Vitamin D: Mechanism of Action and Biological Effects in Uterine Fibroids.

Uterine fibroids (UFs) are the most common benign gynecological tumors. It was estimated that fifty percent of women presenting with UFs has symptomatology that negatively influences their quality of life. Pharmacological and/or surgical treatments are frequently required, depending on the woman's desire to preserve fertility, with a high impact on healthcare costs. Generally, the use of currently available pharmacological treatments may lead to side effects. Therefore, there is a growing interest in a natural and safe approach for UFs. In recent years, epidemiological studies reported a vitamin D deficiency in patients with UFs raised interest in the potential biological effects of vitamin D supplementation. In vitro studies proved vitamin D efficacy in inhibiting UFs growth by targeting pathways involved in the regulation of various biological processes, including proliferation, extracellular matrix (ECM) remodeling, DNA repair, signaling and apoptosis. However, clinical studies supported only in part the beneficial effects of vitamin D supplementation in reducing UFs growth and tumor volume. Randomized controlled trials and large population studies are mandatory as the potential clinical benefits are likely to be substantial.