MASLD can cause halitosis by small intestinal bacterial overgrowth

Objectives Patients with metabolic dysfunction‐associated steatotic liver disease (MASLD) exhibit varying degrees of halitosis. The author speculated that small intestinal bacterial overgrowth (SIBO) might lead to MASLD and subsequent extra‐oral halitosis and aimed to test this hypothesis. Methods This retrospective cross‐sectional study reviewed 885 extra‐oral halitosis patients. Halitosis and exhaled dimethyl sulfide (DMS) were measured by organoleptic score (OLS) (0–5) and OralChroma, respectively. SIBO and MASLD were diagnosed by hydrogen breath test and Fibroscan combined with cardiometabolic criteria. Results In this study, 133/885 (15.05%) of the halitosis patients otherwise healthy had MASLD, while 87/133 (65.41%) of the MASLD patients were SIBO‐positive. No significant differences were observed in physical parameters such as age, serum biochemical parameters such as lipids, or Fibroscan parameters between the SIBO‐positive and SIBO‐negative patients. However, the OLS was 4 (interquartile range: 3–4) and exhaled DMS level was 56 (43–75) parts per billion (ppb) in the SIBO‐positive patients, significantly greater than 2 (2–3) and 43 (25–51) ppb in the SIBO‐negative patients (both p < 0.001). Exhaled hydrogen levels positively correlated with the OLS and exhaled DMS levels ( r = 0.774, r = 0.740, both p < 0.001). Conclusion MASLD can cause halitosis by SIBO.