Vitamin D (Like Every Nutrient) is a Team Player.

Vitamin D is critical for many physiological functions in humans. Numerous population-wide assessments have shown that vitamin D deficiency is very common. Unfortunately, far too many studies intending to assess the clinical efficacy of supplementation are poorly designed. They look at vitamin D as an isolated agent, independent of the complex matrix required for it to be physiologically effective and at dosages inadequate for much of the population. These errors cause inappropriate and invalid results that are then misused to not only recommend against supplementation but to also recommend against even measuring vitamin D levels. This editorial addresses the weaknesses of typical vitamin D research, such as VITAL, and the key factors that must be addressed for accurate vitamin D research.