Impact of red meat consumption on the metabolome of rats

Scope The scope of the present study was to investigate the effects of red versus white meat intake on the metabolome of rats. Methods and results Twenty‐four male Sprague–Dawley rats were randomly assigned to 15 days of ad libitum feeding of one of four experimental diets: (i) lean chicken, (ii) chicken with lard, (iii) lean beef, and (iv) beef with lard. Urine, feces, plasma, and colon tissue samples were analyzed using 1H NMR‐based metabolomics and real‐time PCR was performed on colon tissue to examine the expression of specific genes. Urinary excretion of acetate and anserine was higher after chicken intake, while carnosine, fumarate, and trimethylamine N‐oxide excretion were higher after beef intake. In colon tissue, higher choline levels and lower lipid levels were found after intake of chicken compared to beef. Expression of the apc gene was higher in response to the lean chicken and beef with lard diets. Correlation analysis revealed that intestinal apc gene expression was correlated with fecal lactate content (R2 = 0.65). Conclusion This study is the first to identify specific differences in the metabolome related to the intake of red and white meat. These differences may reflect perturbations in endogenous metabolism that can be linked to the proposed harmful effects associated with intake of red meat. In order to investigate the endogenous metabolic differences between consuming red meat and white meat, diets were formulated with either beef or chicken meat as the meat source and fed to healthy rats. Metabolomics analyses revealed that chicken diets resulted in a higher urinary excretion of anserine and 1‐methylhistidine, two metabolites originating from the chicken muscle tissue. Beef intake increased the urinary excretion of carnosine, fumarate, carnitine, trimethylamine (TMA) and trimethylamine N‐oxide (TMAO) levels. These metabolites from beef need further investigation, as some studies have suggested a connection between TMAO and cardiovascular disease.