What a crazy dance we do! I also have IBS - first it was considered D, then C but more M. I have always avoided magnesium supplement because of it potentially contributing to diarrhea, but I seem to be more C so maybe I should try it. Endo says eat more dairy (calcium! Vitamin D!); gastro says to avoid dairy! Endo who diagnosed and is treating my osteoporosis (Fosamax 8 months/Reclast last July) hasn't recommended any supplements other than 1200 calcium/day and 50,000 prescription Vitamin D2 once/week I think forever (been on it for 18 months, levels are where they should be since 1 year ago but he wants to continue). I asked about K; he said no proven benefit. Nothing else recommended but he is not a Dietician, so I don't expect much. Again, thankful for these sites to see what helps others as I feel we don't get all the information from our doctors which is so unfortunate. To be fair, as there is no specialty in osteoporosis they can't know every single nuance to treatment.