Assessment of TMAO Formation With Egg Intake Versus Choline Supplement in a Healthy Population

Epidemiological data in short term studies, suggests that egg intake does not increase risk
for cardiovascular disease (CVD). In fact, eggs are a great source of phospholipids
(phosphatidylcholine) where choline has many metabolic roles, specially in lipid metabolism
and cell membrane structure. Choline is present in the diet as free choline, which is
absorbed in the small intestines, or choline esters, which is absorbed intact primarily
through the lymphatic system. In addition, recent evidence suggests that the choline found in
eggs may be metabolized by intestinal microbes into trimethylamine N-oxide (TMAO), a compound
that may increase the risk for CVD. However, it is not known to what extent egg intake may
contribute to plasma TMAO concentrations.

Therefore, the objective of this study is to determine the impacts of daily intake of 3 eggs
versus a choline supplement on plasma TMAO as well as other biomarkers for CVD risk, with the
goal of determining if the same amount of choline given as phosphatidylcholine from eggs will
increase plasma choline levels without a concomitant increase in plasma TMAO, such that CVD
risk is not negatively impacted.

Inclusion Criteria:

- Men and women (18-30 years), BMI 18.5 - 29.9 kg/m2, proficient in English, and willing
to consume 3 eggs per day or 397.5 mg of choline supplement (1½ tablets/day) for 4
weeks each.

Exclusion Criteria:

- Self-reported diabetes mellitus, cardiovascular disease, history of stroke, renal
problems, liver disease, cancer, or a diagnosed eating disorder

- Taking any glucose-lowering prescriptions or supplements, triglyceride-lowering
medications, bile acid sequestrants, or high dose chromium or cinnamon supplements

- Taken antibiotics in the previous 1 months, or if they are vegetarian or vegan

- BMI ≤ 18.4 or ≥ 30 kg/m2, or extreme clinical values, such as plasma triglycerides >
500 mg/dL, plasma glucose > 126 mg/dL, plasma cholesterol > 240 mg/dL, plasma
creatinine ≤ 0.5 or ≥ 0.9 mg/dL for females and ≤ 0.7 or ≥ 1.2 mg/dL for males, or
blood pressure > 140/90 mm Hg (average of 3 readings)

- Allergic to eggs or any component of the choline supplement