Food matters: how the microbiome and gut-brain interaction might impact the development and course of anorexia nervosa

Effect of serum concentrations of IL-6 and TNF-α on brain structure in anorexia nervosa: a combined cross-sectional and longitudinal study

Previous studies of brain structure in anorexia nervosa (AN) have reported reduced gray matter in underweight patients, which largely normalizes upon weight gain. One underlying biological mechanism may be glial cell alterations related to low-grade inflammation. Here, we investigated relationships between brain structure as measured by magnetic resonance imaging and serum concentrations of two pro-inflammatory cytokines (interleukin-6 and tumor necrosis factor alpha) cross-sectionally in 82 underweight adolescent and young adult female patients (mean age 16.8 years; 59 of whom were observed longitudinally after short-term weight restoration; mean duration 2.8 months), 20 individuals long-term weight-recovered from AN (mean age 22.7 years) and 105 healthy control (HC) participants (mean age 17.2 years). We measured cortical thickness, subcortical volumes and local gyrification index, a measure of cortical folding. In contrast to most previous studies of cytokine concentrations in AN, we found no cross-sectional group differences (interleukin-6: p = 0.193, tumor necrosis factor alpha: p = 0.057) or longitudinal changes following weight restoration (interleukin-6: p = 0.201, tumor necrosis factor alpha: p = 0.772). As expected, widespread gray matter reductions (cortical thickness, subcortical volumes, cortical folding) were observed in underweight patients with AN compared to HC. However, we found no evidence of associations between cytokine concentrations and structural brain measures in any participant group. Furthermore, longitudinal changes in cytokine concentrations were unrelated to changes in gray matter. In conclusion, we did not identify any association between (sub-)inflammatory processes and structural brain changes in AN. Future studies are needed to elucidate which other factors besides nutritional status may contribute to brain morphological alterations.

Longitudinal changes in brain-derived neurotrophic factor (BDNF) but not cytokines contribute to hippocampal recovery in anorexia nervosa above increases in body mass index

BACKGROUND

Physical sequelae of anorexia nervosa (AN) include a marked reduction in whole brain volume and subcortical structures such as the hippocampus. Previous research has indicated aberrant levels of inflammatory markers and growth factors in AN, which in other populations have been shown to influence hippocampal integrity.

METHODS

Here we investigated the influence of concentrations of two pro-inflammatory cytokines (tumor necrosis factor-alpha [TNF-α] and interleukin-6 [IL-6]) and brain-derived neurotrophic factor (BDNF) on the whole hippocampal volume, as well as the volumes of three regions (the hippocampal body, head, and tail) and 18 subfields bilaterally. Investigations occurred both cross-sectionally between acutely underweight adolescent/young adult females with AN (acAN; n = 82) and people recovered from AN (recAN; n = 20), each independently pairwise age-matched with healthy controls (HC), and longitudinally in acAN after partial renourishment (n = 58). Hippocampal subfield volumes were quantified using FreeSurfer. Concentrations of molecular factors were analyzed in linear models with hippocampal (subfield) volumes as the dependent variable.

RESULTS

Cross-sectionally, there was no evidence for an association between IL-6, TNF-α, or BDNF and between-group differences in hippocampal subfield volumes. Longitudinally, increasing concentrations of BDNF were positively associated with longitudinal increases in bilateral global hippocampal volumes after controlling for age, age2, estimated total intracranial volume, and increases in body mass index (BMI).

CONCLUSIONS

These findings suggest that increases in BDNF may contribute to global hippocampal recovery over and above increases in BMI during renourishment. Investigations into treatments targeted toward increasing BDNF in AN may be warranted.

Every mistake is a treasure: Lessons learned from the TRIANGLE trial for anorexia nervosa

BACKGROUND

Despite several decades of treatment research for anorexia nervosa (AN), many of the same questions remain: how to boost enrollment, engage participants, prevent attrition, and meet the needs of a diverse patient population within the rigorous framework of a randomized controlled trial (RCT).

METHODS

In this research forum, we highlight some of the challenges and opportunities observed over the course of TRIANGLE, the largest RCT for severe AN treatment in the UK to date. We discuss strategies for addressing common challenges and avoiding common pitfalls and propose solutions to future researchers seeking to conduct treatment research in AN.

RESULTS

Our experience underscores the value of involving people with lived experience at every stage of intervention research. We offer additional recommendations for treatment researchers, including, (1) early qualitative research to identify patient barriers and obstacles, (2) clear, systematic collaboration with clinical sites for patient recruitment and passive data collection, (3) careful consideration of assessment metrics, including repeated measurement of quality of life, (4) adopting a flexible, patient-centered approach to clinical trial research, and (5) considering the unique needs and obstacles that might impact carer participation in research and their ability to provide support to their loved ones.

DISCUSSION

We hope that these lessons learned will prove fruitful for the next generation of researchers embarking on treatment research for AN.

PUBLIC SIGNIFICANCE

Using the TRIANGLE trial as an illustrative case study, we highlight the value of lived experience and codesign for developing and testing interventions for AN. We offer several lessons learned over the course of the trial, pertaining to trial enrollment, retention and engagement, measurement of outcomes, and research adaptations for real-world settings, and hope that these recommendations facilitate future treatment research for AN.

Gut microbiota differences in stunted and normal-lenght children aged 36-45 months in East Nusa Tenggara, Indonesia

The role of the gut microbiota in energy metabolism of the host has been established, both in overweight/obesity, as well as in undernutrition/stunting. Dysbiosis of the gut microbiota may predispose to stunting. The aim of this study was to compare the gut microbiota composition of stunted Indonesian children and non-stunted children between 36 and 45 months from two sites on the East Nusa Tenggara (ENT) islands. Fecal samples were collected from 100 stunted children and 100 non-stunted children in Kupang and North Kodi. The gut microbiota composition was determined by sequencing amplicons of the V3-V4 region of the 16S rRNA gene. Moreover, fecal SCFA concentrations were analyzed. The microbiota composition was correlated to anthropometric parameters and fecal metabolites. The phyla Bacteroidetes (Bacteroidota; q = 0.014) and Cyanobacteria (q = 0.049) were significantly higher in stunted children. Three taxa at genus levels were consistently significantly higher in stunted children at both sampling sites, namely Lachnoclostridium, Faecalibacterium and Veillonella (q < 7 * 10-4). These and 9 other taxa positively correlated to the z-score length-for-age (zlen), while 11 taxa negatively correlated with zlen. Several taxa also correlated with sanitary parameters, some of which were also significantly different between the two groups. All three fecal SCFA concentrations (acetate, propionate and butyrate) and their total were lower in stunted children compared to non-stunted children, although not significant for butyrate, indicating lower energy-extraction by the gut microbiota. Also, since SCFA have been shown to be involved in gut barrier function, barrier integrity may be affected in the stunted children. It remains to be seen if the three taxa are involved in stunting, or are changed due to e.g. differences in diet, hygiene status, or other factors. The observed differences in this study do not agree with our previous observations in children on Java, Indonesia. There are differences in infrastructure facilities such as clean water and sanitation on ENT and Java, which may contribute to the differences observed. The role of the gut microbiota in stunting therefore requires more in depth studies. Trial registration: the trial was registered at ClinicalTrials.gov with identifier number NCT05119218.

The Role of the Gut Microbiota in Anorexia Nervosa in Children and Adults-Systematic Review

Among the factors incriminated in the appearance of eating disorders, intestinal microbiota has recently been implicated. Now there is evidence that the composition of gut microbiota is different in anorexia nervosa. We gathered many surveys on the changes in the profile of gut microbiota in patients with anorexia nervosa. This review comprehensively examines the contemporary experimental evidence concerning the bidirectional communication between gut microbiota and the brain. Drawing from recent breakthroughs in this area of research, we propose that the gut microbiota significantly contributes to the intricate interplay between the body and the brain, thereby contributing to overall healthy homeostasis while concurrently impacting disease risk, including anxiety and mood disorders. Particular attention is devoted to elucidating the structure and functional relevance of the gut microbiota in the context of Anorexia Nervosa.

Using 16S rDNA and metagenomic sequencing technology to analyze the fecal microbiome of children with avoidant/restrictive food intake disorder

To investigate the gut microbiota distribution and its functions in children with avoidant/restrictive food intake disorder (ARFID). A total of 135 children were enrolled in the study, including 102 children with ARFID and 33 healthy children. Fecal samples were analyzed to explore differences in gut microbiota composition and diversity and functional differences between the ARFID and healthy control (HC) groups via 16S rDNA and metagenomic sequencing. The gut microbiota composition and diversity in children with ARFID were different from those in heathy children, but there is no difference in the composition and diversity of gut microbiota between children at the age of 3-6 and 7-12 with ARFID. At the phylum level, the most abundant microbes in the two groups identified by 16S rDNA and metagenomic sequencing were the same. At the genus level, the abundance of Bacteroides was higher in the ARFID group (P > 0.05); however, different from the result of 16SrDNA sequencing, metagenomic sequencing showed that the abundance of Bacteroides in the ARFID group was significantly higher than that in the HC group (P = 0.041). At the species level, Escherichia coli, Streptococcus thermophilus and Lachnospira eligens were the most abundant taxa in the ARFID group, and Prevotella copri, Bifidobacterium pseudocatenulatum, and Ruminococcus gnavus were the top three microbial taxa in the HC group; there were no statistically significant differences between the abundance of these microbial taxa in the two groups. LefSe analysis indicated a greater abundance of the order Enterobacterales and its corresponding family Enterobacteriaceae, the family Bacteroidaceae and corresponding genus Bacteroides, the species Bacteroides vulgatus in ARFID group, while the abundance of the phylum Actinobacteriota and its corresponding class Actinobacteria , the order Bifidobacteriales and corresponding family Bifidobacteriaceae, the genus Bifidobacterium were enriched in the HC group. There were no statistically significant differences in the Chao1, Shannon and Simpson indices between the Y1 and Y2 groups (P = 0.1, P = 0.06, P = 0.06). At the phylum level, Bacillota, Bacteroidota, Proteobacteria and Actinobacteriota were the most abundant taxa in both groups, but there were no statistically significant differences among the abundance of these bacteria (P = 0.958, P = 0.456, P = 0.473, P = 0.065). At the genus level, Faecalibacterium was more abundant in the Y2 group than in the Y1 group, and the difference was statistically significant (P = 0.037). The KEGG annotation results showed no significant difference in gut microbiota function between children with ARFID and healthy children; however, GT26 was significantly enriched in children with ARFID based on the CAZy database. The most abundant antibiotic resistance genes in the ARFID group were the vanT, tetQ, adeF, ermF genes, and the abundance of macrolide resistance genes in the ARFID group was significantly higher than that in the HC group (P = 0.041). Compared with healthy children, children with ARFID have a different distribution of the gut microbiota and functional genes. This indicates that the gut microbiome might play an important role in the pathogenesis of ARFID.Clinical trial registration: ChiCTR2300074759.

[Fecal Microbiota Transplants in the Context of (Child and Adolescent) Psychiatric Disorders]

Fecal Microbiota Transplants in the Context of (Child and Adolescent) Psychiatric Disorders Abstract: There has recently been a significant increase in interest in gut microbiota and its interaction with the brain (gut-brain axis). Not only are the findings of microbiome research interesting for basic scientists, they also offer relevant insights for clinical practice. A causal relationship between gut microbiome and various somatic diseases such as diabetes mellitus, inflammatory bowel diseases, and obesity as well as psychiatric diseases such as major depression, anxiety disorders, and eating disorders seems plausible. To study the causal relationship of intestinal bacteria with individual phenotypes, researchers apply so-called stool transplantations (fecal microbiota transplantations) in the preclinical context. For this purpose, they transfer microbiota samples from patients into laboratory animals to observe possible changes in phenotype. In the clinical context, fecal microbiota transplantation is already being used with therapeutic intentions for selected diseases, for example, recurrent infections with Clostridioides difficile or inflammatory bowel diseases; they have already become part of the official clinical guidelines for C. difficile. For many other diseases, however, including mental illnesses, the potential of using fecal transplantations for therapeutic purposes is still being explored. Previous findings suggest that the intestinal microbiome, particularly fecal microbiota transplantations, represent a promising starting point for new therapeutic approaches.

[The Therapeutic Potential of Prebiotics and Probiotics in Child and Adolescent Psychiatric Disorders]

The Therapeutic Potential of Prebiotics and Probiotics in Child and Adolescent Psychiatric Disorders Abstract: This short review summarizes the literature available on therapeutic interventions with prebiotics and probiotics and their potential use in psychiatric disorders in childhood, adolescence, and adulthood. Most studies of children and adolescents are done on ADHD and autism spectrum disorders, whereas single reports exist largely on positive effects on cognitive symptoms and quality of life. Initial studies regarding anorexia nervosa point to a potential effect of weight gain and reduction of gastrointestinal symptoms. To date, the effects of prebiotics and probiotics in depression, bipolar disorder, anxiety disorders, and schizophrenia have been mainly investigated in adults. The best reported evidence exists for depression, whereas the effects on depressive symptomatology are small. Positive effects are seen on gastrointestinal symptoms in these disorders. Given these positive effects, the mixed literature reports may result from very heterogeneous study designs. Nevertheless, the high potential of prebiotics and probiotics may be seen for minors with mental health problems. Further studies that include child and adolescent psychiatric populations and reflect the complexity of the gut-brain axis are urgently needed.

Exploring Caloric Restriction in Inpatients with Eating Disorders: Cross-Sectional and Longitudinal Associations with Body Dissatisfaction, Body Avoidance, Clinical Factors, and Psychopathology

Reduction in food intake is an important feature of eating disorders (EDs). However, whereas self-reported cognitive control over food (i.e., dietary restraint) is commonly assessed, we are not aware of any study evaluating the actual reduction in caloric intake (i.e., caloric restriction, CR) and its relationships with psychopathological, clinical, and anamnestic factors in individuals with EDs. In this study, we quantified caloric intake, CR, and weight suppression in 225 ED inpatients and explored significant relationships with self-reported eating symptoms, body dissatisfaction, body avoidance, personality, and affective symptoms. For underweight inpatients (n = 192), baseline predictors of caloric intake and restriction at discharge were assessed through a data-driven approach. CR at admission was significantly related to eating symptomatology, state anxiety, and body image. In regression models, CR, higher BMI, binge-purging symptoms, and the interaction between weight suppression and CR were significantly related to body dissatisfaction. The best psychopathological predictors of caloric intake and restriction at discharge for underweight inpatients were perfectionistic concern over mistakes and state anxiety. These results suggest that caloric restriction is associated to relevant ED features and warrant for a multidimensional assessment of ED psychopathology.

Gut-Associated Lymphatic Tissue in Food-Restricted Rats: Influence of Refeeding and Probiotic Supplementation

Anorexia nervosa (AN) is a severe and often chronic eating disorder that leads to alterations in the gut microbiome, which is known to influence several processes, such as appetite and body weight regulation, metabolism, gut permeability, inflammation, and gut-brain interactions. Using a translational activity-based anorexia (ABA) rat model, this study examined the effect of chronic food starvation, as well as multistrain probiotic supplementation and refeeding, on the structure of the gut and gut-associated lymphatic tissue (GALT). Our results indicated that ABA had an atrophic influence on intestinal morphology and increased the formation of GALT in the small bowel and colon. Higher formation of GALT in ABA rats appeared to be reversible upon application of a multistrain probiotic mixture and refeeding of the starved animals. This is the first time that increased GALT was found following starvation in the ABA model. Our results underscore a potential role of gut inflammatory alterations in the underlying pathophysiology of AN. Increased GALT could be linked to the gut microbiome, as probiotics were able to reverse this finding. These results emphasize the role of the microbiome-gut-brain axis in the pathomechanisms of AN and point to probiotics as potentially beneficial addendum in the treatment of AN.

The emerging role of the endocannabinoidome-gut microbiome axis in eating disorders

Among the sources of chemical signals regulating food intake, energy metabolism and body weight, few have attracted recently as much attention as the expanded endocannabinoid system, or endocannabinoidome (eCBome), and the gut microbiome, the two systems on which this review article is focussed. Therefore, it is legitimate to expect that these two systems also play a major role in the etiopathology of eating disorders (EDs), in particular of anorexia nervosa, bulimia nervosa and binge-eating disorder. The major mechanisms through which, also via interactions with other endogenous signaling systems, the eCBome, with its several lipid mediators and receptors, and the gut microbiome, via its variety of microbial kingdoms, phyla and species, and armamentarium of metabolites, intervene in these disorders, are described here, based on several published studies in either experimental models or patients. Additionally, in view of the emerging multi-faceted cross-talk mechanisms between these two complex systems, we discuss the possibility that the eCBome-gut microbiome axis is also involved in EDs.

Food, gut barrier dysfunction, and related diseases: A new target for future individualized disease prevention and management

Dysfunction of gut barrier is known as "leaky gut" or increased intestinal permeability. Numerous recent scientific evidences showed the association between gut dysfunction and multiple gastrointestinal tract (GI) and non-GI diseases. Research also demonstrated that food plays a crucial role to cause or remedy gut dysfunction related to diseases. We reviewed recent articles from electronic databases, mainly PubMed. The data were based on animal models, cell models, and human research in vivo and in vitro models. In this comprehensive review, our aim focused on the relationship between dietary factors, intestinal permeability dysfunction, and related diseases. This review synthesizes currently available literature and is discussed in three parts: (a) the mechanism of gut barrier and function, (b) food and dietary supplements that may promote gut health, and food or medication that may alter gut function, and (c) a table that organizes the synthesized information by general mechanisms for diseases related to leaky gut/intestinal permeability and associated dietary influences. With future research, dietary intervention could be a new target for individualized disease prevention and management.

Complementary and Integrative Medicine and Eating Disorders in Youth: Traditional Yoga, Virtual Reality, Light Therapy, Neurofeedback, Acupuncture, Energy Psychology Techniques, Art Therapies, and Spirituality

Eating disorders (EDs) are a non-heterogeneous group of illnesses with significant physical and mental comorbidity and mortality associated with maladaptive coping. With the exception of lisdexamfetamine (Vyvanse) for binge eating disorder, no medications have been effective for the core symptoms of ED. ED requires a multimodal approach. Complementary and integrative medicine (CIM) can be helpful as an adjunct. The most promising CIM interventions are traditional yoga, virtual reality, eye movement desensitization and reprocessing, Music Therapy, and biofeedback/neurofeedback.

Novel ketamine and zinc treatment for anorexia nervosa and the potential beneficial interactions with the gut microbiome

Anorexia nervosa (AN) is a severe illness with diverse aetiological and maintaining contributors including neurobiological, metabolic, psychological, and social determining factors. In addition to nutritional recovery, multiple psychological and pharmacological therapies and brain-based stimulations have been explored; however, existing treatments have limited efficacy. This paper outlines a neurobiological model of glutamatergic and γ-aminobutyric acid (GABA)-ergic dysfunction, exacerbated by chronic gut microbiome dysbiosis and zinc depletion at a brain and gut level. The gut microbiome is established early in development, and early exposure to stress and adversity contribute to gut microbial disturbance in AN, early dysregulation to glutamatergic and GABAergic networks, interoceptive impairment, and inhibited caloric harvest from food (e.g., zinc malabsorption, competition for zinc ions between gut bacteria and host). Zinc is a key part of glutamatergic and GABAergic networks, and also affects leptin and gut microbial function; systems dysregulated in AN. Low doses of ketamine in conjunction with zinc, could provide an efficacious combination to act on NMDA receptors and normalise glutamatergic, GABAergic and gut function in AN.

Gut microbiome-brain interactions in anorexia nervosa: Potential mechanisms and regulatory strategies

Anorexia nervosa (AN) is a psychiatric disorder characterised by malnutrition, fear of weight gain, and body image disturbances. The aetiology of AN is complex, and may involve environmental factors, genetic factors, and biochemical factors, with the latter meaning that AN may be closely associated with neurons, neurotransmitters, and hormones related to appetite and emotional regulation. In addition, an increasing number of studies have shown there is a link between the intestinal microbiota and psychiatric disorders, such as depression. However, few studies and reviews have focused on AN and gut microbes. Accordingly, in this review, we examine the potential pathogenesis of AN in terms of changes in the gut microbiota and its metabolites, and their effects on AN. The neurobiological function of the nervous system in relation to AN are also been mentioned. Furthermore, we suggest future research directions for this field, and note that probiotics may be developed for use as dietary supplements to help alleviate AN in patients.

Dietary management of adults with IBD - the emerging role of dietary therapy

Historically, dietitians played a minor part in the management of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis. Patients were commonly referred for consequences of uncontrolled disease, such as malnutrition and bowel obstruction risk. Today, dietitians are fundamental members of the multidisciplinary IBD team, from educating on the role of diet at diagnosis and throughout the lifespan of a patient with IBD to guiding primary induction therapy. This aspect is reflected in published guidelines for IBD management, which previously placed diet as only a minor factor, but now have diet-specific publications. This Review describes a four-step approach in a dietitian's assessment and management of diet in patients with IBD: (1) identifying and correcting nutritional gaps and dietary imbalances; (2) considering diet to treat active disease with the use of exclusive enteral nutrition (EEN) or emerging diets that could replace EEN; (3) using therapeutic diets to control existing complications of IBD, such as reduced fibre to prevent bowel obstruction in stricturing disease or a fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet to manage co-existing functional gut symptoms; and (4) considering the role of diet in preventing IBD development in high-risk populations.

Are the Effects of Malnutrition on the Gut Microbiota–Brain Axis the Core Pathologies of Anorexia Nervosa?

Anorexia nervosa (AN) is a disabling, costly, and potentially deadly illness. Treatment failure and relapse after treatment are common. Several studies have indicated the involvement of the gut microbiota–brain (GMB) axis. This narrative review hypothesizes that AN is driven by malnutrition-induced alterations in the GMB axis in susceptible individuals. According to this hypothesis, initial weight loss can voluntarily occur through dieting or be caused by somatic or psychiatric diseases. Malnutrition-induced alterations in gut microbiota may increase the sensitivity to anxiety-inducing gastrointestinal hormones released during meals, one of which is cholecystokinin (CCK). The experimental injection of a high dose of its CCK-4 fragment in healthy individuals induces panic attacks, probably via the stimulation of CCK receptors in the brain. Such meal-related anxiety attacks may take part in developing the clinical picture of AN. Malnutrition may also cause increased effects from appetite-reducing hormones that also seem to have roles in AN development and maintenance. The scientific background, including clinical, microbiological, and biochemical factors, of AN is discussed. A novel model for AN development and maintenance in accordance with this hypothesis is presented. Suggestions for future research are also provided.

Inattention, Impulsivity, and Hyperactivity among Individuals with Self-Reported Impaired Wound Healing

Background: Inattention and impulsivity are common causes of accidents and injury. The aim of the current study was to examine the level of attention deficit (AD), hyperactivity, and impulsivity (HI) in individuals with and without self-reported impaired wound healing (IWH). Methods: A survey was conducted among N = 773 Dutch young adults, 18–30 years old. N = 198 were allocated to the IWH group and N = 575 to the control group. All participants completed the Attention Deficit Hyperactivity Disorder (ADHD) Rating Scale. Results: The analysis revealed that the IWH group has significantly higher scores on AD and HI, compared to the control group. Among the IWH group, 12.8% screened positive for AD (compared to 5.8% of the control group) and 14.0% screened positive for HI (compared to 7.4% of the control group). Conclusion: Clinically relevant increased inattention, impulsivity, and hyperactivity were observed among individuals with self-reported impaired wound healing.

The effects of polyunsaturated fatty acid (PUFA) administration on the microbiome-gut-brain axis in adolescents with anorexia nervosa (the MiGBAN study): study protocol for a longitudinal, double-blind, randomized, placebo-controlled trial

Background

Anorexia nervosa (AN) is a severe psychiatric disease that often takes a chronic course due to insufficient treatment options. Emerging evidence on the gut-brain axis offers the opportunity to find innovative treatments for patients with psychiatric disorders. The gut microbiome of patients with AN shows profound alterations that do not completely disappear after weight rehabilitation. In previous studies, the administration of polyunsaturated fatty acids (PUFA) resulted in effects that might be beneficial in the treatment of AN, affecting the microbiome, body weight and executive functions. Therefore, the MiGBAN study aims to examine the effects of a nutritional supplementation with PUFA on the gut microbiome and body mass index (BMI) in patients with AN.

Methods

This is a longitudinal, double-blind, randomized, placebo-controlled trial. Within 2 years, 60 adolescent patients aged 12 to 19 years with AN will receive either PUFA or placebo for 6 months additional to treatment as usual. After 1 year, the long-term effect of PUFA on the gut microbiome and consecutively on BMI will be determined. Secondary outcomes include improvement of gastrointestinal symptoms, eating disorder psychopathology, and comorbidities. Additionally, the interaction of the gut microbiome with the brain (microbiome-gut-brain axis) will be studied by conducting MRI measurements to assess functional and morphological changes and neuropsychological assessments to describe cognitive functioning. Anti-inflammatory effects of PUFA in AN will be examined via serum inflammation and gut permeability markers. Our hypothesis is that PUFA administration will have positive effects on the gut microbiota and thus the treatment of AN by leading to a faster weight gain and a reduction of gastrointestinal problems and eating disorder psychopathology.

Discussion

Due to previously heterogeneous results, a systematic and longitudinal investigation of the microbiome-gut-brain axis in AN is essential. The current trial aims to further analyse this promising research field to identify new, effective therapeutic tools that could help improve the treatment and quality of life of patients. If this trial is successful and PUFA supplementation contributes to beneficial microbiome changes and a better treatment outcome, their administration would be a readily applicable additional component of multimodal AN treatment.

Trial registration

German Clinical Trials Register DRKS00017130. Registered on 12 November 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06413-7.

Anorexia nervosa: Outpatient treatment and medical management

Anorexia nervosa (AN) is a disabling, costly and potentially deadly illness. Treatment failure and relapse are common after completing treatment, and a substantial proportion of patients develop severe and enduring AN. The time from AN debut to the treatment initiation is normally unreasonably long. Over the past 20 years there has been empirical support for the efficacy of several treatments for AN. Moreover, outpatient treatment with family-based therapy or individual psychotherapy is associated with good outcomes for a substantial proportion of patients. Early intervention improves outcomes and should be a priority for all patients. Outpatient treatment is usually the best format for early intervention, and it has been demonstrated that even patients with severe or extreme AN can be treated as outpatients if they are medically stable. Inpatient care is more disruptive, more costly, and usually has a longer waiting list than does outpatient care. The decision as to whether to proceed with outpatient treatment or to transfer the patient for inpatient therapy may be difficult. The core aim of this opinion review is to provide the knowledge base needed for performing safe outpatient treatment of AN. The scientific essentials for outpatient treatment are described, including how to assess and manage the medical risks of AN and how to decide when transition to inpatient care is indicated. The following aspects are discussed: early intervention, outpatient treatment of AN, including outpatient psychotherapy for severe and extreme AN, how to determine when outpatient treatment is safe, and when transfer to inpatient healthcare is indicated. Emerging treatments, ethical issues and outstanding research questions are also addressed.

Shedding light on biological sex differences and microbiota-gut-brain axis: a comprehensive review of its roles in neuropsychiatric disorders

Women and men are suggested to have differences in vulnerability to neuropsychiatric disorders, including major depressive disorder (MDD), generalized anxiety disorder (GAD), schizophrenia, eating disorders, including anorexia nervosa, and bulimia nervosa, neurodevelopmental disorders, such as autism spectrum disorder (ASD), and neurodegenerative disorders including Alzheimer’s disease, Parkinson’s disease. Genetic factors and sex hormones are apparently the main mediators of these differences. Recent evidence uncovers that reciprocal interactions between sex-related features (e.g., sex hormones and sex differences in the brain) and gut microbiota could play a role in the development of neuropsychiatric disorders via influencing the gut–brain axis. It is increasingly evident that sex–microbiota–brain interactions take part in the occurrence of neurologic and psychiatric disorders. Accordingly, integrating the existing evidence might help to enlighten the fundamental roles of these interactions in the pathogenesis of neuropsychiatric disorders. In addition, an increased understanding of the biological sex differences on the microbiota–brain may lead to advances in the treatment of neuropsychiatric disorders and increase the potential for precision medicine. This review discusses the effects of sex differences on the brain and gut microbiota and the putative underlying mechanisms of action. Additionally, we discuss the consequences of interactions between sex differences and gut microbiota on the emergence of particular neuropsychiatric disorders.

The human microbiome is a unique set of organisms affecting health via the gut–brain axis.

Neuropsychiatric disorders, eating disorders, neurodevelopmental disorders, and neurodegenerative disorders are regulated by the microbiota–gut–brain axis in a sex-specific manner.

Understanding the role of the microbiota–gut–brain axis and its sex differences in various diseases can lead to better therapeutic methods.

Enteral feeding, even when the gut does not feel very good?

PURPOSE OF REVIEW

To summarize knowledge on the gut function in relation to enteral nutrition.

RECENT FINDINGS

The gut is certainly suffering during critical illness but our understanding of the exact mechanisms involved is limited. Physicians at bedside are lacking tools to identify how well or bad the gut is doing and whether the gut is responding adequately to critical illness. Sensing nutrition as a signal is important for the gut and microbiome. Enteral nutrition has beneficial effects for the gut perfusion and function. However, early full enteral nutrition in patients with shock was associated with an increased number of rare but serious complications.

SUMMARY

Whenever synthesizing knowledge in physiology and available evidence in critically ill, we suggest that enteral nutrition has beneficial effects but may turn harmful if provided too aggressively. Contraindications to enteral nutrition are listed in recent guidelines. For patients with gastrointestinal dysfunction but without these contraindications, we suggest considering early enteral nutrition as a signal to the gut and to the body rather than an energy and protein provision. With this rationale, we think that low dose of enteral nutrition could and probably should be provided also when the gut does not feel very good. Understanding the feedback from the gut in response to enteral nutrition would be important, however, monitoring tools are currently limited to clinical assessment only.

An In Vitro Approach to Studying the Microbial Community and Impact of Pre and Probiotics under Anorexia Nervosa Related Dietary Restrictions

Individuals with anorexia nervosa (AN) often suffer psychological and gastrointestinal problems consistent with a dysregulated gut microbial community. Psychobiotics have been postulated to modify microbiota and improve mental well-being and gut symptoms, but there is currently a lack of evidence for such approaches in AN. The aim of this study was to use an in vitro colonic model to evaluate the impact of dietary restrictions associated with AN on the intestinal ecosystem and to assess the impact of pre and probiotic intervention. Bacteriology was quantified using flow cytometry combined with fluorescence in situ hybridisation and metabolic end products (including neurotransmitters) by gas chromatography and liquid chromatography mass spectrometry Consistent with previous research, the nutritional changes significantly reduced total microbiota and metabolites compared with healthy conditions. Pre and probiotic supplementation on restricted conditions enhanced the microbial community and modulated metabolic activity to resemble that of a healthy diet. The model system indicates that nutritional changes associated with AN can impact the microbial community, and that these changes can, at least in part, be restored through the use of pre and probiotic interventions.

The effects of probiotics administration on the gut microbiome in adolescents with anorexia nervosa-A study protocol for a longitudinal, double-blind, randomized, placebo-controlled trial

Objective

Knowledge on gut–brain interaction might help to develop new therapies for patients with anorexia nervosa (AN), as severe starvation‐induced changes of the microbiome (MI) do not normalise with weight gain. We examine the effects of probiotics supplementation on the gut MI in patients with AN.

Method

This is a study protocol for a two‐centre double‐blind randomized‐controlled trial comparing the clinical efficacy of multistrain probiotic administration in addition to treatment‐as‐usual compared to placebo in 60 patients with AN (13–19 years). Moreover, 60 sex‐ and age‐matched healthy controls are included in order to record development‐related changes. Assessments are conducted at baseline, discharge, 6 and 12 months after baseline. Assessments include measures of body mass index, psychopathology (including eating‐disorder‐related psychopathology, depression and anxiety), neuropsychological measures, serum and stool analyses. We hypothesise that probiotic administration will have positive effects on the gut microbiota and the treatment of AN by improvement of weight gain, gastrointestinal complaints and psychopathology, and reduction of inflammatory processes compared to placebo.

Conclusions

If probiotics could help to normalise the MI composition, reduce inflammation and gastrointestinal discomfort and increase body weight, its administration would be a readily applicable additional component of multi‐modal AN treatment.

Patients with anorexia nervosa face profound alterations of the gut microbiome which does not normalise with weight gain.

Alterations in the gut microbiome in patients with anorexia nervosa are linked to psychopathological symptoms and neurophysiological deficits, for example, related to the reward system.

This is the first study examining the effects of probiotics administration in adolescents with anorexia nervosa using a randomized controlled trial design.

Correlation between Gut Microbiota and Six Facets of Neuroticism in Korean Adults

A person high in neuroticism is more likely to experience anxiety, stress, worry, fear, anger, and depression. Previous studies have shown that the gut microbiota can influence personality and mental disorders, including stress, anxiety, and depression, through the gut-brain axis. Here, we investigated the correlations between the sub-facet of neuroticism and gut microbiota using the Revised NEO Personality Inventory and the 16S rRNA gene sequencing data 784 adults. We found that the high anxiety and vulnerability group showed significantly lower richness in microbial diversity than a group with low anxiety and vulnerability. In beta diversity, there was a significant difference between the low and high groups of anxiety, self-consciousness, impulsiveness, and vulnerability. In taxonomic compositions, Haemophilus belonging to Gammaproteobacteria was correlated with the Neuroticism domain as well as N1 anxiety and N6 vulnerability facets. The high N1 anxiety and N6 vulnerability group was correlated with a low abundance of Christensenellaceae belonging to Firmicutes Clostridia. High N4 self-consciousness was correlated with a low abundance of Alistipes and Sudoligranulum. N5 impulsiveness was correlated with a low abundance of Oscillospirales. Our findings will contribute to uncovering the potential link between the gut microbiota and neuroticism, and the elucidation of the correlations of the microbiome-gut-brain axis with behavioral changes and psychiatric cases in the general population.

Is there a dysbiosis in individuals with a neurodevelopmental disorder compared to controls over the course of development? A systematic review

Many scientific papers reported that an unbalanced gut microbiota could lead to or worsen neurodevelopmental disorders (NDD). A dysbiosis may then be observed in the course of development and mark a dysfunction within what is called the gut-brain axis. The aim of this systematic review is to investigate potential evidence of dysbiosis in children and young adults with NDD compared to controls. Using the PRISMA guidelines we systematically reviewed studies that compared the gut microbiota in NDD participants (with an age inferior to thirty) to the gut microbiota of controls, regardless of the data analysis methods used. The MEDLINE, Scopus and PsycINFO databases were searched up to September 2018. 31 studies with a total sample size of 3002 ASD (Autism Spectrum Disorder) and 84 ADHD (Attention Deficit Hyperactivity Disorder) participants were included in this systematic review. Independent data extraction and quality assessment were conducted. The quality of the studies was rated from low to high. Population characterization and experimental methods were highly heterogeneous in terms of the data available, selection of criteria, and dysbiosis measurement. A dysbiosis was reported in 28 studies in terms of either diversity, bacterial composition or metabolome dysfunction. Due to heterogeneity, a quantitative synthesis was not applicable. In this paper, we discuss the different biases to understand the complexity of microbiota and neurodevelopmental disorders to provide leads for future cohort studies looking to answer the questions raised by the trillions of microorganisms that inhabit key body niches.

[The Gut Microbiome and Its Clinical Implications in Anorexia Nervosa]

The Gut Microbiome and Its Clinical Implications in Anorexia Nervosa Abstract. The diverse interactions of the gut microbiome with the metabolism, the immune system, and the brain of the host are increasingly becoming to the forefront of relevant research. Studies suggest a connection between an altered intestinal microbiome and somatic diseases, such as colitis ulcerosa, Crohn's disease, and diabetes, as well as mental illnesses such as anxiety and depression. Patients with anorexia nervosa (AN) also show significant changes in their gut microbiome which seem to be associated, among other things, with a different energy uptake from food, immunological and inflammatory processes, genetic predisposition, hormonal changes, and possibly increased intestinal permeability. In rats, stool transplantation from patients with AN resulted in decreased appetite and weight as well as anxious and compulsive behavior. In this review, we summarize the possible mechanisms of interaction between the microbiome and the host, and present initial findings on the microbiome in AN. Research on nutritional interventions, for example, with prebiotics and probiotics or nutritional supplements such as omega-3 fatty acids, which aim to positively influence the intestinal microbiome, could lead to additional treatment options in the therapy of patients with AN.

Caution, "normal" BMI: health risks associated with potentially masked individual underweight-EPMA Position Paper 2021

An increasing interest in a healthy lifestyle raises questions about optimal body weight. Evidently, it should be clearly discriminated between the standardised "normal" body weight and individually optimal weight. To this end, the basic principle of personalised medicine "one size does not fit all" has to be applied. Contextually, "normal" but e.g. borderline body mass index might be optimal for one person but apparently suboptimal for another one strongly depending on the individual genetic predisposition, geographic origin, cultural and nutritional habits and relevant lifestyle parameters-all included into comprehensive individual patient profile. Even if only slightly deviant, both overweight and underweight are acknowledged risk factors for a shifted metabolism which, if being not optimised, may strongly contribute to the development and progression of severe pathologies. Development of innovative screening programmes is essential to promote population health by application of health risks assessment, individualised patient profiling and multi-parametric analysis, further used for cost-effective targeted prevention and treatments tailored to the person. The following healthcare areas are considered to be potentially strongly benefiting from the above proposed measures: suboptimal health conditions, sports medicine, stress overload and associated complications, planned pregnancies, periodontal health and dentistry, sleep medicine, eye health and disorders, inflammatory disorders, healing and pain management, metabolic disorders, cardiovascular disease, cancers, psychiatric and neurologic disorders, stroke of known and unknown aetiology, improved individual and population outcomes under pandemic conditions such as COVID-19. In a long-term way, a significantly improved healthcare economy is one of benefits of the proposed paradigm shift from reactive to Predictive, Preventive and Personalised Medicine (PPPM/3PM). A tight collaboration between all stakeholders including scientific community, healthcare givers, patient organisations, policy-makers and educators is essential for the smooth implementation of 3PM concepts in daily practice.

Metabolomics signatures of acutely ill and short-term weight recovered women with anorexia nervosa

Although metabolomics studies are recently spreading and have allowed the characterization of putative biomarkers in many diseases, they are relatively scanty in anorexia nervosa (AN). In this explorative study we analyzed the fecal metabolomics profiles of women with AN in the underweight phase (n = 24) and after short-term weight restoration (n = 16) and compared them with 20 healthy women. An untargeted metabolomic procedure allowed the characterization of 224 metabolites involved in energy, lipid, and amino acid metabolism. A partial least square discriminant analysis identified 14 metabolites with a variable importance in projection score >1.5 that clearly differentiated underweight from weight-restored patients from healthy women. Compared with healthy women, fecal concentrations of valeric acid and 3-methyl,2-ketobutyric acid were increased in both underweight and weight-restored patients; fecal concentrations of propionic acid, stearic acid, linolenic acid, methyl-galactoside, coprosterol, cycloserine, and lauric acid were increased while fecal levels of xylose, fucose, and rhamnose were decreased in underweight patients and normalized after weight-restoration; fecal concentrations of piperine, phenylalanine, butyric acid, and meso-erythritol-1 were decreased while fecal levels of hydroxystearic acid were increased in weight-restored but normal in underweight AN patients. All these changes point to peculiar fecal metabolomics profiles of acute and short-term weight restored AN patients. The value of these changes to improve our understanding of the pathophysiology of AN and to characterize potential biomarker targets for developing new treatment strategies needs further studies to be clarified.

Role of microbes in the pathogenesis of neuropsychiatric disorders

Microbes inhabit different anatomical sites of the human body including oral cavity, gut, and skin. A growing literature highlights how microbiome variation is associated with human health and disease. There is strong evidence of bidirectional communication between gut and brain mediated by neurotransmitters and microbial metabolites. Here, we review the potential involvement of microbes residing in the gut and in other body sites in the pathogenesis of eight neuropsychiatric disorders, discussing findings from animal and human studies. The data reported provide a comprehensive overview of the current state of the microbiome research in neuropsychiatry, including hypotheses about the mechanisms underlying the associations reported and the translational potential of probiotics and prebiotics.

Gut microbiota alteration in adolescent anorexia nervosa does not normalize with short-term weight restoration

OBJECTIVE

Gut microbiota are linked to metabolic function, body weight regulation, and brain and behavioral changes. Alteration of gut microbiota is repeatedly demonstrated in adults with anorexia nervosa (AN) and transplantation of stool from adult patients with AN reduces weight gain, food consumption and food efficiency in germ-free mice. No similar data are available for adolescents, who might differ from adults due to their shorter duration of illness.

METHOD

Nineteen female adolescent patients with AN at admission and after short-term weight recovery were included in a longitudinal study and compared to 20 healthy controls (HC). DNA was extracted from stool samples and subjected to 16S rRNA gene sequencing and analysis. Group comparisons, indicator genera and simper analysis were applied. Taxon abundances at admission was used to predict inpatient treatment duration.

RESULTS

Alpha diversity is increased in patients with AN after short-term weight recovery, while beta diversity shows clear group differences with HC before and after weight gain. A reduction in Romboutsia and taxa belonging to Enterobacteriaceae at both timepoints and an increase in taxa belonging to Lachnospiraceae at discharge are most indicative of patients. Lachnospiraceae abundance at admission helped to predict shorter inpatient treatment duration.

DISCUSSION

This pilot study provides first evidence of gut microbiota alterations in adolescent patients with AN that do not normalize with weight gain. If verified in larger studies, the predictive power of taxa belonging to Lachnospiraceae for clinical outcome could complement known predictors at admission, inform clinicians and serve as a target for nutritional interventions.

Hair endocannabinoid concentrations in individuals with acute and weight-recovered anorexia nervosa

BACKGROUND

The endocannabinoid system has been suggested to modulate energy metabolism and stress response and could be an important factor in the pathophysiology of anorexia nervosa (AN). In the context of AN, excessive physical activity may influence endocannabinoid concentrations. The objective of this study was to investigate hair endocannabinoid concentrations at different stages of the disorder. Measurement in hair allows for a cumulative assessment of endocannabinoid concentrations independent of circadian rhythms.

METHODS

In a combined cross-sectional and longitudinal design, we measured hair concentrations of the endocannabinoids anandamide and 2-arachidonoylglycerol and the endocannabinoid-related compounds palmitoylethanolamide, oleoylethanolamide, and stearoylethanolamide in female underweight patients with acute AN (n = 67, reassessment of n = 47 after short-term weight restoration with a body mass index increase of at least 14%), individuals long-term recovered from AN (n = 27), and healthy control participants (n = 84).

RESULTS

Hair concentrations of anandamide and all endocannabinoid-related compounds were elevated in acute AN and decreased over the course of short-term weight restoration. Anandamide concentrations remained elevated in long-term recovered AN patients. In long-term recovered patients, physical activity correlated positively with the concentrations of all endocannabinoid-related compounds.

CONCLUSION

The current study provides evidence for a significant alteration of the endocannabinoid system in acute AN, which may partly persist into long-term recovery. The endocannabinoid system may be a possible target for pharmaceutical interventions in AN, which should be explored in further preclinical and subsequently clinical randomized controlled trials.

Metabolic Shifts as the Hallmark of Most Common Diseases: The Quest for the Underlying Unity

A hyper-specialization characterizes modern medicine with the consequence of classifying the various diseases of the body into unrelated categories. Such a broad diversification of medicine goes in the opposite direction of physics, which eagerly looks for unification. We argue that unification should also apply to medicine. In accordance with the second principle of thermodynamics, the cell must release its entropy either in the form of heat (catabolism) or biomass (anabolism). There is a decreased flow of entropy outside the body due to an age-related reduction in mitochondrial entropy yield resulting in increased release of entropy in the form of biomass. This shift toward anabolism has been known in oncology as Warburg-effect. The shift toward anabolism has been reported in most diseases. This quest for a single framework is reinforced by the fact that inflammation (also called the immune response) is involved in nearly every disease. This strongly suggests that despite their apparent disparity, there is an underlying unity in the diseases. This also offers guidelines for the repurposing of old drugs.

Gut microbiota profile of Indonesian stunted children and children with normal nutritional status

The gut microbiota has been shown to play a role in energy metabolism of the host. Dysbiosis of the gut microbiota may predispose to obesity on the one hand, and stunting on the other. The aim of the study was to study the difference in gut microbiota composition of stunted Indonesian children and children of normal nutritional status between 3 and 5 years. Fecal samples and anthropometric measurements, in addition to economic and hygiene status were collected from 78 stunted children and 53 children with normal nutritional status in two regions in Banten and West Java provinces: Pandeglang and Sumedang, respectively. The gut microbiota composition was determined by sequencing amplicons of the V3-V4 region of the 16S rRNA gene. The composition was correlated to nutritional status and anthropometric parameters. Macronutrient intake was on average lower in stunted children, while energy-loss in the form of short-chain fatty acids (SCFA) and branched-chain fatty acids (BCFA) appeared to be higher in stunted children. In stunted children, at the phylum level the relative abundance of Bacteroidetes (44.4%) was significantly lower than in normal children (51.3%; p-value 2.55*10-4), while Firmicutes was significantly higher (45.7% vs. 39.8%; p-value 5.89*10-4). At the genus level, overall Prevotella 9 was the most abundant genus (average of 27%), and it was significantly lower in stunted children than in normal children (23.5% vs. 30.5%, respectively; q-value 0.059). Thirteen other genera were significantly different between stunted and normal children (q-value < 0.1), some of which were at low relative abundance and present in only a few children. Prevotella 9 positively correlated with height (in line with its higher relative abundance in normal children) and weight. In conclusion, Prevotella 9, which was the most abundant genus in the children, was significantly lower in stunted children. The abundance of Prevotella has been correlated with dietary fibre intake, which was lower in these stunted children. Since fibres are fermented by the gut microbiota into SCFA, and these SCFA are a source of energy for the host, increasing the proportion of Prevotella in stunted children may be of benefit. Whether this would prevent the occurrence of stunting or even has the potential to revert it, remains to be seen in follow up research.

Alterations in B cell subsets correlate with body composition parameters in female adolescents with anorexia nervosa

Anorexia nervosa (AN) is a severe eating disorder and often associated with altered humoral immune responses. However, distinct B cell maturation stages in peripheral blood in adolescents with AN have not been characterized. Treatment effects and the relationship between clinical and B cell parameters are also not fully understood. Here we investigated the phenotype of circulating B cell subsets and the relationship with body composition in adolescents with AN before (T0, n = 24) and after 6 weeks (T1, n = 20) of treatment. Using multi-parameter flow cytometry, we found increased percentages of antigen-experienced B cells and plasmablasts in patients with AN compared to healthy controls (n = 20). In contrast, percentages of CD1d⁺CD5⁺ B cells and transitional B cells with immunoregulatory roles were reduced at T0 and T1. These B cell frequencies correlated positively with fat mass, fat mass index (FMI), free fat mass index, and body mass index standard deviation score. In addition, scavenger-like receptor CD5 expression levels were downregulated on transitional B cells and correlated with fat mass and FMI in AN. Our findings that regulatory B cell subgroups were reduced in AN and their strong relationship with body composition parameters point toward an impact of immunoregulatory B cells in the pathogenesis of AN.

A systematic review on the role of microbiota in the pathogenesis and treatment of eating disorders

Background

There is growing interest in new factors contributing to the genesis of eating disorders (EDs). Research recently focused on the study of microbiota. Dysbiosis, associated with a specific genetic susceptibility, may contribute to the development of anorexia nervosa (AN), bulimia nervosa, or binge eating disorder, and several putative mechanisms have already been identified. Diet seems to have an impact not only on modification of the gut microbiota, facilitating dysbiosis, but also on its recovery in patients with EDs.

Methods

This systematic review based on the PICO strategy searching into PubMed, EMBASE, PsychINFO, and Cochrane Library examined the literature on the role of altered microbiota in the pathogenesis and treatment of EDs.

Results

Sixteen studies were included, mostly regarding AN. Alpha diversity and short-chain fatty acid (SCFA) levels were lower in patients with AN, and affective symptoms and ED psychopathology seem related to changes in gut microbiota. Microbiota-derived proteins stimulated the autoimmune system, altering neuroendocrine control of mood and satiety in EDs. Microbial richness increased in AN after weight regain on fecal microbiota transplantation.

Conclusions

Microbiota homeostasis seems essential for a healthy communication network between gut and brain. Dysbiosis may promote intestinal inflammation, alter gut permeability, and trigger immune reactions in the hunger/satiety regulation center contributing to the pathophysiological development of EDs. A restored microbial balance may be a possible treatment target for EDs. A better and more in-depth characterization of gut microbiota and gut–brain crosstalk is required. Future studies may deepen the therapeutic and preventive role of microbiota in EDs.

The Gut Barrier, Intestinal Microbiota, and Liver Disease: Molecular Mechanisms and Strategies to Manage

Liver disease encompasses pathologies as non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, alcohol liver disease, hepatocellular carcinoma, viral hepatitis, and autoimmune hepatitis. Nowadays, underlying mechanisms associating gut permeability and liver disease development are not well understood, although evidence points to the involvement of intestinal microbiota and their metabolites. Animal studies have shown alterations in Toll-like receptor signaling related to the leaky gut syndrome by the action of bacterial lipopolysaccharide. In humans, modifications of the intestinal microbiota in intestinal permeability have also been related to liver disease. Some of these changes were observed in bacterial species belonging Roseburia, Streptococcus, and Rothia. Currently, numerous strategies to treat liver disease are being assessed. This review summarizes and discusses studies addressed to determine mechanisms associated with the microbiota able to alter the intestinal barrier complementing the progress and advancement of liver disease, as well as the main strategies under development to manage these pathologies. We highlight those approaches that have shown improvement in intestinal microbiota and barrier function, namely lifestyle changes (diet and physical activity) and probiotics intervention. Nevertheless, knowledge about how such modifications are beneficial is still limited and specific mechanisms involved are not clear. Thus, further in-vitro, animal, and human studies are needed.

Gut Feelings: How Microbiota Might Impact the Development and Course of Anorexia Nervosa

Anorexia nervosa (AN) can probably be regarded as a "model" for studying the interaction of nutrition with the gut-brain axis, which has drawn increased attention from researchers and clinicians alike. The gut microbiota influences somatic effects, such as energy extraction from food and body weight gain, as well as appetite, gut permeability, inflammation and complex psychological behaviors, such as depression or anxiety, all of which play important roles in AN. As nutrition is one of the main factors that influence the gut microbiota, nutritional restriction and selective eating in AN are likely influencing factors; however, nutritional rehabilitation therapy is surprisingly understudied. Here, we review the general mechanisms of the interactions between nutrition, the gut microbiota and the host that may be relevant to AN, paying special attention to the gut-brain axis, and we present the first specific findings in patients with AN and corresponding animal models. In particular, nutritional interventions, including food selection, supplements, and pre-, pro- and synbiotics that have the potential to influence the gut microbiota, are important research targets to potentially support future AN therapy.

[Gut microbiome and anorexia nervosa : The relationship between microbiome and gut-brain interaction in the context of anorexia nervosa]

In recent years the intestinal microbiome and its interaction with the brain has aroused a growing interest. The findings gained in the course of this research are of great relevance not only to basic scientists but also to clinicians, as studies suggest an association between an altered microbiome and various somatic (e.g. chronic inflammatory intestinal diseases, obesity and diabetes) as well as psychiatric diseases (e.g. anxiety disorders, depression). In addition to a direct influence of the microbiome on the brain and behavior, various mechanisms seem to be relevant, including altered energy intake from food, hormonal changes, probably increased intestinal permeability as well as inflammatory and immunological processes. Anorexia nervosa (AN) is the third most common chronic disease in adolescence and has the highest mortality rate among all mental disorders. In addition to extremely restrictive eating habits, weight loss and comorbid anxiety and depression symptoms, endocrine changes and an increased autoimmune and inflammatory response are characteristic. Since AN is particularly strongly linked to eating behavior and nutrition, research into the microbiome seems very promising, especially with respect to this disease. This article gives a first insight into the underlying processes that play a role in gut-brain interaction in the context of AN and summarizes the previous empirical findings on this topic. Finally, an outlook on future research and possible implications for the therapeutic practice and treatment of AN is given.

Risk factors associated with developing anxiety in Inuit adolescents from Nunavik

This study aimed to examine the relation between anxiety among the at-risk population of Inuit adolescents and diverse developmental risk factors including exposure to environmental chemicals, a subject of concern in Nunavik. Anxiety was assessed in 89 Inuit participants (mean age = 18.4 years; range = 16.2-21.9) with the Screen for Child Anxiety Related Emotional Disorders (SCARED) and the State-Trait Anxiety Inventory (STAI). Potential risk factors for anxiety were documented at birth, 11 years of age and 18 years of age, including blood levels of chemicals (mercury, lead, PCBs) and nutrients, as well as age, sex, estimated IQ, drug and alcohol use, bullying, exposure to domestic violence, food insecurity, crowding and socio-economic status. Results showed that participants scored high on both measures of anxiety, particularly the SCARED, for which the mean score was above the clinical threshold. Multiple regression results show that significant risk predictors obtained from the SCARED scores were female sex (β = 0.32), higher current blood mercury concentration (β = 0.26), food insecurity (β = 0.26) and bullying experiences in the last year (β = 0.21). The significant predictors for the STAI trait anxiety were food insecurity (β = 0.25) and lower estimated IQ (β = -0.31), whereas food insecurity (β = 0.21), lower blood levels of vitamin E (β = -0.25) and higher cord blood mercury concentrations (β = 0.25) were found for STAI situational anxiety. Further regression analyses suggested that the adolescent-related variables were the most important risk factors. Our findings show that Inuit adolescents are at risk for anxiety via multiple contributing factors, particularly current exposure to mercury, food insecurity and female sex.

Eating disorders

Eating disorders are disabling, deadly, and costly mental disorders that considerably impair physical health and disrupt psychosocial functioning. Disturbed attitudes towards weight, body shape, and eating play a key role in the origin and maintenance of eating disorders. Eating disorders have been increasing over the past 50 years and changes in the food environment have been implicated. All health-care providers should routinely enquire about eating habits as a component of overall health assessment. Six main feeding and eating disorders are now recognised in diagnostic systems: anorexia nervosa, bulimia nervosa, binge eating disorder, avoidant-restrictive food intake disorder, pica, and rumination disorder. The presentation form of eating disorders might vary for men versus women, for example. As eating disorders are under-researched, there is a great deal of uncertainty as to their pathophysiology, treatment, and management. Future challenges, emerging treatments, and outstanding research questions are addressed.

A longitudinal analysis of cytokines in anorexia nervosa

OBJECTIVE

Inflammation has been proposed to have a pathophysiological role in anorexia nervosa (AN) and to contribute to the maintenance of the disorder. Longitudinal cytokine research in AN has focused on only a few pro-inflammatory cytokines. We assessed a broad range of cytokines over time in people undergoing specialised treatment for AN.

METHOD

We measured serum concentrations of 27 cytokines in people with AN (n = 23). Body mass index (BMI), eating disorder (ED) symptoms and general psychopathology were assessed and blood samples were collected within four weeks of the commencement of specialised ED treatment (baseline) and at 12- and 24-week follow-ups.

RESULTS

Both BMI and ED symptoms improved over the assessment period. Linear mixed models showed that log IL-6 decreased between baseline and week 12 assessments. By week 12, log IL-6 values were comparable to levels in healthy individuals. Log IL-7 increased from week 12 to week 24.

DISCUSSION

Initially elevated IL-6 serum concentrations appear to 'normalize' during the first 3-months of specialised treatment for AN and this co-occurs with improvements in ED symptoms. Therefore, IL-6 has the potential to be a state biomarker for AN.

Cognitive Interpersonal Model for Anorexia Nervosa Revisited: The Perpetuating Factors that Contribute to the Development of the Severe and Enduring Illness

The cognitive interpersonal model was outlined initially in 2006 in a paper describing the valued and visible aspects of anorexia nervosa (Schmidt and Treasure, 2006). In 2013, we summarised many of the cognitive and emotional traits underpinning the model (Treasure and Schmidt, 2013). In this paper, we describe in more detail the perpetuating aspects of the model, which include the inter- and intrapersonal related consequences of isolation, depression, and chronic stress that accumulate in the severe and enduring stage of the illness. Since we developed the model, we have been using it to frame research and development at the Maudsley. We have developed and tested interventions for both patients and close others, refining the model through iterative cycles of model/intervention development in line with the Medical Research Council (MRC) framework for complex interventions. For example, we have defined the consequences of living with the illness on close others (including medical professionals) and characterised the intense emotional reactions and behaviours that follow. For the individual with an eating disorder, these counter-reactions can allow the eating disorder to become entrenched. In addition, the consequent chronic stress from starvation and social pain set in motion processes such as depression, neuroprogression, and neuroadaptation. Thus, anorexia nervosa develops a life of its own that is resistant to treatment. In this paper, we describe the underpinnings of the model and how this can be targeted into treatment.

Incontinence and constipation in adolescent patients with anorexia nervosa-Results of a multicenter study from a German web-based registry for children and adolescents with anorexia nervosa

OBJECTIVE

Nocturnal enuresis (NE), daytime urinary incontinence (DUI), and fecal incontinence (FI) are common disorders in childhood and are frequently accompanied by comorbid psychiatric disorders. Despite a high association between urinary and fecal incontinence with psychiatric and neurodevelopmental disorders, research on comorbidity between incontinence and anorexia nervosa (AN) remains scarce. Yet, it is well known that somatic consequences of AN include metabolic and gastrointestinal disorders. The study sought to assess the prevalence of incontinence and constipation in children and adolescents with AN and to examine associations of these two symptoms with body weight at admission and with BMI changes during inpatient treatment.

METHODS

Data collected between 2015 and 2017 by a multicenter German web-based registry for AN were analyzed. Three hundred and forty-eight patients with AN (96.3% female, mean age = 15.1 ± 1.8 years) were assessed regarding AN subtype, psychiatric comorbidity, body weight, incontinence, and constipation.

RESULTS

Overall, 27.6% of patients had constipation, 1.8% had NE and 1.8% DUI. Prevalence of constipation did not significantly differ between AN subtypes. Constipation did not lead to any significant differences in weight/BMI changes during inpatient treatment.

DISCUSSION

This is the largest study of incontinence and constipation in patients with AN, so far. Our results indicate that constipation is highly prevalent in adolescent patients with AN and reflects a clinically relevant condition. Despite, patients with AN do not have an increased prevalence of incontinence compared with the general population. Future studies should include medical examinations like ultrasound and physical examination of the lower abdomen to evaluate the severity of constipation.

Recent advances in modulating the microbiome

We are in the midst of “the microbiome revolution”—not a day goes by without some new revelation on the potential role of the gut microbiome in some disease or disorder. From an ever-increasing recognition of the many roles of the gut microbiome in health and disease comes the expectation that its modulation could treat or prevent these very same diseases. A variety of interventions could, at least in theory, be employed to alter the composition or functional capacity of the microbiome, ranging from diet to fecal microbiota transplantation (FMT). For some, such as antibiotics, prebiotics, and probiotics, an extensive, albeit far from consistent, literature already exists; for others, such as other dietary supplements and FMT, high-quality clinical studies are still relatively few in number. Not surprisingly, researchers have turned to the microbiome itself as a source for new entities that could be used therapeutically to manipulate the microbiome; for example, some probiotic strains currently in use were sourced from the gastrointestinal tract of healthy humans. From all of the extant studies of interventions targeted at the gut microbiome, a number of important themes have emerged. First, with relatively few exceptions, we are still a long way from a precise definition of the role of the gut microbiome in many of the diseases where a disturbed microbiome has been described—association does not prove causation. Second, while animal models can provide fascinating insights into microbiota–host interactions, they rarely recapitulate the complete human phenotype. Third, studies of several interventions have been difficult to interpret because of variations in study population, test product, and outcome measures, not to mention limitations in study design. The goal of microbiome modulation is a laudable one, but we need to define our targets, refine our interventions, and agree on outcomes.

Nutritional psychiatry: Towards improving mental health by what you eat

Does it matter what we eat for our mental health? Accumulating data suggests that this may indeed be the case and that diet and nutrition are not only critical for human physiology and body composition, but also have significant effects on mood and mental wellbeing. While the determining factors of mental health are complex, increasing evidence indicates a strong association between a poor diet and the exacerbation of mood disorders, including anxiety and depression, as well as other neuropsychiatric conditions. There are common beliefs about the health effects of certain foods that are not supported by solid evidence and the scientific evidence demonstrating the unequivocal link between nutrition and mental health is only beginning to emerge. Current epidemiological data on nutrition and mental health do not provide information about causality or underlying mechanisms. Future studies should focus on elucidating mechanism. Randomized controlled trials should be of high quality, adequately powered and geared towards the advancement of knowledge from population-based observations towards personalized nutrition. Here, we provide an overview of the emerging field of nutritional psychiatry, exploring the scientific evidence exemplifying the importance of a well-balanced diet for mental health. We conclude that an experimental medicine approach and a mechanistic understanding is required to provide solid evidence on which future policies on diet and nutrition for mental health can be based.