Fig. 1: Microbial AAA metabolism is associated with human body fat accumulation.
a, Diagram of the human cohort (created in BioRender: https://BioRender.com/x34z513). LC–MS, liquid chromatography-tandem mass spectrometry. b, The association of different microbial metabolites in human serum samples (n = 839) with body fat accumulation was assessed and ranked on the basis of beta coefficients. Top-ranked metabolites are shown. AAA-related metabolites are marked in red, and cholic-acid-related metabolites are shown in purple. c,d, Scatter plots showing the association of serum 4HPAA levels with whole-body fat accumulation (c) and the concentration of blood total cholesterol (TC) (d). Multivariable linear regression was used, adjusted for age, sex, body mass index (BMI), smoking status, alcohol status, physical activity, education, income and total energy intake. Regression (β) coefficients with 95% confidence intervals and P values were calculated. All statistical tests were two-sided. e, Schematic of the related microbial Phe and Tyr metabolic pathways in this study. Host and microbial pathways are indicated in black and blue arrows, respectively. Metabolites associated with body fat accumulation in the cohort are highlighted in red. PLA, phenyllactic acid; PPA, phenylpyruvic acid; PP, phenylpropionic acid; PAA, phenylacetic acid; 4HPPA, 4-hydroxyphenylpyruvic acid; 4HPLA, 4-hydroxyphenyllactic acid.
