Functional fibers can help Americans increase their fiber intake by incorporating extracted or synthesized fibers into food products. The United States Food and Drug Administration has recently proposed that "added" fibers must demonstrate a physiological health benefit, such as glucose control, to be included on the Nutrition Facts label as a dietary fiber. The objective of this study was to assess the effects of polydextrose (PDX), a water-soluble glucose polymer resistant to mammalian digestion, on postprandial glucose concentrations when added to relatively high moisture (beverage) versus low moisture (bar) food products. The study was designed as 2 parts with each being controlled, randomized, singe-blinded, cross-over trials. A total of 34 and 19 healthy subjects were asked to consume PDX in a beverage and bar, respectively. PDX was investigated at 0, 8, 12, and 16 g in the beverage and 0 and 12 g in the bar. Blood samples were collected before beverage/bar consumption and for 3 h thereafter to evaluate changes in plasma glucose and insulin concentrations. The 12 g PDX condition had significant impact on both outcomes as glucose was significantly increased in both matrices (P > 0.05) and insulin was increased in bar form only (P > 0.05). PDX was well tolerated at all dosages and matrices investigated. PDX did not lower postprandial glucose or insulin in either matrix at the doses provided; therefore, data do not support reporting PDX as a dietary fiber on the Nutrition Facts label under the current proposed rule using glycemic control as the endpoint for physiological benefit.
Keywords: dietary fiber; functional fiber; glycemia; matrix effect; polydextrose.
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