Two studies by a group of researchers at Washington Hospital Center highlight potential postoperative nutritional deficiencies among patients who undergo gastric bypass surgery to treat obesity.
Research presented at the 72nd Annual Scientific Meeting of the American College of Gastroenterology by Dr. Frederick Finelli and Dr. Timothy Koch suggests that a potentially serious condition can emerge after gastric bypass surgery known as small intestinal bacterial overgrowth that has an impact on absorption of vitamins, minerals and micronutrients such as calcium and zinc.
According to the Washington Hospital Center team, this is a serious issue with widespread implications as approximately 150,000 patients this year will have gastric bypass surgery, and there exists wide variation in surgical techniques. According to Dr. Koch, “patients may develop bacterial overgrowth that interferes with their ability to absorb nutrients, even if they are taking supplements as directed after surgery. Only a gastroenterologist can evaluate these potentially serious small intestinal disorders.”
Dr. Koch and his colleagues hypothesized that by altering the gut ecology, gastric bypass surgery could induce calcium deficiency. Surgical changes to the stomach to create the “gastric pouch” in the Roux-en-Y procedure impact the number of acid producing cells in the stomach lining. Furthermore, many gastric bypass patients are given acid suppressing drugs after their surgery. Researchers suspect that the reduction in acid, known as achlorhydria, contributes to the overgrowth of bacteria in the small intestine. According to Dr. Koch, competition between bacteria and the human host for ingested nutrients leads to malabsorption and potentially serious complications due to micronutrient deficiency.