Large Oral Microbiome Study Identifies Statistical Links Between Specific Bacteria and 44 Metabolic Traits

Researchers have created a statistical atlas linking specific mouth bacteria, genes and biological pathways to 44 metabolic traits using data from more than 9,000 people. Imran Razzak at Mohamed bin Zayed University of Artificial Intelligence in Abu Dhabi, United Arab Emirates, and his colleagues used whole metagenomic sequencing to analyse oral swabs from 9431 participants in the Human Phenotype Project.

The study combined oral microbiome data with liver ultrasound scans, continuous blood glucose monitoring, and body composition analyses.

The resulting atlas connected microbial features to traits that included liver fat, blood sugar swings, and visceral fat around the organs. Streptococcus parasanguinis and Oribacterium sinus were linked to higher body mass index and body fat in the study. Polyamine biosynthesis by bacteria was associated with worse liver measures, poorer glucose control, and higher body fat.

A microbial pathway involved in the breakdown of ceramide-related molecules correlated with worsening blood sugar control. Many of the associations remained even after accounting for common oral health problems such as gum disease. The oral microbiome is the second-largest microbial ecosystem in the body after the gut.

The study cannot prove that these bacteria cause the health outcomes. "Our working hypothesis is that the oral microbiome is not merely a passive indicator but may play an active role in metabolic disease," Imran Razzak stated. Aashish Jha at New York University Abu Dhabi reported earlier in 2025 that Streptococcus parasanguinis and Oribacterium sinus were more abundant in people with obesity.

The new findings build on that earlier observation by tying the same bacteria to higher body mass index and body fat while also identifying functional microbial pathways. Lindsey Edwards at King’s College London described the work as one of the most ambitious attempts yet to map how the oral microbiome reflects metabolic health across multiple organ systems.

"The idea that a simple buccal swab could provide early warning signals for conditions like fatty‑liver disease or impaired glucose regulation is compelling," Lindsey Edwards stated.

685004. @NewScientist reported that both Razzak and Edwards cautioned that further work is needed to confirm the links in other populations and validate them in clinical settings.