Protein counts in mealtime insulin dosing

Type 1 diabetes

By Kate Marsh

7 Oct 2015

Research presented at ISPADAPEG2015 here in Brisbane strengthens the case for considering protein when calculating mealtime insulin doses, especially for larger quantities.

Speaking during the oral session today on Diabetes Education, Exercise and Nutrition Megan Paterson, a Pediatric CNC and Credentialled Diabetes Educator from the John Hunter Children’s Hospital in Newcastle presented the preliminary findings of her research on the impact of protein on post-prandial glycemia.

Previous research by the group had found that only larger quantities (75g) of protein had a significant impact on post-prandial glycemia when consumed without carbohydrate.

“This amount of protein resulted in a glycemic response equivalent to that of 20g of glucose consumed without insulin, however there was a significant difference in the timing of the response, with the protein resulting in a late glycemic response, from 3-5 hours after the meal”, Ms Paterson told the limbic.

Her current study, comparing five test meals containing 30g of carbohydrate, no fat and varying amounts of protein from 0 to 75g,  showed a clear dose response, with increasing amounts of protein resulting in a larger rise in post-prandial glucose from around 120 minutes after the meal.

The study included individuals with type 1 diabetes of at least 12 months duration, aged 7-40 years with no other complications.  Insulin doses were calculated based on individual insulin-to-carbohydrate ratios.

“We are showing significantly greater postprandial glycemic excursions from 180 minutes up to 300 minutes” said Megan.  “The mean maximal difference reached 5mmol/L by 300 minutes with 75mg of protein compared to a carb-only meal”, she explained.

The research team also found a difference during the 30-60 minute post-prandial period, with a lower glucose response for higher amounts of protein.

At this stage this is only statistically significant for the 75g protein meal but with data currently only available for 23 of the planned 35 subjects, Ms Pateron says this finding may change.

Her group are also doing further studies looking at different methods of insulin dosing for protein – for example, for those on a pump trialling a split bolus of 50/50 given over a few hours.

“Our findings further strengthen the recommendations that we should now be considering protein for calculating mealtime insulin doses, especially for larger quantities”, said Megan.  “There is probably no need to adjust for amounts up to 25g,” she added.

This was not a one size fits all approach and was really only appropriate for those who are already accurately counting carbs, monitoring regularly and who are really aware of what they are eating and the impact on their BGLs, Ms Paterson stressed.

“There still needs to be more research so we can safely and accurately calculate insulin doses for the protein content of meals,” she said.

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