A Randomized, Double-Blind, Placebo-Controlled Study on Probiotic Treatment for Halitosis: Novel Insights into Glucose and Phosphorus Metabolism

Background Halitosis, or bad breath, is associated with oral microbial imbalances and the production of volatile sulfur compounds (VSCs). While existing treatments target pathogenic bacteria or oral health indicators, they may not address the underlying systemic complexity. This study explored the efficacy of Complex OK oral probiotics containing Lactobacillus gasseri HHuMIN D and Lactobacillus paracasei OK in mitigating halitosis by evaluating VSC levels and metabolic markers. Results A 12-week, randomized, double-blind, placebo-controlled clinical trial was conducted involving 80 participants, 70 of whom completed the study. Significant reductions in hydrogen sulfide (H₂S) and total VSCs were observed in the experimental group compared to the placebo group, with reductions in H₂S levels statistically significant at both Week 4 and Week 12. Despite the absence of significant changes in oral health indicators such as the Tongue Plaque Index (TPI), Gingival Index (GI), Plaque Index (PI), and Patient Hygiene Performance (PHP) Index, as well as levels of harmful oral bacteria, the probiotic supplementation demonstrated its efficacy in maintaining oral microbial balance. Systemic metabolic effects were also observed, including a significant decrease in blood glucose levels and an increase in blood phosphorus levels in the experimental group. These systemic effects suggest that probiotics modulated metabolic pathways to contribute to VSC reduction beyond local oral microbial effects. Conclusions These findings suggest that Complex OK reduces halitosis through systemic pathways involving enhanced glucose and phosphorus metabolism, rather than direct bacterial inhibition. The probiotic complex's ability to influence VSCs originating in the gastrointestinal tract is particularly significant. This study provides the first evidence linking systemic metabolic regulation to halitosis reduction, offering a novel and sustainable approach for halitosis management.