What is the influence of dietary protein on post meal blood glucose?
Does protein effect blood sugar after a meal? Is there additional math we need to do for improved control after meals?
At present, those of us who use intensive insulin therapy understand how proper mealtime insulin dosing requires appropriate carbohydrate counting. This is based on the thought that carbohydrate is the main nutrient that influences our post meal blood sugar values. However, studies have demonstrated that protein and fat may also play a role in what happens to our post meal blood sugar.
The impact of dietary protein on blood sugar has long been a topic of debate. Early research hypothesized that 100 g of ingested protein produced 50–80 g glucose. Later research showed, it was only ~ 10 g of glucose that showed up in the circulation following consumption of 50 g of protein (this is a serving of cooked meat about the size of a full outstretched woman’s hand). This equates to ~ 1 g of glucose produced from every 5 g of protein consumed. The results of the study below are consistent with this and, indicate consumption of ~ 75g and 100 g of protein ALONE may produce late rises in blood glucose which is similar to that from 15 and 20 g of glucose. This is relevant, given that 20 g of consumed glucose causes significant post meal excursions when insulin is NOT given. However, because the impact from protein (usually not covered by insulin) is delayed and sustained it shows a good reason we need consider dosing for protein dependent on portion consumed.
Protein-rich meals may result in delaying the rise in blood glucose and produce a sustained high blood glucose.
This indicates a need for more insulin for such meals or snacks as well as a new way to think about dosing insulin to offset the slow and extended rise. There are some algorithms to calculate additional insulin for protein, but, when studied these seem to show an increase in post meal low blood glucose.
The effect of protein has been studied only as a component of mixed meals (with carbohydrate, fat and protein present). Until recently, there have been no published studies of the impact of ONLY protein in people with Type 1 diabetes. The objective of the study discussed below was to determine if there is an effect from protein alone. The study evaluated the post meal blood glucose dose-responsive curves to varying amounts of protein, independent of carbohydrate and fat.
(The study was conducted across two centers in Newcastle, Australia by M. A. Paterson1,2, C. E. M. Smart1,3, P. E. Lopez1,2, P. McElduff1, J. Attia1, C. Morbey 4 and B. R. King2,3)
The study looked at participants with Type 1 diabetes mellitus who were 7–40 years old. The participants consumed six 150 ml whey isolate protein drinks