Inclusion Criteria1. Patients, both male and female, >18 years old
2. Undergone angiography for a MI (troponin positive [>0.04 ng/mL] and ACS diagnosis) within the past month
3. Receive follow-up care at an Intermountain Healthcare facility
4. Not taking or taking <1000 IU of vitamin D daily within the last 3 months
5. Willing to provide informed consent and participate in follow-up visits
Exclusion Criteria1. Hypersensitivity to vitamin D products
2. History of previous vitamin D supplementation of >1000 IU daily within the past 3 months (i.e., >40% of the days during the past 3 months).
3. Systemic disease (including terminal cancer, cirrhosis, end stage COPD, etc) with a reduced (<12 months) life expectancy
4. Hypercalcemia (calcium levels >10.6 mg/dL)
5. Subject participation in previous investigational interventional studies within 30 days of the current study.
6. History of psychiatric illness/condition that would interfere with their ability to understand or complete the requirements of the study, a condition that in the opinion of the investigator or their designee places the subject at an unacceptable risk as a participant.
7. Pregnant and/or lactating women and women of child bearing potential who are not using acceptable means of contraception as determined by the clinical investigators.