Participants will be asked to consume 1000 mg of choline bitartrate for 4 weeks prior to and during the testing period.

Participants will be asked to consume 1000 mg of placebo (maltodextrin) for 4 weeks prior to and during the testing period.

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.

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.).

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).