Changes in ghrelin concentrations one year after resective and non-resective gastric bypass: Associations with weight loss and energy and macronutrient intakes

Objective: Ghrelin is a potent stimulator of appetite and synthesized in the stomach. Its role in weight loss after gastric bypass (GBP) is still controversial. The aim of this study was to evaluate the relation between weight loss and food intake and between weight loss and changes in serum ghrelin concentrations 1 y after GBP with resection of the bypassed stomach (R-GBP) and without resection (NR-GBP). Methods: Of 50 women (37.6 +/- 10.2 y old, body mass index 43.8 +/- 4.8 kg/m(2)) with GBP, 26 had R-GBP and 24 had NR-GBP. Body weight, body composition (dual energy x-ray absorptiometry), food intake, and serum ghrelin at baseline and 12 mo after GBP were measured. Results: The percentage of excess weight loss was 68.9 +/- 12.8% at 12 mo after GBP. At 12 mo, the decrease of serum ghrelin was greater in the R-GBP group (-25.3 +/- 22.5%) compared with the NR-GBP group (+11.2 +/- 50.9%, P < 0.005). After adjustment by the baseline excess of body weight, there was a greater percentage of excess weight loss in the R-GBP group only at 6 mo (61.8% versus 54.9%, P = 0.011). After controlling for the baseline intake, a significant lower carbohydrate intake was observed in the R-GBP group 6 mo after surgery (P < 0.05). Conclusion: A greater decrease in ghrelin levels was observed only in patients who underwent R-GBP at 12 mo after surgery. This difference was not associated with differences in dietary intakes or weight loss at the same time point. Therefore, the small gastric pouch is probably more important than decreased ghrelin levels in producing long-term weight loss after R-GBP. (C) 2012 Elsevier Inc. All rights reserved.