Oral Presentation Australian Diabetes Society and the Australian Diabetes Educators Association Annual Scientific Meeting 2017

What is the quantity of additional insulin required for meals high in fat and protein? (#129)

Megan Evans 1 2 , Carmel E Smart 3 4 , Barbara Keating 1 2 , Nirubasini Paramalingam 1 , Grant Smith 1 , Tim W Jones 1 2 , Bruce R King 3 4 , Elizabeth A Davis 1 2
  1. Telethon Kids Institute, University of Western Australia, Perth, WA, Australia
  2. Department of Endocrinology and Diabetes, Princess Margaret Hospital for Children, Perth, WA, Australia
  3. Department of Paediatric Endocrinology and Diabetes, John Hunter Children's Hospital, Newcastle, NSW, Australia
  4. Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW, Australia

It is routine clinical practice to calculate mealtime insulin doses for people with type 1 diabetes (T1D) based on the carbohydrate content of the meal.  Studies have demonstrated that addition of fat and protein to a meal causes prolonged postprandial hyperglycaemia.  We have shown that additional insulin is required for a high protein meal. However, the quantity and distribution of insulin required to cover meals high in both fat and protein remains unclear.  The aim of this study was to determine the insulin requirement for a high fat high protein meal (HFHP) compared to a low fat low protein meal (LFLP) controlling for carbohydrate.

Nine subjects with T1D aged 12-21yrs attended fasted on 2 occasions and were randomised to consume a HFHP (40g fat, 60g protein) meal or LFLP (5g fat, 5g protein) meal with identical carbohydrate content (30g).  An insulin clamp technique was used to titrate IV insulin infusion to maintain blood glucose levels (BGL) in the euglycaemic range for the 5-hour post prandial period.

There was a significant difference in the mean insulin required for the HFHP meal compared with the LFLP meal of 5.3 ± 2.6 units (11.5 ± 3.0 vs 6.2 units ± 2.0 ; P<0.01). This represents a mean increase of 85% compared to our earlier findings of 57% for a high protein meal.  There was inter-individual variation with a range of difference in insulin requirements of 1.7 units to 9.9 units, representing an increase of 30% to 250%.  Postprandial glucose excursions were similar on both study days.

The addition of fat and protein increases the amount of insulin required for a meal.  The effect of fat and protein together is greater than the effect of protein alone. Substantial individual differences indicate the need for individualised advice regarding meal boluses for HFHP meals.