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Insulin sensitivity effects differ between bariatric surgery types
Greater improvements in insulin sensitivity were seen in patients with obesity who underwent Roux-en-Y gastric bypass with very low caloric intake compared with laparoscopic adjustable gastric banding with very low caloric intake.
“Previous studies have failed to distinguish the confounding effects of reduced caloric intake from those of the surgical procedure per se on the early beneficial effects on glucose metabolism,” the researchers wrote. “The purpose of the current study was to quantitate and compare the early (1 week) metabolic effects of two different bariatric surgical procedures ([Roux-en-Y gastric bypass] and [laparoscopic adjustable gastric banding]) with those of [very low caloric intake].”
Amalia Gastaldelli , PhD, head of the cardiometabolic risk unit at CNR Institute of Clinical Physiology in Pisa, Italy, and colleagues evaluated 20 adults (mean age, 35 years) with obesity (mean BMI, 44.2 kg/m2) without diabetes to compare the short-term effects of bariatric surgical procedures with a very low caloric intake diet on insulin sensitivity and insulin secretion.
During a 1-week period, participants were hospitalized and consumed a supervised very low calorie diet (600 kcal per day); insulin sensitivity, insulin secretion and beta-cell function were measured on the first and last day of the very low caloric intake. After discharge participants received nutritional counseling. Three months after discharge, participants were readmitted for either laparoscope adjustable gastric banding (LAGB; n = 10) or Roux-en-Y gastric bypass (RYGB; n = 10).
At baseline, four participants had impaired glucose tolerance and the remaining had normal oral glucose tolerance.
After the week of very low caloric intake, participants lost approximately 2.1 kg and basal rate of endogenous glucose production declined. Lipolysis, hepatic insulin sensitivity, adipose insulin sensitivity and peripheral insulin sensitivity were not significantly improved.
One week after bariatric surgery, body weight was similarly decreased between the two surgical groups. Compared with the LAGB group, the RYGB group had greater improvements in hepatic insulin sensitivity (P < .01), peripheral insulin sensitivity (P < .05) and adipose tissue insulin sensitivity index (P < .05).
“Our results demonstrate that in obese subjects without diabetes, [hepatic insulin sensitivity], peripheral insulin sensitivity, [adipose insulin sensitivity], and insulin clearance improve early after bariatric surgery independently of the low caloric intake, but only after RYGB, and not after LAGB,” the researchers wrote. – by Amber Cox
Disclosure: Gastaldelli reports receiving funding from the Ministry of Education, University and Research (MIUR), project PREMIALE 2012.