Purpose of review: The goal of this review is to give some perspective on the results and conclusions of three recent randomized controlled vitamin D intervention studies that have challenged the health benefit of vitamin D supplementation for reducing risk for cardiovascular disease, cancer, all-cause mortality and type 2 diabetes and improving bone health.
Recent findings: Vitamin D supplementation to adults who were vitamin D sufficient or insufficient did not reduce risk for developing cardiovascular disease, cancer, type 2 diabetes nor increases bone mineral density (BMD). Patients who were vitamin D deficient with cancer and received vitamin D reduced risk for mortality by 25% and prediabetic adults who were vitamin D deficient and received vitamin D reduced their risk of developing type 2 diabetes by 62%. Older adults receiving 4000 and 10 000 IUs of vitamin D3 daily for 3 years had reduced radial BMD but had no change in either total hip areal bone density or bone strength in the radius and tibia.
Summary: Caution is needed when evaluating results and conclusions from randomized controlled trials that investigate health benefits of vitamin D; most studies suggest health benefits when vitamin D supplementation is provided to vitamin D deficient populations and little benefit when given to populations that are vitamin D sufficient/insufficient.