 Eligible participants will be assigned by chance like a coin toss to one of four groups: 1 daily cocoa extract and multivitamin; 2 daily cocoa extract and multivitamin placebo; 3 daily cocoa extract placebo and multivitamin; or 4 daily cocoa extract placebo and multivitamin placebo. Participants have an equal chance of being assigned to any of these four groups and a 3 out of 4 chance of getting at least one active agent. 