Abstract
Objectives
The microbial metabolite trimethylamine n-oxide (TMAO) is associated with cardiovascular and renal disease. The dietary factors contributing to plasma TMAO concentrations are not well characterized in a generally healthy population unmedicated for metabolic diseases. The objective of this study was to assess the relationships among TMAO-precursor foods, TMAO, and classic cardiometabolic markers in a generally healthy population stratified for age, sex, and BMI.
Methods
Fasting plasma TMAO was quantified using liquid chromatography-mass spectrometry in 356 participants (n = 188 female, 18–65 yr, 18–40 BMI) enrolled in the cross-sectional Nutritional Phenotyping Study conducted as the USDA Western Human Nutrition Center. Diet was assessed by averaging 2 weekday and 1 weekend ASA-24hr recalls cleaned by NCBI guidelines. Fasting plasma analytes such as glucose, insulin, triglycerides, and cholesterol were measured using the Cobas Integra 400 Plus. Variables were transformed to conform to the normal distribution. Regression models assessing health parameters and TMAO were adjusted for age, sex, and the kidney function marker, cystatin C. Models assessing TMAO and diet variables were adjusted for age, sex, and energy intake. Composite variables describing average intake of red meat and TMAO-precursor foods were created by summing the appropriate ASA24 variables.
Results
TMAO was associated with age (P = 0.001), but not sex or BMI. A significant interaction (P = 0.006) between sex and age was used in all models. Of the variables analyzed, only refined grains and total energy intake were significantly associated with TMAO (r = −0.11, P = 0.04; r = 0.12, P = 0.03, respectively). Reduced renal function as assessed by circulating cystatin C concentrations was associated with plasma TMAO (r = 0.18, P < 0.001). Average daily red meat consumption as well as average daily TMAO-precursor consumption was not significantly associated with TMAO (P = 0.137, P = 0.554, respectively). In contrast, average daily fiber intake was marginally related to TMAO (B = −0.11, SE = 0.01, P = 0.07).
Conclusions
In this generally healthy population, no relationship between red meat or TMAO-precursor foods and TMAO was identified.
Funding Sources
The Beef Checkoff (R01HL128572); USDA/ARS/Western Human Nutrition Research Center project funds (2032–51,000-025–00D).
Metabolomics and human nutrition
