14(1):2031695
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Previous research has shown a bidirectional relationship between the gut and psychological stress, which could be mediated by intestinal permeability followed by an immune and inflammatory response. However, the exact mechanisms of this relationship are yet to be elucidated. This randomised, double-blind, placebo-controlled trial evaluated the beneficial effects of Lactobacillus rhamnosus CNCM I-3690 on intestinal permeability and stress markers during a public speech in healthy students. Participants consumed either milk containing Lactobacillus rhamnosus CNCM I-3690 or acidified milk twice daily for four weeks to assess subjective and objective stress markers and markers of intestinal permeability. Lactobacillus rhamnosus CNCM I-3690 reduced the stress-induced hyperpermeability to mannitol and subjective stress markers (State-Trait Anxiety Inventory/ STAI). A subgroup of healthy students with stress-induced cortisol >P90 of baseline showed a reduction in perceived stress score following Lactobacillus rhamnosus CNCM I-3690 intervention. To evaluate the additional effects of Lactobacillus rhamnosus CNCM I-3690 on stress and gut health, further robust studies are needed. Healthcare professionals can use the findings of this study to understand the anxiolytic effects of Lactobacillus rhamnosus CNCM I-3690.
Abstract
Psychological stress negatively affects the intestinal barrier function in animals and humans. We aimed to study the effect of Lactobacillus rhamnosus CNCM I-3690 on intestinal permeability and stress-markers during public speech. Healthy students were randomized to L. rhamnosus-containing (test) or acidified (placebo) milk consumed twice daily for 4 weeks, with 46 subjects per treatment group. Small intestinal permeability was quantified by a 2 h urinary lactulose-mannitol ratio (LMR, primary outcome), fractional excretion of lactulose (FEL) and mannitol (FEM). Salivary cortisol, State-Trait Anxiety Inventory (STAI) and Perceived Stress scores (PSS) were collected. No between-treatment differences were found for LMR (p = .71), FEL or FEM. Within-treatment analyses showed similar LMR and FEL but a stress-induced increase of FEM with the placebo (p < .05) but not test product. Despite a similar increase in salivary cortisol, the stress-induced increase in STAI was significantly lower with the test product vs. placebo (p = .01). Moreover, a stress-preventative effect of the probiotic was found for PSS and more pronounced in subjects with high stress-induced cortisol (p = .01). While increased FEM was mediated by salivary cortisol levels, the effect of the test product on subjective stress was not mediated by changes in FEM. No serious adverse events occurred. In conclusion, we demonstrated that L. rhamnosus CNCM I-3690 prevented stress-induced hyperpermeability to mannitol. Subjective but not objective stress-markers were reduced with L. rhamnosus vs. placebo, suggesting anxiolytic effects, which were independent of barrier stabilization and attractive for the reduction of stress in both health and disease. Clinicaltrials.gov, number NCT03408691.
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A randomized trial of probiotic supplementation in nurses to reduce stress and viral illness.
Slykerman, RF, Li, E
Scientific reports. 2022;12(1):14742
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Dynamic communication occurs between the gut microbiota and the central nervous system along multiple physiological pathways. Stress increases glucocorticoid production and activation of the hypothalamic–pituitary–adrenal axis, affecting immunological function and neuronal changes. The aim of this study was to investigate whether supplementation with the probiotic Lactobacillus rhamnosus HN001 could reduce symptoms of stress and anxiety and improve psychological wellbeing in nurses working during the COVID19 pandemic. This study was a large double-blind, placebo-controlled randomised trial of probiotic supplementation with two parallel arms and a ratio of allocation to probiotic or placebo of 1:1. Results showed that following the intervention, stress, anxiety, and psychological wellbeing were not significantly different between nurses supplemented with the probiotic and those who received the placebo. Furthermore, the average number of days per week that nurses reported symptoms of cold or flu-like illness did not significantly differ between the probiotic and placebo supplemented groups. Authors conclude that there weren’t significant differences in outcomes between the probiotic and placebo groups.
Abstract
Animal studies demonstrate how the gut microbiota influence psychological health and immunity to viral infections through their actions along multiple dynamic pathways in the body. Considerable interest exists in probiotics to reduce stress and illness symptoms through beneficial effects in the gut, but translating pre-clinical evidence from animal models into humans remains challenging. We conducted a large trial in nurses working during the 2020 COVID19 pandemic year to establish whether daily ingestion of the probiotic Lactobacillus rhamnosus HN001 reduced perceived stress and the number of days participants reported symptoms of a viral illness. Our results showed no significant difference in perceived stress or the average number of illness days between probiotic supplemented nurses and the placebo group. Stress and viral illness symptoms reduced during the study for all participants, a trajectory likely influenced by societal-level factors. The powerful effect of a well-managed public health response to the COVID19 pandemic and the elimination of COVID19 from the community in 2020 may have altered the trajectory of stress levels and reduced circulating viral infections making it difficult to detect any effect of probiotic supplementation. Our study highlights the challenge in controlling environmental factors in human trials.
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Effects of Microbiota Imbalance in Anxiety and Eating Disorders: Probiotics as Novel Therapeutic Approaches.
Navarro-Tapia, E, Almeida-Toledano, L, Sebastiani, G, Serra-Delgado, M, García-Algar, Ó, Andreu-Fernández, V
International journal of molecular sciences. 2021;22(5)
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The interest in mental health has increased recently. Anxiety and mood disorders are associated with many disabilities and there is a close relationship between eating disorders and anxiety. Although current medical treatments for anxiety disorders are safer than a few decades ago; the effectiveness in some of them has not improved, they have side effects and can cause addiction. Therefore, the development of new tools to restore mental health without the undesired effects is necessary. Recent studies indicate that patients with generalized anxiety or eating disorders (anorexia nervosa, bulimia nervosa, and binge-eating disorders) show a specific gut microbiota profile, and this imbalance can be partially restored after a single or multi-strain probiotic supplementation. The purpose of this review is to look at the main microbial patterns seen in patients with generalized anxiety and/or eating disorders as well as the importance of probiotics as a preventive or a therapeutic tool in these pathologies. The studies reviewed showed an imbalance of microbial communities in patients with anxiety and with eating disorders. The effect of probiotics in reducing anxiety seems to be more effective the higher the baseline anxiety level of the individual. For eating disorders, the correction of dysbiosis may be associated with the physical and emotional well-being of these subjects. Further study of the intestinal microbiota will enable progress in the study of therapeutic approaches of these areas.
Abstract
Anxiety and eating disorders produce a physiological imbalance that triggers alterations in the abundance and composition of gut microbiota. Moreover, the gut-brain axis can be altered by several factors such as diet, lifestyle, infections, and antibiotic treatment. Diet alterations generate gut dysbiosis, which affects immune system responses, inflammation mechanisms, the intestinal permeability, as well as the production of short chain fatty acids and neurotransmitters by gut microbiota, which are essential to the correct function of neurological processes. Recent studies indicated that patients with generalized anxiety or eating disorders (anorexia nervosa, bulimia nervosa, and binge-eating disorders) show a specific profile of gut microbiota, and this imbalance can be partially restored after a single or multi-strain probiotic supplementation. Following the PRISMA methodology, the current review addresses the main microbial signatures observed in patients with generalized anxiety and/or eating disorders as well as the importance of probiotics as a preventive or a therapeutic tool in these pathologies.
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Evolution of the Human Diet and Its Impact on Gut Microbiota, Immune Responses, and Brain Health.
González Olmo, BM, Butler, MJ, Barrientos, RM
Nutrients. 2021;13(1)
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One explanation for the increased prevalence in chronic disease and mental illness is from the evolutionary perspective. This suggests the rapid shift in diet towards processed foods in the past 200 years has not allowed for sufficient adaptation of the gut microbiome. The gut microbiome plays an important role in the digestive, immune and nervous systems via the gut-brain axis, and may be a key factor in modulating inflammation and disease. The aim of this review is to discuss how what we eat affects the immune system and impacts our brain health. The literature currently shows significant associations between the Western diet and its impact on the health of the gut microbiome and the brain. Increased intake of saturated fats, refined carbohydrates and sugar, coupled with a reduction in fiber, negatively impacts the digestive system and elicits an immune response. This response can lead to neuroinflammation, which is now found to be associated with deficits in learning and memory, as well as increased rates of neurodegenerative disease and depression. Based on the existing literature, the authors conclude the human gut microbiome has not had sufficient time to adapt to many modern foods, thus leading to inflammation and disease. The authors recommend that a diet composed of natural whole foods with minimal processing can help prevent and alleviate some of the burden caused by chronic disease, and suggest future studies focus on improving techniques to evaluate neuroinflammation in humans.
Abstract
The relatively rapid shift from consuming preagricultural wild foods for thousands of years, to consuming postindustrial semi-processed and ultra-processed foods endemic of the Western world less than 200 years ago did not allow for evolutionary adaptation of the commensal microbial species that inhabit the human gastrointestinal (GI) tract, and this has significantly impacted gut health. The human gut microbiota, the diverse and dynamic population of microbes, has been demonstrated to have extensive and important interactions with the digestive, immune, and nervous systems. Western diet-induced dysbiosis of the gut microbiota has been shown to negatively impact human digestive physiology, to have pathogenic effects on the immune system, and, in turn, cause exaggerated neuroinflammation. Given the tremendous amount of evidence linking neuroinflammation with neural dysfunction, it is no surprise that the Western diet has been implicated in the development of many diseases and disorders of the brain, including memory impairments, neurodegenerative disorders, and depression. In this review, we discuss each of these concepts to understand how what we eat can lead to cognitive and psychiatric diseases.
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Role of the Intestinal Microbiome, Intestinal Barrier and Psychobiotics in Depression.
Trzeciak, P, Herbet, M
Nutrients. 2021;13(3)
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Major depressive disorder (MDD) is a disorder with feelings of depressed mood or loss of interest or pleasure alongside several other symptoms such as weight or appetite changes, difficulty sleeping and an inability to think or concentrate. The development of MDD is not fully understood and may involve several different factors such as the gut microbiome. The gut microbiome may be involved as it can communicate with the brain in a bidirectional fashion, known as the gut-brain axis. This review study aimed to summarise the data on the use of probiotics thought to confer benefits in the brain, known as psychobiotics. Depression is thought to involve aspects of imbalances in brain signalling molecules, stress hormones, and free radicals and inflammation. One of the newest ideas suggests that the gut microbiome may have a role. Individuals with depression have shown to have altered composition of gut microbiota, which may have an impact in several ways. Alterations in vitamin production, altered intestinal barrier function and poor diet during disease, may all contribute to the development of MDD. Psychobiotics may be of benefit to symptoms of depression shown in numerous animal and human studies. It was concluded that there are several ways that the microbiota may be involved in the development of depression. This study could be used by healthcare professionals to justify the introduction of psychobiotics as an adjuvant to standard therapy for MDD, to relieve symptoms.
Abstract
The intestinal microbiota plays an important role in the pathophysiology of depression. As determined, the microbiota influences the shaping and modulation of the functioning of the gut-brain axis. The intestinal microbiota has a significant impact on processes related to neurotransmitter synthesis, the myelination of neurons in the prefrontal cortex, and is also involved in the development of the amygdala and hippocampus. Intestinal bacteria are also a source of vitamins, the deficiency of which is believed to be related to the response to antidepressant therapy and may lead to exacerbation of depressive symptoms. Additionally, it is known that, in periods of excessive activation of stress reactions, the immune system also plays an important role, negatively affecting the tightness of the intestinal barrier and intestinal microflora. In this review, we have summarized the role of the gut microbiota, its metabolites, and diet in susceptibility to depression. We also describe abnormalities in the functioning of the intestinal barrier caused by increased activity of the immune system in response to stressors. Moreover, the presented study discusses the role of psychobiotics in the prevention and treatment of depression through their influence on the intestinal barrier, immune processes, and functioning of the nervous system.
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The role of the microbiota-gut-brain axis in neuropsychiatric disorders.
Generoso, JS, Giridharan, VV, Lee, J, Macedo, D, Barichello, T
Revista brasileira de psiquiatria (Sao Paulo, Brazil : 1999). 2021;43(3):293-305
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Metabolites produced by the gut microbiota have been shown to influence mood and behaviour via the microbiota-gut-brain axis, and there is increased interest in better understanding this interaction in the context of mental health. This review summarises the evidence around the influence of gut microbiota in various neuropsychiatric disorders, primarily focusing on the metabolic pathways that originate in the gut microbiota. Current research highlights an association between gut microbiota metabolites with neuropsychiatric disorders and that probiotics demonstrate a significant therapeutic role in many of these disorders. Based on the current literature, the authors conclude it is crucial to better understand the complex microbiota-host interaction in health and disease, leading to more targeted and improved therapeutic interventions.
Abstract
The microbiota-gut-brain axis is a bidirectional signaling mechanism between the gastrointestinal tract and the central nervous system. The complexity of the intestinal ecosystem is extraordinary; it comprises more than 100 trillion microbial cells that inhabit the small and large intestine, and this interaction between microbiota and intestinal epithelium can cause physiological changes in the brain and influence mood and behavior. Currently, there has been an emphasis on how such interactions affect mental health. Evidence indicates that intestinal microbiota are involved in neurological and psychiatric disorders. This review covers evidence for the influence of gut microbiota on the brain and behavior in Alzheimer disease, dementia, anxiety, autism spectrum disorder, bipolar disorder, major depressive disorder, Parkinson's disease, and schizophrenia. The primary focus is on the pathways involved in intestinal metabolites of microbial origin, including short-chain fatty acids, tryptophan metabolites, and bacterial components that can activate the host's immune system. We also list clinical evidence regarding prebiotics, probiotics, and fecal microbiota transplantation as adjuvant therapies for neuropsychiatric disorders.
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Improvement in Gastrointestinal Quality of Life Index (GIQLI) following meditation: An open-trial pilot study in India.
Kanchibhotla, D, Sharma, P, Subramanian, S
Journal of Ayurveda and integrative medicine. 2021;12(1):107-111
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Gut health is a complex phenomenon, consisting of micro and macro integrity of various gastrointestinal organs from oesophagus to the rectum, allowing us to eat and digest without discomfort. The aim of this study was to investigate the improvement in gut health and gastrointestinal quality of life with the regular practice of a novel meditation called the Vaishvanara Agni meditation (VAM). This study was an open-trial single-arm, pre-post pilot study. Of all the 80 participants enrolled for the study, 54 participants completed the assessments at all three time points, and were considered for data analysis. Results indicate an overall improvement in the quality of life with regular practice of Vaishvanara Agni meditation. In fact, regular practice of VAM not only improved the physical strength and digestion of the individual, but also contributed to their mental, emotional and social health. Authors conclude that meditation practices which focus on improving digestion can be an effective tool for improving gut health.
Abstract
BACKGROUND Medical science is increasingly recognizing the role of gut health in achieving optimal wellbeing. A healthy gut improves digestion. Additionally, it has a positive impact on multiple physiological networks such as immune system, central nervous system and hepato-endocrine system, thus contributing to the overall quality of life. Functional gastrointestinal disorders: also known as disorders of gut-brain interaction, such as irritable bowel syndrome are increasing worldwide. Conditions like stress, anxiety and mental disorders are correlated with these disorders. Mind-body interventions have been shown to ameliorate stress, anxiety and related conditions that may aggravate functional gastrointestinal disorders. OBJECTIVE The present study aims to investigate the benefits of a novel meditation technique called the Vaishvanara Agni meditation (VAM) on the gastrointestinal quality of life. MATERIALS AND METHODS 54 subjects participated in the study and practiced VAM for 50 days. During the Vaishvanara Agni meditation (VAM), attention is directed to the navel region and the digestive system. The effect of the meditation was evaluated using the gastrointestinal quality of life (GI-QoL) questionnaire, which was administered to subjects at three different time points i.e. day 0, day 24 and day 50. RESULTS GI-QoL was significantly improved with the practice of VAM. Additionally, significant improvements were noticed in all sub domains especially core symptoms, physical strength and the psychological domain. CONCLUSION Meditation practices that focus on improving digestion can be an effective tool for improving gut health.
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Gluten and FODMAPs Relationship with Mental Disorders: Systematic Review.
Aranburu, E, Matias, S, Simón, E, Larretxi, I, Martínez, O, Bustamante, MÁ, Fernández-Gil, MDP, Miranda, J
Nutrients. 2021;13(6)
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There is growing evidence that gluten and FODMAPs, such as fermentable oligosaccharides, disaccharides, monosaccharides and polyols, can cause gastrointestinal symptoms, inflammation, and immune responses in patients with celiac disease and irritable bowel syndrome. In addition, a high intake of gluten and FODMAPs may also be associated with neurological and psychiatric disorders. Thirteen studies were included in this systematic review to examine the relationship between gluten and FODMAP consumption and illnesses affecting the central nervous system. In addition, the studies examined the effects of potential dietary strategies that consider gluten and FODMAP intake on mental disorders, anxiety, depression, schizophrenia, Alzheimer’s disease, and autism spectrum disorders. Several possible mechanisms identified in this systematic review could contribute to neurological and psychiatric disorders, including the release of proinflammatory cytokines, immune responses, gut dysbiosis, intestinal permeability, and interactions between the gut-brain axis. In patients with fibromyalgia, celiac disease, and irritable bowel syndrome, avoiding or limiting gluten may reduce depression, anxiety, and cognitive impairment. However, the effects of a low-FODMAP diet on the central nervous system are inconclusive. There is some evidence that gluten-free diets can improve cognition in schizophrenia patients. In addition, those with autism spectrum disorders may benefit from a gluten-free diet and a low-FODMAP diet. Further robust research is required to evaluate the beneficial effects of interventions that avoid or restrict the consumption of foods high in FODMAPs and gluten. However, healthcare professionals can use the results of this systematic review to understand the potential benefits of therapeutic interventions that consider the intake of FODMAPs and gluten on illnesses affecting the central nervous system and their possible mechanisms of action.
Abstract
Nowadays, gluten and FODMAP food components (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are increasingly studied due to their possible relation with extraintestinal-associated conditions. In recent years, gluten-free diets (GFD) and low-FODMAP diets (LFD) are becoming more popular not only in order to avoid the food components that cause intolerances or allergies in some people, but also due to the direct influence of marketing movements or diet trends on feeding habits. Likewise, neurological and psychiatric diseases are currently of increasing importance in developed countries. For this reason, a bibliographic systematic review has been carried out to analyse whether there is a pathophysiological relationship between the dietary intake of gluten or FODMAPs with mental disorders. This review collects 13 clinical and randomized controlled trials, based on the PRISMA statement, which have been published in the last ten years. Based on these results, limiting or ruling out gluten or FODMAPs in the diet might be beneficial for symptoms such as depression, anxiety (7 out of 7 articles found any positive effect), or cognition deficiency (improvements in several cognition test measurements in one trial), and to a lesser extent for schizophrenia and the autism spectrum. Nevertheless, further studies are needed to obtain completely reliable conclusions.
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Current Perspectives on Gut Microbiome Dysbiosis and Depression.
Capuco, A, Urits, I, Hasoon, J, Chun, R, Gerald, B, Wang, JK, Kassem, H, Ngo, AL, Abd-Elsayed, A, Simopoulos, T, et al
Advances in therapy. 2020;37(4):1328-1346
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The gut microbiome has been implicated in several neurological disorders; however exact mechanisms are still not fully understood. This review of recent studies, aimed to investigate the relationship between an imbalanced gut microbiome and depression. The authors first looked at the epidemiology of disease, concluding that significant burden needs to be assessed through improved preventative measures. This will depend upon the correct identification of risk factors, and the study focused on the role of the gut microbiome in this through animal and human studies. Imbalances in inflammation through altered gut microbiota, depleted biodiversity and stress induced microbiome changes were all implicated in the development of depression. It was concluded that studies on the role of microbiota in depression remain promising but are small and follow many different methodologies. This study could be used by healthcare professionals to better understand the role of gut microbiota in the development of depression and that ensuring a healthy gut may improve symptoms.
Abstract
The human gut microbiome partakes in a bidirectional communication pathway with the central nervous system (CNS), named the microbiota-gut-brain axis. The microbiota-gut-brain axis is believed to modulate various central processes through the vagus nerve as well as production of microbial metabolites and immune mediators which trigger changes in neurotransmission, neuroinflammation, and behavior. Little is understood about the utilization of microbiome manipulation to treat disease. Though studies exploring the role of the microbiome in various disease processes have shown promise, mechanisms remain unclear and evidence-based treatments for most illnesses have not yet been developed. The animal studies reviewed here offer an excellent array of basic science research that continues to clarify mechanisms by which the microbiome may affect mental health. More evidence is needed, particularly as it relates to translating this work to human subjects. The studies presented in this paper largely demonstrate encouraging results in the treatment of depression. Limitations include small sample sizes and heterogeneous methodology. The exact mechanism by which the gut microbiota causes or alters neuropsychiatric disease states is not fully understood. In this review, we focus on recent studies investigating the relationship between gut microbiome dysbiosis and the pathogenesis of depression. This article is based on previously conducted studies and does not contain any studies with human participants or animals performed by any of the authors.