FIGURE 1.

Concentration of TMAO in plasma. Six healthy volunteers (subjects) consumed a standardized low-choline diet on the day before each of 5 randomly assigned doses of 0, 1, 2, 4, or 6 egg yolks. Subjects consumed the egg dose for breakfast followed by the same standardized low-choline lunch, dinner, and snacks as consumed the previous day. Each egg dose delivered 1.14 mmol (119 mg) total choline. Therefore, the 0, 1, 2, 4, and 6 egg doses provided 0, 1.1, 2.3, 4.6, and 6.8 mmol (0, 119, 238, 476, and 714 mg) total choline, respectively, in addition to the standardized diet. TMAO was measured in plasma collected from each volunteer immediately before and 1, 2, 6, 8, and 24 h after the egg dose was consumed by using liquid chromatography and electrospray ionization–isotope dilution mass spectrometry. Doses were separated by a 2–4-wk washout period. Doses are represented as follows: 0, diamond with dotted line; 1, square with solid light-gray line; 2, triangle with solid-gray line; 4, circle with solid dark-gray line; and 6, asterisks with black solid line. TMAO, trimethylamine-N-oxide.