Patients with obesity may have unique oral microbiomes, marked by a higher presence of proinflammatory and lactate-producing bacteria in the mouth, according to a study recently published in Cell Reports.
Additionally, obesity may be associated with changes in oral metabolic activity, with related metabolites linked to markers of cardiometabolic disease, the authors wrote.
“Oral microbiome composition and functions differ significantly in obesity,” wrote the authors, led by Ahmed A. Shibl, PhD, of the New York University Abu Dhabi Public Health Research Center (Cell Rep, January 22, 2026, 116819).
The study examined a prospective cohort of 628 adults in the United Arab Emirates, providing a comprehensive analysis of the oral microbiome. Using 16S rRNA sequencing, the researchers identified obesity as a major factor influencing oral microbial variation across the full cohort, they wrote.
Then they performed multiomics profiling on mouthwash samples from 192 participants, including 97 individuals with obesity and 95 matched healthy-weight controls. This approach combined shotgun metagenomics and untargeted metabolomics to link microbial composition and function with metabolic profiles. The integrated data were further correlated with clinical biomarkers from blood and urine to better understand obesity-related oral microbiome changes.
Random forest analysis based on oral microbial species differentiated obese participants from controls with moderate accuracy (feature out of bag = 33%, area under the curve [AUC] = 0.75). Bacteria enriched in individuals with obesity included several proinflammatory species such as Streptococcus as well as Actinomyces oris. The increased abundance of these taxa may promote an oral environment favorable to cariogenic bacteria such as Lactobacillus gasseri and Limosilactobacillus fermentum, which, while less frequently detected, were more abundant in participants with obesity, they wrote.
A separate random forest classifier further distinguished obese from control individuals with comparable performance (out-of-bag error = 34%, AUC = 0.84). Variable importance analysis highlighted elevated obesity-associated serum markers, including triglycerides, gamma-glutamyl transferase, alanine aminotransferase, and alkaline phosphatase. Together, these markers reflect insulin resistance, hepatic stress, impaired glycemic control, and increased cardiometabolic risk associated with obesity.
Nevertheless, this study had limitations. The study lacked reliable dietary data and could not fully account for smoking or post-meal timing, factors that may affect both microbiome and metabolomic results, the authors added.
“These findings reveal mechanistic oral microbiome-metabolite shifts, highlighting oral microbiome-host interactions as novel targets for obesity prevention and intervention,” Shibl and colleagues concluded.
