Couldn't find any reference to the work of this German doctor and thought it was worth posting the link http://www.iacfsme.org/Portals/0/pdf/Attachment E Annedore Hoeck, Vitamin D.pdf
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D is one of those that I was deficient in (10) but I can't say I feel any better since getting it to around 50. Others however do feel better. But yeah, there is something going on there like mell said when so few of us are ever in the high range per-supplement.