Short Term Choline and Cardiovascular Health

Virginia Polytechnic Institute and State University20 enrolled

Overview

Trimethylamine-N-oxide (TMAO), a metabolite produced by gut microbial metabolism of dietary choline, has recently been causally linked to atherosclerosis in animal models and has been shown to be predictive of cardiovascular disease (CVD) risk in some but not all cohort studies. The relevance of observations in animals to humans is unclear and little information is available on the mechanisms linking TMAO to increased CVD risk. Vascular dysfunction plays a critical role in the initiation and progression of atherothrombotic disease. Whether TMAO impairs vascular function in humans is not known. The purpose of this study is to determine if short term supplementation of dietary choline, which increase TMAO, impairs vascular function.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

DOUBLE

Enrollment

Conditions

Cardiovascular Risk Factor

Interventions

Participants will consume 1000 mg (2x500 mg) of choline bitartrate (over-the-counter supplement) for 28 consecutive days. At baseline, some participants will also be randomly assigned to consume 1000 mg of choline bitartrate the evening before the third testing session to study its acute effects.

PlaceboDIETARY_SUPPLEMENT

Participants will consume 1000 mg (2x500 mg) of placebo for 28 consecutive days. At baseline, some participants will also be randomly assigned to consume 1000 mg of placebo the evening before the third testing session to study its acute effects.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * 18-65 years old, healthy, non-smoking weight stable for previous 6 months (±2.0 kg), BMI\<35 kg/m\^2, verbal and written informed consent, approved for participation by study medical director (Jose Rivero, M.D.) Exclusion Criteria: * Smoking, pregnancy, obese (BMI\>35 kg/m\^2), altered dietary patterns within the last month of recruitment, vegetarians, vegans, unstable heart disease or diabetes, untreated high blood pressure or high cholesterol, allergies to choline supplement, taking any medications that could affect the results (ex., aspirin, antibiotics, pre/probiotics 1 month prior to enrollment), those with trimethylaminuria

Outcomes

Primary Outcomes

Change in brachial artery function after supplementation

Brachial artery function or flow mediated dilation (FMD), the blood flow and diameter of the brachial artery in the forearm (fMD), will be measured using a duplex ultrasound machine before and after the inflation of a blood pressure cuff on the forearm for 5 minutes and after placing a nitroglycerine tablet (0.4 mg) under the participant's tongue. This test will be conducted once at baseline and then once after each 5-day period of the randomly-assigned supplement (choline or placebo), including a 1-week washout period (crossover design). Off-line analysis of baseline and post-reactive hyperemic diameters and velocities will be performed using edge detection software (Vascular Analysis Tools, Medical Imaging Applications, Inc.).

Time frame: 30-minute measurement in laboratory

Secondary Outcomes

Change in arterial stiffness after supplementation

The blood flow and diameter in the common arteries in the neck will be measured from the image obtained from an ultrasound unit (GE Vivid S6) equipped with a high resolution linear array transducer. For applanation tonometry, the carotid, brachial, radial and femoral artery pressure waveform and amplitude will be obtained by a fingertip probe incorporating a high-fidelity strain gauge transducer. Each of these measures are used to calculate arterial stiffness. These tests will be conducted once at baseline and then once after each 5-day period of the randomly-assigned supplement (choline or placebo), including a 1-week washout period (crossover design).

Time frame: 45-minute measurement in laboratory

Change in gut-mediated TMAO levels after supplementation

At baseline, a fasting blood sample will be collected to measure plasma TMAO concentration after supplementation consumption 8 hours prior to the third testing session.

Time frame: 5-minute measurement in laboratory