Glycemic index and insulin response to a liquid nutritional formula compared with a standard meal

To determine the glycemic index and metabolic responses to a nutritional formula, and to compare these responses to those following an oral glucose meal and a standard test meal.

Six male and six female healthy non-diabetic volunteers aged 18 to 48 years met screening examination and laboratory assessment criteria. Three test meals were administered, each containing 50 g of carbohydrate: nutritional formula (NF), standard test meal (ST) and a glucose test meal (GT). Each subject underwent the three test meals on separate days in randomized sequence. Blood samples were taken at intervals over 5 hours for determination of glucose, insulin and triglycerides.

The glycemic index was similar for the NF (60.8 +/- 13.1) and for the ST (57.8 +/- 12.9) meals. The incremental area under the curve for glucose was similar for NF and ST, but each was significantly lower than for the GT meal. The total area under the curve for insulin was significantly greater for the NF meal than for the ST meal. The serum triglyceride responses were similar for NF and ST meals.

In healthy non-diabetic subjects, the blood glucose and triglyceride responses are similar for a nutritional formula compared to an isoenergetic standard test meal. However, the insulin response differs. This information is important in managing tube-fed patients.