Short Term Choline and Cardiovascular Health

• Choline (Dietary supplement): 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.
• Placebo (Dietary 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.

Primary outcomes

• Change in brachial artery function after supplementation [30-minute measurement in laboratory]: 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.).

Secondary outcomes

• Change in arterial stiffness after supplementation [45-minute measurement in laboratory]: 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).
• Change in gut-mediated TMAO levels after supplementation [5-minute measurement in laboratory]: 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.

Sex: All, ages: 18 Years to 65 Years, accepts healthy volunteers

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

• Kevin Davy, PhD, Principal investigator, Virginia Polytechnic Institute and State University