PRIMARY OBJECTIVES: I. To assess patients with regards to changes in 25(OH)-D3 changes after supplementation. II. To develop a pharmacokinetic model to describe the time course of the relationship of vitamin D3 (cholecalciferol) supplementation that drives the levels of 25(OH)-D3 during the intensive induction chemotherapy. III. To determine the safety and toxicity of vitamin D3 supplementation in AML patients undergoing intensive induction chemotherapy. SECONDARY OBJECTIVES: I. To explore whether rapid (loading dose of vitamin D3) normalization of 25(OH)-D3 levels will have an effect on the progression free and overall survival. II. To explore whether a relationship exists between the pharmacokinetics of the 25-hydroxy-vitamin D3 and white blood cell count. OUTLINE: Patients with pretreatment 25(OH)-D3 levels 20-31.9 ng/mL (insufficient levels) are randomized to 1 of 2 treatment arms. ARM I: Patients receive a loading dose of cholecalciferol orally (PO) on day 1. Patients then receive lower-dose cholecalciferol PO beginning on day 8. ARM II: Patients receive a loading dose of cholecalciferol PO on day 1. Patients then receive higher-dose cholecalciferol PO beginning on day 8. Patients with pretreatment 25(OH)-D3 levels < 20 ng/mL (deficient levels) receive a loading dose of cholecalciferol PO on days 1 and 8. Patients then receive lower-dose cholecalciferol PO beginning on day 15. For all patients, treatment continues in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 30 days.