Essential trace elements in Norwegian obese patients before and 12 months after Roux-en-Y gastric bypass surgery: Copper, manganese, selenium and zinc.

Essential trace elements were below or in the lower reference range twelve months after RYGB. Our results indicate a need for updated guidelines in Nordic countries for trace metal monitoring and supplements in patients after bariatric surgery, especially when gastric bypass surgery is used. Further studies are required to explore and prevent trace element deficiency related to obesity and bariatric surgery.