The aim of this article is to highlight the nutritional deficiencies of the weight loss surgery patient as they may relate to the patient's subsequent planned plastic surgery procedures. The clinical manifestation of these nutritional deficiencies and their prevention and treatment are the subjects of a subsequent publication
Laparoscopic adjustable banding is a restrictive procedure, in which a small gastric pouch with a small outlet is created, resulting in early and prolonged satiety. Because the normal absorptive surface is left intact, specific nutrient deficiencies are rare.The Roux-en-Y gastric bypass procedure involves both restrictive and malabsorptive components. The stomach size is decreased to less than 30 ml with a 75- to 150-cm Roux-limb connected as an enteroenterostomy to the jejunum. By reducing the stomach, the patient loses storage capacity and hydrochloric acid, pepsinogen, intrinsic factor, gastrin, and mucus. In addition, elimination of the body of the stomach severely restricts the process of food grinding, which is important in releasing vitamins and minerals. By forming the Roux-en-Y anastomosis, the coordination between gastric emptying and release of pancreatic enzymes is lost, which could lead to maldigestion and malabsorption. Finally, bypassing the duodenum and proximal jejunum leads to diminished absorptive surface area.
It is important to know which weight-loss procedure the patient had.
Vitamin B12Because the small intestine remains intact after vertical banded gastroplasty, micronutrient deficiencies are rare provided that adequate food intake is maintained.In contrast, micronutrient deficiencies are common in Roux-en-Y gastric bypass and biliopancreatic diversion.
Vitamin B12 and folate deficiencies occur most often in Roux-en-Y gastric bypass patients, although other malabsorptive procedures can also increase the risk.
Decreased gastric acid and pepsin hydrolysis results in incomplete liberation of food-bound vitamin B12.Bypassing of the duodenum results in incomplete release of vitamin B12 from salivary R-binder proteins by the pancreatic enzymes.Finally, reduced intrinsic factor (from the parietal cells) release causes diminished absorption of vitamin B12 at the terminal ileum.
Because only approximately 1% of free vitamin B12 is absorbed, recommendations for postsurgical patients range from 500 to 600 micrograms/day in an oral form or 100 micrograms monthly by means of intramuscular injection. Despite the recommended B12 supplementation, 3.6 percent of post–laparoscopic Roux-en-Y gastric bypass patients continue to be deficient in vitamin B12 at 1 year.
Serum folate deficiency has been observed in 45% of obese patients before gastric bypass surgery and 9 to 35% after bypass operations. It appears to be less common than vitamin B12 and iron deficiencies.
Similar to vitamin B12, most Roux-en-Y gastric bypass patients with folate deficiency are asymptomatic or suffer from subclinical disease. However, those with severe deficiency can present with megaloblastic anemia.This can be prevented by ingestion of regular vitamin preparations, containing 400 micrograms of folate, after Roux-en-Y gastric bypass.
Vitamin B1 (Thiamine)
A multivitamin supplement is usually adequate in preventing thiamine deficiency. If deficiency occurs, it should be treated with parenteral thiamine, 50 to 200 mg/day until symptoms clear and then 10 to 100 mg by mouth daily.Thiamine deficiency is particularly associated with vertical banded gastroplasty procedures because of reduced dietary intake.In Roux-en-Y gastric bypass patients on vitamin supplementation, the incidence of thiamine deficiency was 18.3 and 11.2 % at the 1- and 2-year follow-up, respectively.However, clinical manifestations (e.g., weakness, peripheral neuropathy) are rare and were seen in only two of the 493 patients (0.4 %). The development of Wernicke encephalopathy is a rare long-term complication of weight loss surgery.
Vitamin B2 (Riboflavin)
Deficiency should be treated by 6 to 30 mg of riboflavin by mouth daily.It has recently been reported that riboflavin deficiency in Roux-en-Y gastric bypass patients was13.6 and 7.1% at the 1- and 2-year follow-up, respectively, despite vitamin supplementation.
Vitamin B6 (Pyridoxine)
Despite vitamin supplementation, Clements et al have recently shown deficiency of vitamin B6 in 17.6 and 14.2% of post–laparoscopic Roux-en-Y gastric bypass patients at the 1- and 2-year follow-up, respectively.
MALABSORPTION OF FAT-SOLUBLE VITAMINS
The high degree of fat malabsorption associated with biliopancreatic diversion and Roux-en-Y gastric bypass tends to also cause malabsorption of fat-soluble vitamins, such as vitamins A, D, and K.
Dolan et al.21 reported vitamin A deficiency in 61% of patients following biliopancreatic diversion at 28-month follow-up. This was despite an 80% compliance rate with multivitamin supplementation.Brolin and Leung observed that prophylactic supplementation of vitamin A did not prevent deficiency in up to 10% of those patients who had distal Roux-en-Y gastric bypass after 2 years.Similarly, the incidence of vitamin A deficiency was 11 and 8.3% at the 1- and 2-year follow-up, respectively,despite vitamin supplementation.
Calcium and Vitamin D
Supplementation is recommended for all Roux-en-Y gastric bypass and biliopancreatic diversion patients. Current recommendations range from 1000 to 1500 mg/day for calcium and 8 micrograms/day for vitamin D.The incidence of vitamin D deficiency in purely malabsorptive procedures varies from 17% at 9 to 18 months to 63% at 4 years after surgery.The incidence in distal Roux-en-Y gastric bypass, which is a combination of restrictive and malabsorption procedures, was significantly higher.Despite calcium and vitamin D supplementation after Roux-en-Y gastric bypass, Coates et al. found that within 3 to 9 months after surgery, patients have an increase in bone resorption associated with a decrease in bone mass.
Vitamin KA fat-soluble vitamin that aids in blood coagulation. It is found in fats, green vegetables, and various grains. Deficiencies are very uncommon, but can lead to hemorrhaging.
A study of 170 patients following biliopancreatic diversion and biliopancreatic diversion with duodenal switch found that the incidence of vitamin K deficiency was 68% by the fourth year. However, there was no clinical manifestation of increased bleeding.
The incidence of iron deficiency in Roux-en-Y gastric bypass patients has been estimated to be between 30 and 50% and is higher in menstruating women.
In Roux-en-Y gastric bypass patients, the pathophysiology of this deficiency is related to reduced intake of iron, bypassing the acid environment of the stomach, and reduced absorptive surface of the small intestine.
Zinc is an essential trace mineral that is required for cellular growth and replication. Major food sources for zinc are proteins, and there is a direct correlation between dietary protein and zinc intake. Approximately 30 % of ingested zinc is absorbed from the small intestine.
A report by Madan et al. demonstrated a significant deficiency of this trace element in 30% of 100 preoperative morbid patients. Postoperatively, this increased to 36 % despite vitamin supplementation of the diet. In post– bariatric surgery patients, zinc deficiency is often subclinical and only manifests itself as hair thinning and loss.
Nutritional Deficiency of Post-Bariatric Surgery Body Contouring Patients: What Every Plastic Surgeon Should Know; Plastic and Reconstructive Surgery:Volume 122(2)August 2008pp 604-613; Agha-Mohammadi, Siamak M.B., B.Chir., Ph.D.; Hurwitz, Dennis J. M.D.
Blog Posts on Bariatric Surgery
- On the bandwagon
- Groening of Weight-loss Surgery
- Unforeseeen Consequences
Chris Oliver Blogspot (an orthopaedic surgeon who writes his story post-banding)
- Laparoscopic Gastric Band Adjustment