Objectives. To evaluate how a snack influences the blood glucose profile during treatment with preprandial regular human insulin.
Design. In a randomized study a mid-morning snack either was or was not served. Insulin was given 30 min before the usual breakfast of the patients. Plasma free insulin and blood glucose were repeatedly determined for 5 h.
Setting. Outpatient clinic at a university hospital.
Subjects. Twenty patients with type 1 diabetes treated with multiple injections of regular insulin (Actrapid®) and eight non-diabetic subjects.
Interventions. A mid-morning snack either was or was not served 2 h after the usual morning insulin injection.
Main outcome measures. A difference in the blood glucose profile after a mid-morning snack.
Results. With a snack there was no difference in blood glucose fasting and at 12.30 h, whilst without a snack there was a decrease of almost 4 mmol L−1, several patients experienced low blood glucose and three had hypoglycaemia. An extended peak of free insulin was reached 30 min after the insulin injection with a slow decrease to the fasting level after 5 h. After the insulin injection a significant decrease in blood glucose occurred within 30–45 min
Conclusions. A snack 2 h after the insulin injection results in a smoother blood glucose profile and reduces the risk of hypoglycaemia in patients with type 1 diabetes treated with preprandial regular human insulin. Furthermore, the recommended interval of 30 min between insulin injection and a meal may be too long.