In D-fence of vitamin D sufficiency- A perspective.

Vitamin D is well-established in its essential role in maintaining bone health. In recent years, however, researchers have explored potential influences of vitamin D on extra-skeletal functions, with vitamin D deficiency being implicated in several acute and chronic illnesses. Thus, large-scale randomised controlled trials (RCTs) have investigated the impact of vitamin D supplements on conditions including cardiovascular disease, diabetes, sarcopenia, frailty, and even some cancers. In this perspective, we weigh the evidence from these recent trials, drawing a cohesive understanding of vitamin D's potentially diverse effects. Limitations of the field and possible future directions of vitamin D research are considered, along with a discussion of the utility of repetitive vitamin D testing and supplementation for many of these conditions.