Increasing the protein quantity in a meal results in dose‐dependent effects on postprandial glucose levels in individuals with Type 1 diabetes mellitus

• Published in: Diabetic medicine 2017-06, Vol.34 (6), p.851-854
• Main Authors: Paterson, M. A., Smart, C. E. M., Lopez, P. E., Howley, P., McElduff, P., Attia, J., Morbey, C., King, B. R.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Blood glucose; Blood Glucose - drug effects; Blood Glucose - metabolism; Blood Glucose Self-Monitoring; Carbohydrates; Child; Diabetes; Diabetes mellitus; Diabetes Mellitus, Type 1 - blood; Diabetes Mellitus, Type 1 - drug therapy; Dietary Proteins - administration & dosage; Dietary Proteins - pharmacology; Dose-Response Relationship, Drug; Female; Glucose; Glucose monitoring; Humans; Hypoglycemic Agents - administration & dosage; Insulin; Insulin - administration & dosage; Male; Meals; Postprandial Period - drug effects; Proteins; Whey; Young Adult
• ISSN: 0742-3071; 1464-5491
• DOI: 10.1111/dme.13347

Aim To determine the glycaemic impact of increasing protein quantities when consumed with consistent amounts of carbohydrate in individuals with Type 1 diabetes on intensive insulin therapy. Methods Participants with Type 1 diabetes [aged 10–40 years, HbA1c ≤ 64 mmol/mol (8%), BMI ≤ 91st percentile] received a 30‐g carbohydrate (negligible fat) test drink daily over 5 days in randomized order. Protein (whey isolate 0 g/kg carbohydrate, 0 g/kg lipid) was added in amounts of 0 (control), 12.5, 25, 50 and 75 g. A standardized dose of insulin was given for the carbohydrate. Postprandial glycaemia was assessed by 5 h of continuous glucose monitoring. Results Data were collected from 27 participants (15 male). A dose–response relationship was found with increasing amount of protein. A significant negative relationship between protein dose and mean excursion was seen at the 30‐ and 60‐min time points (P = 0.007 and P = 0.002, respectively). No significant relationship was seen at the 90‐ and 120‐min time points. Thereafter, the dose–response relationship inverted, such that there was a significant positive relationship for each of the 150–300‐min time points (P < 0.004). Mean glycaemic excursions were significantly greater for all protein‐added test drinks from 150 to 300 min (P < 0.005) with the 75‐g protein load, resulting in a mean excursion that was 5 mmol/l higher when compared with the control test drink (P < 0.001). Conclusions Increasing protein quantity in a low‐fat meal containing consistent amounts of carbohydrate decreases glucose excursions in the early (0–60‐min) postprandial period and then increases in the later postprandial period in a dose‐dependent manner. What's new? This research looks at the postprandial glycaemic impact of dietary protein when consumed with carbohydrate and minimal fat. Results indicate that increasing amounts of protein result in dose‐dependent changes in glycaemia. This impact has an inverse relationship in the early and late postprandial period. This is the first study to show that the effect of protein on postprandial glycaemic control is dose‐dependent and bi‐phasic. This study has significant implications for insulin dosing for meals containing protein.