Metabolic surgery and nutritional deficiencies.

The increasing prevalence of morbid obesity in Germany is associated with an increasing number of metabolic surgical interventions. Short-term surgical and long-term metabolic complications such as nutrient deficiencies can be considered as the main risks of metabolic surgery with its malabsorptive but also restrictive procedures. The aim of this review was to characterize the most relevant metabolic complications specific for the various bariatric procedures, which, subsequently, require a permanent surveillance and supplementation, respectively. Furthermore, we aimed to identify if there are diagnostic and therapeutic measures that can prevent those complications. Restrictive bariatric surgery such as "gastric banding" and "sleeve gastrectomy" can be associated with deficiencies related to B-vitamins whereas iron, folate, vitamin B1, B12 and D deficiencies are associated with the malabsorptive procedure 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 medical and dietetic surveillance. The recently published guidelines of the "American Association of Bariatric and Metabolic Surgery" are the basis for recommendations on supplementation and treatment following weight loss surgery.