Dietary fiber type reflects physiological functionality: Comparison of grain fiber, inulin, and polydextrose

Kaisa Raninen, Jenni Lappi, Hannu Mykkänen, Kaisa Poutanen (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

182 Citations (Scopus)


Dietary fiber is a nutritional concept based not on physiological functions but on defined chemical and physical properties. Recent definitions of dietary fiber differentiate inherent plant cell wall-associated fiber from isolated or synthetic fiber. For the latter to be defined as fiber, beneficial physiological effects should be demonstrated, such as laxative effects, fermentability, attenuation of blood cholesterol levels, or postprandial glucose response. Grain fibers are a major natural source of dietary fiber worldwide, while inulin, a soluble indigestible fructose polymer isolated from chicory, and polydextrose, a synthetic indigestible glucose polymer, have more simple structures. Inulin and polydextrose show many of the same functionalities of grain fiber in the large intestine, in that they are fermentable, bifidogenic, and laxative. The reported effects on postprandial blood glucose and fasting cholesterol levels have been modest, but grain fibers also show variable effects. New biomarkers are needed to link the physiological functions of specific fibers with long-term health benefits.
Original languageEnglish
Pages (from-to)9-21
JournalNutrition Reviews
Issue number1
Publication statusPublished - Jan 2011
MoE publication typeA1 Journal article-refereed


  • dietary fiber
  • functionality
  • grain fiber
  • inulin
  • polydextrose


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