Article

Differential effect of weight loss on insulin resistance in surgically treated obese patients

Università di Pisa, Pisa, Tuscany, Italy
The American Journal of Medicine (Impact Factor: 5). 01/2005; 118(1):51-7. DOI: 10.1016/j.amjmed.2004.08.017
Source: PubMed

ABSTRACT

To compare the effects of equivalent weight loss induced by two bariatric surgical techniques on insulin action in severely obese patients. Eighteen nondiabetic patients with severe obesity (mean [± SD] body mass index: 53.5 ± 9.0 kg/m 2) and 20 sex- and age-matched lean subjects (body mass index: 23.8 ± 3.0 kg/m 2) underwent metabolic studies, including measurement of insulin sensitivity by the insulin clamp technique. Patients then underwent either vertical banded gastroplasty with Roux-en-Y gastric bypass, or biliopancreatic diversion, and were restudied at 5 to 6 months and again at 16 to 24 months postsurgery. At baseline, patients were hyperinsulinemic (194 ± 47 pmol/L vs. 55 ± 25 pmol/L, P < 0.0001), hypertriglyceridemic (1.56 ± 0.30 mmol/L vs. 0.78 ± 0.32 mmol/L, P < 0.0001), and profoundly insulin resistant (insulin-mediated glucose disposal: 20.8 ± 4.4 μmol/min/kg fat-free mass vs. 52.0 ± 10.1 μmol/min/kg, P < 0.0001) as compared with controls. Weight loss by the two procedures was equivalent in both amount (averaging -53 kg) and time course. In the gastric bypass group, insulin sensitivity improved (23.8 ± 6.0 μmol/min/kg at 5 months and 33.7 ± 11.3 μmol/min/kg at 16 months, P < 0.01 vs. baseline and controls). In contrast, in the biliopancreatic diversion group, insulin sensitivity was normalized already at 6 months (52.5 ± 12.4 μmol/min/kg, P = 0.72 vs. controls) and increased further at 24 months (68.7 ± 9.5 μmol/min/kg, P < 0.01 vs. controls) despite a persistent obese phenotype (body mass index: 33.2 ± 8.0 kg/m 2). In surgically treated obese patients, insulin sensitivity improves in proportion to weight loss with use of predominantly restrictive procedures (gastric bypass), but is reversed completely by predominantly malabsorptive approaches (biliopancreatic diversion) long before normalization of body weight. Selective nutrient absorption and gut hormones may interact with one another in the genesis of the metabolic abnormalities of obesity.

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    • "severely obese individuals at 6 months after surgery. This result confirms the previous studies about the cardiovascular risk factors measured [6] [7] [46] [47]. "
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    ABSTRACT: Background: Bariatric surgery is considered an effective method for sustained weight loss, but may cause various nutritional complications. The aim of this study was to evaluate the nutritional status of minerals and vitamins, food consumption, and to monitor physiologic parameters in patients with obesity before and 6 months after Roux-en-Y gastric bypass surgery (RYGB). Methods: Thirty-six patients who had undergone RYGB were prospectively evaluated before and 6 months after surgery. At each phase their weight, height, body mass index (BMI), Electro Sensor Complex (ES Complex) data, food consumption, and total protein serum levels, albumin, prealbumin, parathyroid hormone (PTH), zinc (Zn), B12 vitamin (VitB12), iron (Fe), ferritin, copper (Cu), ionic calcium (CaI), magnesium (Mg), and folic acid were assessed. Results: The mean weight loss from baseline to 6 months after surgery was 35.34±4.82%. Markers of autonomic nervous system balance (P<.01), stiffness index (P<.01), standard deviation of normal-to-normal R-R intervals (SDNN) (P<.01), and insulin resistance (P<.001) were also improved. With regard to the micronutrients measured, 34 patients demonstrated some kind of deficiency. There was a high percentage of Zn deficiency in both pre- (55.55%) and postoperative (61.11%) patients, and 33.33% of the patients were deficient in prealbumin postoperatively. The protein intake after 6 months of surgery was below the recommended intake (<70 g/d) for 88.88% of the patients. Laboratory analyses demonstrated an average decrease in total protein (P<.05), prealbumin (P = .002), and PTH (P = .008) between pre- and postsurgery, and a decrease in the percentage of deficiencies for Mg (P<.05), CaI (P<.05), and Fe (P = .021). Conclusion: Despite improvements in the autonomic nervous system balance, stiffness index markers and insulin resistance, we found a high prevalence of hypozincemia at 6 months post-RYGB. Furthermore, protein supplements were needed to maintain an adequate protein intake up to 6 months postsurgery.
    Full-text · Article · May 2014 · Surgery for Obesity and Related Diseases
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    • "In type 2 diabetes, GB improves insulin sensitivity, as defined by hyperinsulinemic euglycemic clamps [17], in parallel with reduced basal insulin levels and increased postprandial insulin secretion [6]. In type 1 diabetes, endogenous insulin levels are low to absent secondary to autoimmune beta cell destruction. "
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    ABSTRACT: In severely obese type 2 diabetes patients, gastric bypass surgery (GB) reduces body mass index (BMI) and hemoglobin A1c (HbA1c) and allows reduced doses of insulin and other medications. Data regarding the effects of GB on severely obese patients with type 1 diabetes are limited. Severely obese women with type 1 diabetes (n = 9) were studied immediately before and after GB (7.7 ± 5.8 weeks, mean ± SD). On average, GB reduced mean BMI by 11 % and mean HbA1c by 0.9 % (from 8.0 to 7.1 %), with a parallel 38 % decrease in basal insulin requirements (expressed per kilogram of body weight). GB rapidly decreased BMI, HbA1c, and insulin requirements in severely obese women with type 1 diabetes. However, physiologic insulin replacement remains necessary in patients with type 1 diabetes.
    Full-text · Article · Mar 2014 · Obesity Surgery
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    • "severely obese individuals at 6 months after surgery. This result confirms the previous studies about the cardiovascular risk factors measured [6] [7] [46] [47]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Bariatric surgery is considered an effective method for sustained weight loss, but may cause various nutritional complications. Objectives The aim of this study was to evaluate the nutritional status of minerals and vitamins, food consumption and to monitor physiological parameters in patients with obesity before and 6 months after Roux-en-Y gastric bypass surgery (RYGB). Methods Thirty-six patients who had undergone RYGB were prospectively evaluated before and 6 months after surgery. At each phase their weight, height, body mass index (BMI), ES Complex data, food consumption and total protein serum levels, albumin, prealbumin, parathyroid hormone (PTH), zinc (Zn), B12 vitamin (VitB12), iron (Fe), ferritin, copper (Cu), ionic calcium (CaI), magnesium (Mg) and folic acid were assessed. Results The mean weight loss from baseline to 6 months after surgery was 35.34±4.82%. Markers of autonomic nervous system balance (p<0.01), stiffness Index (p< 0.01), standard deviation of normal to normal R-R intervals (SDNN) (p< 0.01) and Insulin resistance (p< 0.001) were also improved. With regard to the micronutrients measured, 34 patients demonstrated some kind of deficiency. There was a high percentage of zinc deficiency in both pre- (55.55%) and post-operative (61.11%) patients and 33.33% of the patients were deficient in pre-albumin post-operatively. The protein intake after 6 months of surgery was below the recommended intake (<70g/day) for 88.88% of the patients. Laboratory analyses demonstrated an average decrease in total protein (p<0.05), pre-albumin (p=0.002), and PTH (p=0.008) between pre and post-surgery, and a decrease in the percentage of deficiencies for Mg (p<0.05), CaI (p<0.05) and Fe (p=0.021). Conclusions Despite improvements in the autonomic nervous system balance, stiffness index markers and insulin resistance, we found a high prevalence of hypozincemia at 6 months post-RYGB. Furthermore, protein supplements were needed to maintain an adequate protein intake up to 6 months post-surgery.
    Full-text · Article · Jan 2014 · Surgery for Obesity and Related Diseases
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