NHLBI funded an ancillary study of DASH entitled, Folic Acid Dose Response. The purpose of the study was to determine the dose-response relationship between dietary folic acid intake and plasma folate and homocysteine. A total of 133 healthy people aged 60 years or older were enrolled. Participants were assigned to either 0, 100, 400, 1000, or 2000 micrograms of folic acid for 6 weeks. Study participants were newly recruited and were not DASH participants.