Malabsorption - Looking for Information
For RNY the malabsorption is limited, and most people malabsorb some fats, and fat soluable vitamins as well. Also calcium and mild protein malabsorption due to the bypassed portion of the intestines. For most people this helps in the initial weight loss, and means taking vitamins for life.
For the DS post-op, this malabsorption is greater and also includes more fats and protein loss to the body, so the those people have to push the protein more and increase the vitamins. For RNY and DS, the body adjusts and begins to absorb more of the fats as time goes one, although DS will most likely always have a little more malabsorption of fats and proteins than most RNY post-ops. The ones with Distal RNY will always have a little more fat and protein malabsorption for life than Proximal RNY.
For some people this has little or no effect other than to help with initial weight loss. For others this causes low iron, calcium, vit D and A , pernicious anemia ( low B12) and low protein. The best way to avoid problems is to supplement the way your doctor orders, and to have labs done every 6 months initially, then every year if things are going well, more often if you have a problem.
Edited to add: unfortunately, this malabsorption doesn't extend to carbs for anybody! We all absorb carbs and will regain weight if we eat much in the way of simple carbs and sugars. So every surgical post-op still has to watch the sugar and carbs.
Twinlab makes a Dry A&D formula - Allergy A&D. That's what I use.
You should talk to your surgeon about the amounts to increase according to your lab results. While harder for WLS patients than "normies," you don't want to get too much A or D. They can be toxic, so don't go adding them in willy nilly on your own.
Jeanie