Investigating the Salivary Biomarker Profile in Obesity: A Systematic Review

This systematic review aims to map the existing literature on salivary biomarkers in adults with metabolically unhealthy obesity (MUO), identify key biomarkers associated with this high-risk group, and highlight areas requiring further research to advance this emerging field.

Obesity is characterized by an abnormal accumulation of body fat and chronic inflammation. However, not all individuals with obesity experience metabolic dysfunction. This review focuses on MUO, which is strongly linked to metabolic disorders such as insulin resistance, cardiovascular disease, type 2 diabetes, and systemic inflammation. Linking MUO and salivary biomarkers may enhance our understanding of how systemic health influences salivary composition and could enable the early identification of high-risk individuals through non-invasive saliva testing. This review synthesized findings from recent studies and identified key salivary biomarkers consistently elevated in individuals with MUO, including 8-OHdG, IL-6, IL-8, resistin, TNFR1, PTX-3, AEA, OEA, TNF-α, and sICAM-1. These biomarkers are associated with inflammation, oxidative stress, and metabolic dysregulation. The majority of studies utilized cross-sectional designs and used various saliva collection methods. Salivary biomarkers hold promise as non-invasive indicators of obesity-related metabolic dysfunction, particularly in MUO. However, their clinical diagnostic utility remains uncertain due to heterogeneity in study designs, a lack of biomarker validation, and limited longitudinal studies. Further research is needed to establish their bona fide diagnostic potential.