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. 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.
Keywords: Cancer prevention; Mechanisms; Mendelian randomization; Randomized controlled trials; Vitamin D; Vitamin D deficiency.