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nightsurfer on 2009-03-29Why is it that vitamin D deficiency can manifest in so many different ways in different people? One big reason is something called vitamin D receptor (VDR) genotypes, the variation in the receptor for vitamin D.
Why is it that the dose of vitamin D necessary to reach a specific level differs so widely from one person to the next? VDR genotype, again. Variation in blood levels of 25-hydroxy vitamin D from a specific dose of vitamin D can vary three-fold, as shown by a University of Toronto study. In other words, a dose of 4000 units per day may yield a 25-hydroxy vitamin D blood level of 30 ng/ml in Mary, 60 ng/ml in Paul, and 90 ng/ml in Pete--same dose, different blood levels.