Malabsorption
Boy - I really don't know for sure. I know when I went to a seminar locally the doctor there said with the proximal (Dr. Aguirre does 125 cm proximal) that it's not so much a malabsorptive procedure as it is that the surgery itself causes us to not absorb a couple of things regardless of proximal or distal.
All I know is that with taking 1 chewable multi-vitamin and sublingual b complex (that didn't have thiamin in it!!!) at the start, I ended up deficient in thiamin (which actually wasn't in anything I had), borderline iron, and potassium. Everything else was fine at that first set of tests. I just had my labs done again about a month ago and everything must have been fine because I haven't heard back from them. I know I feel much better. Currently I take 1 Costco version of the Centrum Complete (and yes, it's a horse pill but it has been no problem...oddly enough!), sublingual b complex every other day and calcium chews every day. When I have a bad period I have to take iron also, but there is already iron in the multi I take now, so it shouldn't be too much of an issue.
Hope that helps a little.
Dina