Difficulty absorbing vitamins- especially B vitamins, calcium, and iron. The part of the intestine that absorbs B vitamins is bypassed so you will absorb these vitamins much more slowly.
Calcium and iron absorption is affected by the drop in acidity of your intestinal tract. Taking vitamins as instructed by your doctor is critical to avoiding nutritional deficiencies after surgery.
Dumping syndrome- your pouch is connected to a piece of bowel that has never seen sugar. If you eat sugar after bypass surgery (not on your eating list), it will drop into this piece of the small bowel. Sugar is a large molecule that draws water into the lumen of your bowel causing bowel distention. Your bowel reacts to this distention, producing nausea, vomiting, and diarrhea. This reaction is called dumping syndrome and occurs in almost all bypass patients. Avoid sugar and processed foods that may contain sugar.