The human clinical trial, which involved ten participants, was conducted by Glycemic Index Laboratories for Glanbia Nutritionals. NutraIngredients.com has not seen the full study, which is unpublished. Glanbia said it currently has no plans to publish the study. According to Glanbia, participants experienced a statistically significant reduction of up to 37.8 Glycemic Index units when Prolibra was added to a liquid meal consisting of 50 g of glucose. Prolibra is a partially hydrolyzed whey protein isolate, high in protein and low in fat. Glanbia's suggested uses for the ingredient include beverages, powdered beverage mixes and snack bars. Testing
Participants in the latest study, who had an average BMI of 33.6kg/m², fasted for 10-14 hours. They were then weighed and a blood sample was taken, before they consumed a test meal. Blood samples were then taken as 15, 30, 45, 60, 90 and 125 minutes after the meal. Three Prolibra dose levels were used to determine the glycemic index lowering potential of the ingredient within a liquid meal - 6.1g, 12.2g and 24.4g, said Glanbia. As the dose of Prolibra increased, a corresponding decrease in GI values was observed.
"The addition of Prolibra to a liquid meal in the dose range of 6.1 - 24.4g will result in a reduction of GI value of the product by approximately 7.6 - 37.8 GI units, respectively," found the study. Glycemic Index The Glycemic Index is considered to be one dietary approach to weight management. It measures how quickly certain foods release carbohydrates into the body, which then raise consumers' blood glucose levels. High GI foods cause blood sugar levels to rise more rapidly. Low GI foods are thought to provide more sustained energy levels, thereby promoting feelings of satiety.
Previous studies Another recent study with Prolibra found that the ingredient could help reduce body fat and maintain lean muscle mass. The randomised, double-blind study, published in the open access journal Nutrition & Metabolism, was performed in collaboration with researchers from the Minnesota Applied Research Center (MARC) and the Veterans Administration Medical Center in Minneapolis. Obese subjects were assigned to a reduced calorie diet for 12 weeks and receiving daily supplements containing Glanbia's Prolibra ingredient lost an average 6.1 per cent of their body fat mass.
Last year, a 12-week double-blind, placebo-controlled study found that adults consuming Prolibra lost 82 per cent more fat than the placebo group, and retained twice as much lean muscle mass. The company announced the results of its first Prolibra study in 2004. A double-blind, placebo-controlled study of 42 participants confirmed the effect of supplementing the diet with Prolibra. The study subjects were asked to reduce their caloric intake to between 600-700 calories for the study yet most failed to do so. However those taking Prolibra still managed to reduce body fat by 6 per cent over a 16-week period, according to the firm.
The weight loss and management market is estimated to already be worth $7bn (€5.2bn) globally.