Relative Abundance in Bacterial and Fungal Gut Microbes in Obese Children: A Case Control Study

Gut microbiota and childhood malnutrition: Understanding the link and exploring therapeutic interventions

Childhood malnutrition is a metabolic condition that affects the physical and mental well-being of children and leads to resultant disorders in maturity. The development of childhood malnutrition is influenced by a number of physiological and environmental factors including metabolic stress, infections, diet, genetic variables, and gut microbiota. The imbalanced gut microbiota is one of the main environmental risk factors that significantly influence host physiology and childhood malnutrition progression. In this review, we have evaluated the gut microbiota association with undernutrition and overnutrition in children, and then the quantitative and qualitative significance of gut dysbiosis in order to reveal the impact of gut microbiota modification using probiotics, prebiotics, synbiotics, postbiotics, fecal microbiota transplantation, and engineering biology methods as new therapeutic challenges in the management of disturbed energy homeostasis. Understanding the host-microbiota interaction and the remote regulation of other organs and pathways by gut microbiota can improve the effectiveness of new therapeutic approaches and mitigate the negative consequences of childhood malnutrition.

Mechanisms and risk factors of metabolic syndrome in children and adolescents

Metabolic syndrome (MetS) is a complex disorder characterized by abdominal obesity, elevated blood pressure, hyperlipidemia, and elevated fasting blood glucose levels. The diagnostic criteria for MetS in adults are well-established, but there is currently no consensus on the definition in children and adolescents. The etiology of MetS is believed to involve a complex interplay between genetic predisposition and environmental factors. While genetic predisposition explains only a small part of MetS pathogenesis, modifiable environmental risk factors play a significant role. Factors such as maternal weight during pregnancy, children's lifestyle, sedentariness, high-fat diet, fructose and branched-chain amino acid consumption, vitamin D deficiency, and sleep disturbances contribute to the development of MetS. Early identification and treatment of MetS in children and adolescents is crucial to prevent the development of chronic diseases later in life. In this review we discuss the latest research on factors contributing to the pathogenesis of MetS in children, focusing on non-modifiable and modifiable risk factors, including genetics, dysbiosis and chronic low-grade inflammation.

Associations between bacterial and fungal communities in the human gut microbiota and their implications for nutritional status and body weight

This study examined the interplay between bacterial and fungal communities in the human gut microbiota, impacting on nutritional status and body weight. Cohorts of 10 participants of healthy weight, 10 overweight, and 10 obese individuals, underwent comprehensive analysis, including dietary, anthropometric, and biochemical evaluations. Microbial composition was studied via gene sequencing of 16S and ITS rDNA regions, revealing bacterial (bacteriota) and fungal (mycobiota) profiles. Bacterial diversity exceeded fungal diversity. Statistically significant differences in bacterial communities were found within healthy-weight, overweight, and obese groups. The Bacillota/Bacteroidota ratio (previously known as the Firmicutes/Bacteroidetes ratio) correlated positively with body mass index. The predominant fungal phyla were Ascomycota and Basidiomycota, with the genera Nakaseomyces, Kazachstania, Kluyveromyces, and Hanseniaspora, inversely correlating with weight gain; while Saccharomyces, Debaryomyces, and Pichia correlated positively with body mass index. Overweight and obese individuals who harbored a higher abundance of Akkermansia muciniphila, demonstrated a favorable lipid and glucose profiles in contrast to those with lower abundance. The overweight group had elevated Candida, positively linked to simple carbohydrate consumption. The study underscores the role of microbial taxa in body mass index and metabolic health. An imbalanced gut bacteriota/mycobiota may contribute to obesity/metabolic disorders, highlighting the significance of investigating both communities.

Correlation of Gut Microbiota with Children Obesity and Weight Loss

Children obesity is a serious public health problem drawing much attention around the world. Recent research indicated that gut microbiota plays a vital role in children obesity, and disturbed gut microbiota is a prominent characteristic of obese children. Diet and exercise are efficient intervention for weight loss in obesity children, however, how the gut microbiota is modulated which remains largely unknown. To characterize the feature of gut microbiota in obese children and explore the effect of dietary and exercise on gut microbiota in simple obese children, 107 healthy children and 86 obese children were recruited, and among of the obese children 39 received the dietary-exercise combined weight loss intervention (DEI). The gut microbiota composition was detected by the 16S amplicon sequencing method. The gut microbiota composition was significantly different between obese children and the healthy cohort, and DEI significantly reduced the body weight and ameliorated the gut microbiota dysbiosis. After DEI, the abundance of the Akkermansia muciniphila was increased, while the abundance of the Sutterella genus was decreased in simple obese children. Our results may provide theoretical reference for future personalized obesity interventions based on gut microbiota.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-023-01088-3.

The Role of Early Life Gut Mycobiome on Child Health

The human gut microbiota is composed of bacteria (microbiota or microbiome), fungi (mycobiome), viruses, and archaea, but most of the research is primarily focused on the bacterial component of this ecosystem. Besides bacteria, fungi have been shown to play a role in host health and physiologic functions. However, studies on mycobiota composition during infancy, the factors that might shape infant gut mycobiota, and implications to child health and development are limited. In this review, we discuss the factors likely shaping gut mycobiota, interkingdom interactions, and associations with child health outcomes and highlight the gaps in our current knowledge of this ecosystem.

Gut mycobiome alterations in obesity in geographically different regions

The gut fungi play important roles in human health and are involved in energy metabolism. This study aimed to examine gut mycobiome composition in obese subjects in two geographically different regions in China and to identify specific gut fungi associated with obesity. A total of 217 subjects from two regions with different urbanization levels [Hong Kong (HK): obese, n = 59; lean, n = 59; Kunming (KM): obese, n = 50; lean, n = 49. Mean body mass index (BMI) for obesity = 33.7] were recruited. We performed deep shotgun metagenomic sequencing on fecal samples to compare gut mycobiome composition and trophic functions in lean and obese subjects across these two regions. The gut mycobiome of obese subjects in both HK and KM were altered compared to those of lean subjects, characterized by a decrease in the relative abundance of Nakaseomyces, Schizosaccharomyces pombe, Candida dubliniensis and an increase in the abundance of Lanchanceathermotolerans, Saccharomyces paradox, Parastagonospora nodorum and Myceliophthorathermophila. Reduced fungal - bacterial and fungal - fungal correlations as well as increased negative fungal-bacterial correlations were observed in the gut of obese subjects. Furthermore, the anti-obesity effect of fungus S. pombe was further validated using a mouse model. Supplementing high-fat diet-induced obese mice with the fungus for 12 weeks led to a significant reduction in body weight gain (p < 0.001), and an improvement in lipid and glucose metabolism compared to mice without intervention. In conclusion, the gut mycobiome composition and functionalities of obese subjects were altered. These data shed light on the potential of utilizing fungus-based therapeutics for the treatment of obesity. S. pombe may serve as a potential fungal probiotic in the prevention of diet-induced obesity and future human trials are needed.

Exploring Gut Microbiota and the Influence of Physical Activity Interventions on Overweight and Obese Children and Adolescents: A Systematic Review

The recognition that the gut microbiota of obese children differs from lean children has grown, and some studies suggest that physical activity positively influences the gut microbiota. This systematic review explores the changes in the gut microbiota composition of obese and non-obese children and adolescents and provides an understanding of the effects of physical activity interventions in modulating their microbiota. The PRISMA protocol was used across PubMed, Scopus, and Web of Science. Overall, twenty-four research papers were included in accordance with the chosen inclusion and exclusion criteria, eighteen studies compared the gut microbiota of obese and normal-weight children and adolescents, and six studies explored the effect of physical activity interventions on the gut microbiota. The analysis indicated that obese gut microbiota is reduced in Bacteroidetes, Bifidobacterium and alpha diversity but enriched in Proteobacteria and Lactobacillus. Interventions with physical activity seem to improve the alpha diversity and beneficial bacteria linked to body weight loss in children and adolescents. The gut microbiota of obese children exhibited a remarkably individual variation. More interventions are needed to clearly and accurately explore the relationships between child obesity, gut microbiota, and physical activity and to develop approaches to decrease the incidence of paediatric obesity.

Effects of Physical Activity and Nutrition Education on the Gut Microbiota in Overweight and Obese Children

Childhood obesity continues to represent a growing challenge, and it has been associated with gut microbiota dysbiosis. This study examines the gut microbiota composition in overweight and obese school children and assesses whether a 12-week multidisciplinary intervention can induce changes in the gut microbiota. The intervention, which combined recreational football and nutritional education, was implemented among 15 school children, aged 7-10 years, with a Body Mass Index ≥ 85th percentile. The children were assigned into two groups: Football Group (n = 9) and Nutrition and Football Group (n = 6). Faecal samples were collected at the beginning and end of the program and analysed by sequencing the 16S rRNA gene. Over the intervention, a significant decrease was found collectively for Bifidobacterium genera (p = 0.011) and for Roseburia genera in the Football Group (p = 0.021). The relative abundance of Roseburia (p = 0.002) and Roseburia faecis (p = 0.009) was negatively correlated with moderate to vigorous physical activity (MVPA), while Prevotella copri was positively correlated with MVPA (p = 0.010) and with the daily intake of protein (p = 0.008). Our findings suggest that a multidisciplinary intervention was capable of inducing limited but significant positive changes in the gut microbiota composition in overweight and obese school children.

360-Degree Perspectives on Obesity

Alarming statistics show that the number of people affected by excessive weight has surpassed 2 billion, representing approximately 30% of the world's population. The aim of this review is to provide a comprehensive overview of one of the most serious public health problems, considering that obesity requires an integrative approach that takes into account its complex etiology, including genetic, environmental, and lifestyle factors. Only an understanding of the connections between the many contributors to obesity and the synergy between treatment interventions can ensure satisfactory outcomes in reducing obesity. Mechanisms such as oxidative stress, chronic inflammation, and dysbiosis play a crucial role in the pathogenesis of obesity and its associated complications. Compounding factors such as the deleterious effects of stress, the novel challenge posed by the obesogenic digital (food) environment, and the stigma associated with obesity should not be overlooked. Preclinical research in animal models has been instrumental in elucidating these mechanisms, and translation into clinical practice has provided promising therapeutic options, including epigenetic approaches, pharmacotherapy, and bariatric surgery. However, more studies are necessary to discover new compounds that target key metabolic pathways, innovative ways to deliver the drugs, the optimal combinations of lifestyle interventions with allopathic treatments, and, last but not least, emerging biological markers for effective monitoring. With each passing day, the obesity crisis tightens its grip, threatening not only individual lives but also burdening healthcare systems and societies at large. It is high time we took action as we confront the urgent imperative to address this escalating global health challenge head-on.

Size-dependent effects of polystyrene microplastics on gut metagenome and antibiotic resistance in C57BL/6 mice

Microplastic pollution is an emerging threat for marine and terrestrial ecosystems, which has raised global concerns about its implications for human health. Mounting evidence has shown that the gut microbiota plays a key role in human health and diseases. The gut bacteria could be disturbed by many environmental factors, including the microplastic particles. However, the size effect of polystyrene microplastics on mycobiome, as well as gut functional metagenome has not been well studied. In this study, we performed ITS sequencing to explore the size effect of polystyrene microplastics on the fungal composition, in combination with the shotgun metagenomics sequencing to reveal the size effects of polystyrene on the functional metagenome. We found that polystyrene microplastic particles with 0.05-0.1 µm diameter showed greater impact on the bacterial and fungal composition of gut microbiota as well as the metabolic pathways than the polystyrene microplastic particles with 9-10 µm diameter. Our results suggested that size-depended effects should not be ignored in the health risk assessment of microplastics.

Infants' gut microbiome data: A Bayesian Marginal Zero-inflated Negative Binomial regression model for multivariate analyses of count data

The infants' gut microbiome is dynamic in nature. Literature has shown high inter-individual variability of gut microbial composition in the early years of infancy compared to adulthood. Although next-generation sequencing technologies are rapidly evolving, several statistical analysis aspects need to be addressed to capture the variability and dynamic nature of the infants' gut microbiome. In this study, we proposed a Bayesian Marginal Zero-inflated Negative Binomial (BAMZINB) model, addressing complexities associated with zero-inflation and multivariate structure of the infants' gut microbiome data. Here, we simulated 32 scenarios to compare the performance of BAMZINB with glmFit and BhGLM as the two other widely similar methods in the literature in handling zero-inflation, over-dispersion, and multivariate structure of the infants' gut microbiome. Then, we showed the performance of the BAMZINB approach on a real dataset using SKOT cohort (I and II) studies. Our simulation results showed that the BAMZINB model performed as well as those two methods in estimating the average abundance difference and had a better fit for almost all scenarios when the signal and sample size were large. Applying BAMZINB on SKOT cohorts showed remarkable changes in the average absolute abundance of specific bacteria from 9 to 18 months for infants of healthy and obese mothers. In conclusion, we recommend using the BAMZINB approach for infants' gut microbiome data taking zero-inflation and over-dispersion properties into account in multivariate analysis when comparing the average abundance difference.

Body Mass Index and Gut Microbiome: A Cluster-Randomized, Controlled, Pilot Feasibility Study

Background: Prebiotic fiber has been examined as a way to foster gut bacteria less associated with obesity. Tests of prebiotic fiber in reducing obesity have been conducted mainly in animals, adults, and Caucasians when the highest obesity rates are in African American and Latinx youth. Response to prebiotic fiber is determined by the pre-existing intestinal microbiota. The type of microbiota varies based on diet and physical activity (PA), so it is important to examine acceptability and response to prebiotic fiber in those most at risk for obesity. Methods: This cluster-randomized, controlled feasibility trial included an online program designed to improve diet and PA along with administration of a prebiotic fiber for 12 weeks in 123 students of 4th and 5th grade where 98% were eligible for free or reduced-fee lunch. Of these 56% were male; 71% Latinx; 15% African American; and 14% other. Results: Decrease in body fat (BF) was associated with higher pretest BF. Lower body mass index (BMI) was associated with decrease in fecal Tenericutes and increase in Actinobacteria. Conclusions: Prebiotic fiber can be helpful in supporting healthy weight, so inclusion in culturally congruent foods usually eaten by children from groups at high risk for obesity should be considered following additional studies. Determining those most responsive to prebiotic fibers can also permit individual recommendations for greater inclusion in usual diet choices. Clinical Trial Registration Number NCT05671731.

Gut microbiota in obesity and related comorbidities in children and adolescents: the role of biotics in treatment

INTRODUCTION

Obesity is a complex pathology, globally spread, with a multifactorial pathogenesis, strictly linked with lifestyle, hormones, genetic and epigenetic factors. Evidence supports that obesity, and its comorbidities, are related to changes in gut microbiota, partially responsible of the modulation of energy metabolism.

EVIDENCE ACQUISITION

Pediatric obesity has been associated with lower bacterial diversity and differences in composition of the gut microbiota, also varying according to the metabolic status of obese subjects. Indeed, differences in distributions and activity of microorganisms in the gut of metabolically healthy and unhealthy obese children have been highlighted.

EVIDENCE SYNTHESIS

Based on human studies, this review aims to discuss gut microbiota alterations in obese children and adolescents and its role in obese-related complications. Moreover, the role of biotics (probiotics, prebiotics, synbiotics and -marginally- postbiotics) has been analyzed as modulator of obesity-related dysbiosis.

CONCLUSIONS

As a conclusion, a deeper knowledge about biotic mechanisms of action would be of great interest to implement the clinical care of children and adolescents with obesity and related comorbidities.

Comprehensive bibliometric and visualized analysis of research on fecal microbial transplantation published from 2000 to 2021

Background

Fecal microbial transplantation has emerged in recent years as a method of treating disease by rebuilding the intestinal flora. However, few bibliometric analyses have systematically studied this area of research. We aimed to use bibliometric analysis to visualize trends and topical research in fecal microbial transplantation to help provide insight into future trends in clinical and basic research.

Materials and methods

Articles and reviews related to fecal microbial transplantation were collected from the Web of Science Core Collection. Significant information associated with this field was visually analyzed by using Biblioshiny and CtieSpace software.

Results

A total of 3144 articles and overviews were included. The number of publications related to fecal microbial transplantation significantly increased yearly. These publications mainly came from 100 countries, led by the US and China, and 521 institutions. The most prolific and influential author is KHORUTS A. The main disciplines and application fields of fecal microbial transplantation included molecular /biology/immunology and medicine/clinical medicine, and the research foundation of fecal microbial transplantation was molecular /biology/genetics and health/nursing/medicine. An alluvial flow visualization showed several landmark articles. New developments were identified in terms of reference and keyword citation bursts. Data analysis showed that different FMT preparation and delivery methods gradually appeared as research hotspots. The main research keywords in the last 3 years were chain fatty acids, Akkermansia muciniphila, and insulin sensitivity, other keywords were current and developing research fields.

Conclusion

Research on fecal microbial transplantation is flourishing and many new applications of fecal microbial transplantation are emerging. Microbial metabolites such as short-chain fatty acids and the microbiota–gut–brain axis have become the focus of current research and are future research trends.

Mycobiota composition and changes across pregnancy in patients with gestational diabetes mellitus (GDM)

The gut mycobiota has never been studied either during pregnancy or in patients with gestational diabetes (GDM). This study aimed to analyze the fecal mycobiota of GDM patients during the second (T2) and third (T3) trimester of pregnancy and to compare it with the mycobiota of pregnant normoglycemic women (controls). Forty-one GDM patients and 121 normoglycemic women were studied. GDM mycobiota was composed almost exclusively by the Ascomycota phylum; Basidiomicota accounted for 43% of the relative frequency of the controls. Kluyveromyces (p < 0.001), Metschnikowia (p < 0.001), and Pichia (p < 0.001) showed a significantly higher frequency in GDM patients, while Saccharomyces (p = 0.019), were more prevalent in controls. From T2 to T3, a reduction in fungal alpha diversity was found in GDM patients, with an increase of the relative frequency of Candida, and the reduction of some pro-inflammatory taxa. Many associations between fungi and foods and nutrients were detected. Finally, several fungi and bacteria showed competition or co-occurrence. Patients with GDM showed a predominance of fungal taxa with potential inflammatory effects when compared to normoglycemic pregnant women, with a marked shift in their mycobiota during pregnancy, and complex bacteria-fungi interactions.

"Molding" immunity-modulation of mucosal and systemic immunity by the intestinal mycobiome in health and disease

Fungi are important yet understudied contributors to the microbial communities of the gastrointestinal tract. Starting at birth, the intestinal mycobiome undergoes a period of dynamic maturation under the influence of microbial, host, and extrinsic influences, with profound functional implications for immune development in early life, and regulation of immune homeostasis throughout life. Candida albicans serves as a model organism for understanding the cross-talk between fungal colonization dynamics and immunity, and exemplifies unique mechanisms of fungal-immune interactions, including fungal dimorphism, though our understanding of other intestinal fungi is growing. Given the prominent role of the gut mycobiome in promoting immune homeostasis, emerging evidence points to fungal dysbiosis as an influential contributor to immune dysregulation in a variety of inflammatory and infectious diseases. Here we review current knowledge on the factors that govern host-fungi interactions in the intestinal tract and immunological outcomes in both mucosal and systemic compartments.

The Yin-Yang Concept of Pediatric Obesity and Gut Microbiota

The era of pediatric obesity is no longer a myth. Unfortunately, pediatric obesity has reached alarming incidence levels worldwide and the factors that contribute to its development have been intensely studied in multiple recent and emerging studies. Gut microbiota was recently included in the wide spectrum of factors implicated in the determination of obesity, but its role in pediatric obese patients is far from being fully understood. In terms of the infant gut microbiome, multiple factors have been demonstrated to shape its content, including maternal diet and health, type of delivery, feeding patterns, weaning and dietary habits. Nevertheless, the role of the intrauterine environment, such as the placental microbial community, cannot be completely excluded. Most studies have identified Firmicutes and Bacteroidetes as the most important players related to obesity risk in gut microbiota reflecting an increase of Firmicutes and a decrease in Bacteroidetes in the context of obesity; however, multiple inconsistencies between studies were recently reported, especially in pediatric populations, and there is a scarcity of studies performed in this age group.

Akkermansia muciniphila: is it the Holy Grail for ameliorating metabolic diseases?

The increasing prevalence of metabolic diseases has become a severe public health problem. Gut microbiota play important roles in maintaining human health by modulating the host's metabolism. Recent evidences demonstrate that Akkermansia muciniphila is effective in improving metabolic disorders and is thus considered as a promising "next-generation beneficial microbe". In addition to the live A. muciniphila, similar or even stronger beneficial effects have been observed in pasteurized A. muciniphila and its components, including the outer membrane protein Amuc_1100, A. muciniphila-derived extracellular vesicles (AmEVs), and secreted protein P9. Hence, this paper presents a systemic review of recent progress in the effects and mechanisms of A. muciniphila and its components in the treatment of metabolic diseases, including obesity, type 2 diabetes mellitus, cardiovascular disease, and nonalcoholic fatty liver disease, as well as perspectives on its future study.

The critical role of gut microbiota in obesity

Obesity is a global epidemic characterized by energy disequilibrium, metabolic disorder, fat mass development, and chronic low-grade inflammation, which significantly affects the health state of individuals of all ages and strains the socioeconomic system. The prevalence of obesity is rising at alarming rates and its etiology involves complicated interplay of diet, genetic, and environmental factors. The gut microbiota, as an important constituent of environmental factors, has been confirmed to correlate with the onset and progression of obesity. However, the specific relationship between obesity and the gut microbiota, and its associated mechanisms, have not been fully elucidated. In this review, we have summarized that the microbial diversity was significantly decreased and the Firmicutes/Bacteroidetes ratio was significantly increased in obesity. The altered gut microbiota and associated metabolites contributed to the progression of the disease by disrupting energy homeostasis, promoting lipid synthesis and storage, modulating central appetite and feeding behavior, as well as triggering chronic inflammation, and that the intentional manipulation of gut microbiota held promise as novel therapies for obesity, including probiotics, prebiotics, and fecal microbiota transplantation.

Fecal microbiota relationships with childhood obesity: A scoping comprehensive review

Childhood obesity is a costly burden in most regions with relevant and adverse long-term health consequences in adult life. Several studies have associated excessive body weight with a specific profile of gut microbiota. Different factors related to fecal microorganism abundance seem to contribute to childhood obesity, such as gestational weight gain, perinatal diet, antibiotic administration to the mother and/or child, birth delivery, and feeding patterns, among others. This review reports and discusses diverse factors that affect the infant intestinal microbiota with putative or possible implications on the increase of the obesity childhood rates as well as microbiota shifts associated with excessive body weight in children.

Dysbiosis, Host Metabolism, and Non-communicable Diseases: Trialogue in the Inborn Errors of Metabolism

Inborn errors of metabolism (IEMs) represent a complex system model, in need of a shift of approach exploring the main factors mediating the regulation of the system, internal or external and overcoming the traditional concept of biochemical and genetic defects. In this context, among the established factors influencing the metabolic flux, i.e., diet, lifestyle, antibiotics, xenobiotics, infectious agents, also the individual gut microbiota should be considered. A healthy gut microbiota contributes in maintaining human health by providing unique metabolic functions to the human host. Many patients with IEMs are on special diets, the main treatment for these diseases. Hence, IEMs represent a good model to evaluate how specific dietary patterns, in terms of macronutrients composition and quality of nutrients, can be related to a characteristic microbiota associated with a specific clinical phenotype (“enterophenotype”). In the present review, we aim at reporting the possible links existing between dysbiosis, a condition reported in IEMs patients, and a pro-inflammatory status, through an altered “gut-liver” cross-talk network and a major oxidative stress, with a repercussion on the health status of the patient, increasing the risk of non-communicable diseases (NCDs). On this basis, more attention should be paid to the nutritional status assessment and the clinical and biochemical signs of possible onset of comorbidities, with the goal of improving the long-term wellbeing in IEMs. A balanced intestinal ecosystem has been shown to positively contribute to patient health and its perturbation may influence the clinical spectrum of individuals with IEMs. For this, reaching eubiosis through the improvement of the quality of dietary products and mixtures, the use of pre-, pro- and postbiotics, could represent both a preventive and therapeutic strategy in these complex diseases.

Serum vitamin E concentration is negatively associated with body mass index change in girls not boys during adolescence

BACKGROUND

Vitamin E is the most abundant lipid-soluble antioxidants present in plasma; however, the relationship between serum vitamin E and change in body mass index (BMI)-for-age Z scores in adolescents has not been well described.

METHODS

This study is a cross-sectional study. Data were analyzed from 4014 adolescents who participated in the National Health and Nutrition Examination Survey. The nutritional status was calculated by BMI Z scores and was classified into normal weight, overweight, and obese. Multivariable-adjusted logistic regression was used to examine the association between serum vitamin E levels with overweight/obesity. Besides, the interaction effects between potential confounders and vitamin E on obesity were further evaluated.

RESULTS

After adjusting potential confounders, serum vitamin E levels were negatively associated with overweight/obesity in girls but not in boys. Per standard deviation increment in vitamin E concentrations was associated with a 92% decreased risk of obesity in females. Besides, lower quartiles of serum vitamin E were associated with a higher risk of overweight/obesity in girls. Moreover, the inverse association between serum vitamin E levels and obesity was also found in most subgroups through subgroup analysis.

CONCLUSIONS

Our study supports the negative association between serum vitamin E levels and overweight/obesity in adolescents. A higher serum vitamin E level may be associated with a reduced probability of obesity in girls, but not in boys.

Composition and Functions of the Gut Microbiome in Pediatric Obesity: Relationships with Markers of Insulin Resistance

The gut microbiome is hypothesized to play a crucial role in the development of obesity and insulin resistance (IR); the pathways linking the microbiome to IR in pediatrics have yet to be precisely characterized. We aimed to determine the relationship between the gut microbiome composition and metabolic functions and IR in children with obesity. In a cross-sectional study, fecal samples from children with obesity (10-16 years old) were collected for taxonomical and functional analysis of the fecal microbiome using shotgun metagenomics. The homeostatic model assessment for insulin resistance (HOMA-IR) was determined using fasting glucose and insulin. Associations between HOMA-IR and α-diversity measures as well as metabolic pathways were evaluated using Spearman correlations; relationships between HOMA-IR and β-diversity were assessed by permutational multivariate analysis of variance. Twenty-one children (nine males; median: age = 12.0 years; BMI z-score = 2.9; HOMA-IR = 3.6) completed the study. HOMA-IR was significantly associated with measures of α-diversity but not with β-diversity. Children with higher HOMA-IR exhibited lower overall species richness, Firmicutes species richness, and overall Proteobacteria species Shannon diversity. Furthermore, HOMA-IR was inversely correlated with the abundance of pathways related to the biosynthesis of lipopolysaccharides, amino acids, and short-chain fatty acids, whereas positive correlations between HOMA-IR and the peptidoglycan biosynthesis pathways were observed. In conclusion, insulin resistance was associated with decreased microbial α-diversity measures and abundance of genes related to the metabolic pathways. Our study provides a framework for understanding the microbial alterations in pediatric obesity.

Polycystic Ovary Syndrome in Insulin-Resistant Adolescents with Obesity: The Role of Nutrition Therapy and Food Supplements as a Strategy to Protect Fertility

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in young reproductive-aged women. PCOS is often associated with obesity and impairs reproductive health. Even though several theories have been proposed to explain the pathogenic mechanism of PCOS, the role of insulin resistance (IR) as a key etiological component, independently of (but amplified by) obesity, is well recognized. The consequent hyperinsulinemia activates excessive ovarian androgen production, leading to PCOS. Additionally, the state of chronic inflammation related to obesity impacts ovarian physiology due to insulin sensitivity impairment. The first-line treatment for adolescents with obesity and PCOS includes lifestyle changes; personalized dietary interventions; and, when needed, weight loss. Medical nutrition therapy (MNT) and the use of specific food supplements in these patients aim at improving symptoms and signs, including insulin resistance and metabolic and reproductive functions. The purpose of this narrative review is to present and discuss PCOS in adolescents with obesity, its relationship with IR and the role of MNT and food supplements in treatment. Appropriate early dietary intervention for the management of adolescents with obesity and PCOS should be considered as the recommended approach to restore ovulation and to protect fertility.

Diet, adiposity, and the gut microbiota from infancy to adolescence: A systematic review

Early life gut microbiota are affected by several factors that make identification of microbial-adiposity relationships challenging. This review evaluates studies that have investigated the gut microbiota composition associated with adiposity in infants, children, and adolescents and provides evidence-based nutrition recommendations that address microbiota-adiposity links. Electronic databases were systematically searched through January 2020. Eligible studies were published in English and analyzed gut microbiota and adiposity among individuals aged birth to 18 years. Abstracts and full-text articles were reviewed by three independent reviewers. Of 45 full-text articles reviewed, 33 were included. No difference in abundance was found for Bacteroidetes (n = 7/15 articles), Firmicutes (n = 10/17), Actinobacteria (n = 8/12), Proteobacteria (n = 8/12), Tenericutes (n = 4/5), and Verrucomicrobia (n = 4/6) with adiposity. Lower abundance of Christensenellaceae (n = 3/5) and Rikenellaceae (n = 6/8) but higher abundance of F. prausnitzii (n = 3/5) and Prevotella (n = 5/7) were associated with adiposity. A lack of consensus exists for gut microbial composition associations with adiposity. A healthy gut microbiota is associated with a diet rich in fruits and vegetables with moderate consumption of animal fat and protein. Future research should use more robust sequencing technologies to identify all bacterial taxa associated with adiposity and evaluate how diet effects these adiposity-associated microbes.

Chronic oral exposure to pesticides and their consequences on metabolic regulation: role of the microbiota

Pesticides have long been used in agriculture and household treatments. Pesticide residues can be found in biological samples for both the agriculture workers through direct exposure but also to the general population by indirect exposure. There is also evidence of pesticide contamination in utero and trans-generational impacts. Whilst acute exposure to pesticides has long been associated with endocrine perturbations, chronic exposure with low doses also increases the prevalence of metabolic disorders such as obesity or type 2 diabetes. Dysmetabolism is a low-grade inflammation disorder and as such the microbiota plays a role in its etiology. It is therefore important to fully understand the role of microbiota on the genesis of subsequent health effects. The digestive tract and mostly microbiota are the first organs of contact after oral exposure. The objective of this review is thus to better understand mechanisms that link pesticide exposure, dysmetabolism and microbiota. One of the key outcomes on the microbiota is the reduced Bacteroidetes and increased Firmicutes phyla, reflecting both pesticide exposure and risk factors of dysmetabolism. Other bacterial genders and metabolic activities are also involved. As for most pathologies impacting microbiota (including inflammatory disorders), the role of prebiotics can be suggested as a prevention strategy and some preliminary evidence reinforces this axis.

The Burden of Antipsychotic-Induced Weight Gain and Metabolic Syndrome in Children

Antipsychotic medications are critical to child and adolescent psychiatry, from the stabilization of psychotic disorders like schizophrenia, bipolar disorder, and psychotic depression to behavioral treatment of autism spectrum disorder, tic disorders, and pediatric aggression. While effective, these medications carry serious risk of adverse events-most commonly, weight gain and cardiometabolic abnormalities. Negative metabolic consequences affect up to 60% of patients and present a major obstacle to long-term treatment. Since antipsychotics are often chronically prescribed beginning in childhood, cardiometabolic risk accumulates. An increased susceptibility to antipsychotic-induced weight gain (AIWG) has been repeatedly documented in children, particularly rapid weight gain. Associated cardiometabolic abnormalities include central obesity, insulin resistance, dyslipidemia, and systemic inflammation. Lifestyle interventions and medications such as metformin have been proposed to reduce risk but remain limited in efficacy. Furthermore, antipsychotic medications touted to be weight-neutral in adults can cause substantial weight gain in children. A better understanding of the biological underpinnings of AIWG could inform targeted and potentially more fruitful treatments; however, little is known about the underlying mechanism. As yet, modest genetic studies have nominated a few risk genes that explain only a small percentage of the risk. Recent investigations have begun to explore novel potential mechanisms of AIWG, including a role for gut microbiota and microbial metabolites. This article reviews the problem of AIWG and AP metabolic side effects in pediatric populations, proposed mechanisms underlying this serious side effect, and strategies to mitigate adverse impact. We suggest future directions for research efforts that may advance the field and lead to improved clinical interventions.

The intestinal mycobiota and its relationship with overweight, obesity and nutritional aspects

BACKGROUND

The fungal community of the gastrointestinal tract has recently become of interest, and knowledge of its relationship with the development of obesity is scarce. The present study aimed to evaluate the cultivable fungal fraction from the microbiota and to analyze its relationship with obesity.

METHODS

Samples were taken from 99 participants with normal weight, overweight and obesity (n = 31, 34 and 34, respectively) and were cultivated in selective medium, and the cultivable yeasts were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Anthropometric and biochemical measures were also evaluated.

RESULTS

Eutrophic, overweight and obese groups presented concentrations of 1.6, 2.16 and 2.19 log₁₀  colony-forming units g^-1 yeast, respectively. Ascomycota and Basidiomycota were the two identified phyla. At the genus level, Candida spp. showed a relatively high prevalence, and 10 different species were detected: Candida glabrata, Candida orthopsilosis, Candida lambica, Candida kefyr, Candida albicans, Candida krusei, Candida valida, Candida parapsilosis, Candida utilis and Candida humilis (with relative abundances of 71.72%, 5.05%, 21.21%, 6.06%, 29.29%, 27.27%, 8.08%, 16.16%, 1.01% and 2.02%, respectively).

CONCLUSIONS

The obese group presented a higher prevalence of Candida albicans. Furthermore, Candida albicans, Candida kefyr and Rhodotorula mucilaginosa showed a high positive correlation with obesity, weight gain and fat mass and showed a negative correlation with high-density lipoprotein and lean mass, parameters related to weight loss.

A comprehensive review for gut microbes: technologies, interventions, metabolites and diseases

Gut microbes have attracted much more attentions in the recent decade since their essential roles in the development of metabolic diseases, cancer and neurological diseases. Considerable evidence indicates that the metabolism of gut microbes exert influences on intestinal homeostasis and human diseases. Here, we first reviewed two mainstream sequencing technologies involving 16s rRNA sequencing and metagenomic sequencing for gut microbes, and data analysis methods assessing alpha and beta diversity. Next, we introduced some observational studies reflecting that many factors, such as lifestyle and intake of diets, drugs, contribute to gut microbes' quantity and diversity. Then, metabolites produced by gut microbes were presented to understand that gut microbes exert on host homeostasis in the intestinal epithelium and immune system. Finally, we focused on the molecular mechanism of gut microbes on the occurrence and development of several common diseases. In-depth knowledge of the relationship among interventions, gut microbes and diseases might provide new insights in to disease prevention and treatment.

Eukaryotic and Prokaryotic Microbiota Interactions

The nature of the relationship between the communities of microorganisms making up the microbiota in and on a host body has been increasingly explored in recent years. Microorganisms, including bacteria, archaea, viruses, parasites and fungi, have often long co-evolved with their hosts. In human, the structure and diversity of microbiota vary according to the host’s immunity, diet, environment, age, physiological and metabolic status, medical practices (e.g., antibiotic treatment), climate, season and host genetics. The recent advent of next generation sequencing (NGS) technologies enhanced observational capacities and allowed for a better understanding of the relationship between distinct microorganisms within microbiota. The interaction between the host and their microbiota has become a field of research into microorganisms with therapeutic and preventive interest for public health applications. This review aims at assessing the current knowledge on interactions between prokaryotic and eukaryotic communities. After a brief description of the metagenomic methods used in the studies were analysed, we summarise the findings of available publications describing the interaction between the bacterial communities and protozoa, helminths and fungi, either in vitro, in experimental models, or in humans. Overall, we observed the existence of a beneficial effect in situations where some microorganisms can improve the health status of the host, while the presence of other microorganisms has been associated with pathologies, resulting in an adverse effect on human health.

Microbiota, epidemiological and nutritional factors related to ketoacidosis at the onset of type 1 diabetes

AIMS

The incidence of type 1 diabetes has increased over the last decades. The pathological pathway is not yet clear, even if genetic and environmental risk factors are known. An early diagnosis can avoid ketoacidosis and its complications. This work aims to discuss the determinants of both ketoacidosis at the onset and access by hospital emergency departments without a suspected diagnosis.

METHODS

An observational bi-centric prospective study was conducted in Northern Italy, on a paediatric population including Italian and migrant patients at the diabetes onset. Seventy-four type 1 diabetes patients, both Italian and migrant, were included in the study. Anthropometric, socio-economic, behavioural, clinical data were collected, and microbiota analyses were performed using stool samples.

RESULTS

Regular physical activity is associated with lower ketoacidosis incidence at onset (OR 0.33 95% CI 0.12-0.95 p < 0.05), as is higher blood vitamin D level (OR 0.92 95% CI 0.85-0.99 p < 0.05). Moreover, a higher weaning age (OR 0.49 95% CI 0.27-0.89 p < 0.05), higher vitamin D level (OR 0.90 95% CI 0.83-0.98 p < 0.05) and a higher level of Akkermansia muciniphila (OR 0.46 95% CI 0.25-0.87 p < 0.05) are associated factors to lower frequency of type 1 diabetes onset without a suspected diagnosis. Diabetes migrant status is not a risk factor for severe type 1 diabetes onset; on the other hand, some protective factors are significantly more diffused among Italians, such as regular sport activity and non-critical vitamin D levels.

CONCLUSION

Behavioural and nutritional data, such as microbiota bio-indicators, seem to be useful to identify an at-risk population to prevent ketoacidosis and its severe complications.

Association between the body weight of growing pigs and the functional capacity of their gut microbiota

Gastrointestinal microbiota impact host's biological activities, including digestion of indigestible feed components, energy harvest, and immunity. In this study, fecal microbiota of high body weight (HW) and low body weight (LW) growing pigs at 103 days of age were compared. Principal coordinates analysis separated the HW and LW groups into two clusters, indicating their potential differences between microbial community composition. Although the abundances of two major phyla, Firmicutes and Bacteroidetes, did not significantly differ between the HW and LW groups, some genera showed significant differences. Among them, Peptococcus and Eubacterium exhibited strong positive correlations with body weight (BW) and average daily gain (ADG) (Rho > 0.40), whereas Treponema, Desulfovibrio, Parabacteroides, and Ruminococcaceae_unclassified exhibited strong negative correlations with BW and ADG (Rho < -0.40). Based on these results, the structure of intestinal microbiota may affect growth traits in pigs through host-microbe interactions. Further in-depth studies will provide insights into how best to reshape host-microbe interactions in pigs and other animals as well.

Adipose Tissue Development and Expansion from the Womb to Adolescence: An Overview

Prevalence rates of pediatric obesity continue to rise worldwide. Adipose tissue (AT) development and expansion initiate in the fetus and extend throughout the lifespan. This paper presents an overview of the AT developmental trajectories from the intrauterine period to adolescence; factors determining adiposity expansion are also discussed. The greatest fetal increases in AT were observed in the third pregnancy trimester, with growing evidence suggesting that maternal health and nutrition, toxin exposure, and genetic defects impact AT development. From birth up to six months, healthy term newborns experience steep increases in AT; but a subsequent reduction in AT is observed during infancy. Important determinants of AT in infancy identified in this review included feeding practices and factors shaping the gut microbiome. Low AT accrual rates are maintained up to puberty onset, at which time, the pattern of adiposity expansion becomes sex dependent. As girls experience rapid increases and boys experience decreases in AT, sexual dimorphism in hormone secretion can be considered the main contributor for changes. Eating patterns/behaviors and interactions between dietary components, gut microbiome, and immune cells also influence AT expansion. Despite the plasticity of this tissue, substantial evidence supports that adiposity at birth and infancy highly influences its levels across subsequent life stages. Thus, a unique window of opportunity for the prevention and/or slowing down of the predisposition toward obesity, exists from pregnancy through childhood.

Shifts in the bacterial community of saliva give insights on the relationship between obesity and oral microbiota in adolescents

The current study aimed at the determination of the impact of obesity on the salivary microbiome in adolescents. Sixty subjects ranging 14-17 years old were enrolled (obese: n = 30-50% females, and normal weight: n = 30-50% females). Stimulated saliva was collected for denaturing gradient gel electrophoresis (DGGE) band patterns and massive 16S rRNA gene sequencing using the Ion Torrent platform. Overall, data analysis revealed that male subjects harbored a higher diverse salivary microbiome, defined by a significant higher richness (32.48 versus 26.74) and diversity (3.36 versus 3.20), higher Simpson values (0.96 versus 0.95) and distinct bacterial community structure considering either sex or condition (p < 0.05). Bacterial community fingerprinting analysis in human saliva showed a positive correlation with increased body mass index (BMI) in adolescents. Veillonella, Haemophilus and Prevotella occurrence was found to be affected by BMI, whereas Neisseria and Rothia occurrence was significantly impacted by sex in obese subjects. Our findings suggest that male and female adolescents may harbor a naturally distinct salivary microbiota and that obesity may specifically have an impact on their oral bacterial community. The potential dysbiotic oral microbiome in obese adolescents raises new insights on the etiology and prevention of future conditions in these populations.

Time of Feeding Alters Obesity-Associated Parameters and Gut Bacterial Communities, but Not Fungal Populations, in C57BL/6 Male Mice

BACKGROUND

Fasting and timed feeding strategies normalize obesity parameters even under high-fat dietary intake. Although previous work demonstrated that these dietary strategies reduce adiposity and improve metabolic health, limited work has examined intestinal microbial communities.

OBJECTIVES

We determined whether timed feeding modifies the composition of the intestinal microbiome and mycobiome (yeast and fungi).

METHODS

Male C57BL/6 mice were fed a high-fat diet (HF) for 6 wk. Animals were then randomly assigned to the following groups (n = 8-10/group): 1) HF ad libitum; 2) purified high-fiber diet (Daniel Fast, DF); 3) HF-time-restricted feeding (TRF) (6 h); 4) HF-alternate-day fasting (ADF); or 5) HF at 80% total caloric restriction (CR). After 8 wk, obesity and gut parameters were characterized. We also examined changes to the gut microbiome and mycobiome before, during, and following dietary interventions.

RESULTS

Body mass gain was reduced with all restricted dietary groups. HF-fed microbiota displayed lower α-diversity along with reduced phylum levels of Bacteroidetes and increased Firmicutes. Animals switched from HF to DF demonstrated a rapid transition in bacterial taxonomic composition, α-, and β-diversity that initially resembled HF, but was distinct after 4 and 8 wk of DF feeding. Time-or calorie-restricted HF-fed groups did not show changes at the phylum level, but α-diversity was increased, with specific genera altered. Six weeks of HF feeding reduced various fungal populations, particularly Alternaria, Aspergillus, Cladosporium, and Talaromyces, and increased Candida, Hanseniaspora, and Kurtzmaniella. However, 8 wk of intervention did not change the fungal populations, with the most abundant genera being Candida, Penicillium, and Hanseniaspora.

CONCLUSIONS

These data suggest that timed-feeding protocols and diet composition do not significantly affect the gut fungal community, despite inducing measurable shifts in the bacterial population that coincide with improvements in metabolism.

Childhood Obesity and Firmicutes/Bacteroidetes Ratio in the Gut Microbiota: A Systematic Review

BACKGROUND

The aim of the present study was to undertake a systematic review exploring the relationship between childhood obesity and fecal microorganisms, to answer the following question: "Are Firmicutes and Bacteroidetes a significant risk indicator/factor for obesity in children?" The main search terms were "child" and "obesity" together with "gut microbiota" (PubMed: 2005-2017). The minimal requirements for inclusion were the evaluation of gut microbiota composition and BMI in children between 0 and 13 years of age.

METHODS

Assessed articles were carefully classified according to a predetermined criterion, and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were considered. Seven articles were critically appraised and used as a basis for conclusions.

RESULTS

Three studies showed a positive association between Bacteroides fragilis and obesity. In addition, a high value of evidence indicated that a decrease in the Bacteroidetes phylum and in Bacteroides/Prevotella groups was related to high BMI. For the Firmicutes phylum, one high-quality study highlighted that it was positively correlated with weight gain. With regard to Firmicutes species, Clostridium leptum, Eubacterium hallii, and Lactobacillus spp. indicated adipose tissue storage, while Clostridium difficile and the Staphylococcus genus were correlated with low BMI. Despite the fact that only one study did not perform real-time polymerase chain reaction to quantify the microorganisms, its results corroborated those of the studies that did.

CONCLUSIONS

Changes in Firmicutes and Bacteroidetes phyla/species levels might in fact be significant indicators/factors for childhood obesity. However, given the small number of articles appraising these entire phyla and the heterogeneity among the species assessed, further well-designed studies are required to improve the knowledge.

Gut Prevotella as a possible biomarker of diet and its eubiotic versus dysbiotic roles: a comprehensive literature review

The gut microbiota has a profound impact on human health. Emerging data show that dietary patterns are associated with different communities of bacterial species within the gut. Prevotella species have been correlated with plant-rich diets, abundant in carbohydrates and fibres. Dysbiosis within the gut ecosystem has been associated with the development of non-communicable diseases such as obesity, the metabolic syndrome, inflammatory bowel disease, irritable bowel syndrome, colorectal cancer, type 1 diabetes, allergies and other diseases. The purpose of this comprehensive literature review was to evaluate the available data on the impact of diet on the Prevotella genus, as a dietary fibre fermenter in the gut as well as its implications as a potential biomarker for homeostasis or disease state through its metabolite signature. Studies were identified by conducting PubMed, Web of Science Core Collection and Google Scholar electronic searches. We found eighty-five publications reporting the impact of dietary patterns on gut microbial communities, including Prevotella or Prevotella/Bacteroides ratio in particular. Moreover, the role of Prevotella species on health status was also evaluated. Prevotella possess a high genetic diversity, representing one of the important groups found in the oral cavity and large intestine of man. The gut commensal Prevotella bacteria contribute to polysaccharide breakdown, being dominant colonisers of agrarian societies. However, studies also suggested a potential role of Prevotella species as intestinal pathobionts. Further metagenomic studies are needed in order to reveal health- or disease-modulating properties of Prevotella species in the gut.

The effects of antipsychotic medications on microbiome and weight gain in children and adolescents

BACKGROUND

Atypical antipsychotics, also known as second-generation antipsychotics, are commonly prescribed as treatment for psychotic disorders in adults, as well as in children and adolescents with behavioral problems. However, in many cases, second-generation antipsychotics have unwanted side effects, such as weight gain, potentially further increasing risk for morbidities including obesity, diabetes, and cardiovascular disease. While various mechanisms for this weight gain have been proposed, including effects on metabolic hormone signaling, recent evidence points to the importance of the gut microbiome in this process. The microbial communities residing within the gut are affected by second-generation antipsychotics and can confer weight gain.

MAIN TEXT

This review summarizes recent findings and presents data linking second-generation antipsychotics, gut microbiota alterations and weight gain. The review focuses on children and adolescent populations, which have not previously received much attention, but are of great interest because they may be most vulnerable to gut microbiome changes and may carry long-term metabolic effects into adulthood.

CONCLUSIONS

We present correlations between second-generation antipsychotics, gut microbiota alterations and weight gain, and suggest some mechanisms that may link them. A better understanding of the underlying mechanisms may lead to the design of improved treatments for psychotic disorders with fewer harmful side effects.

Gut microbiota and overweight in 3-year old children

BACKGROUND

The gut microbiota has been associated with overweight and obesity in adults, but the evidence in children is limited. Our aim was to study whether composition of the gut microbiota at the age of 3 years is associated with overweight/obesity in children cross-sectionally.

METHODS

Children, who participated in a clinical trial of prenatal vitamin-D supplementation (VDAART), underwent standardized height and weight measurements, and collection of stool samples at 3 years of age. 16 S rRNA sequencing (V4 region) of the stool samples were performed with Illumina MiSeq. Associations between microbiota and overweight/obesity (body mass index z-scores >85th percentile) was analyzed using logistic regression.

RESULTS

Out of 502 children, 146 (29%) were categorized as overweight/obese. Maternal pre-pregnancy BMI, birth weight and length, formula feeding during the first year, high frequency of fast food consumption, and time watching TV or computer screen at 3 years were the risk factors for overweight/obesity. Of the top 20 most abundant genera, high relative abundance of Parabacteroidetes (Bacteroidetes; Bacteroidales) (aOR(95% CI): 0.69 (0.53, 0.90, p = 0.007) per interquartile increase) and unassigned genus within Peptostreptococcae family were inversely associated with overweight/obesity, whereas high relative abundance of Dorea (Firmicutes;Clostridiales) (1.23 (1.05, 1.43, p = 0.009)) was positively associated. Associations were independent of each other. No associations were found between diversity indices and overweight/obesity.

CONCLUSIONS

Our data suggest that some of the differences in gut composition of bacteria between obese and non-obese adults can already be observed in 3-year old children. Longitudinal studies will be needed to determine long-term effects.

Lentil ( Lens culinaris Medikus) Diet Affects the Gut Microbiome and Obesity Markers in Rat

Lentil, a moderate-energy high-protein pulse crop, provides significant amounts of essential nutrients for healthy living. The objective of this study was to determine if a lentil-based diet affects food and energy intake, body weight, percent body fat, liver weight, and body plasma triacylglycerols (TGs) as well as the composition of fecal microbiota in rats. A total of 36 Sprague-Dawley rats were treated with either a standard diet, a 3.5% high amylose corn starch diet, or a 70.8% red lentil diet for 6 weeks. By week 6, rats fed the lentil diet had significantly lower mean body weight (443 ± 47 g/rat) than those fed the control (511 ± 51 g/rat) or corn (502 ± 38 g/rat) diets. Further, mean percent body fat and TG concentration were lower, and lean body mass was higher in rats fed the lentil diet than those fed the corn diet. Fecal abundance of Actinobacteria and Bacteriodetes were greater in rats fed the lentil or corn starch diets than those fed the control diet. Fecal abundance of Firmicutes, a bacterial phylum comprising multiple pathogenic species, decreased in rats fed the lentil and high-amylose corn starch diets vs the control diet. The lentil-based diet decreased body weight, percent body fat, and plasma triacylglycerols in rats and suppressed intestinal colonization by pathogens.

Association of Exposure to Formula in the Hospital and Subsequent Infant Feeding Practices With Gut Microbiota and Risk of Overweight in the First Year of Life

IMPORTANCE

The effect of neonatal and infant feeding practices on childhood obesity is unclear. The gut microbiome is strongly influenced by feeding practices and has been linked to obesity.

OBJECTIVE

To characterize the association between breastfeeding, microbiota, and risk of overweight during infancy, accounting for the type and timing of supplementary feeding.

DESIGN, SETTING, AND PARTICIPANTS

In this study of a subset of 1087 infants from the prospective CHILD pregnancy cohort, mothers were recruited between January 1, 2009, and December 31, 2012. Statistical analysis was performed from February 1 to December 20, 2017.

MAIN OUTCOMES AND MEASURES

Feeding was reported by mothers and documented from hospital records. Fecal microbiota at 3 to 4 months (from 996 infants) and/or 12 months (from 821 infants) were characterized by 16S ribosomal RNA sequencing. Infants with a weight for length exceeding the 85th percentile were considered to be at risk for overweight.

RESULTS

There were 1087 infants in the study (507 girls and 580 boys); at 3 months, 579 of 1077 (53.8%) were exclusively breastfed according to maternal report. Infants who were exclusively formula fed at 3 months had an increased risk of overweight in covariate-adjusted models (53 of 159 [33.3%] vs 74 of 386 [19.2%]; adjusted odds ratio, 2.04; 95% CI, 1.25-3.32). This association was attenuated (adjusted odds ratio, 1.33; 95% CI, 0.79-2.24) after further adjustment for microbiota features characteristic of formula feeding at 3 to 4 months, including higher overall richness and enrichment of Lachnospiraceae. A total of 179 of 579 infants who were exclusively breastfed (30.9%) received formula as neonates; this brief supplementation was associated with lower relative abundance of Bifidobacteriaceae and higher relative abundance of Enterobacteriaceae at 3 to 4 months but did not influence the risk of overweight. At 12 months, microbiota profiles differed significantly according to feeding practices at 6 months; among partially breastfed infants, formula supplementation was associated with a profile similar to that of nonbreastfed infants (higher diversity and enrichment of Bacteroidaceae), whereas the introduction of complementary foods without formula was associated with a profile more similar to that of exclusively breastfed infants (lower diversity and enrichment of Bifidobacteriaceae and Veillonellaceae). Microbiota profiles at 3 months were more strongly associated with risk of overweight than were microbiota profiles at 12 months.

CONCLUSIONS AND RELEVANCE

Breastfeeding may be protective against overweight, and gut microbiota may contribute to this effect. Formula feeding appears to stimulate changes in microbiota that are associated with overweight, whereas other complementary foods do not. Subtle microbiota differences emerge after brief exposure to formula in the hospital. These results identify important areas for future research and distinguish early infancy as a critical period when transient gut dysbiosis may lead to increased risk of overweight.

Phenylketonuric diet negatively impacts on butyrate production

BACKGROUND AND AIMS

Phenylalanine (Phe) restricted diet, combined with Phe-free l-amino acid supplementation, is the mainstay of treatment for phenylketonuria (PKU). Being the diet a key factor modulating gut microbiota composition, the aim of the present paper was to compare dietary intakes, gut microbiota biodiversity and short chain fatty acids (SCFAs) production in children with PKU, on low-Phe diet, and in children with mild hyperphenylalaninemia (MHP), on unrestricted diet.

METHODS AND RESULTS

We enrolled 21 PKU and 21 MHP children matched for gender, age and body mass index z-score. Dietary intakes, including glycemic index (GI) and glycemic load (GL), and fecal microbiota analyses, by means of denaturing gradient gel electrophoresis (DGGE) and Real-time PCR were assessed. Fecal SCFAs were quantified by gas chromatographic analysis.

RESULTS

We observed an increased carbohydrate (% of total energy), fiber and vegetables intakes (g/day) in PKU compared with MHP children (p = 0.047), as well a higher daily GI and GL (maximum p < 0.001). Compared with MHP, PKU showed a lower degree of microbial diversity and a decrease in fecal butyrate content (p = 0.02). Accordingly, two of the most abundant butyrate-producing genera, Faecalibacterium spp. and Roseburia spp., were found significantly depleted in PKU children (p = 0.02 and p = 0.03, respectively).

CONCLUSION

The low-Phe diet, characterized by a higher carbohydrate intake, increases GI and GL, resulting in a different quality of substrates for microbial fermentation. Further analyses, thoroughly evaluating microbial species altered by PKU diet are needed to better investigate gut microbiota in PKU children and to eventually pave the way for pre/probiotic supplementations.

Gut microbiota alterations and dietary modulation in childhood malnutrition - The role of short chain fatty acids

The gut microbiome affects the health status of the host through different mechanisms and is associated with a wide variety of diseases. Both childhood undernutrition and obesity are linked to alterations in composition and functionality of the gut microbiome. One of the possible mechanisms underlying the interplay between microbiota and host metabolism is through appetite-regulating hormones (including leptin, ghrelin, glucagon-like peptide-1). Short chain fatty acids, the end product of bacterial fermentation of non-digestible carbohydrates, might be able to alter energy harvest and metabolism through enteroendocrine cell signaling, adipogenesis and insulin-like growth factor-1 production. Elucidating these mechanisms may lead to development of new modulation practices of the gut microbiota as a potential prevention and treatment strategy for childhood malnutrition. The present overview will briefly outline the gut microbiota development in the early life, gut microbiota alterations in childhood undernutrition and obesity, and whether this relationship is causal. Further we will discuss possible underlying mechanisms in relation to the gut-brain axis and short chain fatty acids, and the potential of probiotics, prebiotics and synbiotics for modulating the gut microbiota during childhood as a prevention and treatment strategy against undernutrition and obesity.

Body Mass Index and Sex Affect Diverse Microbial Niches within the Gut

Gut microbiota is considered a separate organ with endocrine capabilities, actively contributing to tissue homeostasis. It consists of at least two separate microbial populations, the lumen-associated (LAM) and the mucosa-associated microbiota (MAM). In the present study, we compared LAM and MAM, by collecting stools and sigmoid brush samples of forty adults without large-bowel symptoms, and through a 16S rRNA gene next-generation sequencing (NGS) approach. MAM sample analysis revealed enrichment in aerotolerant Proteobacteria, probably selected by a gradient of oxygen that decreases from tissue to lumen, and in Streptococcus and Clostridium spp., highly fermenting bacteria. On the other hand, LAM microbiota showed an increased abundance in Bacteroides, Prevotella, and Oscillospira, genera able to digest and to degrade biopolymers in the large intestine. Predicted metagenomic analysis showed LAM to be enriched in genes encoding enzymes mostly involved in energy extraction from carbohydrates and lipids, whereas MAM in amino acid and vitamin metabolism. Moreover, LAM and MAM communities seemed to be influenced by different host factors, such as diet and sex. LAM is affected by body mass index (BMI) status. Indeed, BMI negatively correlates with Faecalibacterium prausnitzii and Flavonifractor plautii abundance, putative biomarkers of healthy status. In contrast, MAM microbial population showed a significant grouping according to sex. Female MAM was enriched in Actinobacteria (with an increased trend of the genus Bifidobacterium), and a significant depletion in Veillonellaceae. Interestingly, we found the species Gemmiger formicilis to be associated with male and Bifidobacterium adolescentis, with female MAM samples. In conclusion, our results suggest that gut harbors microbial niches that differ in both composition and host factor susceptibility, and their richness and diversity may be overlooked evaluating only fecal samples.

Gut Microbiota in Obesity and Metabolic Abnormalities: A Matter of Composition or Functionality?

The obesity pandemic and the metabolic complications derived from it represent a major public health challenge worldwide. Although obesity is a multifactorial disease, research from the past decade suggests that the gut microbiota interacts with host genetics and diet, as well as with other environmental factors, and thus contributes to the development of obesity and related complications. Despite abundant research on animal models, substantial evidence from humans has only started to accumulate over the past few years. Thus, the aim of the present review is to discuss structural and functional characteristics of the gut microbiome in human obesity, challenges associated with multi-omic technologies, and advances in identifying microbial metabolites with a direct link to obesity and metabolic complications. To date, studies suggests that obesity is related to low microbial diversity and taxon depletion sometimes resulting from an interaction with host dietary habits and genotype. These findings support the idea that the depletion or absence of certain taxa leaves an empty niche, likely leading to compromised functionality and thus promoting dysbiosis. Although the role of altered gut microbiota as cause or consequence of obesity remains controversial, research on microbial genomes and metabolites points towards an increased extraction of energy from the diet in obesity and suggests that metabolites, such as trimethylamine-N-oxide or branched-chain amino acids, participate in metabolic complications. Future research should be focused on structural and functional levels to unravel the mechanism linking gut microbiota and obesity.

High-Fat Diet Changes Fungal Microbiomes and Interkingdom Relationships in the Murine Gut

Recent research shows that gut microbes are involved in the development of obesity, a growing health problem in developed countries that is linked to increased risk for cardiovascular disease. However, studies showing links between microbes and metabolism have been limited to the analysis of bacteria and have ignored the potential contribution of fungi in metabolic health. This study provides evidence that ingestion of a high-fat diet is associated with changes to the fungal (and bacterial) microbiome in a mouse model. In addition, we find that interkingdom structural and functional relationships exist between fungi and bacteria within the gut and that these are perturbed by high-fat diet.

Dietary fat intake and shifts in gut bacterial community composition are associated with the development of obesity. To date, characterization of microbiota in lean versus obese subjects has been dominated by studies of gut bacteria. Fungi, recently shown to affect gut inflammation, have received little study for their role in obesity. We sought to determine the effects of high-fat diet on fungal and bacterial community structures in a mouse model using the internal transcribed spacer region 2 (ITS2) of fungal ribosomal DNA (rDNA) and the 16S rRNA genes of bacteria. Mice fed a high-fat diet had significantly different abundances of 19 bacterial and 6 fungal taxa than did mice fed standard chow, with high-fat diet causing similar magnitudes of change in overall fungal and bacterial microbiome structures. We observed strong and complex diet-specific coabundance relationships between intra- and interkingdom microbial pairs and dramatic reductions in the number of coabundance correlations in mice fed a high-fat diet compared to those fed standard chow. Furthermore, predicted microbiome functional modules related to metabolism were significantly less abundant in high-fat-diet-fed than in standard-chow-fed mice. These results suggest a role for fungi and interkingdom interactions in the association between gut microbiomes and obesity.

IMPORTANCE Recent research shows that gut microbes are involved in the development of obesity, a growing health problem in developed countries that is linked to increased risk for cardiovascular disease. However, studies showing links between microbes and metabolism have been limited to the analysis of bacteria and have ignored the potential contribution of fungi in metabolic health. This study provides evidence that ingestion of a high-fat diet is associated with changes to the fungal (and bacterial) microbiome in a mouse model. In addition, we find that interkingdom structural and functional relationships exist between fungi and bacteria within the gut and that these are perturbed by high-fat diet.

Association of altered gut microbiota composition with chronic urticaria

BACKGROUND

An altered gut microbiota composition has recently been linked to some types of allergies.

OBJECTIVE

To compare the relative amounts of Akkermansia muciniphila, Clostridium leptum, Faecalibacterium prausnitzii, and Enterobacteriaceae as members of gut microbiota among patients with chronic urticaria (CU) and healthy controls.

METHODS

A total of 20 patients with CU and 20 healthy individuals matched by age and sex participated in the study. Fresh fecal samples were collected, and DNA extracted from stool samples was analyzed by real-time polymerase chain reaction for the qualitative and quantitative assays of the so-called bacteria.

RESULTS

The frequencies of A muciniphila, C leptum, and F prausnitzii in healthy controls' stool samples were significantly more than those of patients with CU (P < .001, P < .01, and P < .05, respectively), whereas the Enterobacteriaceae family was detected in all patients and healthy controls' stool samples. The relative amounts of A muciniphila in healthy control positive samples were significantly higher than those of samples from patients with CU (P < .001). Furthermore, there was a corresponding increase of relative amounts of C leptum and F prausnitzii in healthy control positive samples compared with those of patients with CU (P = .09 and P = .08, respectively). The mean of the relative amounts of Enterobacteriaceae family in the stool samples from patients with CU was more than that of healthy controls; however, the difference was nearly significant (P = .12).

CONCLUSION

The results reveal a change of frequency and relative amounts of A muciniphila, C leptum, and F prausnitzii in patients with CU compared with healthy controls. This is the first study, to our knowledge, to show the change of microbiota composition in patients with CU.