Additional Insulin for Coping with Fat- and Protein-Rich Meals in Adolescents with Type 1 Diabetes: The Protein Unit.

Objective: Dietary proteins raise blood glucose levels; dietary fats delay this rise. We sought to assess the insulin amount required to normalize glucose levels after a fat- and protein-rich meal (FPRM).

Methods: Sixteen adolescents (5 female) with type 1 diabetes (median age: 18.2 years; range: 15.2-24.0; duration: 7.1 years; 2.3-14.3; HbA1c: 7.2%; 6.2-8.3%) were included. FPRM (carbohydrates 57 g; protein 92 g; fat 39 g; fibers 7 g; calories 975 Kcal) was served in the evening, with 20 or 40% extra insulin compared to a standard meal (SM) (carbohydrates 70 g; protein 28 g; fat 19 g; fibers 10 g; calories 579 Kcal) or carbohydrates only. Insulin was administered for patients on intensified insulin therapy or as a 4-hour-delayed bolus for those on pump therapy. The 12-hour post-meal glucose levels were compared between FPRM and SM, with the extra insulin amount calculated based on 100 g proteins as a multiple of the carbohydrate unit.

Results: Glucose levels (median, mg/dL) 12-hour post-meal with 20% extra insulin vs. 40% vs. insulin dose for SM were 116 vs. 113 vs. 91. Glucose-AUC over 12-hour post-meal with 20% extra insulin vs. 40% vs. insulin dose for SM was 1603 mg/dL/12 h vs. 1527 vs. 1400 (no significance). Glucose levels in the target range with 20% extra insulin vs. 40% were 60% vs. 69% (p=0.1). Glucose levels <60 mg/dL did not increase with 40% extra insulin. This corresponds to the 2.15-fold carbohydrate unit for 100 g protein.

Conclusions: We recommend administering the same insulin dose given for 1 carbohydrate unit (10 g carbs) to cover 50 g protein.