The bariatric surgery patient--nutrition considerations.

BACKGROUND: Bariatric surgery is an effective method of weight loss for the treatment of morbid obesity. It is more effective when combined with nutritional care, which is sometimes complex, always ongoing and differs between surgical procedures. In Australia, the three most common bariatric surgical procedures are the adjustable gastric banding, sleeve gastrectomy and the Roux-en-Y gastric bypass. OBJECTIVE: This article introduces the nutritional and dietary considerations for each procedure, and provides practical advice to support the general practitioner's role in managing patients who are considering, or who have had, bariatric surgery. DISCUSSION: While bariatric procedures influence the volume of food consumed, none of the procedures necessarily improve the quality of food consumed or compliance with recommended supplement usage, leaving nutrition care and food choice important lifelong considerations. Ongoing coordinated care by the GP, that links with the bariatric dietitian and others in the health management team, maximises the benefits and health outcomes for the patient through ongoing monitoring of nutritional status, prevention of nutrient deficiencies and maximising long term weight loss.

Serum fat-soluble vitamin deficiency and abnormal calcium metabolism after malabsorptive bariatric surgery.

Weight loss after biliopancreatic diversion or duodenal switch is due to decreased calorie absorption secondary to fat malabsorption. Fat malabsorption may also cause essential fat-soluble vitamin deficiencies, which may have severe clinical consequences and alter calcium metabolism. Serum vitamins A, D, E, and K, zinc, parathyroid hormone, corrected calcium, and alkaline phosphatase levels were measured in a cohort of patients who had previously undergone biliopancreatic diversion. Two bariatric surgery units were involved in the study: New York University School of Medicine (New York, NY), and the Wesley Medical Center (Brisbane, Australia). A total of 170 patients completed the study. The incidence of vitamin A deficiency was 69%, vitamin K deficiency 68%, and vitamin D deficiency 63% by the fourth year after surgery. The incidence of vitamin E and zinc deficiency did not increase with time after surgery. The incidence of hypocalcemia increased from 15% to 48% over the study period with a corresponding increase in serum parathyroid hormone values in 69% of patients in the fourth postoperative year. There is a progressive increase in the incidence and severity of hypovitaminemia A, D, and K with time after biliopancreatic diversion and duodenal switch. Calcium metabolism is affected with an increasing incidence of secondary hyperparathyrodisim and evidence of increased bone resorption in 3% of patients. Long-term nutritional monitoring is necessary after malabsorptive operations for morbid obesity.