Participants will consume 1000 mg (2x500 mg) of choline bitartrate the evening before each testing session.

Participants will consume 1000 mg (2x500 mg) of placebo the evening before each testing session.

Participants will consume 1000 mg (2x500 mg) of choline bitartrate (over-the-counter supplement) between 10PM and 12AM the evening before the scheduled testing session and arrive fasted to the laboratory. There will be 2 testing sessions separated by 1 week.

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 two times separated by about 1 week. The participant will be randomly-assigned to a supplement (choline or placebo) followed by a 1-week washout period (crossover design). The supplement will be taken with water between 10PM and 12AM the evening before the scheduled testing session. 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.).

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 two times separated by about 1 week. The participant will be randomly-assigned to a supplement (choline or placebo) followed by a 1-week washout period (crossover design). The supplement will be taken with water between 10PM and 12AM the evening before the scheduled testing session.