Effects of a Combined Strength and Endurance Training Program on Gut Microbiota Composition, Functionality, and Inflammatory Status in Obese Children

Childhood obesity is a major public health concern, often associated with metabolic syndrome and non-alcoholic fatty liver disease (NAFLD). Alterations in the gut microbiota are implicated in the pathogenesis of these conditions. Previous research suggests that physical exercise can positively modulate the gut microbiota, improving metabolic parameters and reducing inflammation. However, studies specifically examining the effects of combined strength and endurance training on the gut microbiota in obese children are limited. This study aimed to determine whether a 12-week combined strength and endurance training protocol could favorably modify the intestinal microbiota composition, functionality, and inflammatory status in children with obesity.

Existing literature shows a correlation between gut microbiota, energy homeostasis, and inflammation in obesity. Studies suggest that obese children exhibit a distinct gut microbiota profile compared to healthy controls, often characterized by an increase in Proteobacteria and a decrease in beneficial bacteria like Actinobacteria. While physical exercise is recognized as a beneficial intervention for reducing obesity and improving metabolic health, evidence regarding its effects on gut microbiota modulation in children is still emerging. Discrepancies exist in methodologies used across studies, highlighting the need for further research.

Fifty-three subjects (39 obese, 14 healthy controls) aged 7–12 years participated. Obese children were randomly assigned to either a training group (n=25) or a control group (n=14). The training group underwent a 12-week combined strength and endurance program (2 sessions/week). Baseline data were collected one week before and after the intervention. Assessments included dual X-ray absorptiometry (DXA) for body composition, anthropometric measurements, one-repetition maximum (1RM) testing, and gut microbiota analysis (16S rRNA sequencing) and metabolomics analysis (NMR). Blood samples were collected for hematological and biochemical analyses, and Western blotting was used to assess inflammatory markers (NLRP3, CASP-1, OPN, TLR4). Statistical analyses included Kruskal-Wallis, Mann-Whitney U, Spearman's correlation, two-way ANOVA with repeated measures, and others.

The 12-week training program significantly increased dynamic strength in both upper and lower extremities in the training group compared to the control group. While no significant changes in anthropometric data were observed, the exercise intervention resulted in reduced glucose levels and decreased activity of GOT and LDH enzymes. Gut microbiota analysis revealed a higher abundance of Bacteroidetes and Proteobacteria and lower abundance of Firmicutes and Actinobacteria in obese children compared to healthy controls. The training program significantly reduced the abundance of Proteobacteria and Gammaproteobacteria, and increased beneficial genera like Blautia, Dialister, and Roseburia, leading to a microbiota profile closer to that of healthy controls. Metabolomic analysis showed a reduction in branched-chain amino acids and sugars in the training group. Western blot analysis showed a significant downregulation of NLRP3, CASP-1, and OPN in the training group, indicative of reduced inflammation. TLR4 levels showed a non-significant decreasing trend in the training group.

The study demonstrated that a combined strength and endurance training program positively modifies the gut microbiota composition and functionality in obese children. The reduction in Proteobacteria and Gammaproteobacteria, coupled with an increase in beneficial genera and altered fecal metabolites, suggests a shift towards a healthier gut microbiome. The downregulation of inflammatory markers further supports the anti-inflammatory effects of exercise. The lack of significant changes in anthropometric parameters may be attributed to the relatively short duration of the training program and the ongoing growth phase of the children. These findings highlight the potential of exercise as a non-pharmacological therapeutic approach for managing childhood obesity.

This study provides evidence for the beneficial effects of a combined strength and endurance training program on the gut microbiota and inflammatory status in obese children. The positive modulation of the gut microbiota and reduction in inflammatory markers underscore the importance of exercise as a non-pharmacological intervention. Future research should focus on longer-term studies with larger sample sizes, including normal-weight controls, to further elucidate the mechanisms underlying the interaction between exercise, gut microbiota, and inflammation in childhood obesity.

This study has some limitations, including a relatively small sample size, the absence of a normal-weight control group, and the relatively short duration of the intervention. The lack of dietary control and the ongoing growth phase of the participants might also influence the observed results. Furthermore, a more direct link between gut microbiota changes and the observed improvements in inflammation needs to be further investigated.