Diet improves insulin sensitivity and beta-cell function similar to that of surgery
28 million Americans have diabetes or 8.3 percent of the U.S. Population. Of these, 7 million do not know they have the disease. In 2010, about 1.9 million people ages 20 or older were diagnosed with diabetes. Type 2 diabetes accounts for 90 to 95 percent of all diagnosed cases of diabetes in adults. Type 2 diabetes is increasingly being diagnosed in children and adolescents.
Marked improvement in glycemic control occurs in patients with type 2 diabetes shortly after Roux-en-Y gastric bypass surgery (RYGB) and before there is major weight loss.
Dr. Judith Korner, MD, PhD, Florence Irving Assistant Professor of Clinical Medicine, of Columbia University in New York City, and lead author of this study along with colleagues examined whether if the improvement in glycemic control is primarily due to caloric restriction or is unique to the surgical procedure.
The study included 11 patients who had gastric bypass and compared them with 14 matched patients who were put on a very-low-calorie diet.
The patients in the diet group, who were evaluated as inpatients, ate a total of 500 calories per day with a macronutrient content similar to that of the diet given to patients after bypass surgery.
Frequently sampled intravenous glucose tolerance tests were performed before and after interventions.
Both groups lost an equivalent amount of weight over a mean study period of 21 days — 8.1% of body weight for gastric bypass patients and 7.2% for those on the very-low-calorie diet, which was not significantly different.
Reseachers found that other measures of insulin sensitivity and beta-cell function improved to a similar extent in both the bypass group and in the diet group, respectively; HOMA-IR: from 9.5 to 3.5 (P<0.01), and from 6.2 to 1.8 (P<0.001) and Acute C-Peptide response: 12.1% to 28.5% (P<0.05), and from 12.1% to 24% (P<0.01) .
Declines in fasting glucose and fructosamine levels were similar between groups as well, they reported.
The researchers write “Based on these data, VLCD improves insulin sensitivity and beta-cell function just as well as RYGB in the short term..”
The research team cautions t hat the results don’t suggest that gastric bypass is less beneficial in the long run, “since the degree of caloric restriction required to mimic surgical results cannot be maintained in most individuals.”
This study was registered in ClinicalTrials.gov NCT00627484.
This study appears in the journal Diabetes.
More information on Diabetes can be viewed online at the National Diabetes Education Program.
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