Gastric Emptying and Insulin Response to Test Drink

Assessment of Insulin Response Following Ingestion of a Carbohydrate/Whey Protein Drink. A Cross-over Randomized Double Blind Study.

Surgery is a stress on the body and recovering well after surgery is very important to patients and their doctors. It is therefore important to prepare patient's bodies for the stress of surgery, and one way to do this is to provide proper nutrition. In the past, patients were asked to prepare for surgery by fasting from midnight before surgery. Today, it is known that this practice is not beneficial to patient's recovery. In fact, it has been recognized that drinking a sugary beverage (e.g., juice) before surgery stimulates the production of insulin, which is a hormone that helps make the proteins needed for wound healing after surgery. This is currently practiced at the MUHC. It might also be beneficial, however, to drink a beverage that contains sugar and whey proteins (a protein isolated from milk) before surgery. In fact, whey proteins stimulate insulin and may also have the added benefit of improving muscular strength. In this study, investigators will measure the level of insulin produced after drinking a carbohydrate (i.e., sugar)-whey protein beverage to determine how it compares to the level of insulin produced after drinking the sugary beverage used at the MUHC.

It is hypothesized that the increase in plasma insulin following a mixed carbohydrate whey protein drink is significantly greater than that elicited by a carbohydrate drink.

Patients in this arm will drink a 425 mL 100% clear apple juice (carbohydrate 50 g, 700 mOsmol). 1.5 g of acetaminophen will be dissolved in the beverage for determination of gastric emptying.

Patients in this arm will drink a 330 mL Boost fruit flavoured clear beverage (whey protein 12.2 g, carbohydrate 50 g, 700 mOsmol).1.5 g of acetaminophen will be dissolved in the beverage for determination of gastric emptying.

Patients will consume a carbohydrate or a whey protein based drink and their insulin response will be monitored every 30 minutes for 3 hours.

The acetaminophen absorption test, as an indirect assessment of gastric emptying.Since gastric emptying is the rate-limiting step in delivering the drug to its absorption site, it is believed that the rate of appearance of acetaminophen in the blood reflects the rate of gastric emptying. Blood samples will be collected every 30 minutes for 3 hours.

Inclusion Criteria: - Healthy volunteer Exclusion Criteria: diabetes, neurological disorders chronic kidney failure chronic liver disease disorders of gastric motility gastro-esophageal reflux achalasia gastroparesis intestinal obstruction previous abdominal surgery lactose intolerance body mass index below 17 or above 29 allergy to acetaminophen.