Sleeve gastrectomy (SG) is supposed to induce fewer nutritional deficiencies than gastric bypass (GBP). However, few studies have compared nutritional status after these two procedures, and the difference in weight loss (WL) between procedures may alter the results. Thus, our aim was to compare nutritional status after SG and GBP in subjects matched for postoperative weight. Forty-three subjects who underwent SG were matched for age, gender, and 6-month postoperative weight with 43 subjects who underwent GBP. Dietary intakes (DI), metabolic (MP), and nutritional parameters (NP) were recorded before and at 6 and 12 months after both procedures. Multivitamin supplements were systematically prescribed after surgery. Before surgery, BMI, DI, MP, and NP were similar between both groups. After surgery, LDL cholesterol, serum prealbumin, vitamin B12, urinary calcium, and vitamin D concentrations were lower after GBP than after SG, whereas WL and DI were similar after both procedures. However, the total number of deficiencies did not increase after surgery regardless of the procedure. In addition, we found a significant increase in liver enzymes and a greater decrease in C-reactive protein after GBP. In conclusion, during the first year after surgery, in patients with the same WL and following the same strategy of vitamin supplementation, global nutritional status was only slightly impaired after SG and GBP. However, some nutritional parameters were specifically altered after GBP, which could be related to malabsorption or other mechanisms, such as alterations in liver metabolism.
