Impact of chronic dietary red meat, white meat, or non-meat protein on trimethylamine N-oxide metabolism and renal excretion in healthy men and women.
Wang Z, Bergeron N, Levison BS, Li XS, Chiu S, Jia X, Koeth RA, Li L, Wu Y, Tang WHW, Krauss RM, Hazen SL
Eur Heart J. Feb 2019. doi: 10.1093/eurheartj/ehy799
COMMENT: This work is focused on Trimethylamine N-oxide (TMAO). TMAO is a metabolite generated by gut microbiome that has been linked to the pathogenesis of atherosclerotic heart disease. A randomized 2-arm (high- or low-saturated fat) crossover design study was carried out to analyze the impact of different diets (red meat, white meat, or non-meat) on TMAO levels. The diets were isocaloric and with the same percentage of proteins. Only the type of proteins was different. After analyzing the results of this study the authors conclude that dietary red meat increases systemic TMAO levels and discontinuation of dietary red meat reduces plasma TMAO within 4 weeks.
We performed randomized-controlled dietary intervention studies to explore the impact of chronic dietary patterns on TMAO levels, metabolism and renal excretion.
Volunteers (N= 113) were enrolled in a randomized 2-arm (high- or low-saturated fat) crossover design study. Within each arm, three 4-week isocaloric diets (with washout period between each) were evaluated (all meals prepared in metabolic kitchen with 25% calories from protein) to examine the effects of red meat, white meat, or non-meat protein on TMAO metabolism. Trimethylamine N-oxide and other trimethylamine (TMA) related metabolites were quantified at the end of each diet period.
... the present studies reveal that switching from a diet rich in red meat to either a white meat or non-meat protein source (yet maintaining same calories, and proportion of protein in the diet) can substantially reduce TMAO levels within several weeks
… beyond quantity, the quality of diet composition (with respect to protein source, but not saturated fat content) impacts overall TMAO metabolism and excretion
Chronic dietary red meat increases systemic TMAO levels through: (i) enhanced dietary precursors; (ii) increased microbial TMA/TMAO production from carnitine, but not choline; and (iii) reduced renal TMAO excretion. Discontinuation of dietary red meat reduces plasma TMAO within 4 weeks.