Choline and one-carbon metabolite response to egg, beef and fish among healthy young men: A short-term randomized clinical study

Background Homeostatic mechanisms that regulate long-term circulating concentrations of choline and one-carbon metabolites can obscure the relationship between diet and nutritional response. As such, we sought to determine the acute response of one-carbon metabolites to animal source foods enriched in one-carbon nutrients. Methods As part of a crossover feeding trial with one-week washout intervals, healthy young men (n = 40) were randomized to animal food sources of choline (eggs, beef and fish) and a fruit control. A panel of one-carbon metabolites was measured in blood and urine samples collected at baseline and throughout the 6-h study period. Results Consumption of the test foods yielded 1.1–2.7 times higher (P < 0.0001) maximum peak circulating concentrations of choline, betaine, dimethylglycine (DMG) and methionine relative to the fruit control. Similarly, urinary excretion was 1.5–2.6 times higher (P < 0.0001) for these same metabolites across the 6-h study period. Of the test foods, eggs had the greatest effects on plasma choline and betaine, while fish had the greatest effects on plasma methionine. Nutritional response across the study period was modified by time with a delay in peak plasma concentrations of choline and betaine after egg consumption. In addition, the FMO3 G472A genotype (rs 2266782) modified plasma DMG, urinary trimethylamine-N-oxide and urinary methionine responses to the test foods (P