Verifying Fibers Meet Regulatory Definitions for Nutrition Facts Labeling: A Randomized, Controlled Trial Evaluating Polydextrose in Dry Form

摘要

National concern over low fiber intake in America has prompted the food industry to supplement processed foods with added fibers. The U.S. Food and Drug Administration (FDA) proposed a new rule for Nutrition Facts labeling requiring added/functional fibers to demonstrate a physiological health benefit to be considered as dietary fiber on the Nutrition Facts label. Physiological benefits, however, can be affected by the fiber's physiochemical properties and environment (i.e. food matrix). Polydextrose (PDX) is a synthetic polymer of glucose resistant to digestion with mixed reports regarding its contribution to producing physiological effects based on "acceptable" fiber benefits: glucose control, cholesterol lowering and laxation effect. Previously we showed that PDX does not lower postprandial glucose when added to a sugar drink (wet matrix). In the present study, we tested PDX in a dry cereal bar to determine if the dry matrix would reveal differential effects of PDX on postprandial glycemia. In a randomized, 3 h postprandial, crossover clinical trial, nineteen participants (10 male, 9 female) with a mean (+/- SD) age of 35.1 +/- 8.5 y and BMI 25.0 +/- 3.6 kg/m2 consumed a cereal bar with either 0 g or 12 g of PDX as a light breakfast on two separate occasions. Consumption of the cereal bar with 12 g of PDX significantly increased the postprandial glucose and insulin responses compared to 0 g control (p=0.02 and p=0.01, respectively). Total area under the curve (AUC) values for glucose over 3 hours was not significantly higher than control (p=0.16), but total AUC for insulin was significantly higher (p=0.03). Gastrointestinal (GI) tolerability was evaluated using scores ranked according to usual feelings of GI sensitivity. Overall, no significant changes or differences between treatments in GI tolerability were observed (p>0.05). Based on the endpoint of glycemia and the proposed FDA rule for fiber labeling, PDX would not qualify as a dietary fiber on the Nutrition Facts label.