Protein Ingestion in Reducing the Risk of Late-Onset Post-Exercise Hypoglycemia: A Pilot Study in Adolescents and Youth with Type 1 Diabetes

Dietary protein causes dose-dependent hyperglycemia in individuals with type 1 diabetes (T1D). This study investigated the effect of consuming 50 g of protein on overnight blood glucose levels (BGLs) following late-afternoon moderate-intensity exercise. Six participants (3M:3F) with T1D, HbA1c 7.5 +/- 0.8% (58.0 +/- 8.7 mmol/mol) and aged 20.2 +/- 3.1 years exercised for 45 min at 1600 h and consumed a protein drink or water alone at 2000 h, on two separate days. A basal insulin euglycemic clamp was employed to measure the mean glucose infusion rates (m-GIR) required to maintain euglycemia on both nights. The m-GIR on the protein and water nights during the hypoglycemia risk period and overnight were 0.27 +/- 043 vs. 1.60 +/- 0.66 mg/kg/min (p = 0.028, r = 0.63) and 0.51 +/- 0.16 vs. 1.34 +/- 0.71 mg/kg/min (p = 0.028, r = 0.63), respectively. Despite ceasing intravenous glucose infusion on the protein night, the BGLs peaked at 9.6 +/- 1.6 mmol/L, with a hypoglycemia risk period mean of 7.8 +/- 1.5 mmol/L compared to 5.9 +/- 0.4 mmol/L (p = 0.028) on the water night. The mean plasma glucagon levels were 51.5 +/- 14.1 and 27.2 +/- 10.1 ng/L (p = 0.028) on the protein and water night, respectively. This suggests that an intake of protein is effective at reducing the post-exercise hypoglycemia risk, potentially via a glucagon-mediated stimulation of glucose production. However, 50 g of protein may be excessive for maintaining euglycemia.