A new study exposes the risk of nutritional deficiencies in severely obese teens - both those who had weight loss surgery and those who did not. At least five years after undergoing gastric bypass surgery, teens and young adults maintained significant weight loss but were at risk of nutritional deficiencies, particularly low iron, mild anemia and low vitamin D. The study also found low iron and low vitamin D in severely obese teens who did not undergo weight loss surgery. Those who didn't have surgery also had low levels of protein in their blood. Continued at MedicalNewsToday>>