Best Insulin Dosing When Eating Pizza

Study finds way to keep glucose levels in check

The folks at Penn State Hershey Medical Center want diabetics to feel safe when chowing down on a few slices of pizza. Nurses and dietitians at the medical center became concerned when they realized diabetic patients had trouble keeping their glucose levels in check after dining on pizza.

"We noticed that it was very difficult for those with diabetes who were using insulin pumps to maintain good glucose values when they ate pizza," said nurse practitioner Susan M. Jones. "Because pizza is a favorite food for so many people, and good quality of life is eating what you want every now and again, we suggested a study to see how best to help those with diabetes enjoy this common favorite food while maintaining good glucose levels."

Researchers conducted a three-day study to determine the best way diabetics can deliver insulin to counter the glucose-raising effects of the carbohydrate-dense crust and high-fat toppings.

The study showed that diabetics who eat pizza are best served by a slow, steady dose of insulin.

During the study, 26 volunteers with Type 1 diabetes ate pizza for their evening meal for three straight days.

Investigators monitored patients’ glucose levels with a new system called CGMS, which averages blood glucose levels every five minutes. The suggested glucose range is between 80 mg/dl and 124 mg/dl.

On the first day, insulin was given immediately before the meal, resulting in glucose levels of 133 mg/dl.

On day two, volunteers had half their insulin dose immediately before the meal and the other half slowly administered via a continuous insulin pump over four hours after the meal. Glucose levels were measured at 145 mg/dl.

On the third day, volunteers received a half-dose of insulin before the meal and the other half slowly administered via insulin pump over eight hours after the meal. Glucose levels on the third day measured a much safer 104 mg/dl.

"Our study shows that after a high-carbohydrate, high-fat meal like the pizza, spacing out insulin given by an insulin pump in two doses, one of which is over an eight-hour period, may keep glucose levels in a more favorable range than a single dose of insulin or a double dose taken over a shorter period," Gabbay said.

"Pizza is a complex food and causes prolonged post-meal hyperglycemia," Gabbay said. "For now, generalization to food types other than pizza may best be based on foods that are known to cause the same type of prolonged hyperglycemia and not necessarily those that have only the same composition."

Gabbay’s study is the first of its kind to investigate the timing of insulin administered in two doses. The results stand out because the slow, prolonged dose of insulin after the meal did not cause patients to become hypoglycemic, which is common.

"Blood glucose control after a pizza meal was improved by extending the time of delivery of insulin to eight hours without varying the total amount of insulin administered," Gabbay said. "We showed that the eight-hour extended dose of insulin better controlled post-meal glucose levels and did not decrease glucose levels enough to cause any hypoglycemic events, which is unusual."
Diabetes Technology & Therapeutics, April 2005