Researchers have discovered a unique oral microbiome signature in people with obesity, potentially offering early detection and prevention strategies. The finding, based on saliva samples from Emirati adults, highlights differences in bacteria and metabolic pathways associated with metabolic dysfunction. However, scientists caution that the relationship's causality remains unclear.
A team led by Aashish Jha at New York University Abu Dhabi analyzed saliva from 628 Emirati adults, including 97 with obesity and 95 healthy-weight controls matched for age, sex, lifestyle, oral health, and brushing habits. The study, published in Cell Reports, revealed that individuals with obesity harbor elevated levels of inflammation-promoting bacteria such as Streptococcus parasanguinis, Actinomyces oris, and Oribacterium sinus, the latter producing lactate linked to poor metabolism.
Further analysis uncovered 94 variations in microbial metabolic pathways. Those with obesity showed enhanced carbohydrate breakdown and histidine metabolism but reduced production of B vitamins and heme, essential for oxygen transport. Key metabolites like lactate, histidine derivatives, choline, uridine, and uracil were more abundant, correlating with elevated triglycerides, liver enzymes, and blood glucose—markers of metabolic issues.
"The oral microbiome is the second largest microbial ecosystem in the human body, so we decided to study whether it is associated with systemic diseases," Jha explained. Lindsey Edwards of King's College London noted, "This study provides some of the clearest evidence to date that the oral microbiome reflects, and may contribute to, metabolic changes associated with obesity."
The oral cavity, with over 700 bacterial species, may influence systemic health via blood vessels that could shuttle metabolites directly into the bloodstream, Jha hypothesizes. Future research will examine microbe and metabolite transfer to the gut to clarify if oral changes drive or result from obesity. Potential interventions include microbe-transfer gels, prebiotics, targeted antimicrobials, pH-balancing rinses, and dietary sugar reduction. Even as an effect, this signature could enable simple saliva tests for early obesity detection.
