[Nutritional deficiencies after bariatric surgery: why they happen?].

Nutritional deficiencies following bariatric surgery are commonly reported in scientific literature on surgery and nutrition. It has been estimated that approximately 400,000 large obeses underwent bariatric surgery in 2010. The surgery technique and consequent altered gastrointestinal function done will particularly imply in variations on those deficiencies and health complications. A systematic review of several database was done from 1978 until 2010, using as keywords protein and micronutrients deficiencies, related to bariatric surgery. The better understand of these studies can provide an important improvement on this obese therapy, assuring a successful and health weight loss maintenance for long term. Therefore, this review provides a significant contribution about this topic, pointing several ways on the nutritional intervention and management of those patients.