The gut microbiome and diet in psychiatry: focus on depression

Chinese medicine formula Kai-Xin-San ameliorates depression-like behaviours in chronic unpredictable mild stressed mice by regulating gut microbiota-inflammation-stress system

ETHNOPHARMACOLOGICAL RELEVANCE

Kai-Xin-San (KXS) has been prescribed by TCM doctors for treating psychiatric diseases with the core symptoms of anhedonia, amnesia, and dizziness. According to the symptoms of patients, KXS series formulae are created by varying the compatible ratio of herbs. Today, these formulae are still used in the clinic to treat major depressive disorders.

AIM OF THE STUDY

We hoped to evaluate the antidepressant-like effect of Kai-Xin-San via regulation of the gut-brain axis.

MATERIALS AND METHODS

Standardized extracts of three representative compatible ratios of KXS had been prepared, and quality control of the extracts was performed by HPLC-MS/MS. Chronic unpredictable mild stress (CUMS)-induced depression-like mice were used as the depression animal model. After KXS treatment, the antidepressant-like effects of KXS were assessed by behavioural tests. The gut microbiota compositions in the faeces were determined by 16S rRNA sequencing technology. The levels of LPS, pro-inflammatory cytokines and HPA-axis-related hormones were measured by ELISA kits, and the expression of barrier proteins in the small intestines and prefrontal cortex were determined by Western blot analysis. Furthermore, antibiotics were used to determine the correlation between KXS exerting an antidepressant-like effect and regulating the gut-brain axis.

RESULTS

KXS alleviated depression-like behaviours in CUMS-exposed mice. Furthermore, these parameters were also found to be changed after KXS treatment. Alteration of the gut microbiota composition were found in the small intestines. A decrease in the LPS and the pro-inflammatory cytokines were found in both the small intestine and brain. An increase in the tight junction proteins was found in the gut epithelium barrier and the blood-brain barrier. A decrease in the stress-related hormones was found in the central nervous system. Furthermore, antibiotic treatment attenuated the antidepressant-like effect of KXS in CUMS-exposed mice.

CONCLUSIONS

KXS exerted an antidepressant-like effect regulating the gut-brain axis, which included gut micro-environment modification, suppression of neuronal inflammation in the brain and inhibition of HPA axis activation in CUMS-induced depression-like mice.

The association of red meat consumption and mental health in women: A cross-sectional study

OBJECTIVES

Previous studies have shown that red meat consumption has beneficial effects on health. The purpose of this study was to determine the relationship between red meat consumption and depression, anxiety and psychological distress in Tehrani women.

METHODS

In this cross-sectional study, 482 women aged 20-50 years old referred to the health centers of Tehran University of Medical Sciences in 2018 were selected by multistage cluster sampling. The usual dietary intake was evaluated using a semi-quantitative food frequency questionnaire containing 168 items that its validity and reliability were approved previously. The red meat category was defined as the sum of red meats (beef, lamb), and organ meats (beef liver, kidney, and heart, ruminant meat). Psychological disorders were assessed using a validated Depression, Anxiety, Stress Scales (DASS) questionnaires with 21-items. In the logistic regression analysis, the results were adjusted to the confounding factors.

RESULTS

The mean age of the study participants was 31.87 ± 7.6 years. The prevalence of depressive symptoms, anxiety and psychological distress among participants was 34%, 40% and 42%, respectively. After controlling for potential confounders, women in the highest quartile of red meat had a highest prevalence of depressive symptoms (OR: 2.51; 95% CI: 1.32-4.76; p = 0.002), anxiety (OR: 1.82; 95% CI: 1.00-3.29; p = 0.034) and stress (OR: 3.47; 95% CI: 1.88-6.42; p < 0.001) compared with those in the lowest quartile.

CONCLUSIONS

We found a significant association between red meat intake and mental health in women. Prospective studies are needed to confirm these findings.

An Almond-Based Low Carbohydrate Diet Improves Depression and Glycometabolism in Patients with Type 2 Diabetes through Modulating Gut Microbiota and GLP-1: A Randomized Controlled Trial

Background: Alow carbohydrate diet (LCD) is more beneficial for the glycometabolism in type 2 diabetes (T2DM) and may be effective in reducing depression. Almond, which is a common nut, has been shown to effectively improve hyperglycemia and depression symptoms. This study aimed to determine the effect of an almond-based LCD (a-LCD) on depression and glycometabolism, as well as gut microbiota and fasting glucagon-like peptide 1 (GLP-1) in patients with T2DM. Methods: This was a randomized controlled trial which compared an a-LCD with a low-fat diet (LFD). Forty-five participants with T2DM at a diabetes club and the Endocrine Division of the First and Second Affiliated Hospital of Soochow University between December 2018 to December 2019 completed each dietary intervention for 3 months, including 22 in the a-LCD group and 23 in the LFD group. The indicators for depression and biochemical indicators including glycosylated hemoglobin (HbA1c), gut microbiota, and GLP-1 concentration were assessed at the baseline and third month and compared between the two groups. Results: A-LCD significantly improved depression and HbA1c (p < 0.01). Meanwhile, a-LCD significantly increased the short chain fatty acid (SCFAs)-producing bacteria Roseburia, Ruminococcus and Eubacterium. The GLP-1 concentration in the a-LCD group was higher than that in the LFD group (p < 0.05). Conclusions: A-LCD could exert a beneficial effect on depression and glycometabolism in patients with T2DM. We speculate that the role of a-LCD in improving depression in patients with T2DM may be associated with it stimulating the growth of SCFAs-producing bacteria, increasing SCFAs production and GPR43 activation, and further maintaining GLP-1 secretion. In future studies, the SCFAs and GPR43 activation should be further examined.

Chronic minocycline treatment exerts antidepressant effect, inhibits neuroinflammation, and modulates gut microbiota in mice

RATIONAL

Minocycline is a second-generation, semi-synthetic tetracycline, and has broad spectrum-antibacterial activity. Interestingly, many studies have demonstrated that minocycline is beneficial for depression, which may be due to its effects on neuroinflammation modulation. Recently, gut microbiota imbalance has been found in depression patient and animal models.

OBJECTIVES

Based on the fact of minocycline usually acting as an antibiotic and the relationship between depression, gut microbiota, and neuroinflammation, we designed this study to detect the effects of chronic minocycline treatment on antidepression, neuroinflammation, and gut microbiota modulation.

RESULTS

Our results showed that minocycline treatment for 4 weeks, not acute treatment, exerted antidepressant effect in mice exposed to unpredictable chronic mild stress (CUMS). Further results suggested that chronic minocycline treatment inhibited neuroinflammation of hippocampus and altered species abundance and metabolites of gut microbiota. Meantime, we found that chronic minocycline treatment ameliorated intestinal barrier disruption and reduced the bacteriological indexes, such as diamine oxidase, C-reaction protein, and endotoxin in peripheral blood of CUMS mice.

CONCLUSIONS

To sum up, our findings confirm that chronic minocycline treatment exerts the antidepressant effect, inhibits neuroinflammation, and modulates gut microbiota. All of these imply that the antidepressant mechanism of chronic minocycline treatment is maybe due to the combined action of neuroinflammation and gut microbiota modulation, which need further prospective studies.

Non-alcoholic fatty liver disease (NAFLD) as a neglected metabolic companion of psychiatric disorders: common pathways and future approaches

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis in over 5% of the parenchyma in the absence of excessive alcohol consumption. It is more prevalent in patients with diverse mental disorders, being part of the comorbidity driving loss of life expectancy and quality of life, yet remains a neglected entity. NAFLD can progress to non-alcoholic steatohepatitis (NASH) and increases the risk for cirrhosis and hepatic carcinoma. Both NAFLD and mental disorders share pathophysiological pathways, and also present a complex, bidirectional relationship with the metabolic syndrome (MetS) and related cardiometabolic diseases.

MAIN TEXT

This review compares the demographic data on NAFLD and NASH among the global population and the psychiatric population, finding differences that suggest a higher incidence of this disease among the latter. It also analyzes the link between NAFLD and psychiatric disorders, looking into common pathophysiological pathways, such as metabolic, genetic, and lifestyle factors. Finally, possible treatments, tailored approaches, and future research directions are suggested.

CONCLUSION

NAFLD is part of a complex system of mental and non-communicable somatic disorders with a common pathogenesis, based on shared lifestyle and environmental risks, mediated by dysregulation of inflammation, oxidative stress pathways, and mitochondrial function. The recognition of the prevalent comorbidity between NAFLD and mental disorders is required to inform clinical practice and develop novel interventions to prevent and treat these complex and interacting disorders.

Brain foods - the role of diet in brain performance and health

The performance of the human brain is based on an interplay between the inherited genotype and external environmental factors, including diet. Food and nutrition, essential in maintenance of brain performance, also aid in prevention and treatment of mental disorders. Both the overall composition of the human diet and specific dietary components have been shown to have an impact on brain function in various experimental models and epidemiological studies. This narrative review provides an overview of the role of diet in 5 key areas of brain function related to mental health and performance, including: (1) brain development, (2) signaling networks and neurotransmitters in the brain, (3) cognition and memory, (4) the balance between protein formation and degradation, and (5) deteriorative effects due to chronic inflammatory processes. Finally, the role of diet in epigenetic regulation of brain physiology is discussed.

KiwiC for Vitality: Results of a Randomized Placebo-Controlled Trial Testing the Effects of Kiwifruit or Vitamin C Tablets on Vitality in Adults with Low Vitamin C Levels

Consumption of vitamin C-rich fruit and vegetables has been associated with greater feelings of vitality. However, these associations have rarely been tested in randomized controlled trials. The aim of the current study was to test the effects of eating a vitamin C-rich food (kiwifruit) on subjective vitality and whether effects are driven by vitamin C. Young adults (n = 167, 61.1% female, aged 18-35) with plasma vitamin C <40 µmol/L were randomized into three intervention conditions: kiwifruit (2 SunGold™ kiwifruit/day), vitamin C (250 mg tablet/day), placebo (1 tablet/day). The trial consisted of a two-week lead-in, four-week intervention, and two-week washout. Plasma vitamin C and vitality questionnaires (total mood disturbance, fatigue, and well-being) were measured fortnightly. Self-reported sleep quality and physical activity were measured every second day through smartphone surveys. Nutritional confounds were assessed using a three-day food diary during each study phase. Plasma vitamin C reached saturation levels within two weeks for the kiwifruit and vitamin C groups. Participants consuming kiwifruit showed significantly improved mood and well-being during the intervention period; improvements in well-being were sustained during washout. Decreased fatigue and increased well-being were observed following intake of vitamin C alone, but only for participants with consistently low vitamin C levels during lead-in. Diet records showed that participants consuming kiwifruit reduced their fat intake during the intervention period. Intervention effects remained significant when adjusting for age and ethnicity, and were not explained by sleep quality, physical activity, BMI, or other dietary patterns, including fat intake. There were no changes in plasma vitamin C status or vitality in the placebo group. Whole food consumption of kiwifruit improved subjective vitality in adults with low vitamin C status. Similar, but not identical, changes were found for vitamin C tablets suggesting that additional properties of kiwifruit may contribute to improved vitality.

Alterations of the GH/IGF-I Axis and Gut Microbiome after Traumatic Brain Injury: A New Clinical Syndrome?

CONTEXT

Pituitary dysfunction with abnormal growth hormone (GH) secretion and neurocognitive deficits are common consequences of traumatic brain injury (TBI). Recognizing the comorbidity of these symptoms is of clinical importance; however, efficacious treatment is currently lacking.

EVIDENCE ACQUISITION

A review of studies in PubMed published between January 1980 to March 2020 and ongoing clinical trials was conducted using the search terms "growth hormone," "traumatic brain injury," and "gut microbiome."

EVIDENCE SYNTHESIS

Increasing evidence has implicated the effects of TBI in promoting an interplay of ischemia, cytotoxicity, and inflammation that renders a subset of patients to develop postinjury hypopituitarism, severe fatigue, and impaired cognition and behavioral processes. Recent data have suggested an association between abnormal GH secretion and altered gut microbiome in TBI patients, thus prompting the description of a hypothesized new clinical syndrome called "brain injury associated fatigue and altered cognition." Notably, these patients demonstrate distinct characteristics from those with GH deficiency from other non-TBI causes in that their symptom complex improves significantly with recombinant human GH treatment, but does not reverse the underlying mechanistic cause as symptoms typically recur upon treatment cessation.

CONCLUSION

The reviewed data describe the importance of alterations of the GH/insulin-like growth factor I axis and gut microbiome after brain injury and its influence in promoting neurocognitive and behavioral deficits in a bidirectional relationship, and highlight a new clinical syndrome that may exist in a subset of TBI patients in whom recombinant human GH therapy could significantly improve symptomatology. More studies are needed to further characterize this clinical syndrome.

Role of inflammation in the pathogenesis of schizophrenia: A review of the evidence, proposed mechanisms and implications for treatment

AIM

Over the past several decades, there has been a growing research interest in the role of inflammation in the pathogenesis of schizophrenia. This review aims to summarize evidence in support of this relationship, to discuss biological mechanisms that might explain it, and to explore the translational impact by examining evidence from trials of anti-inflammatory and immunomodulatory agents in the treatment of schizophrenia.

METHODS

This narrative review of the literature summarizes evidence from observational studies, clinical trials and meta-analyses to evaluate the role of inflammation in the pathogenesis of schizophrenia and to discuss associated implications for treatment.

RESULTS

Epidemiological evidence and animal models support a hypothesis of maternal immune activation during pregnancy, which increases the risk of schizophrenia in the offspring. Several biomarker studies have found associations between classical pro-inflammatory cytokines and schizophrenia. The precise biological mechanisms by which inflammatory processes might contribute to the pathogenesis of schizophrenia remain unclear, but likely include the actions of microglia and the complement system. Importantly, several trials provide evidence that certain anti-inflammatory and immunomodulatory agents show beneficial effects in the treatment of schizophrenia. Nevertheless, there is a need for further precision-focused basic science and translational research.

CONCLUSIONS

Increasing our understanding of the role of inflammation in schizophrenia will enable novel opportunities for therapeutic and preventative interventions that are informed by the underlying pathogenesis of this complex disorder.

Cecal motility and the impact of Lactobacillus in feather pecking laying hens

The gut-microbiota-brain axis is implicated in the development of behavioural disorders in mammals. As such, its potential role in disruptive feather pecking (FP) in birds cannot be ignored. Birds with a higher propensity to perform FP have distinct microbiota profiles and feed transit times compared to non-pecking counterparts. Consequently, we hypothesize that the gut microbiota is intimately linked to FP and gut motility, which presents the possibility of using probiotics to control FP behaviour. In the present study, we aim to assess the relationship between cecal motility and the probiotic Lactobacillus rhamnosus in chickens classified as peckers (P, 13 birds) and non-peckers (NP, 17 birds). We show that cecal contractions were 68% less frequent and their amplitude increased by 58% in the presence of L. rhamnosus. Furthermore, the number of FP bouts performed by P birds was positively correlated with contraction velocity and amplitude. We present the first account of gut motility measurements in birds with distinct FP phenotypes. Importantly, the present work demonstrates the clear impact of a probiotic on cecal contractions. These findings lay the foundation for identifying biological differences between P and NP birds which will support the development of FP control strategies.

Sodium and potassium excretion predict increased depression in urban adolescents

This study examined the prospective role of urinary sodium and potassium excretion in depressive symptoms among urban, low-income adolescents, and whether these relationships vary by gender. A total of 84 urban adolescents (mean age 13.36 years; 50% male; 95% African American) self-reported on their depressive symptoms at baseline and 1.5 years later. At baseline, the youth also completed a 12-h (overnight) urine collection at home which was used to measure sodium and potassium excretion. After adjusting for baseline depressive symptoms, age, BMI percentile, and pubertal development, greater sodium excretion and lower potassium excretion predicted more severe depressive symptoms at follow-up, with no significant gender differences. The results suggest that consumption of foods high in sodium and low in potassium contributes to the development of depressive symptoms in early adolescence, and that diet is a modifiable risk factor for adolescent depression. Interventions focusing on diet may improve mental health in urban adolescents.

Flavonoid-Rich Orange Juice Intake and Altered Gut Microbiome in Young Adults with Depressive Symptom: A Randomized Controlled Study

Depression is not just a general mental health problem but a serious medical illness that can worsen without treatment. The gut microbiome plays a major role in the two-way communication system between the intestines and brain. The current study examined the effects of flavonoids on depression by observing the changes in the gut microbiome and depressive symptoms of young participants consuming flavonoid-rich orange juice. The depressive symptom was assessed using the Center for Epidemiological Studies Depression Scale (CES-D), a psychiatric screening tool used to detect preexisting mental disorders. The study population was randomly divided into two groups: the flavonoid-rich orange juice (FR) and an equicaloric flavonoid-low orange cordial (FL) group. For 8 weeks, participants consumed FR (serving a daily 380 mL, 600 ± 5.4 mg flavonoids) or FL (serving a daily 380 mL, 108 ± 2.6 mg flavonoids). In total, 80 fecal samples from 40 participants (mean age, 21.83 years) were sequenced. Regarding depression, we observed positive correlations between brain-derived neurotrophic factor (BDNF) and the Lachnospiraceae family (Lachnospiraceae_uc and Murimonas) before flavonoid orange juice treatment. Most notably, the abundance of the Lachnospiraceae family (Lachnospiraceae_uc, Eubacterium_g4, Roseburia_uc, Coprococcus_g2_uc, Agathobacter_uc) increased after FR treatment compared to that after FL treatment. We also validated the presence of unclassified Lachnospiraceae through sensitive real-time quantitative polymerase chain reaction using stool samples from participants before and after flavonoid treatment. Our results provide novel interventional evidence that alteration in the microbiome due to flavonoid treatment is related to a potential improvement in depression in young adults.

Effect of fecal microbiota transplant on symptoms of psychiatric disorders: a systematic review

BACKGROUND

The Gut-Brain-Axis is a bidirectional signaling pathway between the gastrointestinal (GI) tract and the brain. The hundreds of trillions of microorganisms populating the gastrointestinal tract are thought to modulate this connection, and have far reaching effects on the immune system, central and autonomic nervous systems, and GI functioning. These interactions Diagnostic and statistical manual of mental disorders have also been linked to various psychiatric illnesses such as depression, anxiety, substance abuse, autism spectrum disorder, and eating disorders. It is hypothesized that techniques aimed at strengthening and repopulating the gut microbiome, such as Fecal Microbiota Transplant (FMT), may be useful in the prevention and treatment of psychiatric illnesses.

METHODS

A systematic search of five databases was conducted using key terms related to FMT and psychiatric illnesses. All results were then evaluated based on specific eligibility criteria.

RESULTS

Twenty-one studies met the eligibility criteria and were analysed for reported changes in mood and behavioural measures indicative of psychiatric wellbeing. The studies included were either entirely clinical (n = 8), preclinical with human donors (n = 9), or entirely preclinical (n = 11). All studies found a decrease in depressive and anxiety-like symptoms and behaviours resulting from the transplantation of healthy microbiota. The inverse was also found, with the transmission of depressive and anxiety-like symptoms and behaviours resulting from the transplantation of microbiota from psychiatrically ill donors to healthy recipients.

CONCLUSION

There appears to be strong evidence for the treatment and transmission of psychiatric illnesses through FMT. Further research with larger sample sizes and stronger scientific design is warranted in order to fully determine the efficacy and safety of this potential treatment. Registered on PROSPERO, IRD: CRD42019126795.

The Association of Race/Ethnicity, Dietary Intake, and Physical Activity with Depression

OBJECTIVE

This study investigated the association of race/ethnicity, dietary intake, and physical activity with depression and potential other barriers associated with the use of mental health services among depressed people.

METHODS

We used the nationally representative data, 2011-2016 National Health and Nutrition Examination Survey. Depression status was defined using a Patient Health Questionnaire. Multivariable logistic regressions were conducted on depression status and the use of mental health specialists among depressed adults, accounting for the complex sampling design.

RESULTS

The prevalence of depression was 8.3% with substantial racial/ethnic differences (8.0% for white, 3.1% for Asian, 9.2% for black, 7.6% for Mexican Hispanics, 13.0% for other Hispanics). Good/acceptable diet and a high level of physical activity were negatively associated with depression. Among depressed people, no significant racial/ethnic differences were observed in using mental health specialists.

CONCLUSION

Prevalence for depression was lower among people who have good or acceptable diet and moderate physical activity. These modifiable factors as well as race/ethnicity should be incorporated into psychotherapeutic interventions to improve depression.

The Safety, Efficacy, and Tolerability of Microbial Ecosystem Therapeutic-2 in People With Major Depression and/or Generalized Anxiety Disorder: Protocol for a Phase 1, Open-Label Study

BACKGROUND

The bidirectional signaling between the gut microbiota and the brain, known as the gut-brain axis, is being heavily explored in current neuropsychiatric research. Analyses of the human gut microbiota have shown considerable individual variability in bacterial content, which is hypothesized to influence brain function, and potentially mood and anxiety symptoms, through gut-brain axis communication. Preclinical and clinical research examining these effects suggests that fecal microbiota transplant (FMT) may aid in improving the severity of depression and anxiety symptoms by recolonizing the gastrointestinal (GI) tract with healthy bacteria. The microbial ecosystem therapeutic (ie, microbial ecosystem therapeutic-2 [MET-2]) used in this study is an alternative treatment to FMT, which comprises 40 different strains of gut bacteria from a healthy donor.

OBJECTIVE

The primary objective of this study is to assess subjective changes in mood and anxiety symptoms before, during, and after administration of MET-2. The secondary objectives of this study are to assess the changes in metabolic functioning and the level of repopulation of healthy gut bacteria, the safety and tolerability of MET-2, and the effects of early stress on biomarkers of depression/anxiety and the response to treatment.

METHODS

Adults experiencing depressive or anxiety symptoms will be recruited from the Kingston area. These participants will orally consume an encapsulated MET-2 once daily-containing 40 strains of purified and laboratory-grown bacteria from a single healthy donor-for 8 weeks, followed by a 2-week treatment-free follow-up period. Participants will undergo a series of clinical assessments measuring mood, anxiety, and GI symptoms using validated clinical scales and questionnaires. Molecular data will be collected from blood and fecal samples to assess metabolic changes, neurotransmitter levels, inflammatory markers, and the level of engraftment of the fecal samples that may predict outcomes in depression or anxiety.

RESULTS

Given the association between the gut bacteria and the risk factors of depression, we expect to observe an improvement in the severity of depressive and anxiety symptoms following treatment, and we expect that this improvement is mediated by the recolonization of the GI tract with healthy bacteria. The recruitment for this study has been completed, and the data obtained are currently being analyzed.

CONCLUSIONS

This is the first time MET-2 is being tested in psychiatric indications, specifically depression and anxiety. As such, this may be the first study to show the potential effects of microbial therapy in alleviating psychiatric symptoms as well as its safety and tolerability.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/17223.

Crosstalk between the microbiota-gut-brain axis and depression

Nutritional and microbiological psychiatry, especially the contribution of the gut microbiota to depression, has become a promising research field over the past several decades. An imbalance in the "microbiota-gut-brain axis", which reflects the constant bidirectional communication between the central nervous system and the gastrointestinal tract, has been used as a hypothesis to interpret the pathogenesis of depression. Alterations in gut microbiota composition could increase the permeability of the gut barrier, activate systemic inflammation and immune responses, regulate the release and efficacy of monoamine neurotransmitters, alter the activity and function of the hypothalamic-pituitary-adrenal (HPA) axis, and modify the abundance of brain-derived neurotrophic factor (BDNF), eventually leading to depression. In this article, we review changes in gut microbiota in depressive states, the association between these changes and depression-like behavior, the potential mechanism linking gut microbiota disruptions and depression, and preliminary attempts at using gut microbiota intervention for the treatment of depression. In summary, although the link between gut microbiota and depression and the potential mechanism have been discussed, a more detailed mechanistic understanding is needed to fully realize the importance of the microbiota-gut-brain axis in depression. Future efforts should aim to determine the potential causative mechanisms, which will require further animal and clinical research as well as the development of analytical approaches.

The Unique Nature of Depression and Anxiety among College Students with Adverse Childhood Experiences

It is well established that adverse childhood experiences (ACEs) contribute to the development of mental disorders in adulthood. However, less is known about how childhood trauma impacts the mind and the body, whether the resulting mental disorders have different characteristics than those occurring without these antecedent conditions, and if treatment modalities need to reflect the unique nature of mental disorders rooted in trauma. Survey and biomarker data were gathered from a sample of college students (n = 93) to explore the relationship between childhood trauma and mental health. We examine how neuroimmune systems (inflammation and neuroplasticity) relate to depression and anxiety and whether these associations vary for those with and without a history of childhood trauma. Findings reveal that students with 4 or more ACEs are more likely to have depression and anxiety than students without these experiences. In addition, we find that inflammation (CRP) and neuronal health (BDNF) are associated with mental health disorders among students with four or more ACEs, but not for students without this history. These findings suggest that mental disorders associated with four or more ACEs may be uniquely tied to physiological processes, and consequently, warrant tailored treatments. The implications for mental health intervention include, 1) screening for childhood trauma, inflammation, and neuronal health and 2) referral to treatments which are theoretically and empirically tied to the root causes of mental disorders rather than those designed merely to suppress their symptoms.

pepFunk: a tool for peptide-centric functional analysis of metaproteomic human gut microbiome studies

Motivation

Enzymatic digestion of proteins before mass spectrometry analysis is a key process in metaproteomic workflows. Canonical metaproteomic data processing pipelines typically involve matching spectra produced by the mass spectrometer to a theoretical spectra database, followed by matching the identified peptides back to parent-proteins. However, the nature of enzymatic digestion produces peptides that can be found in multiple proteins due to conservation or chance, presenting difficulties with protein and functional assignment.

Results

To combat this challenge, we developed pepFunk, a peptide-centric metaproteomic workflow focused on the analysis of human gut microbiome samples. Our workflow includes a curated peptide database annotated with Kyoto Encyclopedia of Genes and Genomes (KEGG) terms and a gene set variation analysis-inspired pathway enrichment adapted for peptide-level data. Analysis using our peptide-centric workflow is fast and highly correlated to a protein-centric analysis, and can identify more enriched KEGG pathways than analysis using protein-level data. Our workflow is open source and available as a web application or source code to be run locally.

Availability and implementation

pepFunk is available online as a web application at https://shiny.imetalab.ca/pepFunk/ with open-source code available from https://github.com/northomics/pepFunk.

Contact

dfigeys@uottawa.ca

Supplementary information

Supplementary data are available at Bioinformatics online.

Diet and Mental Health: Review of the Recent Updates on Molecular Mechanisms

Over the last decades, there has been a substantial increase in the prevalence of mental health disorders, including an increased prevalence of depression, anxiety, cognitive, and sleep disorders. Diet and its bioactive components have been recognized among the modifiable risk factors, possibly influencing their pathogenesis. This review aimed to summarize molecular mechanisms underlying the putative beneficial effects toward brain health of different dietary factors, such as micro- and macronutrient intake and habits, such as feeding time and circadian rhythm. The role of hormonal homeostasis in the context of glucose metabolism and adiponectin regulation and its impact on systemic and neuro-inflammation has also been considered and deepened. In addition, the effect of individual bioactive molecules exerting antioxidant activities and acting as anti-inflammatory agents, such as omega-3 fatty acids and polyphenols, considered beneficial for the central nervous system via modulation of adult neurogenesis, synaptic and neuronal plasticity, and microglia activation has been summarized. An overview of the regulation of the gut–brain axis and its effect on the modulation of systemic inflammation and oxidative stress has been provided. Finally, the impact of bioactive molecules on inflammation and oxidative stress and its association with brain health has been summarized.

The Prospects for the Therapeutic Implications of Genetically Engineered Probiotics

The interest in the therapeutic use of probiotic microorganisms has been increased during the last decade although the doubts have ascended about the probiotics mainly because their beneficial effects are not fully understood, and, in many cases, their usefulness has not been validated in clinical trials. Consequently, the notion got a considerable interest in those strains having proven probiotic potential to be engineered for improvement in their beneficial features. The process of genetic engineering can also be used for probiotic strains for the reversion of antimicrobial resistance and other modifications for their safer and effective human applications. The lactic acid bacilli are predominantly opposite as they already have gained attention owing to their health-promoting benefits and their safety for human consumption; therefore, their use, especially as a delivery agent of vaccines and drugs, is gaining attention. The tailoring of probiotic strains will not only improve the data regarding the probiotic potential of these strains but also clinch the doubts concerning these probiotics. This article focuses on the approaches of bioengineered probiotics and discusses the potential prospects for their therapeutic applications including immunomodulation, cognitive health, and anticancer therapeutics.

Diet and Neurocognition in Mood Disorders - An Overview of the Overlooked

Bipolar disorder and major depression are associated with significant disability, morbidity, and reduced life expectancy. People with mood disorders have shown higher ratios of unhealthy lifestyle choices, including poor diet quality and suboptimal nutrition. Diet and nutrition impact on brain /mental health, but cognitive outcomes have been less researched in psychiatric disorders. Neurocognitive dysfunction is a major driver of social dysfunction and a therapeutic target in mood disorders, although effective cognitive-enhancers are currently lacking. This narrative review aimed to assess the potential cognitive benefits of dietary and nutritional interventions in subjects diagnosed with mood disorders. Eight clinical trials with nutrients were identified, whereas none involved dietary interventions. Efficacy to improve select cognitive deficits has been reported, but results are either preliminary or inconsistent. Methodological recommendations for future cognition trials in the field are advanced. Current evidence and future views are discussed from the perspectives of precision medicine, clinical staging, nutritional psychiatry, and the brain-gut-microbiota axis.

The diet-microbiome tango: how nutrients lead the gut brain axis

Nutrients and the microbiome have a profound impact on the brain by influencing its development and function in health and disease. The mechanisms by which they shape brain function have only started to be uncovered. Here we propose that the interaction of diet with the microbiome is at the core of most mechanisms by which gut microbes affect host brain function. The microbiome acts on the host by altering the nutrients in the diet and by using them as precursors for synthetizing psychoactive metabolites. Diet is also a major modulator of gut microbiome composition making this another key mechanism by which they affect the host brain. Nutrient-microbiome-host interactions therefore provide an overarching framework to understand the function of the gut-brain axis.

Treatment with the traditional Chinese medicine BuYang HuanWu Tang induces alterations that normalize the microbiome in ASD patients

Autism spectrum disorders (ASDs) are prevalent neurobiological conditions with complicated causes worldwide. Increasing researcher awareness of ASD and accumulated evidence suggest that the development of ASD may be strongly linked to the dysbiosis of the gut microbiota. In addition, most of the current studies have compared autistic children and neurotypical children or have compared ASD patients before and after antibiotic treatment. Treatment of autism with traditional Chinese medicine (TCM) has increasingly been promoted, but the relationship between its efficacy and intestinal flora has rarely been reported. Under the premise that treatment with the TCM BuYang HuanWu Tang is effective, we conducted a comparative bioinformatics analysis to identify the overall changes in gut microbiota in relation to ASD by comparing the intestinal flora before and after treatment with TCM and contrasting the intestinal flora with that of healthy controls. At the phylum level, Proteobacteria showed a significant increase in children with ASD, which may be a signature of dysbiosis in the gut microbiota. At the genus level, Blautia, Coprococcus 1, the Lachnospiraceae family, and the Ruminococcaceae family were found at the lowest levels of relative abundance in children with ASD, whereas the abundances of Escherichia-Shigella, Klebsiella, and Flavonifractor were significantly increased compared with those in the healthy control group. In sum, this study characterized the alterations of the intestinal microbiome in children with ASD and its normalization after TCM treatment (TCMT), which may provide novel insights into the diagnosis and therapy of ASD.

Adverse childhood experiences and depressive symptoms: Protective effects of dietary flavonoids

OBJECTIVES

Adverse childhood experiences (ACEs) are associated with increased inflammation, stress, and depression. Diet patterns rich in flavonoids may buffer the effects of ACEs on depression through neuroprotective mechanisms. No studies have examined the protective effects of dietary flavonoids on depressive symptoms after ACEs. We examine the relationships among ACEs, perceived stress, depressive symptoms, and flavonoid intake in older adults.

METHODS

In this longitudinal cohort study, flavonoid intake was provided by 6404 Seventh-day Adventist adults in North America who, as part of the Adventist Health Study-2, completed a validated food frequency questionnaire in 2002-6. ACEs, perceived stress, and depressive symptoms were assessed in the Biopsychosocial Religion and Health Study in 2006-7 and 2010-11. Bootstrapping models predicting depression were tested after controls.

RESULTS

ACEs were associated with adult depressive symptoms and perceived stress mediated this relationship. A moderated mediation model indicates that flavonoid intake buffers the association between perceived stress and depressive symptoms after ACEs. Flavonoid consumption was negatively associated with depressive symptoms (β = -0.034, p = .03). As ACEs increased by one standard deviation, depressive symptoms increased through the interaction of perceived stress and flavonoids when flavonoids were consumed a standard deviation below the mean (effect = 0.040 SD, BC 95% CI [0.030, 0.052]). Depressive symptoms were lower for those that consumed flavonoids a standard deviation above the mean (effect =. 035 SD, BC 95% CI [0.025, 0.046]).

CONCLUSION

A varied diet rich in flavonoids may reduce depressive symptoms associated with perceived stress following ACEs exposure.

Mental, behavioral and neurodevelopmental disorders in the ICD-11: an international perspective on key changes and controversies

An update of the chapter on Mental, Behavioral and Neurodevelopmental Disorders in the International Classification of Diseases and Related Health Problems (ICD) is of great interest around the world. The recent approval of the 11th Revision of the ICD (ICD-11) by the World Health Organization (WHO) raises broad questions about the status of nosology of mental disorders as a whole as well as more focused questions regarding changes to the diagnostic guidelines for specific conditions and the implications of these changes for practice and research. This Forum brings together a broad range of experts to reflect on key changes and controversies in the ICD-11 classification of mental disorders. Taken together, there is consensus that the WHO's focus on global applicability and clinical utility in developing the diagnostic guidelines for this chapter will maximize the likelihood that it will be adopted by mental health professionals and administrators. This focus is also expected to enhance the application of the guidelines in non-specialist settings and their usefulness for scaling up evidence-based interventions. The new mental disorders classification in ICD-11 and its accompanying diagnostic guidelines therefore represent an important, albeit iterative, advance for the field.

A multidisciplinary approach to mental illness: do inflammation, telomere length and microbiota form a loop? A protocol for a cross-sectional study on the complex relationship between inflammation, telomere length, gut microbiota and psychiatric disorders

INTRODUCTION

Severe psychiatric disorders are typically associated with a significant reduction in life expectancy compared with the general population. Among the different hypotheses formulated to explain this observation, accelerated ageing has been increasingly recognised as the main culprit. At the same time, telomere shortening is becoming widely accepted as a proxy molecular marker of ageing. The present study aims to fill a gap in the literature by better defining the complex interaction/s between inflammation, age-related comorbidities, telomere shortening and gut microbiota in psychiatric disorders.

METHODS AND ANALYSIS

A cross-sectional study is proposed, recruiting 40 patients for each of three different diagnostic categories (bipolar disorder, schizophrenia and major depressive disorder) treated at the Section of Psychiatry and at the Unit of Clinical Pharmacology of the University Hospital Agency of Cagliari (Italy), compared with 40 age-matched and sex-matched non-psychiatric controls. Each group includes individuals suffering, or not, from age-related comorbidities, to account for the impact of these medical conditions on the biological make-up of recruited patients. The inflammatory state, microbiota composition and telomere length (TL) are assessed.

ETHICS AND DISSEMINATION

The study protocol was approved by the Ethics Committee of the University Hospital Agency of Cagliari (PG/2018/11693, 5 September 2018). The study is conducted in accordance with the principles of good clinical practice and the Declaration of Helsinki, and in compliance with the relevant Italian national legislation. Written, informed consent is obtained from all participants. Participation in the study is on a voluntary basis only. Patients will be part of the dissemination phase of the study results, during which a local conference will be organised and families of patients will also be involved. Moreover, findings will be published in one or more research papers and presented at national and international conferences, in posters or oral communications.

Stress and the gut microbiota-brain axis

Stress is a nonspecific response of the body to any demand imposed upon it, disrupting the body homoeostasis and manifested with symptoms such as anxiety, depression or even headache. These responses are quite frequent in the present competitive world. The aim of this review is to explore the effect of stress on gut microbiota. First, we summarize evidence of where the microbiota composition has changed as a response to a stressful situation, and thereby the effect of the stress response. Likewise, we review different interventions that can modulate microbiota and could modulate the stress according to the underlying mechanisms whereby the gut-brain axis influences stress. Finally, we review both preclinical and clinical studies that provide evidence of the effect of gut modulation on stress. In conclusion, the influence of stress on gut microbiota and gut microbiota on stress modulation is clear for different stressors, but although the preclinical evidence is so extensive, the clinical evidence is more limited. A better understanding of the mechanism underlying stress modulation through the microbiota may open new avenues for the design of therapeutics that could boost the pursued clinical benefits. These new designs should not only focus on stress but also on stress-related disorders such as anxiety and depression, in both healthy individuals and different populations.

Gut Microbiota Dysbiosis Enhances Migraine-Like Pain Via TNFα Upregulation

Migraine is one of the most disabling neurological diseases worldwide; however, the mechanisms underlying migraine headache are still not fully understood and current therapies for such pain are inadequate. It has been suggested that inflammation and neuroimmune modulation in the gastrointestinal tract could play an important role in the pathogenesis of migraine headache, but how gut microbiomes contribute to migraine headache is unclear. In the present study, we investigated the effect of gut microbiota dysbiosis on migraine-like pain using broad-spectrum antibiotics and germ-free (GF) mice. We observed that antibiotics treatment-prolonged nitroglycerin (NTG)-induced acute migraine-like pain in wild-type (WT) mice and the pain prolongation was completely blocked by genetic deletion of tumor necrosis factor-alpha (TNFα) or intra-spinal trigeminal nucleus caudalis (Sp5C) injection of TNFα receptor antagonist. The antibiotics treatment extended NTG-induced TNFα upregulation in the Sp5C. Probiotics administration significantly inhibited the antibiotics-produced migraine-like pain prolongation. Furthermore, NTG-induced migraine-like pain in GF mice was markedly enhanced compared to that in WT mice and gut colonization with fecal microbiota from WT mice robustly reversed microbiota deprivation-caused pain enhancement. Together, our results suggest that gut microbiota dysbiosis contributes to chronicity of migraine-like pain by upregulating TNFα level in the trigeminal nociceptive system.

Breast Cancer: Lifestyle, the Human Gut Microbiota/Microbiome, and Survivorship

Patients with a current diagnosis of breast cancer are enjoying dramatic cure rates and survivorship secondary to an increase in awareness, earlier detection, and more effective therapies. Although strategies such as Breast Cancer Awareness Month in October focus on early detection, lifestyle changes are seldom discussed other than dietary concerns and physical activity. Lifestyle modifications centered on diet and exercise have been demonstrated to affect overall disease-free survival in breast cancer. Since the early 2000s, the role of the human gut microbiota and its relation to breast cancer has become a major area of interest in the scientific and medical community. We live and survive owing to the symbiotic relationship with the microorganisms within us: the human microbiota. Scientific advances have identified a subset of the gut microbiota: the estrobolome, those bacteria that have the genetic capability to metabolize estrogen, which plays a key role in most breast cancers. Recent research provides evidence that the gut microbiome plays a substantial role in estrogen regulation. Gut microbiota diversity appears to be an essential component of overall health, including breast health. Future research attention should include a more extensive focus on the role of the human gut microbiota in breast cancer.

The chemo-gut study: investigating the long-term effects of chemotherapy on gut microbiota, metabolic, immune, psychological and cognitive parameters in young adult Cancer survivors; study protocol

BACKGROUND

The gut microbiota is an important modulator of immune, metabolic, psychological and cognitive mechanisms. Chemotherapy adversely affects the gut microbiota, inducing acute dysbiosis, and alters physiological and psychological function. Cancer among young adults has risen 38% in recent decades. Understanding chemotherapy's long-term effects on gut microbiota and psycho-physiological function is critical to improve survivors' physical and mental health, but remains unexamined. Restoration of the gut microbiota via targeted therapies (e.g. probiotics) could potentially prevent or reverse the psycho-physiological deficits often found in young survivors following chemotherapy, ultimately leading to reduced symptom burden and improved health.

METHODS

This longitudinal study investigates chemotherapy induced long-term gut dysbiosis, and associations between gut microbiota, and immune, metabolic, cognitive and psychological parameters using data collected at < 2 month (T1), 3-4 months (T2), and 5-6 months (T3) post-chemotherapy. Participants will be 18-39 year old blood or solid tumor cancer survivors (n = 50), and a healthy sibling, partner or friend as a control (n = 50). Gut microbiota composition will be measured from fecal samples using 16 s RNA sequencing. Psychological and cognitive patient reported outcome measures will include depression, anxiety, post-traumatic stress disorder symptoms, pain, fatigue, and social and cognitive function. Dual-energy X-ray Absorptiometry (DXA) will be used to measure fat and lean mass, and bone mineral concentration. Pro-inflammatory cytokines, C-reactive protein (CRP), lipopolysaccharide (LPS), serotonin, and brain derived neurotrophic factor (BDNF) will be measured in serum, and long-term cortisol will be assayed from hair. Regression and linear mixed model (LMM) analyses will examine associations across time points (T1 - T3), between groups, and covariates with gut microbiota, cognitive, psychological, and physiological parameters.

CONCLUSION

Knowing what bacterial species are depleted after chemotherapy, how long these effects last, and the physiological mechanisms that may drive psychological and cognitive issues among survivors will allow for targeted, integrative interventions to be developed, helping to prevent or reverse some of the late-effects of treatment that many young cancer survivors face. This protocol has been approved by the Health Research Ethics Board of Alberta Cancer Committee (ID: HREBA.CC-19-0018).

Is dairy consumption associated with depressive symptoms or disorders in adults? A systematic review of observational studies

Diet quality is associated with depression risk, however the possible role of dairy products in depression risk is unclear. A number of epidemiological studies have examined associations between dairy consumption and depressive symptoms, but results have been inconsistent. Therefore, this systematic review aimed to examine whether an association exists between dairy consumption and depressive symptoms or disorders in adults. Anxiety symptoms were also explored as a secondary outcome. CINAHL, Cochrane, MEDLINE complete, EMBASE, Scopus and PsycINFO databases were searched from database inception to December 2018. Studies were included if they used a case-control, cross-sectional, or cohort study design, and included community dwelling or institutionalized adults (≥18 years). Seven prospective and six cross-sectional studies (N = 58,203 participants) reported on the association between dairy consumption and depressive symptoms or disorders. Findings were mixed, with one study reporting a positive association; five studies reporting no association; and seven studies reporting mixed associations depending on dairy type, gender or population group. We found conflicting and inconsistent associations in studies that were generally of fair quality. Future longitudinal and intervention studies that employ more rigorous dietary assessment methods are warranted.

Minor compositional alterations in faecal microbiota after five weeks and five months storage at room temperature on filter papers

The gut microbiota is recognized as having major impact in health and disease. Sample storage is an important aspect to obtain reliable results. Mostly recommended is immediate freezing, however, this is not always feasible. Faecal occult blood test (FOBT) papers are an appealing solution in such situations, and most studies find these to be applicable, showing no major changes within 7 days storage at room temperature (RT). As fieldwork often requires RT storage for longer periods, evaluation of this is warranted. We performed 16S rRNA gene sequencing of 19 paired faecal samples immediately frozen or kept five weeks and five months at RT on FOBT papers. Alpha-diversity evaluation revealed no effect of FOBT storage, and evaluation of beta-diversity showed that host explained 65% of community variation, while storage method explained 5%. Evaluation of community dispersion and the Firmicutes/Bacteroidetes ratio revealed a larger effect of storage time for fresh-frozen samples. Single taxa evaluation (order-to-genus level) showed significant alterations of four (of 37) genera after five weeks and five genera after five months. When comparing the two timepoints, alterations were only detectable for fresh-frozen samples. Our findings reveal that long term storage on FOBT papers is an applicable approach for microbiota research.

Modification of the gut microbiome to combat neurodegeneration

The gut microbiome was extensively researched for its biological variety and its potential role in propagating diseases outside of the gastrointestinal (GI) tract. Recently, a lot of effort was focused on comprehending the gut-brain axis and the bizarre communication between the GI system and the nervous system. Ample amount of studies being carried out also revealed the involvement of the gut microbiome in enhancing the degree of many neurological disorders, including neurodegenerative diseases. It was widely observed that there were distinct microbiome profiles and dysbiosis within patients suffering from Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis. Various approaches to re-establish the balance of the gut microbiome, from antibiotic therapy, fecal microbiota transplant, or ingestion of psychobiotics, are discussed within this review within the specific context of combating neurodegenerative diseases. Present studies and clinical trials indicate that although there is an immense potential of gut microbiome modification to be preventive or therapeutic, there are still many intercalated components of the gut-brain axis at play and thus, more research needs to be carried out to delineate microbiome factors that may potentially alleviate symptoms of neurodegeneration.

The gut microbiome in psychiatry: A primer for clinicians

Research in the past decade has shown that variations in the gut microbiome may influence behavior, and vice versa. As such, interest in the role of the gut microbiome in psychiatric conditions has drawn immense interest. This is evidenced by the recent surge in published studies examining microbial dysbiosis in clinical psychiatric populations, particularly autism spectrum disorder and depression. However, critical examination of these studies reveals methodological flaws in design and execution, suggesting that they may not be held to the same standards as other bodies of clinical research. Given the complex nature of the gut microbiome, this narrative review attempts to clarify concepts critical to effectively examine its potential role in psychopathology to appropriately inform mental health researchers. More specifically, the numerous variables known to affect the gut microbiome are discussed, including inflammation, diet, weight, and medications. A comprehensive review of the extant microbiome literature in clinical psychiatric populations is also provided, in addition to clinical implications and suggestions for future directions of research. Although there is a clear need for additional studies to elucidate the gut microbiome's role in psychiatric disorders, there is an even greater need for well-designed, appropriately controlled studies to truly impact the field.

The efficacy and safety of nutrient supplements in the treatment of mental disorders: a meta-review of meta-analyses of randomized controlled trials

The role of nutrition in mental health is becoming increasingly acknowledged. Along with dietary intake, nutrition can also be obtained from "nutrient supplements", such as polyunsaturated fatty acids (PUFAs), vitamins, minerals, antioxidants, amino acids and pre/probiotic supplements. Recently, a large number of meta-analyses have emerged examining nutrient supplements in the treatment of mental disorders. To produce a meta-review of this top-tier evidence, we identified, synthesized and appraised all meta-analyses of randomized controlled trials (RCTs) reporting on the efficacy and safety of nutrient supplements in common and severe mental disorders. Our systematic search identified 33 meta-analyses of placebo-controlled RCTs, with primary analyses including outcome data from 10,951 individuals. The strongest evidence was found for PUFAs (particularly as eicosapentaenoic acid) as an adjunctive treatment for depression. More nascent evidence suggested that PUFAs may also be beneficial for attention-deficit/hyperactivity disorder, whereas there was no evidence for schizophrenia. Folate-based supplements were widely researched as adjunctive treatments for depression and schizophrenia, with positive effects from RCTs of high-dose methylfolate in major depressive disorder. There was emergent evidence for N-acetylcysteine as a useful adjunctive treatment in mood disorders and schizophrenia. All nutrient supplements had good safety profiles, with no evidence of serious adverse effects or contraindications with psychiatric medications. In conclusion, clinicians should be informed of the nutrient supplements with established efficacy for certain conditions (such as eicosapentaenoic acid in depression), but also made aware of those currently lacking evidentiary support. Future research should aim to determine which individuals may benefit most from evidence-based supplements, to further elucidate the underlying mechanisms.

Early nutrition and gut microbiome: interrelationship between bacterial metabolism, immune system, brain structure, and neurodevelopment

Disturbances of diet during pregnancy and early postnatal life may impact colonization of gut microbiota during early life, which could influence infant health, leading to potential long-lasting consequences later in life. This is a nonsystematic review that explores the recent scientific literature to provide a general perspective of this broad topic. Several studies have shown that gut microbiota composition is related to changes in metabolism, energy balance, and immune system disturbances through interaction between microbiota metabolites and host receptors by the gut-brain axis. Moreover, recent clinical studies suggest that an intestinal dysbiosis in gut microbiota may result in cognitive disorders and behavioral problems. Furthermore, recent research in the field of brain imaging focused on the study of the relationship between gut microbial ecology and large-scale brain networks, which will help to decipher the influence of the microbiome on brain function and potentially will serve to identify multiple mediators of the gut-brain axis. Thus, knowledge about optimal nutrition by modulating gut microbiota-brain axis activity will allow a better understanding of the molecular mechanisms involved in the crosstalk between gut microbiota and the developing brain during critical windows. In addition, this knowledge will open new avenues for developing novel microbiota-modulating based diet interventions during pregnancy and early life to prevent metabolic disorders, as well as neurodevelopmental deficits and brain functional disorders.

Gut Microbiota as a Therapeutic Target to Ameliorate the Biochemical, Neuroanatomical, and Behavioral Effects of Traumatic Brain Injuries

Current efficacious treatments for traumatic brain injury (TBI) are lacking. Establishment of a protective gut microbiota population offers a compelling therapeutic avenue, as brain injury induces disruptions in the composition of the gut microbiota, i.e., gut dysbiosis, which has been shown to contribute to TBI-related neuropathology and impaired behavioral outcomes. The gut microbiome is involved in the modulation of a multitude of cellular and molecular processes fundamental to the progression of TBI-induced pathologies including neuroinflammation, blood brain barrier permeability, immune system response, microglial activation, and mitochondrial dysfunction, as well as intestinal motility and permeability. Additionally, gut dysbiosis further aggravates behavioral impairments in animal models of TBI and spinal cord injury, as well as negatively affects health outcomes in murine stroke models. Recent studies indicate that microbiota transplants and probiotics ameliorate neuroanatomical damage and functional impairments in animal models of stroke and spinal cord injury. In addition, probiotics have been shown to reduce the rate of infection and time spent in intensive care of hospitalized patients suffering from brain trauma. Perturbations in the composition of the gut microbiota and its metabolite profile may also serve as potential diagnostic and theragnostic biomarkers for injury severity and progression. This review aims to address the etiological role of the gut microbiome in the biochemical, neuroanatomical, and behavioral/cognitive consequences of TBI, as well as explore the potential of gut microbiome manipulation in the form of probiotics as an effective therapeutic to ameliorate TBI-induced pathology and symptoms.

Caring for people with mental health conditions in general clinical settings

Nurses often care for people with mental health conditions in general clinical settings. In these situations, they have a responsibility to ensure that the individual's physical, social and psychological needs are assessed and met. Nurses practising in general clinical settings should be familiar with the skills and knowledge required to meet the needs of people with mental health conditions. This article aims to provide nurses practising in general clinical settings with an understanding of such conditions and the associated effects on an individual's physical health. It also details the signs and symptoms of various mental health conditions, and outlines the communication skills that nurses can use when caring for people with these conditions in general clinical settings.

What Is the Role of Dietary Inflammation in Severe Mental Illness? A Review of Observational and Experimental Findings

Severe mental illnesses (SMI), including major depressive disorder, bipolar disorder, and schizophrenia, are associated with increased inflammation. Given diet's role in modulating inflammatory processes, excessive calorie-dense, nutrient-deficient processed food intake may contribute toward the heightened inflammation observed in SMI. This review assesses the evidence from observational and experimental studies to investigate how diet may affect physical and mental health outcomes in SMI through inflammation-related pathways. Cross-sectional studies indicate that individuals with SMI, particularly schizophrenia, consume more pro-inflammatory foods and fewer anti-inflammatory nutrients than the general population. Cohort studies indicate that high levels of dietary inflammation are associated with increased risk of developing depression, but there is currently a lack of evidence for schizophrenia or bipolar disorder. Randomized controlled trials show that dietary interventions improve symptoms of depression, but none have tested the extent to which these benefits are due to changes in inflammation. This review summarizes evidence on dietary inflammation in SMI, explores the directionality of these links, and discusses the potential use of targeted nutritional interventions for improving psychological well-being and physical health outcomes in SMI. Establishing the extent to which diet explains elevated levels of inflammatory markers observed in SMI is a priority for future research.

The impact of urbanization on mood disorders: an update of recent evidence

PURPOSE OF REVIEW

Mood disorders are highly prevalent and represent a leading cause of global disability. Urbanization holds great public health implications spanning various environmental, lifestyle behavioural, economic and social domains. Underlying risk factors for mood disorders are heterogeneous but the psychiatric literature has extended beyond individual-level risk, to account for population-level environment and social-related precursors to mental ill health. This review summarizes recent studies published since 2017 examining the impact of urbanization and associated environmental, social and lifestyle risks for mood disorders, specifically depression.

RECENT FINDINGS

All identified studies examined depression or subclinical mood-related symptomatology. Recent evidence suggests individuals residing in urban areas experience increased risk of depression. Mechanistic pathways include increased exposure to noise, light and air pollution, poor quality housing, reduced diet quality, physical inactivity, economic strain and diminished social networks. The role of the gut microbiome in the development of mood disorders represents a novel research domain expected to hold potential for the psychiatric and environmental field. Further research is needed to extrapolate the relationship between increased sedentary lifestyles and technology use and depression in urban societies.

SUMMARY

Recent evidence highlights the complexity and reciprocity of underlying driving factors in the relationship between urbanization and mood disorders. Future epidemiological research should continue to untangle such complexity. There was a dearth of evidence relating to urbanization and mood disorders other than depression. Future research should identify the unique experiences of vulnerable subgroups who experience disproportionate increased risk of adverse health experiences associated with urbanization.

Dietary Patterns: A New Therapeutic Approach for Depression?

Introduction:

The field of nutritional psychiatry is a fast-growing one. Although initially, it focused on the effects of vitamins and micronutrients in mental health, in the last decade, its focus also extended to the dietary patterns. The possibility of a dietary cost-effective intervention in the most common mental disorder, depression, cannot be overlooked due to its potential large-scale impact.

Method:

A classic review of the literature was conducted, and studies published between 2010 and 2018 focusing on the impact of dietary patterns in depression and depressive symptoms were included.

Results:

We found 10 studies that matched our criteria. Most studies showed an inverse association between healthy dietary patterns, rich in fruits, vegetables, lean meats, nuts and whole grains, and with low intake of processed and sugary foods, and depression and depressive symptoms throughout an array of age groups, although some authors reported statistical significance only in women. While most studies were of cross-sectional design, making it difficult to infer causality, a randomized controlled trial presented similar results.

Discussion:

he association between dietary patterns and depression is now well-established, although the exact etiological pathways are still unknown. Dietary intervention, with the implementation of healthier dietary patterns, closer to the traditional ones, can play an important role in the prevention and adjunctive therapy of depression and depressive symptoms.

Conclusion:

More large-scale randomized clinical trials need to be conducted, in order to confirm the association between high-quality dietary patterns and lower risk of depression and depressive symptoms.

The microbiome and ophthalmic disease

IMPACT STATEMENT

This review describes a growing body of research on relationships between the microbiome and eye disease. Several groups have investigated the microbiota of the ocular surface; dysregulation of this delicate ecosystem has been associated with a variety of pro-inflammatory states. Other research has explored the effects of the gastrointestinal microbiota on ophthalmic diseases. Characterizing the ways these microbiotas influence ophthalmic homeostasis and pathogenesis may lead to research on new techniques for managing ophthalmic disease.

Promoting Mental Health and Wellness in Youth Through Physical Activity, Nutrition, and Sleep

The medical benefits to youth conferred by physical activity, balanced nutrition, and quality sleep have been increasingly encouraged by medical and mental health providers. Emerging evidence continues to reveal benefits for youth mental health and well-being, including for youth with psychiatric disorders. This evidence seems multifactorial through both neurobiological and psychosocial systems, with common mechanisms present between physical activity, nutrition, and sleep. This article reviews the benefits of optimizing physical activity, nutrition, and sleep; how to assess these lifestyle domains with patients and their parents; and appropriate interventions to optimize well-being in youth.

Differential Sensitivity to Plasmodium yoelii Infection in C57BL/6 Mice Impacts Gut-Liver Axis Homeostasis

Experimental models of malaria have shown that infection with specific Plasmodium species in certain mouse strains can transiently modulate gut microbiota and cause intestinal shortening, indicating a disruption of gut homeostasis. Importantly, changes in gut homeostasis have not been characterized in the context of mild versus severe malaria. We show that severe Plasmodium infection in mice disrupts homeostasis along the gut-liver axis in multiple ways compared to mild infection. High parasite burden results in a larger influx of immune cells in the lamina propria and mice with high parasitemia display specific metabolomic profiles in the ceca and plasma during infection compared to mice with mild parasitemia. Liver damage was also more pronounced and longer lasting during severe infection, with concomitant changes in bile acids in the gut. Finally, severe Plasmodium infection changes the functional capacity of the microbiota, enhancing bacterial motility and amino acid metabolism in mice with high parasite burden compared to a mild infection. Taken together, Plasmodium infections have diverse effects on host gut homeostasis relative to the severity of infection that may contribute to enteric bacteremia that is associated with malaria.

Association of dietary phytochemical index and mental health in women: a cross-sectional study

Previous studies have shown that unhealthy dietary patterns are among the most important modifiable risk factors in the development of mental health disorders. We examined the association of dietary phytochemical index (DPI) with symptoms of depression, anxiety and psychological distress in Iranian women. In this cross-sectional study, a total of 488 women aged 20–50 years old attending health centres in the south of Tehran in 2018 were included. A validated and reliable FFQ was used for dietary assessment. Symptoms of depression, anxiety and psychological distress were assessed using a validated depression, anxiety, stress scales questionnaires with twenty-one-items. DPI was estimated using the following formula: (daily energy derived from phytochemical-rich foods (kJ)/total daily energy intake (kJ))×100. The mean age of the study participants was 31·9 (sd7·7) years. The prevalence of depressive symptoms, anxiety and psychological distress among study participants was 34·6, 40·6 and 42·4 %, respectively. After controlling for potential confounders, women in the highest tertile of DPI had a lower prevalence of depressive symptoms (OR 0·22; 95 % CI 0·12, 0·38) and anxiety (OR 0·33; 95 % CI 0·20, 0·55), as well as psychological distress (OR 0·30; 95 % CI 0·18, 0·49) compared with those in the lowest tertile. In conclusion, we found a significant association between DPI and mental health in women. Prospective studies are needed to confirm these findings.

Therapeutic Potential of the Microbiome in the Treatment of Neuropsychiatric Disorders

The search for rational treatment of neuropsychiatric disorders began with the discovery of chlorpromazine in 1951 and continues to evolve. Day by day, new details of the intestinal microbiota–brain axis are coming to light. As the role of microbiota in the etiopathogenesis of neuropsychiatric disorders is more clearly understood, microbiota-based (or as we propose, “fecomodulation”) treatment options are increasingly discussed in the context of treatment. Although their history dates back to ancient times, the importance of psychobiotics and fecal microbiota transplantation (FMT) has only recently been recognized. Despite there being few preclinical and clinical studies, the evidence gathered to this point suggests that consideration of the microbiome in the treatment of neuropsychiatric disorders represents an area of significant therapeutic potential. It is increasingly hoped that such treatment options will be more reliable in terms of their side effects, cost, and ease of implementation. However, there remains much to be researched. Questions will be answered through germ-free animal experiments and randomized controlled trials. In this article, the therapeutic potential of microbiota-based options in the treatment of neuropsychiatric disorders is discussed in light of recent research.