My takeaway is that the widespread measure of serum 25(OH)D represents the total Vitamin D reserve store while the rarely measured 1,25(OH)2D [2 in 2D should be

My takeaway is that the widespread measure of serum 25(OH)D represents the total Vitamin D reserve store while the rarely measured 1,25(OH)2D [2 in 2D should be subscript] represents the actual active level. It is low 1,25(OH)2D or a reduced ability to convert storage to active that is associated with a less diverse gut microbiome. We may be over supplementing. To use a car analogy, our gas tank is overflowing and we are obsessed with the gauge reading Full while the gauge reading Empty is the critical measure. What we need is a measure of how fast our 25(OH)D is depleted and what level represents an empty tank.