The Ambiguous Correlation of Blautia with Obesity: A Systematic Review

Obesity is a complex and multifactorial disease with global epidemic proportions, posing significant health and economic challenges. Whilst diet and lifestyle are well-established contributors to the pathogenesis, the gut microbiota's role in obesity development is increasingly recognized. Blautia, as one of the major intestinal bacteria of the Firmicutes phylum, is reported with both potential probiotic properties and causal factors for obesity in different studies, making its role controversial. To summarize the current understanding of the Blautia-obesity correlation and to evaluate the evidence from animal and clinical studies, we used "Blautia" AND "obesity" as keywords searching through PubMed and SpringerLink databases for research articles. After removing duplicates and inadequate articles using the exclusion criteria, we observed different results between studies supporting and opposing the beneficial role of Blautia in obesity at the genus level. Additionally, several studies showed probiotic effectiveness at the species level for Blautia coccoides, B. wexlerae, B. hansenii, B. producta, and B. luti. Therefore, the current evidence does not demonstrate Blautia's direct involvement as a pathogenic microbe in obesity development or progression, which informs future research and therapeutic strategies targeting the gut Blautia in obesity management.