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1.
Mood Disorders: The Gut Bacteriome and Beyond.
McGuinness, AJ, Loughman, A, Foster, JA, Jacka, F
Biological psychiatry. 2024;(4):319-328
Abstract
Knowledge of the microbiome-gut-brain axis has revolutionized the field of psychiatry. It is now well recognized that the gut bacteriome is associated with, and likely influences, the pathogenesis of mental disorders, including major depressive disorder and bipolar disorder. However, while substantial advances in the field of microbiome science have been made, we have likely only scratched the surface in our understanding of how these ecosystems might contribute to mental disorder pathophysiology. Beyond the gut bacteriome, research into lesser explored components of the gut microbiome, including the gut virome, mycobiome, archaeome, and parasitome, is increasingly suggesting relevance in psychiatry. The contribution of microbiomes beyond the gut, including the oral, lung, and small intestinal microbiomes, to human health and pathology should not be overlooked. Increasing both our awareness and understanding of these less traversed fields of research are critical to improving the therapeutic benefits of treatments targeting the gut microbiome, including fecal microbiome transplantation, postbiotics and biogenics, and dietary intervention. Interdisciplinary collaborations integrating systems biology approaches are required to fully elucidate how these different microbial components and distinct microbial niches interact with each other and their human hosts. Excitingly, we may be at the start of the next microbiome revolution and thus one step closer to informing the field of precision psychiatry to improve outcomes for those living with mental illness.
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The use of diet for preventing and treating depression in young men: current evidence and existing challenges.
Bayes, J, Schloss, J, Sibbritt, D
The British journal of nutrition. 2024;(2):214-218
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Abstract
Emerging evidence suggests that diet therapy (nutrients, foods and dietary patterns) could be effective as a potential adjunctive treatment option for major depressive disorder. Numerous mechanisms have been proposed, including the role inflammation, oxidative stress, brain-derived neurotrophic factor, the gastrointestinal tract microbiome and tryptophan/serotonin metabolism. Despite known differences in depression characteristics and treatment responses between males and females, there are limited sex-specific studies examining the role of diet in young men specifically. This is important as young men are often reluctant to seek mental health support, so finding treatment strategies which appeal to this demographic is crucial. This brief report provides an overview of the most recent advances in the use of diet for preventing and treating depression in young men, highlighting existing challenges and opportunities for future research. We recommend that clinicians discuss the role of diet with depressed young men, so that diet may be used alongside current treatment options.
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Evaluating the efficacy and mechanisms of a ketogenic diet as adjunctive treatment for people with treatment-resistant depression: A protocol for a randomised controlled trial.
Gao, M, Kirk, M, Lash, E, Knight, H, Michalopoulou, M, Guess, N, Browning, M, Weich, S, Burnet, P, Jebb, SA, et al
Journal of psychiatric research. 2024;:230-236
Abstract
BACKGROUND One-third of people with depression do not respond to antidepressants, and, after two adequate courses of antidepressants, are classified as having treatment-resistant depression (TRD). Some case reports suggest that ketogenic diets (KDs) may improve some mental illnesses, and preclinical data indicate that KDs can influence brain reward signalling, anhedonia, cortisol, and gut microbiome which are associated with depression. To date, no trials have examined the clinical effect of a KD on TRD. METHODS This is a proof-of-concept randomised controlled trial to investigate the efficacy of a six-week programme of weekly dietitian counselling plus provision of KD meals, compared with an intervention involving similar dietetic contact time and promoting a healthy diet with increased vegetable consumption and reduction in saturated fat, plus food vouchers to purchase healthier items. At 12 weeks we will assess whether participants have continued to follow the assigned diet. The primary outcome is the difference between groups in the change in Patient Health Questionnaire-9 (PHQ-9) score from baseline to 6 weeks. PHQ-9 will be measured at weeks 2, 4, 6 and 12. The secondary outcomes are the differences between groups in the change in remission of depression, change in anxiety score, functioning ability, quality of life, cognitive performance, reward sensitivity, and anhedonia from baseline to 6 and 12 weeks. We will also assess whether changes in reward sensitivity, anhedonia, cortisol awakening response and gut microbiome may explain any changes in depression severity. DISCUSSION This study will test whether a ketogenic diet is an effective intervention to reduce the severity of depression, anxiety and improve quality of life and functioning ability for people with treatment-resistant depression.
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Decoding the role of the gut microbiome in gut-brain axis, stress-resilience, or stress-susceptibility: A review.
Sah, RK, Nandan, A, Kv, A, S, P, S, S, Jose, A, Venkidasamy, B, Nile, SH
Asian journal of psychiatry. 2024;:103861
Abstract
Increased exposure to stress is associated with stress-related disorders, including depression, anxiety, and neurodegenerative conditions. However, susceptibility to stress is not seen in every individual exposed to stress, and many of them exhibit resilience. Thus, developing resilience to stress could be a big breakthrough in stress-related disorders, with the potential to replace or act as an alternative to the available therapies. In this article, we have focused on the recent advancements in gut microbiome research and the potential role of the gut-brain axis (GBA) in developing resilience or susceptibility to stress. There might be a complex interaction between the autonomic nervous system (ANS), immune system, endocrine system, microbial metabolites, and bioactive lipids like short-chain fatty acids (SCFAs), neurotransmitters, and their metabolites that regulates the communication between the gut microbiota and the brain. High fiber intake, prebiotics, probiotics, plant supplements, and fecal microbiome transplant (FMT) could be beneficial against gut dysbiosis-associated brain disorders. These could promote the growth of SCFA-producing bacteria, thereby enhancing the gut barrier and reducing the gut inflammatory response, increase the expression of the claudin-2 protein associated with the gut barrier, and maintain the blood-brain barrier integrity by promoting the expression of tight junction proteins such as claudin-5. Their neuroprotective effects might also be related to enhancing the expression of brain-derived neurotrophic factor (BDNF) and glucagon-like peptide (GLP-1). Further investigations are needed in the field of the gut microbiome for the elucidation of the mechanisms by which gut dysbiosis contributes to the pathophysiology of neuropsychiatric disorders.
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Depression and Microbiome - NED Infobite
BANT's scientific NED InfoBites are designed to provide key elements of the latest research using plain language. They provide quick overviews on particular health issues and nutrition topics for a speedy introduction to the science. Visually attractive and easily shareable with clients and social media followers.
2024
Abstract
The gut-brain axis is an increasingly recognised, bi-directional, relationship. Recent research examines the impact of changing the gut microbiome on aspects of mental health. This NED Infobite includes studies on the use of probiotics as a strategy for mental health issues such as anxiety, cognition and depression. Study authors conclude that the microbiome is a promising avenue to explore when considering prevention and management of mental health diseases in the future.
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Dietary inflammatory index and neuropsychiatric disorders.
Nasab, MG, Heidari, A, Sedighi, M, Shakerian, N, Mirbeyk, M, Saghazadeh, A, Rezaei, N
Reviews in the neurosciences. 2024;(1):21-33
Abstract
Neuropsychiatric disorders (NPDs) are considered a potential threat to mental health. Inflammation predominantly plays a role in the pathophysiology of NPDs. Dietary patterns are widely postulated to be involved in the physiological response to inflammation. This review aims to discuss the literature on how dietary inflammatory index (DII) is related to inflammation and, consequently, NPDs. After comprehensive scrutiny in different databases, the articles that investigated the relation of DII score and various NPDs and psychological circumstances were included. The association between dietary patterns and mental disorders comprising depression, anxiety, and stress proved the role of a proinflammatory diet in these conditions' exacerbation. Aging is another condition closely associated with DII. The impact of proinflammatory and anti-inflammatory diet on sleep quality indicated related disorders like sleep latency and day dysfunctions among the different populations are in relation with the high DII score. The potential effects of genetic backgrounds, dietary patterns, and the gut microbiome on DII are discussed as well. To plan preventive or therapeutic interventions considering the DII, these factors, especially genetic variations, should be considered as there is a growing body of literature indicating the role of personalized medicine in different NPDs. To the best of our knowledge, there is a limited number of RCTs on this subject, so future research should evaluate the causality via RCTs and look for therapeutic interventions with an eye on personalized medicine using information about DII in NPDs.
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BDNF/CREB signaling pathway contribution in depression pathogenesis: A survey on the non-pharmacological therapeutic opportunities for gut microbiota dysbiosis.
Matin, S, Dadkhah, M
Brain research bulletin. 2024;:110882
Abstract
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.
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Mind, Mood and Microbiota-Gut-Brain Axis in Psychiatric Disorders.
Toader, C, Dobrin, N, Costea, D, Glavan, LA, Covache-Busuioc, RA, Dumitrascu, DI, Bratu, BG, Costin, HP, Ciurea, AV
International journal of molecular sciences. 2024;(6)
Abstract
Psychiatric disorders represent a primary source of disability worldwide, manifesting as disturbances in individuals' cognitive processes, emotional regulation, and behavioral patterns. In the quest to discover novel therapies and expand the boundaries of neuropharmacology, studies from the field have highlighted the gut microbiota's role in modulating these disorders. These alterations may influence the brain's processes through the brain-gut axis, a multifaceted bidirectional system that establishes a connection between the enteric and central nervous systems. Thus, probiotic and prebiotic supplements that are meant to influence overall gut health may play an insightful role in alleviating psychiatric symptoms, such as the cognitive templates of major depressive disorder, anxiety, or schizophrenia. Moreover, the administration of psychotropic drugs has been revealed to induce specific changes in a microbiome's diversity, suggesting their potential utility in combating bacterial infections. This review emphasizes the intricate correlations between psychiatric disorders and the gut microbiota, mentioning the promising approaches in regard to the modulation of probiotic and prebiotic treatments, as well as the antimicrobial effects of psychotropic medication.
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The Power of Psychobiotics in Depression: A Modern Approach through the Microbiota-Gut-Brain Axis: A Literature Review.
Dziedzic, A, Maciak, K, Bliźniewska-Kowalska, K, Gałecka, M, Kobierecka, W, Saluk, J
Nutrients. 2024;(7)
Abstract
The microbiota-gut-brain (MGB) axis is a complex communication network linking the gut, microbiota, and brain, influencing various aspects of health and disease. Dysbiosis, a disturbance in the gut microbiome equilibrium, can significantly impact the MGB axis, leading to alterations in microbial composition and function. Emerging evidence highlights the connection between microbiota alterations and neurological and psychiatric disorders, including depression. This review explores the potential of psychobiotics in managing depressive disorders, emphasizing their role in restoring microbial balance and influencing the MGB axis. Psychobiotics exhibit positive effects on the intestinal barrier, immune response, cortisol levels, and the hypothalamic-pituitary-adrenal (HPA) axis. Studies suggest that probiotics may serve as an adjunct therapy for depression, especially in treatment-resistant cases. This review discusses key findings from studies on psychobiotics interventions, emphasizing their impact on the gut-brain axis and mental health. The increasing acceptance of the expanded concept of the MGB axis underscores the importance of microorganisms in mental well-being. As our understanding of the microbiome's role in health and disease grows, probiotics emerge as promising agents for addressing mental health issues, providing new avenues for therapeutic interventions in depressive disorders.
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Clinical trial: A Mediterranean diet is feasible and improves gastrointestinal and psychological symptoms in irritable bowel syndrome.
Staudacher, HM, Mahoney, S, Canale, K, Opie, RS, Loughman, A, So, D, Beswick, L, Hair, C, Jacka, FN
Alimentary pharmacology & therapeutics. 2024;(4):492-503
Abstract
BACKGROUND Diet is fundamental to the care of irritable bowel syndrome (IBS). However, some approaches are not appropriate for individuals experiencing psychological symptoms. AIMS To assess feasibility of a Mediterranean diet in IBS and its impact on gastrointestinal and psychological symptoms. METHODS We recruited adults with Rome IV IBS and mild or moderate anxiety and/or depressive symptoms to an unblinded 6-week randomised controlled trial. Patients were randomised to Mediterranean diet counselling or habitual diet. We collected gastrointestinal and psychological symptom data, dietary data and stool samples for metagenomic sequencing. RESULTS We randomised 59 individuals (29 Mediterranean diet, 30 control); 48 completed the study. The Mediterranean Diet Adherence Screener score was higher in the Mediterranean diet group than controls at week 6 (7.5 [95% CI: 6.9-8.0] vs. 5.7 [5.2-6.3], p < 0.001), and there was a greater score increase than controls (2.1 [95% CI: 1.3-2.9] vs. 0.5 [95% CI: 0.1-1.0], p = 0.004), demonstrating Mediterranean diet feasibility. There was a greater proportion of gastrointestinal symptom responders in the Mediterranean diet group than controls (24/29, 83% vs. 11/30, 37%, p < 0.001) and depression responders (15/29, 52% vs. 6/30 20%, p = 0.015). There was no difference in FODMAP intake at week 6 (p = 0.51). Gastrointestinal adverse events were similar (p = 0.588). There were no differences in change in microbiome parameters between groups. CONCLUSIONS A Mediterranean diet is feasible in IBS and leads to improvement in gastrointestinal and psychological symptoms. Although this study was unblinded, these findings together with the broader benefits of the Mediterranean diet, provide strong impetus for future research in IBS. Australia New Zealand Clinical Trials Registry: ACTRN12620001362987.