Comparison of nutritional consequences of conventional therapy of obesity, adjustable gastric banding, and gastric bypass

Background: Roux-en-Y gastric bypass (RYGBP) is more efficient than adjustable gastric banding (AGB) in weight loss and relieving co-morbidities, but nutritional complications of each surgical procedure have been poorly evaluated. Methods: A cross-sectional study was performed to compare nutritional parameters in 201 consecutive obese patients, who had been treated either by conventional behavioral and dietary therapy (CT, n=110) or by bariatric surgery, including 51 AGB and 40 RYGBP. Results: BMI was similar after AGB (36.6 +/- 5.3 kg/m(2)) and RYGBP (35.4 +/- 6.3 kg/m(2)), but patients in the RYGBP group had lost more weight and had less metabolic disturbances than those in the AGB group. On the other hand, the prevalence of nutritional deficits was significantly higher in the RYGBP group than in the 2 other groups (P<0.01), whereas the AGB group did not differ from CT. Particularly, the RYGBP group presented an unexpected high frequency of deficiencies in fat-soluble vitamins. Moreover, vitamin B-12, hemoglobin, plasma prealbumin and creatinine concentrations were low in the RYGBP group. Conclusion: RYGBP is more efficient than AGB in correcting obesity, but this operation is associated with a higher frequency of nutritional deficits that should be carefully monitored.