A randomized, double-blind, crossover, placebo-controlled clinical trial to assess effects of the single ingestion of a tablet containing lactoferrin, lactoperoxidase, and glucose oxidase on oral malodor

BACKGROUND: The main components of oral malodor have been identified as volatile sulfur compounds (VSCs) including hydrogen sulfide (H(2)S) and methyl mercaptan (CH(3)SH). VSCs also play an important role in the progression of periodontal disease. The aim of the present study was to assess the effects of the single ingestion of a tablet containing 20 mg of lactoferrin, 2.6 mg of lactoperoxidase, and 2.6 mg of glucose oxidase on VSCs in the mouth. METHOD: Subjects with VSCs greater than the olfactory threshold in their mouth air ingested a test or placebo tablet in two crossover phases. The concentrations of VSCs were monitored at baseline and 10 and 30 min after ingestion of the tablets using portable gas chromatography. RESULTS: Thirty-nine subjects were included in the efficacy analysis based on a full analysis set (FAS). The concentrations of total VSCs and H(2)S at 10 min were significantly lower in the test group than in the placebo group (−0.246 log ng/10 ml [95 % CI −0.395 to −0.098], P = 0.002; −0.349 log ng/10 ml; 95 % CI −0.506 to −0.192; P < 0.001, respectively). In the subgroup analysis, a significant difference in the concentration of total VSCs between the groups was also observed when subjects were fractionated by sex (male or female) and age (20–55 or 56–65 years). The reducing effect on total VSCs positively correlated with the probing pocket depth (P = 0.035). CONCLUSIONS: These results suggest that the ingestion of a tablet containing lactoferrin, lactoperoxidase, and glucose oxidase has suppressive effects on oral malodor. TRIAL REGISTRATION: This trial was registered with the University Hospital Medical Information Network Clinical Trial Registry (number: UMIN000015140, date of registration: 16/09/2014). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12903-016-0199-7) contains supplementary material, which is available to authorized users.