This review article points out that the majority of patients with congestive heart failure have vitamin D insufficiency (serum 25-hydroxyvitamin D < 50 nmol/L or < 20 ng/ml). Vitamin D deficiency in these patients is presumably due in part to relatively low amounts of outdoor activity. Vitamin D deficiency may contribute to the pathogenesis of heart failure, or may exacerbate heart failure, by promoting the development of hypertension or by increasing parathyroid hormone levels, which is believed to contribute to the development of cardiovascular disease.
In recent years, evidence has accumulated that vitamin D deficiency is very common and may contribute to the development of muscle weakness and pain, some autoimmune diseases, osteoporosis, infections, and cancer. While vitamin D deficiency has not been proven to cause or exacerbate heart failure, it would be worthwhile to measure serum 25hydroxyvitamin D levels in patients with heart failure and to correct deficiencies either with supplementation or sunlight exposure. The amount of oral vitamin D required to optimize 25-hydroxyvitamin D levels might be higher in patients with heart failure than in healthy people, because heart failure is often accompanied by bowel wall edema, which could inhibit nutrient absorption.
Zittermann A, Schleithoff SS, Koerfer R. Vitamin D insufficiency in congestive heart failure: why and what to do about it? Heart Fail Rev. 2006;11:25-33.
Reprinted with exclusive permission from The Townsend Letter, Aug 2007.