An isoenergetic multifactorial diet reduces pancreatic fat and increases postprandial insulin response in patients with type 2 diabetes: a randomized controlled trial

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, fibre, 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 3D mDixon MRI sequence, plasma insulin and glucose concentrations were measured over a 4h 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 (iAUC0-120) significantly increased with the multifactorial diet (from 36340±34954 to 44138±31878 pmol/L·min, p=0.037), while it did not change significantly in the MUFA diet (from 31754±18446 to 26976±12265 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 T2D patients, an isocaloric multifactorial diet including several beneficial dietary components markedly reduced PF. This reduction was associated with an improved postprandial insulin response.