Philadelphia, PA, October 15, 2007— 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.