Roles of gut microbes in the development of obesity. The human gut harbors a complex community of microbes that affect many aspects of our health. The relative abundance of christensenellaceae in the human gut is inversely related to host body mass index bmi in different populations and multiple studies, making its relationship with bmi the most robust and reproducible link between the microbial ecology of. For the oral microbiome, less is known about its relationship with obesity, although specific bacteria have also been found to vary with obesity in both adolescents and adults 4,11. Obesity, motility, diet, and intestinal microbiota. Metaanalyses of human gut microbes associated with.
Human gastrointestinal tract, in special the colon, is densely populated by bacteria, fungi, archea, viruses, collectively called as gut microbiota. The gut microbiota in human energy homeostasis and obesity. Obesity results from an imbalance between energy intake and expenditure, associated with a chronic lowgrade inflammation. Cholesterol lowering drugs can improve composition of gut. As early as the 1980s, the gut microbiota has been associated with obesity in human 19 and rats 20 by utilizing culturedependent methods, which only sees pieces of microbes in the gut. The human gut harbors more than 100 trillion microbial cells, which have an essential role in human metabolic regulation via their symbiotic interactions with the host.
Schwiertz a, taras d, schafer k, beijer s, bos n, donus c, et al. Objective bacterial translocation to various organs including human adipose tissue at due to increased intestinal permeability remains poorly understood. Intestinal microbiota dysbiosis in obesity and physiological perturbation. Presence of acids in stomach and bile acids and pancreatic juice in the duodenum and jejunum can inhibit the growth of. Two groups of beneficial bacteria are dominant in the human gut, the bacteroidetes and. Microbiota and scfa in lean and overweight healthy subjects. Geographic variation of human gut microbes tied to obesity. Symbiotic gut microbes modulate human metabolic phenotypes pnas. Obesity is a worldwide public health problem continuing to rise rapidly, affecting more than 107.
The human gut is a lush microbial ecosystem containing about 100 trillion microorganisms, whose collective genome, the microbiome, contains 100fold more genes than the entire human genome. In this article, we summarize some of the studies that have advanced the understanding of the. Metaanalyses of human gut microbes associated with obesity and ibd. Anaerobic bacteria are also present on human skin, with colony counts up to 10 6 bacteria per cm 2. Design we quantified and sequenced the bacterial 16s rrna gene in blood and. Nicholson1,2 and marcemmanuel dumas2 abstract the human gut harbors more than 100 trillion microbial cells, which have an essential role in human metabolic. Longitudinal changes of microbiome composition and microbial.
Obesity is associated with complications during pregnancy and increased health risks in the newborn. Although microbes are by no means the sole factor in the obesity epidemic, alterations in the gut microbiota have been observed in obese humans, microbial differences have been reported to classify people as lean or obese with. The gut microbiota associated with human obesity is depleted in m. Jun 10, 2019 the lack of sustainability of some of the changes observed in the microbiome andor the lack of full rescue of obesity associated microbial characteristics suggest that mechanisms others than the microbiome are implicated in metabolic improvement after bariatric surgery, and that the richness of the microbiome alone does may not predict the. Gut microbiota and obesity british society for immunology. Mouse models are far from perfect for deciphering the relationship between diet, gut microbiota, and human obesity, and although alteration of the gut microbiota using antibiotics has been shown to markedly influence obesity and insulin resistance in mice 22, 23, it resulted in limited effects in humans. This indicates that certain groups of bacteria, such as firmicutes, are taking the place of the bacterial groups that have decreased in abundance, such as bacteroidetes 3 18. Composition and function of the humanassociated microbiota. They hypothesized that bacterial lipopolysaccharide lps derived from gramnegative bacteria residing in the gut. The role of short chain fatty acids in appetite regulation and energy homeostasis.
Modulation of gut microbiota dysbioses in type 2 diabetic patients by macrobiotic mapi 2 diet. The biological basis of disease is one avenue for further exploration in this context. As a consequence, the study of gut ecology has emerged as one of the most active and exciting fields in biology and medicine. Gut microbiota composition is associated with body weight.
Ley re, turnbaugh pj, klein s, gordon ji 2006 microbial ecology. Annals of the american thoracic society ats journals. Although host associated microbes are presumably acquired from the environment, the composition of the mammalian microbiota, especially in the gut, is surprisingly different from freeliving microbial communities. To investigate the relation between gut microbial ecology and body fat in humans, we studied 12 obese people, who were randomly assigned to either a fatrestricted fatr or to a. Gut bacterial microbiota and obesity clinical microbiology. Human gut microbes associated with obesity, authorruth e. This research could point the way to new treatments for obesity. Convincing experimental data suggest a causal role for intestinal microbes. In recent years, the gut microbiota the microorganisms that live in our digestive tract has. The objective of the present study was to establish possible relationships between gut microbiota, body weight, weight gain and biochemical parameters in pregnant women.
Human gut microbes associated with obesity anna vrabel obesity is a growing problem both nationally and internationally. Jul 19, 2009 the human gut is a lush microbial ecosystem containing about 100 trillion microorganisms, whose collective genome, the microbiome, contains 100fold more genes than the entire human genome. Gut microbes and diet interact to affect obesity national. Pdf two groups of beneficial bacteria are dominant in the human gut, the bacteroidetes and the firmicutes. Here we show that the relative proportion of bacteroidetes is decreased in obese people by comparison with lean people, and that this proportion increases with weight loss. As the prevalence of obesity and associated disease continues to rise and concerns for the spiralling economic and social costs also escalate, innovative management strategies beyond primary prevention and traditional lifestyle interventions are urgently needed. The human gut microbiota see glossary consists of up to 100 trillion microbes that exist in largely symbiotic relationship with their human hosts, and carry at least 150 times more genes the microbiome than are present in the entire human genome 1,2. Antibiotics, obesity and the link to microbes what are we. Cultivation of human skin reveals numerous bacteria and at least one fungus to be normal inhabitants of this ecosystem. Dec 21, 2006 to investigate the relation between gut microbial ecology and body fat in humans, we studied 12 obese people, who were randomly assigned to either a fatrestricted fatr or to a carbohydrate. Special emphasis is given on mechanisms interconnecting gut microbiome and microbial metabolites with metabolic disorders as well as on potential preventive and therapeutic perspectives with a bench to bedside approach.
Here we show that the relative proportion of bacteroidetes is decreased in obese people by comparison with lean people, and that this proportion increases with weight loss on two types of lowcalorie diet. Expertise in data analytics, host microbe interactions, microbiome, gastrointestinal health, plant pathogens, fermentation, microbial ecology and exobiology. Also, obese people with a less diverse supply of germs gained more weight. This work suggests that the gut microbiome associated with obesity might be a biomarker and possibly a therapeutic target. Gut microbiome diversity and highfibre intake are related. Gordon, journalnature, year2006, volume444, pages10221023 two groups of beneficial bacteria are dominant in.
Dec 21, 2006 this work suggests that the gut microbiome associated with obesity might be a biomarker and possibly a therapeutic target. The stratum corneum, cellular layer, hair shaft and follicle, eccrine, apocrine, and sebaceous glands may each have associated. In the united states alone, 65% of adults are overweight while 30% are considered to be obese2. Gut bacterial microbiota and obesity sciencedirect. The first definite evidence for the role of the gut microbiota in the regulation of host energy homeostasis and adiposity came from gordon and colleagues group experiments. The human body is an ecosystem harboring complex sitespecific microbial communities.
Obesity is a growing public health problem that predisposes to cardiovascular diseases and type 2 diabetes. Gut microbes are considered to contribute to body weight regulation and related disorders by influencing metabolic and immune host functions. Two groups of beneficial bacteria are dominant in the human gut, the. Do interactions between gut ecology and environmental.
The christensenellaceae, a recently described family in the phylum firmicutes, is emerging as an important player in human health. Longitudinal changes of microbiome composition and. Oct, 2014 although microbes are by no means the sole factor in the obesity epidemic, alterations in the gut microbiota have been observed in obese humans 7, 8, microbial differences have been reported to classify people as lean or obese with. It is in this context that maneuvers to alter or modify the microbiota. Proposed mechanisms linking the microbiota to fat content. The human gut bacteria christensenellaceae are widespread. The gut microbiota is fundamental to human health 1, and its modulation may prove pivotal to the future of personalized medicine and nutrition 2. Impact of the gut microbiota on inflammation, obesity, and. Gut microbiota and obesity clinical nutrition experimental.
Although microbes are by no means the sole factor in the obesity epidemic, alterations in the gut microbiota have been observed in obese humans 7, 8, microbial differences have been reported to classify people as lean or obese with. The symbiosis of our extended genome plays a role in host homeostasis and energy extraction from diet. Although probiotics and antibiotics have been used for decades as growth promoters in animals, attention has only recently been drawn to the association between the gut microbiota composition, its manipulation, and obesity. On the basis that obesity and insulin resistance is associated with lowgrade chronic systemic inflammation, cani et al. This ecosystem may contain trillions of microorganisms, a number 10 times larger than the human cells amount. Aug 28, 20 the gut germs in the obese people were less diverse than in the others, and had more abnormalities in terms of metabolism. The majority of these human associated microbes are found in the intestinal tract, where they play important roles in energy uptake, vitamin synthesis, and epithelial and immunity development. Review open access impact of the gut microbiota on inflammation, obesity, and metabolic disease claire l. Obesity, and its related comorbidities, is a globally prevalent issue, and is expected to affect over half a billion people by 2030. Obesity is also associated with a decrease in the overall microbial diversity of the gut, although the total amount of microbes remains the same. Recent work has shown obesity to be associated with a shift in the representation of the dominant phyla of bacteria in the gut, both in humans and animal models.
Adipose tissue derived bacteria are associated with. Studies in mice have associated the phylum firmicutes with obesity and the phylum bacteroidetes with weight loss. The descriptive profiling of gut microbiota has revealed a correlation between obesity and microbial classes in both humans and rodents 77, 79,80,85,87,103,107108109. Two groups of beneficial bacteria are dominant in the human gut, the bacteroidetes and the firmicutes. Along these lines, studies that address early microbial colonization and transgenerational effects of the gut microbiome relative to obesity risk can strengthen our knowledge of microbial maturation and interventional windows of time, adding to the utility of using gut microbes as biomarkers for disease.
Evidence for the role of gut microbiota in the regulation of energy homeostasis and fat storage. Obesity is a major public health issue as it is causally related to several chronic disorders, including type2 diabetes, cvd and cancer. Nov 17, 2014 although microbes are by no means the sole factor in the obesity epidemic, alterations in the gut microbiota have been observed in obese humans 7, 8, microbial differences have been reported to classify people as lean or obese with. Assessment of gut microbiota populations in lean and obese. In this article, we summarize some of the studies that have advanced the. Modulation of gut microbiota dysbioses in type 2 diabetic patients by macrobiotic ma. Microbial ecology of human skin in health and disease. Therefore, gut microbiota composition at the species level is related to body weight and obesity, which might be of relevance for further studies and. Although microbes are by no means the sole factor in the obesity epidemic, alterations in the gut microbiota have been observed in obese humans 7, 8, microbial differences have been reported to classify people as lean or.
Here we show that the relative proportion of bacteroidetes is decreased in obese people by. Obesity, inflammation, and the gut microbiota the lancet. Some bifidobacterium or lactobacillus species were associated with normal weight b. Classification of the lean and obese zucker rat intestinal. The connection between gut microbiota and energy homeostasis and inflammation and its role in the pathogenesis of obesity related disorders are increasingly recognized.
Modern techniques employing nucleic acidbased microbial identification methods demonstrate the limitations of cultivation for appreciating microbial diversity in many ecosystems. Animals models of obesity connect an altered microbiota composition to the development of obesity, insulin resistance, and diabetes in the host through several mechanisms. In the 1990s, the application of cultureindependent molecular techniques based on 16s ribosomal rna rrna genes e. Metaanalyses of human gut microbes associated with obesity. Humans have evolved intimate symbiotic relationships with a consortium of gut microbes microbiome and individual variations in the microbiome influence host health, may be implicated in disease etiology, and affect drug metabolism, toxicity, and efficacy. Understanding the role of the gut microbiome and microbial. However, the molecular basis of these microbehost interactions and the roles of individual bacterial species are obscure. We find that microbial metabolites, particularly short. Our findings indicate that obesity has a microbial component, which might have.
Apr 19, 2016 childhood obesity and overweight are among the greatest health challenges in the pediatric population. Microbial changes in the human gut were proposed as a possible cause of obesity 5, 9, 10. Zhang h, dibaise jk, zuccolo a, dave kudrna, michele braidotti, et al 2009 human gut microbiota in obesity and after gastric bypass. Microbial ecology human gut microbes associated with obesity two groups of beneficial bacteria are dominant in the human gut, the bacteroidetes and the firmicutes. These changes in the gut microbiota precede the clinical manifestation of overweight. Obesity has been linked to changes in the intestinal microbiota, but the composi. Certain phyla and classes of bacteria are associated with improved transfer of calories from the diet to the host, and with changes in the host metabolism of absorbed calories.
Available formats pdf please select a format to send. Obesity is a major public health issue as it enhances the risk of suffering several chronic diseases of increasing prevalence. Obesity, diabetes, and gut microbiota diabetes care. Gut microbes from lean people helped prevent mice from becoming obesebut only if the animals ate a healthy diet. Obese individuals exhibit marked differences in the composition of the intestinal microbial community as compared to lean subjects. Gut microorganisms ferment dietary polysaccharides into monosaccharides and shortchain fatty acids, and thus allow the. Your gut bacteria may predict your obesity risk webmd. There is significant crosssectional variability in the microbiota between individuals and longitudinal variability within individuals. Walters department of molecular, cellular and developmental biology, university of colorado, boulder, co 80309, usa. Composition and energy harvesting capacity of the gut. An obesityassociated gut microbiome with increased. In addition, skin structures within a specific skin zone may harbor unique microbes. Catalysing innovative solutions in the areas of gut health, skin health, protein science, enzymology, microbial ecology, multiomics data analytics and drug discovery. Altered gut microbial ecosystems have been associated with increased metabolic and immune disorders in animals and humans.
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