Adopting a Mediterranean-style eating pattern with low, but not moderate, unprocessed, lean red meat intake reduces fasting serum trimethylamine N-oxide (TMAO) in adults who are overweight or obese

Authors: KRISHNAN, SRIDEVI - University Of California, Davis; O'CONNOR, LAUREN - National Institutes Of Health (NIH); WANG, YU - Purdue University; Gertz, Erik; CAMPBELL, WAYNE - Purdue University; Bennett, Brian

Submitted to: British Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2021
Publication Date: 11/26/2021
Citation: Krishnan, S., O'Connor, L., Wang, Y., Gertz, E.R., Campbell, W.W., Bennett, B.J. 2021. Adopting a Mediterranean-style eating pattern with low, but not moderate, unprocessed, lean red meat intake reduces fasting serum trimethylamine N-oxide (TMAO) in adults who are overweight or obese. British Journal of Nutrition. https://doi.org/10.1017/S0007114521004694.
DOI: https://doi.org/10.1017/S0007114521004694

Interpretive Summary: Trimethylamine N-oxide (TMAO) is a gut-mediated metabolite associated with cardiovascular disease. Acute diet challenges demonstrate that circulating TMAO concentrations are diet-responsive; however, long-term trials investigating how different dietary patterns affect circulating TMAO concentrations are sparse. In the current study we examine the impact of 200g unprocessed lean red meat/wk and a Mediterranean diet pattern on circulating TMAO concentrations. This suggests that a Mediterranean diet pattern with low lean red meat is capable of reducing circulating TMAO concentrations in generally healthy subjects, and this may have implications for cardiometabolic disease risk.

Technical Abstract: A Mediterranean diet pattern recommends moderate red meat intake. However, it is unknown if the pro-atherogenic metabolite TMAO is affected by the amount of red meat consumed while on a Mediterranean diet. A single-blinded, randomized, controlled feeding (5wk), crossover trial (4wk washout) was done to determine if a Mediterranean diet pattern with 200g unprocessed lean red meat/wk (Med-Control) is capable of reducing TMAO compared to one with 500g unprocessed lean red meat/wk (Med-Red). Participants were 41 men (n=28) and women (n=13) who were either overweight or obese (BMI: 30.5 ± 0.3 kg/m2 mean ± SEM). Plasma samples were obtained following an overnight fast both before (pre) and after (post) each intervention. Fasting TMAO, choline, creatinine, carnitine and betaine were measured using a targeted LC-MS protocol. Data were analyzed to evaluate if (a) TMAO and related metabolites were different by intervention, and (b) if change in TMAO and related metabolites were associated with change in clinical risk surrogates (HOMA-IR, Framingham 10y risk score). Plasma TMAO was lower following Med-Control compared to Med-Red intervention (post Med-Control vs post Med-Red, p<0.001), and lower following Med-Control (pre vs post Med-Control, p = 0.025). Stepwise regression, and generalized linear regression models identified a positive association between TMAO and HOMA-IR (p = 0.036). This suggests that a Mediterranean diet pattern with low lean red meat is capable of reducing circulating TMAO concentrations in generally healthy subjects, and this may have implications for cardiometabolic disease risk.