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

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

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.

Study Overview

• Status: Completed
• Conditions: Cardiovascular Risk Factor
• Intervention / Treatment: Other: Pre-cooked, pre-peeled whole hardboiled eggs; Dietary supplement: Choline Bitartrate; Other: Egg whites from pre-cooked, pre-peeled hardboiled eggs; Dietary supplement: Phosphatidylcholine capsules

Detailed Description

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 However, another pilot study by a collaborator (unpublished) did not show the same increase in plasma TMAO levels following the ingestion of whole eggs, a major dietary source of choline.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.

• Study Type: Interventional
• Enrollment (Actual): 86
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Ohio
    • Cleveland, Ohio, United States, 44195
      • Cleveland Clinic Foundation

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Men and women age 18 years or above.
• Willing to remain on aspirin or stay off aspirin or aspirin products for 1 week prior to starting the study and throughout the study period.
• Able to provide informed consent and comply with study protocol.
• Able to be off all other supplements during the study period.

Exclusion Criteria:

• Significant chronic illness.
• Active infection or received antibiotics within 1 month of study enrollment.
• Use of over-the-counter probiotic within the past month
• Chronic gastrointestinal disorders, such as ulcerative colitis or Crohn's disease.
• Allergy to eggs or lactose.
• Having undergone bariatric procedures or surgeries such as gastric banding or bypass.
• Pregnancy.
• Any condition that, in the judgment of the Investigator, would place a patient at undue risk by being enrolled in the trial or cause inability to comply with the trial.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Whole Hardboiled Eggs; Subjects will consume four (4) pre-cooked, pre-peeled whole hardboiled eggs per day for 28 days.	Other: Pre-cooked, pre-peeled whole hardboiled eggs; Obtained from a commercial source.
Experimental: Choline Bitartrate Tablets; Subjects will consume two (2) 500mg choline bitartrate tablets per day for 28 days.	Dietary supplement: Choline Bitartrate; 500mg choline bitartrate tablets
Experimental: Hardboiled Eggs + Choline Bitartrate Tablets; Subjects will consume both four (4) whole, pre-cooked, pre-peeled hardboiled eggs and two (2) 500mg choline bitartrate tablets per day for 28 days.	Other: Pre-cooked, pre-peeled whole hardboiled eggs; Obtained from a commercial source.; Dietary supplement: Choline Bitartrate; 500mg choline bitartrate tablets
Experimental: Egg Whites + Choline Bitartrate Tablets; Subjects will consume both the egg whites (no yolks) of four (4) pre-cooked, pre-peeled hardboiled eggs and two (2) 500mg choline bitartrate tablets per day for 28 days.	Dietary supplement: Choline Bitartrate; 500mg choline bitartrate tablets; Other: Egg whites from pre-cooked, pre-peeled hardboiled eggs; Egg whites from pre-cooked, pre-peeled hardboiled eggs. The yolks are removed and discarded.
Experimental: Phosphatidylcholine Capsules; Subjects will consume six (6) 420 mg phosphatidylcholine capsules by mouth per day for 28 days.	Dietary supplement: Phosphatidylcholine capsules; 420 mg phosphatidylcholine capsules obtained from a commercial source.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in Plasma Levels of Fasting Trimethylamine-N-oxide (TMAO), a Choline Metabolite	Changes in levels of non-labeled TMAO from baseline to end-of-study (day 28) as measured by established techniques by mass spectrometry.	Baseline, 28 days
Changes in Platelet Function With Increased Choline Intake	The activation and functioning of platelets within a single subject will be compared before and after increased choline intake.	Baseline, Day 28

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in Levels of Fasting Trimethylamine-N-oxide (TMAO) in 24-hour Urine Collections	Changes in levels of non-labeled TMAO from baseline to Day 28 measured by established mass spectrometry techniques.	Baseline, Day 28
Changes in Plasma Levels of Fasting Choline	Fasting plasma levels of choline from samples obtained at baseline and at day 28 were compared.	Baseline, Day 28
Changes in Plasma Levels of Fasting Carnitine.	Fasting plasma levels of carnitine from samples obtained at baseline and at day 28 were compared.	Baseline, Day 28
Changes in Plasma Levels of Fasting Betaine.	Fasting plasma levels of betaine from samples obtained at baseline and at day 28 were compared.	Baseline, Day 28
Changes in Lipid Profile, Total Cholesterol	Changes in total cholesterol levels between baseline and Day 28	Baseline, Day 28
Changes in Lipid Profile, HDL	Changes in measured HDL levels between baseline and Day 28	Baseline, Day 28
Changes in Lipid Profile, LDL	Changes in measured LDL levels between baseline and Day 28	Baseline, Day 28
Changes in Lipid Profile, Triglycerides	Changes in measured triglyceride levels between baseline and Day 28	Baseline, Day 28

Collaborators and Investigators

• Sponsor: The Cleveland Clinic
• Investigators: Principal Investigator: W. H. Wilson Tang, MD, The Cleveland Clinic

Publications and helpful links

General Publications

• Wang Z, Klipfell E, Bennett BJ, Koeth R, Levison BS, Dugar B, Feldstein AE, Britt EB, Fu X, Chung YM, Wu Y, Schauer P, Smith JD, Allayee H, Tang WH, DiDonato JA, Lusis AJ, Hazen SL. Gut flora metabolism of phosphatidylcholine promotes cardiovascular disease. Nature. 2011 Apr 7;472(7341):57-63. doi: 10.1038/nature09922.
• Rebouche CJ, Chenard CA. Metabolic fate of dietary carnitine in human adults: identification and quantification of urinary and fecal metabolites. J Nutr. 1991 Apr;121(4):539-46. doi: 10.1093/jn/121.4.539.
• Bidulescu A, Chambless LE, Siega-Riz AM, Zeisel SH, Heiss G. Repeatability and measurement error in the assessment of choline and betaine dietary intake: the Atherosclerosis Risk in Communities (ARIC) study. Nutr J. 2009 Feb 20;8:14. doi: 10.1186/1475-2891-8-14.
• Wilcox J, Skye SM, Graham B, Zabell A, Li XS, Li L, Shelkay S, Fu X, Neale S, O'Laughlin C, Peterson K, Hazen SL, Tang WHW. Dietary Choline Supplements, but Not Eggs, Raise Fasting TMAO Levels in Participants with Normal Renal Function: A Randomized Clinical Trial. Am J Med. 2021 Sep;134(9):1160-1169.e3. doi: 10.1016/j.amjmed.2021.03.016. Epub 2021 Apr 17.

Helpful Links

• Patterson K, Bhagwat S, Williams J, Howe J, and Holden J. USDA Database for the Choline Content of Common Foods, Release Two. January 2008.

Study record dates

Study Major Dates

• Study Start (Actual): September 2, 2016
• Primary Completion (Actual): April 10, 2018
• Study Completion (Actual): September 3, 2020

Study Registration Dates

• First Submitted: January 19, 2017
• First Submitted That Met QC Criteria: January 30, 2017
• First Posted (Estimated): February 1, 2017

Study Record Updates

• Last Update Posted (Estimated): November 4, 2025
• Last Update Submitted That Met QC Criteria: October 14, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: healthy volunteers; eggs; choline; TMAO; gastrointestinal microbiome
• Additional Relevant MeSH Terms: Organic Chemicals; Lipids; Amines; Alcohols; Amino Alcohols; Ethanolamines; Quaternary Ammonium Compounds; Onium Compounds; Trimethyl Ammonium Compounds; Membrane Lipids; Glycerophospholipids; Phosphatidic Acids; Glycerophosphates; Phospholipids; Choline; Phosphatidylcholines
• Other Study ID Numbers: 16-1048

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No