Bariatric surgery or medical therapy for obesity.

To the Editor: Mingrone et al. and Schauer et al. (April 26 issue)1,2 report the results of rigorous randomized, controlled trials comparing various types of bariatric surgery with medical therapy for obesity-associated type 2 diabetes. However, we would like to raise the important issue of micronutrient assessment and management in patients undergoing bariatric surgery. The risk of deficiency (of thiamine; vitamins B6, B12, and D; calcium; iron; or copper, zinc, or both) is increasingly recognized after malabsorptive bariatric surgery, but these deficiencies may be inadequately diagnosed.3 For example, we recently described the incidence and prevalence of copper deficiency after Roux-en-Y gastric bypass surgery as 18.8% and 9.6%, respectively.4 Consensus guidelines recommend that patients should be comprehensively monitored for micronutrient deficiencies after bariatric surgery.5 Unfortunately, the articles by Mingrone et al. and Schauer et al. do not describe such monitoring. Given the high prevalence of preoperative and postoperative deficiencies of specific nutrients,3 it is important for clinicians to be aware of these potential complications and to appropriately monitor and treat patients for deficiencies of vitamins, minerals, and trace elements after these increasingly common surgical procedures for obesity.