[Nutritional deficiencies and supplementation after metabolic surgery]

Increasing prevalence of morbid obesity in Germany is associated with an increasing number of bariatric surgical interventions.Based on the effectiveness of bariatric surgery with regard to a significant reduction of body weight and comorbidity as well as improvement of the quality of life compared with conservative measures, its value and impact has been substantially increased. Long-term metabolic deficits such as nutrient deficiencies can be considered the main risks of various restrictive, combined and malabsorptive procedures of bariatric surgery.The aim of this overview is to characterize metabolic complications after bariatric surgery and their prophylaxis, which require a temporary or permanent surveillance and, if necessary, effective supplementation.Bariatric surgical interventions such as gastric banding (GB) and sleeve gastrectomy (SG) can be subsequently associated with deficiencies related to B‑vitamins whereas iron, folate, and vitamins B1, B12 and D deficiencies might be consequences of malabsorptive procedures such as biliopancreatic diversion, duodenal switch and Roux-en-Y gastric bypass.Due to possible metabolic and surgical complications after bariatric surgery, patients need to undergo life-long follow-up investigations. The currently available guidelines of the American Association of Bariatric and Metabolic Surgery are the basis for the latest recommendations on supplementation and treatment in bariatric surgery.