22 Mar 2010 --- A University of Toronto research team, led by G. Harvey Anderson, Ph.D., has published results of a new study in the American Journal of Clinical Nutrition, showing that the quantity of resistant starch in foods correlates with blood glucose response and reduced food intake after two hours. The team also found that Hi-maize wholegrain corn flour and Hi-maize resistant starch, a natural starch from corn that “resists” digestion in the small intestine, increased satiety and reduced food intake after two hours. This is the first time that resistant starch content alone has been shown to correlate with a satiety benefit.

This randomized, crossover, two-part study investigated the short-term effects of consuming Hi-maize wholegrain corn flour and Hi-maize resistant starch in a group of healthy men, aged 20 to 30 years. “We found that estimates of the resistant starch content predicted the effect on blood glucose concentrations and subsequent food intake, while the dietary fibre content of these particular ingredients did not,” said Anderson, professor of nutritional sciences at the University of Toronto and the principal investigator of the study. “This study suggests a dose response for resistant starch and satiety because of this positive correlation. It also suggests that the resistant starch content of starch-based fibre ingredients should be utilised as a predictive model in designing foods for enhanced satiety.”

Terry Finocchiaro, Ph.D., director of nutrition research and development at National Starch Food Innovation, USA, and a contributing author of the study, was especially pleased with the outcomes. “I am very excited about the satiety effects of Hi-maize whole grain corn flour. The wholegrain corn flour containing high levels of resistant starch enhanced satiety more robustly than we had expected or could have predicted based upon the resistant starch content alone. It appears that the non-starch components of Hi-maize whole grain corn flour enhance the benefits of resistant starch to produce even stronger satiety benefits. This study complements the growing body of scientific evidence linking the consumption of Hi-maize resistant starch to increased satiety and expands those favourable outcomes to Hi-maize whole grain corn flour."

After consuming a standard breakfast, the participants consumed one of five soups - three soups contained 50 grammes of added starch-based ingredients, and two soups served as controls. Fifty grammes of maltodextrin in one soup served as a high glycemic control, and another soup containing no additional carbohydrate ingredients served as a low-calorie control. Glycemic response, subjective satiety and subsequent food intake (with participants instructed to eat until they were comfortably full) information was collected after a defined period of time. Each treatment was separated by a one week washout period.

Sixteen men participated in part one of the study, which collected the glycemic and satiety responses at 30 minutes after consumption of the test soups. The study found that the high glycemic control boosted satiety at 30 minutes but did not reduce cumulative food intake. Ingredients with high resistant starch content had no effect on satiety or food intake at 30 minutes.

Seventeen men participated in part two of the study, which collected glycemic and satiety responses at two hours after consumption of the test soups. At two hours, resistant starch correlated with satiety and reduced food intake. Ingredients with the highest levels of resistant starch had the most pronounced effect. Hi-maize whole grain corn flour had the highest resistant starch content (66 per cent) and reduced cumulative food intake by 15 per cent (244 kilocalories) compared to the high glycemic control.

Hi-maize 260 (48 per cent resistant starch) reduced food intake by 7 per cent (116 kilocalories) and uncooked cornstarch (39 per cent resistant starch) reduced food intake by 7 per cent (113 kilocalories), also compared to the high glycemic control. All of the soups containing resistant starch (including the ones with low dietary fibre) reduced food intake at two hours.