Nutritional Deficiencies

Nutritional deficiencies:
* Hyperparathyroidism, due to inadequate absorption of calcium, may occur in over 30% of GBP patients. Calcium is primarily absorbed in the duodenum, which is bypassed by the surgery. Most patients can achieve adequate calcium absorption by supplementation with Vitamin D and Calcium Citrate (carbonate may not be absorbed - it requires an acidic stomach, which is bypassed).
* Iron frequently is seriously deficient, particularly in menstruating females, and must be supplemented. Again, it is normally absorbed in the duodenum. Ferrous sulfate can cause considerable GI distress in normal doses; alternatives include ferrous fumarate, or a chelated form of iron. Occasionally, a female patient develops severe anemia, even with supplements, and must be treated with parenteral iron.
* Vitamin B12 requires intrinsic factor from the gastric mucosa to be absorbed. In patients with a small gastric pouch, it may not be absorbed, even if supplemented orally, and deficiencies can result in pernicious anemia and neuropathies. Sublingual B12 appears to be adequately absorbed.
* Thiamine deficiency (also known as beriberi) will, rarely, occur as the result of its absorption site in the jejunum being bypassed. This deficiency can also result from inadequate nutritional supplements being taken post operatively.
* Protein malnutrition is a real risk. Some patients suffer troublesome vomiting after surgery, until their GI tract adjusts to the changes, and cannot eat adequate amounts even with 6 meals a day. Many patients require protein supplementation during the early phases of rapid weight loss, to prevent excessive loss of muscle mass.
* Vitamin A deficiencies generally occur as a result of the deficiencies that involve the fat-soluble vitamins. This often comes after intestinal bypass procedures such as jejunoileal bypass (no longer performed) or biliopancreatic diversion/duodenal switch procedures. In these procedures, fat absorption is markedly impaired. There is also the possibility of a vitamin A deficiency with use of Xenical or Alli weight loss medications.