Abstract
BackgroundAn altered gut microbiota composition has recently been linked to obesity. The principal aim of this study is to investigate and compare the gut microbiota composition in obese and lean children. Secondly, associations between analysed gut bacterial species, dietary compounds, energy intake and biochemical blood parameters are evaluated.MethodsIn this prospective cross-sectional study, 26 overweight/obese (mean BMI: 28.7 ± 6.5) and 27 lean (mean BMI: 16.5 ± 2.1) children aged 6 to 16 were included. Faecal samples were collected and subjected to selective plating and quantitative real-time PCR (qPCR) in order to determine the concentrations of bacterial species belonging to the genera: Bacteroides, Bifidobacterium, Clostridium, Staphylococcus and Lactobacillus. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was applied for an in-depth identification of species of Bacteroides fragilis group. Differences in the concentrations of gut bacterial species between obese and lean children were statistically analysed using Mann Whitney U test. Subsequently, random forest analysis and multiple linear regression analysis were performed in order to test associations between gut bacterial species, dietary compounds and blood parameters.ResultsObese children showed an elevated Firmicutes-to-Bacteroidetes ratio compared with lean children. Furthermore, low relative proportions of B. vulgatus and high concentrations of Lactobacillus spp. were observed in the obese microbiota. In all children, Staphylococcus spp. were positively associated with energy intake. Additionally, in obese children, Lactobacillus spp. were positively associated with plasma hs-CRP.ConclusionsOur findings corroborate a significant difference in the gut microbiota composition of important bacterial species between obese and lean children. In future, non-invasive manipulation of gut microbiota composition in early infancy could offer a new approach to manage childhood obesity and associated disorders.
Highlights
An altered gut microbiota composition has recently been linked to obesity
In-depth analysis of species belonging to the Bacteroides fragilis group using MALDI-TOF Matrix-Assisted Laser-Desorption /Ionization Time-Of-Flight Mass Spectrometry (MS) revealed dominating relative proportions of B. fragilis
We found a positive association between energy intake and the presence of Staphylococcus spp. in faeces of children, independent of their body mass index (BMI) status
Summary
An altered gut microbiota composition has recently been linked to obesity. The principal aim of this study is to investigate and compare the gut microbiota composition in obese and lean children. Associations between analysed gut bacterial species, dietary compounds, energy intake and biochemical blood parameters are evaluated. Physiological and environmental predispositions underlying obesity and associated metabolic disorders are still underexplored. Recent evidence suggests that our gut microbiota is involved in energy regulation as well as inflammation [9], and should be considered as an environmental factor playing a role in the pathophysiology of obesity [10,11]. Energy intake can affect the gut microbiota composition [12], it is still unclear whether the gut microbiota play a causal role in the development of obesity in humans
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