Studies

Adequate vitamin D is important for normal bone health, and low vitamin D status is consistently associated with poorer health and higher mortality in observational research. Those associations do not establish that supplementation prevents the linked conditions: illness and other health factors may also influence vitamin D levels.

Trials in generally healthy adults have not consistently shown improvements in well-being, physical function or prevention of cardiovascular disease and cancer. Mortality results vary between reviews, with possible benefits reported in older populations or for cancer-related deaths, but no reliable overall benefit across all adults. Disease-specific findings are also mixed and cannot establish a general health boost. Evidence supporting selected life stages or clinical groups remains distinct from routine supplementation in people without an established need.

The preparation and treatment setting matter. Findings with vitamin D metabolites or combined supplements cannot automatically be applied to ordinary vitamin D alone. Some supplementation regimens have worsened selected strength or mobility measures, while vitamin D combined with calcium has increased kidney-stone risk. These results reinforce that raising vitamin D levels does not guarantee better health.

115 linked studies · 32 sampled for detail · Sep 27, 2026