Vitamin D supplementation in cancer prevention and the management of cancer therapy

Vitamin D is an important steroid hormone that exerts immunomodulatory actions, controls calcium and phosphate homeostasis, and significantly affects human health. Vitamin D deficiency is a global health problem, affecting approximately 60% of adults worldwide, and has been implicated in a range of different types of diseases, e.g., cancer. Vitamin D is involved in the regulation of cell proliferation, differentiation, energetic metabolism, and different types of cell death (e.g., apoptosis, autophagy, etc.). In physiological conditions, it is also able to modulate immune responses, angiogenesis, etc., which belongs to fundamental cancer-related processes. Vitamin D deficiency has been associated with an increased risk of some types of cancer, e.g., colorectal, breast, ovarian, prostate, pancreatic, etc. The role of vitamin D in cancer prevention, carcinogenesis, and cancer treatment is still under investigation and depends on the type of cancer. This review summarizes the role of vitamin D in all three above-mentioned aspects and discusses the mechanism of action and potential possibilities in cancer treatment.