Nutrition deficiencies after weight loss surgery

Deficiencies in vitamins and other nutrients are common after bariatric surgery, particularly with RYGB and BPD-DS, since these operations result in decreased intestinal surface area and bypass the duodenum (Fig. 6.5). Since BPD-DS results in more significant malabsorption than does RYGB, there are more nutrient deficiencies reported among BPD-DS patients. Although not as prevalent, nutritional deficiencies have also been reported after AGB and SG, primarily because of decreased food intake and the avoidance of certain nutrient-rich foods because of individual intolerances.

In order to better understand what the postoperative nutrition needs are for pregnant women who have had bariatric surgery, it is important to first understand the nutritional deficiencies that commonly accompany these procedures. The main deficiencies reported among postoperative patients are protein, iron, vitamin B12, folate, calcium, vitamin D, and fat-soluble vitamins [15]. Below is a brief review of studies that have been carried out as well as the assessments that are recommended as a check for nutrient deficiencies following bariatric surgery.

  • Protein. In a prospective randomized study of patients with a BMI greater than 50 kg/m2, 13% of the patients who underwent distal RYGB experienced protein deficiency 2 years after surgery [16]. Protein deficiency occurred more frequently after BPD-DS than RYGB due to the more severe malabsorption caused by this operation. It is recommended that total serum protein and albumin be assessed on a regular basis after bariatric surgery to measure protein stores, typically 3, 6, and 12 months after surgery, then annually.
  • Iron. In a study of RYGB patients before surgery and up to 5 years after the procedure, iron deficiency was identified in 26% of patients preoperatively, in 39% at 4 years postop-eratively, and in 25% of those 5 years postoperatively [17]. The anatomic changes resulting from RYGB reduce the exposure of iron-containing food to the acidic environment in the stomach, which is required for the release of iron from protein and conversion into its absorbable ferrous form [18]. It is recommended that hemoglobin, hematocrit, iron, ferritin, and total iron binding capacity be evaluated for diagnosis of iron deficiency or anemia.
  • Vitamin B12 (cobalamin) and folate. Deficiencies of vitamin B12 and folate are common in bariatric surgery patients. Halverson studied patients 1 year after RYGB and found 33% of patients had a vitamin B12 deficiency, and 63% had a folate deficiency [19]. As with iron digestion after RYGB, the absence of an acidic environment prevents the release of vitamin B12 from food [17]. In addition, intrinsic factor (IF), secreted from parietal cells of the stomach, is responsible for the absorption of vitamin B12. Therefore, after bariatric surgery, inadequate IF secretion or function is a possible mechanism for vitamin B12 deficiency [20]. It is recommended that vitamin B12 and folate be assessed regularly. Blood levels of >300 pg/ml for B12 are considered normal.

Salivary amylase


Gastric juice

Pancreatic juice • bicarbonate ^_• enzymes



Intestinal brush border enzymes


Intestinal brush border enzymes


CI-, SO4-iron calcium magnesium zinc glucose, galactose, fructose vitamin C thiamin f" water soluble riboflavin vitamins pyridoxine folic acid protein vitamins A, D, E, K fat cholesterol

bile salts and * vitamin B12

vitamin K formed by bacterial action

Fig. 6.5. Sites of absorption of nutrients within the gastrointestinal tract. (Adapted from: Mahan and Escott-Stump: Krause's Food, Nutrition and Diet Therapy, 9/e, p 13, ©1996, with permission from Elsevier)

  • Calcium and vitamin D. Calcium and vitamin D are usually assessed together since vitamin D promotes the intestinal absorption of calcium. Brolin et al. found a 10% incidence of calcium deficiency and 51% incidence of vitamin D deficiency in patients who had distal RYGB [16]. Parathyroid hormone (PTH) levels may be a more sensitive indicator of calcium deficiency [18]. If PTH is elevated, then calcium deficiency is presumed. As for vitamin D, it is important to check 25(OH) vitamin D levels rather than 1,25(OH)2 vitamin D. Although the normal range of vitamin D is variable depending on the lab, it is usually recommended that serum 25(OH) vitamin D to be >20 ng/ml.
  • Other fat-soluble vitamins: A, E, K. Malabsorption of these vitamins is most commonly seen after BPD-DS. Slater et al. studied 170 patients following BPD and BPD-DS and reported that 69% were deficient in vitamin A and 68% were deficient in vitamin K 4 years after surgery [21]. Dolan et al. showed that 5% of patients had low levels of vitamin E an average of 28 months after BPD and BPD-DS [22]. Therefore, vitamin A, vitamin E (tocopherol), and INR (the International Normalized Ratio, used to measure clotting and indirectly assess vitamin K deficiency) should be assessed at least annually.
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Virtual Gastric Banding

Virtual Gastric Band Hypnosis Audio Programm that teaches your mind to use only the right amount of food to keep you slim. The Virtual Gastric Band is applied using mind management techniques, giving you the experience of undergoing surgery to install a virtual gastric band or virtual lap-band, creating a small pouch at the top of the stomach which limits how much food can be eaten. Once installed, the Virtual Gastric Band creates the sensation of having a smaller stomach that is easily filled and satisfied with smaller amounts of food.

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