18-OR: The Effect of a Dietary Intervention on Insulin Sensitivity in Type 1 Diabetes and the Role of Dietary Advanced Glycation End-Products—A 12-Week Randomized Clinical Trial

Background: This study compared the effect of a low-fat vegan diet with a portion-controlled diet on insulin sensitivity in people with type 1 diabetes and explored the role of dietary advanced glycation end-products (AGEs).

Methods: Fifty-eight adults with type 1 diabetes were randomly assigned to a vegan (n=29), or a portion-controlled group (n=29) for 12 weeks. Insulin sensitivity was assessed, using the carbohydrate to insulin ratio. The content of all meals was recorded using the Cronometer mobile application. Total insulin dose was calculated as a sum of basal and bolus insulin units injected per day.

Results: Insulin sensitivity increased in the vegan group by 6.6 (p=0.002), compared with no significant change in the portion-controlled group (-1.6; p=0.26; treatment effect +8.2 [95% CI, +3.6 to +12.8]; p=0.001). Total dietary AGEs decreased in the vegan group by 7,123 ku/day (95% CI, -9,493 to -4,756; p<0.001), compared with no significant change in the portion-controlled group (treatment effect -5,076 ku/day [95% CI, -8,605 to -1,548]; p=0.006). Change in total dietary AGEs correlated negatively with changes in insulin sensitivity (r=-0.48; p=0.004) and remained significant after adjustment for changes in BMI (r=-0.35; p=0.048). A 1-unit increase in insulin sensitivity was associated with a reduction in dietary AGEs by 2,090 ku/day.

Conclusions and Interpretation: This study suggests that a low-fat vegan diet improves insulin sensitivity in people with type 1 diabetes compared with a portion-controlled diet, and the reduction in dietary AGEs seems to be one of the mediating mechanisms. Larger trials are needed to confirm these findings.