An Isoenergetic Multifactorial Diet Reduces Pancreatic Fat and Increases Postprandial Insulin Response in Patients With Type 2 Diabetes: A Randomized Controlled Trial

Abstract

OBJECTIVE To compare the effect of an isocaloric multifactorial diet with a diet rich in monounsaturated fatty acids (MUFA) and similar macronutrient composition on pancreatic fat (PF) and postprandial insulin response in type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS According to a randomized controlled parallel-group design, 39 individuals with T2D, 35–75 years old, in satisfactory blood glucose control, were assigned to an 8 week isocaloric intervention with a multifactorial diet rich in MUFA, polyunsaturated fatty acids, fiber, polyphenols, and vitamins (n = 18) or a MUFA-rich diet (n = 21). Before/after the intervention, PF content was measured by the proton-density fat fraction using a three-dimensional mDIXON MRI sequence, and plasma insulin and glucose concentrations were measured over a 4 h test meal with a similar composition as the assigned diet. RESULTS After 8 weeks, PF significantly decreased after the multifactorial diet (from 15.7 ± 6.5% to 14.1 ± 6.3%; P = 0.024), while it did not change after the MUFA diet (from 17.1 ± 10.1% to 18.6 ± 10.6%; P = 0.139) with a significant difference between diets (P = 0.014). Postprandial glucose response was similar in the two groups. Early postprandial insulin response (incremental postprandial areas under the curve [iAUC0–120]) significantly increased with the multifactorial diet (from 36,340 ± 34,954 to 44,138 ± 31,878 pmol/L/min; P = 0.037), while it did not change significantly in the MUFA diet (from 31,754 ± 18,446 to 26,976 ± 12,265 pmol/L/min; P = 0.178), with a significant difference between diets (P = 0.023). Changes in PF inversely correlated with changes in early postprandial insulin response (r = −0.383; P = 0.023). CONCLUSIONS In patients with T2D, an isocaloric multifactorial diet, including several beneficial dietary components, markedly reduced PF. This reduction was associated with an improved postprandial insulin response.