Effects of probiotic supplementation on serum trimethylamine-N-oxide level and gut microbiota composition in young males: a double-blinded randomized controlled trial

Purpose To explore whether probiotic supplementation could attenuate serum trimethylamine-N-oxide (TMAO) level and impact the intestinal microbiome composition. Design Forty healthy males (20–25 years old) were randomized into the probiotic group (1.32 × 10 11 CFU live bacteria including strains of Lactobacillus acidophilus , Lactobacillus rhamnosus GG, Bifidobacterium animalis, and Bifidobacterium longum daily) or the control group for 4 weeks. All participants underwent a phosphatidylcholine challenge test (PCCT) before and after the intervention. Serum TMAO and its precursors (TMA, choline and betaine) were measured by UPLC-MS/MS. The faecal microbiome was analyzed by 16S rRNA sequencing. Results Serum TMAO and its precursors were markedly increased after the PCCT. No statistical differences were observed in the probiotic and the control group in area under the curve (AUC) (14.79 ± 0.97 μmol/L 8 h vs. 19.17 ± 2.55 μmol/L 8 h, P = 0.106) and the pre- to post-intervention AUC alterations (∆AUC) (− 6.33 ± 2.00 μmol/L 8 h vs. − 0.73 ± 3.04 μmol/L 8 h, P = 0.131) of TMAO; however, higher proportion of participants in probiotic group showed their TMAO decrease after the intervention (78.9% vs. 45.0%, P = 0.029). The abundance of Faecalibacterium prausnitzii ( P = 0.043) and Prevotella ( P = 0.001) in the probiotic group was significantly increased after the intervention but without obvious differences in α - and β -diversity. Conclusions The current probiotic supplementation resulted in detectable change of intestinal microbiome composition but failed to attenuate the serum TMAO elevation after PCCT. Clinicaltrials.gov Identifier NCT03292978. Clinicaltrials.gov website https://clinicaltrials.gov/ct2/show/NCT03292978 .