Improved glucose metabolism after gastric bypass: evolution of the paradigm.
Study Goal
The researchers aimed to quantify the contributions of calorie restriction, nutrient rerouting, and adipose tissue reduction to improved glucose metabolism after Roux-en-Y gastric bypass (RYGB) in type 2 diabetes patients.
Results Summary
The study found that RYGB improved whole-body insulin sensitivity and postprandial glucose response early after surgery, with further improvements at one year. Calorie restriction and nutrient rerouting contributed through distinct mechanisms, while weight loss enhanced insulin sensitivity via increased glucose oxidation and nonoxidative glucose disposal.
Population
Fifteen diabetic patients (age 47±9 years, BMI 41.3±4.2 kg/m²).
Effective Dosage
Not specified
Duration
2 weeks of very low-calorie diet (VLCD) pre-surgery, 2 weeks post-surgery, and 1-year follow-up.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Roux-en-Y gastric bypass (RYGB) | increase | glucose metabolism | patients with type 2 diabetes | - | improved | #1 |
very low calorie diet (VLCD) | increase | M (insulin sensitivity) | diabetic patients | 2.9±1.3 to 4.2±1.1 mg/kg/min | improved | #2 |
very low calorie diet (VLCD) | no change | M (insulin sensitivity) | diabetic patients | - | no further change | #3 |
Roux-en-Y gastric bypass (RYGB) | no change | M (insulin sensitivity) | diabetic patients | 4.7±1.7 versus 4.2±1.1 | similar | #4 |
Roux-en-Y gastric bypass (RYGB) | increase | M (insulin sensitivity) | diabetic patients | - | improved further | #5 |
very low calorie diet (VLCD) and Roux-en-Y gastric bypass (RYGB) | increase | insulin-stimulated glucose uptake | diabetic patients | - | entirely accounted for | #6 |
weight loss | increase | nonoxidative glucose disposal (NOGD) and glucose oxidation | diabetic patients | - | associated with an increase | #7 |
very low calorie diet (VLCD) | increase | postprandial glucose | diabetic patients | - | improved | #8 |
Roux-en-Y gastric bypass (RYGB) | increase | postprandial glucose | diabetic patients | - | improved even more | #9 |
Roux-en-Y gastric bypass (RYGB) | no change | postprandial glucose | diabetic patients | - | no further change | #10 |
Roux-en-Y gastric bypass (RYGB) | increase | whole-body insulin sensitivity and postprandial glucose response | - | - | improved | #11 |
weight loss | increase | whole-body insulin sensitivity, including glucose oxidation and NOGD | - | - | contributes by increasing | #12 |
BACKGROUND: Glucose metabolism is improved in patients with type 2 diabetes after Roux-en-Y gastric bypass (RYGB). OBJECTIVES: To quantify the relative contribution of calorie restriction, rerouting of nutrients, and adipose tissue reduction. SETTING: University Hospital. METHODS: Fifteen diabetic patients, (47±9 yr, body mass index 41.3±4.2 kg/m RESULTS: In the VLCD group, after 2 weeks of calorie restriction, M improved (2.9±1.3 to 4.2±1.1 mg/kg/min, P = .005) with no further change at 2 weeks postoperatively. In the normal diet group 2 weeks postoperatively, M was similar to the VLCD group (4.7±1.7 versus 4.2±1.1, P = .61). One year postoperatively, M improved further in both groups. The improvement in insulin-stimulated glucose uptake after VLCD and RYGB was entirely accounted for by nonoxidative glucose disposal (NOGD), whereas weight loss at 1 year postoperatively was associated with an increase in NOGD and glucose oxidation. Postprandial glucose improved after VLCD (P<.05) and even more 2 weeks after RYGB (P<.05) with no further change after 1 year. CONCLUSION: Improved whole-body insulin sensitivity and postprandial glucose response occur early after RYGB. Low calorie intake and rerouting of nutrients contribute through distinct mechanisms. Weight loss contributes by increasing whole-body insulin sensitivity, including glucose oxidation and NOGD. These data suggest that the combination of different mechanisms is what makes RYGB an effective intervention for type 2 diabetes.