Effects of Choline From Eggs vs. Supplements on the Generation of TMAO in Humans

Overview

The investigators are interested in learning more about choline, a nutrient required by the body. The body does make some choline, but it does not make enough to support health and the rest must be acquired through diet. Eggs, and especially egg yolks, are a major dietary source of choline. Choline can also be given as a dietary supplement. Ingestion of choline supplements has been linked to an increased concentration of a compound called TMAO (trimethylamine N-oxide). Elevated TMAO levels have been linked to higher heart disease risk. With this study, the investigators hope to learn whether there is a difference in the way your body responds to the ingestion of a choline supplement versus the choline found within eggs.

The principal goal for the study is to examine whether there is a difference between the ingestion of choline through supplements versus choline found within eggs on plasma TMAO levels. The investigators have previously shown that dietary intake of trimethylamines, including the choline group of phosphatidylcholine (PC), is mechanistically linked to cardiovascular disease risk and that the metabolism of these trimethylamine nutrients in humans is modulated by the intestinal microbes (gut microbes). Additionally, extensive animal studies link an essential role of gut microbiota to the metabolism of choline and the production of metabolites that promote / accelerate atherosclerotic processes. The investigators have also recently shown a 10-fold increase in plasma TMAO levels following supplementation with choline bitartrate supplements. However, another pilot study by a collaborator (unpublished) did not show the same increase in plasma TMAO levels following the ingestion of whole eggs, a major dietary source of choline. Therefore, with this study the investigators wish to examine the differences, if any, between the ingestion of an equivalent mass of total choline in the free form (as bitartrate salt) as a supplement vs. within whole eggs. Eggs, and specifically the egg yolk, contain a large amount of total choline. However, egg white contains potential anti-microbial peptides that could influence gut microbial composition and function, and therefore impact conversion of choline into TMA and TMAO observed in subjects. Therefore, the investigators hypothesize that the consumption of whole eggs (hardboiled) will not elevate plasma TMAO levels to the same extent as a comparable amount of total choline ingested in capsule form as the choline bitartrate salt. The investigators further hypothesize that the consumption of egg white with choline bitartrate tablets may result in less of a rise in TMAO levels than ingestion of the choline bitartrate supplement alone.