Correction: The Gut-Brain Axis in Healthy Females: Lack of Significant Association between Microbial Composition and Diversity with Psychiatric Measures.

[This corrects the article DOI: 10.1371/journal.pone.0170208.].

Daily Changes in Composition and Diversity of the Intestinal Microbiota in Patients with Anorexia Nervosa: A Series of Three Cases.

Anorexia nervosa, a severe psychiatric illness, is associated with an intestinal microbial dysbiosis. Individual microbial signatures dominate in healthy samples, even over time and under controlled conditions, but whether microbial markers of the disorder overcome inter-individual variation during the acute stage of illness or renourishment is unknown. We characterized daily changes in the intestinal microbiota in three acutely ill patients with anorexia nervosa over the entire course of hospital-based renourishment and found significant, patient-specific changes in microbial composition and diversity. This preliminary case series suggests that even in a state of pathology, individual microbial signatures persist in accounting for the majority of intestinal microbial variation. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

The Gut-Brain Axis in Healthy Females: Lack of Significant Association between Microbial Composition and Diversity with Psychiatric Measures.

OBJECTIVE: This study examined associations between the composition and diversity of the intestinal microbiota and measures of depression, anxiety, eating disorder psychopathology, stress, and personality in a group of healthy adult females. METHODS: Female participants (n = 91) ages 19-50 years with BMI 18.5-25 kg/m2 were recruited from central North Carolina between July 2014 and March 2015. Participants provided a single fecal sample and completed an online psychiatric questionnaire that included five measures: (i) Beck Anxiety Inventory; (ii) Beck Depression Inventory-II; (iii) Eating Disorder Examination-Questionnaire; (iv) Perceived Stress Scale; and (v) Mini International Personality Item Pool. Bacterial composition and diversity were characterized by Illumina sequencing of the 16S rRNA gene, and associations were examined using Kendall's tau-b correlation coefficient, in conjunction with Benjamini and Hochberg's False Discovery Rate procedure. RESULTS: We found no significant associations between microbial markers of gut composition and diversity and scores on psychiatric measures of anxiety, depression, eating-related thoughts and behaviors, stress, or personality in a large cohort of healthy adult females. DISCUSSION: This study was the first specifically to examine associations between the intestinal microbiota and psychiatric measures in healthy females, and based on 16S rRNA taxonomic abundances and diversity measures, our results do not suggest a strong role for the enteric microbe-gut-brain axis in normal variation on responses to psychiatric measures in this population. However, the role of the intestinal microbiota in the pathophysiology of psychiatric illness may be limited to more severe psychopathology.

Genetic epidemiology of eating disorders.

PURPOSE OF REVIEW: We capture recent findings in the field of genetic epidemiology of eating disorders. As analytic techniques evolve for twin, population, and molecular genetic studies, new findings emerge at an accelerated pace. We present the current status of knowledge regarding the role of genetic and environmental factors that influence risk for eating disorders. RECENT FINDINGS: We focus on novel findings from twin studies, population studies using genetically informative designs, and molecular genetic studies. Over the past 2 years, research in this area has yielded insights into: comorbidity with other psychiatric and medical disorders and with metabolic traits; developmental factors associated with the emergence of eating disorders; and the molecular genetics of anorexia nervosa. SUMMARY: Insights from genetic epidemiology provide an important explanatory model for patients with eating disorders, family members, and clinicians. Understanding core biological determinants that explain the severity and persistence of the illnesses, their frequent co-occurrence with other conditions, and their familial patterns raises awareness and increases compassion for individuals living with these disorders. Large-scale genomic studies are currently underway. Ultimately, this domain of research may pave the way to greater understanding of the underlying neurobiology and inform the development of novel and effective interventions.

Can attention to the intestinal microbiota improve understanding and treatment of anorexia nervosa?

Anorexia nervosa (AN) is characterized by severe dietary restriction or other weight loss behaviors and exhibits the highest mortality rate of any psychiatric disorder. Therapeutic renourishment in AN is founded primarily on clinical opinion and guidelines, with a weak evidence base. Genetic factors do not fully account for the etiology of AN, and non-genetic factors that contribute to the onset and persistence of this disease warrant investigation. Compelling evidence that the intestinal microbiota regulates adiposity and metabolism, and more recently, anxiety behavior, provides a strong rationale for exploring the role of this complex microbial community in the onset, maintenance of, and recovery from AN. This review explores the relationship between the intestinal microbiota and AN and a potential role for this enteric microbial community as a therapy for this severe illness.

The Intestinal Microbiota in Acute Anorexia Nervosa and During Renourishment: Relationship to Depression, Anxiety, and Eating Disorder Psychopathology.

OBJECTIVE: The relevance of the microbe-gut-brain axis to psychopathology is of interest in anorexia nervosa (AN), as the intestinal microbiota plays a critical role in metabolic function and weight regulation. METHODS: We characterized the composition and diversity of the intestinal microbiota in AN, using stool samples collected at inpatient admission (T1; n = 16) and discharge (T2; n = 10). At T1, participants completed the Beck Depression and Anxiety Inventories and the Eating Disorder Examination-Questionnaire. Patients with AN were compared with healthy individuals who participated in a previous study (healthy comparison group; HCG). Genomic DNA was isolated from stool samples, and bacterial composition was characterized by 454 pyrosequencing of the 16S rRNA gene. Sequencing results were processed by the Quantitative Insights Into Microbial Ecology pipeline. We compared T1 versus T2 samples, samples from both points were compared with HCG (n = 12), and associations between psychopathology and T1 samples were explored. RESULTS: In patients with AN, significant changes emerged between T1 and T2 in taxa abundance and beta (between-sample) diversity. Patients with AN had significantly lower alpha (within-sample) diversity than did HCG at both T1 (p = .0001) and T2 (p = .016), and differences in taxa abundance were found between AN patients and HCG. Levels of depression, anxiety, and eating disorder psychopathology at T1 were associated with composition and diversity of the intestinal microbiota. CONCLUSIONS: We provide evidence of an intestinal dysbiosis in AN and an association between mood and the enteric microbiota in this patient population. Future directions include mechanistic investigations of the microbe-gut-brain axis in animal models and association of microbial measures with metabolic changes and recovery indices.

The Intestinal Microbiome in Bariatric Surgery Patients.

With nearly 39% of the worldwide adult population classified as obese, much of the globe is facing a serious public health challenge. Increasing rates of obesity, coupled with the failure of many behavioural and pharmacological interventions, have contributed to a rise in popularity of bariatric surgery as a treatment for obesity. Surgery-mediated weight loss was initially thought to be a direct result of mechanical alterations causing restriction and calorie malabsorption. However, the mounting evidence suggests that indirect factors influence the accumulation and storage of fat in patients that have undergone this procedure. Given the established impact the intestinal microbiota has on adiposity, it is likely that this complex enteric microbial community contributes to surgery-mediated weight loss and maintenance of weight loss postsurgery. In this review, we discuss the physiological and psychological traits exhibited by bariatric surgery candidates that can be influenced by the intestinal microbiota. Additionally, we detail the studies that investigated the impact of bariatric surgery on the intestinal microbiota in humans and mouse models of this procedure.

Prevalence of screening-detected eating disorders in chinese females and exploratory associations with dietary practices.

OBJECTIVE: China is undergoing dramatic Westernization, hence may be able to provide unique insights into the role of sociocultural factors in disease. The purpose of this exploratory study was two-fold: to describe the prevalence of screening-detected eating disorders and disordered eating in China at the first occasion of assessment in the large-scale China Health and Nutrition Survey (CHNS) and to explore the associations between dietary practices and disordered eating. Regarding the first objective, participants are provincially representative and in subsequent waves will be followed longitudinally. METHOD: CHNS participants were recruited using multistage, cluster random sampling, beginning in 1989. In this study, participants comprised 259 female adolescents (12-17 years) and 979 women (18-35 years) who participated in the CHNS 2009 survey, which is the first CHNS survey to assess disordered eating. Dietary practice-disordered eating associations were investigated with logistic regression adjusting for age, body mass index, and urbanization. RESULTS: Of the participants, 6.3% (95% CI: 4.8, 8.2) of adults and 7.8% (95% CI: 5.0, 12.0) of adolescents had a screening-detected eating disorder. Dietary practices had non-significant associations with disordered eating at the general population level, except for protein consumption among women. There was evidence that skipping meals and a high-fat diet may confer risk. DISCUSSION: Screening-detected eating disorders in China are lower in prevalence than in developed countries. Dietary practices had fairly limited associations with disordered eating at the general population level; protein consumption, skipping meals, and a high-fat diet are candidate dietary practice exposures for disordered eating. Copyright © 2014 John Wiley & Sons, Ltd and Eating Disorders Association.

The association between internet and television access and disordered eating in a Chinese sample.

OBJECTIVE: China has historically reported a low prevalence of eating disorders. However, the rapid social and economic development of this country as well as Western ideals widely disseminated by television and the Internet have led to distinct patterns of behavioral choices that could affect eating disorder risk. Thus, the current study explored the relation between disordered eating and media use. METHOD: Participants were females from the 2009 wave of the China Health and Nutrition Survey (N = 1,053). Descriptive statistics were obtained and logistic regression models, stratified by age (adolescents ages 12-17 years and adults ages 18-35 years), were used to evaluate the association of media use with disordered eating. RESULTS: In adolescents, 46.8% had access to the Internet and those with access averaged one hour per day each of Internet and television use. In adults, 41.4% had access to the Internet, and those with access averaged 1 h per day of Internet use and 2 h per day of television use. Internet access was significantly associated with a subjective belief of fatness (OR = 2.8, 95% CI: 1.6, 4.9) and worry over losing control over eating (OR = 4.8, 95% CI: 2.3, 9.8) only in adults. DISCUSSION: These findings help characterize the overall pattern of media use and report of eating disorder symptoms in a large sample of female Chinese adolescents and adults. That Internet access in adults was significantly associated with disordered eating cognitions might suggest that media access negatively influences these domains; however, more granular investigations are warranted.