The snack is critical for the blood glucose profile during treatment with regular insulin preprandially

Objectives. To evaluate how a snack influences the blood glucose profile du ring treatment with preprandial regular human insulin. Design. In a randomized study a mid-morning snack either was or was not ser ved. Insulin was given 30 min before the usual breakfast of the patients. P lasma 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 inject ions of regular insulin (Actrapid(R)) and eight non-diabetic subjects. Interventions. A mid-morning snack either was or was not served 2 h after t he usual morning insulin injection. Main outcome measures. A difference in the blood glucose profile after a mi d-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 hypoglycaem ia. An extended peak of free insulin was reached 30 min after the insulin i njection with a slow decrease to the fasting level after 5 h. After the ins ulin injection a significant decrease in blood glucose occurred within 30-4 5 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 wit h type 1 diabetes treated with preprandial regular human insulin. Furthermo re, the recommended internal of 30 min between insulin injection and a meal may be too long.