Vitamin D₃ from Ultraviolet-B Exposure or Oral Intake in Relation to Cancer Incidence and Mortality

Purpose of Review: This review summarizes the understanding of vitamin D₃’s role in reducing risk of cancer incidence and mortality. Recent Findings: Recent randomized clinical trials and observational studies of participants who took part in vitamin D₃ supplementation studies provide increasing evidence that concentrations of serum 25-hydroxyvitamin D₃ [25(OH)D₃] up to ~ 60 ng/ml are inversely correlated with all cancer and some specific cancers’ incidence and death, with a stronger effect on survival and death than on incidence. Mechanisms linking vitamin D₃ to effects on cellular proliferation, anti-angiogenesis, and anti-metastasis continue to be found. Summary: Vitamin D₃ reduces cancer risk causally. Maintaining 25(OH)D₃ in the range of 40–60 ng/ml reduces the risk of many cancers. Raising 25(OH)D₃ concentrations after diagnosis to that range increases survival rates and could significantly reduce the global burden of cancer incidence and death.