Amin A, et al. - In this prospective study, researchers investigated if biochemical findings and functional capacity of patients with heart failure (HF) could be improved with vitamin D supplementation. They included 100 patients with New York Heart Association (NYHA) class I through III HF. They assessed 25-hydroxyvitamin D levels of all participants. For 4 months, oral vitamin D₃ (cholecalciferol) was administered to patients with insufficient or deficient serum levels of 25(OH) D (<30 ng/mL and <20 ng/mL, respectively). A marked attenuation in serum level of pro-brain natriuretic peptide and high-sensitivity C-reactive protein was found following vitamin D supplementation. A substantial improvement in NYHA class and 6-minute walk distance was evident in relation to restoration of serum 25(OH) D level.