The use of inulin in foods as a fiber source has increased recently. Consumption of
inulin products can cause gastrointestinal (GI) distress. Acceptable intakes of inulin
need to be determined.
To determine the GI tolerance of two inulin fibers, shorter chain length oligofructose
and native inulin, at 5- and 10-g doses compared to a placebo.
A randomized, double-blind, controlled, crossover design that included a phone screening
and five visits for breakfast fiber challenges consisting of a bagel, cream cheese,
and orange juice.
Twenty-six healthy men and women ages 18 to 60 years participated in the study. Healthy
subjects with no history of GI conditions consumed diets with typical amounts of fiber.
Main outcome measures
GI tolerance was calculated as the sum of scores on seven GI tolerance domains via
questionnaire administered at t=0, 2, 4, 24, and 48 hours following fiber challenge.
Statistical analyses performed
A mixed effects linear model was used to compare the tolerance scores among the five
The two inulin fibers tended to increase GI symptoms mildly. Most frequently reported
symptoms were flatulence followed by bloating. The 10-g dose of oligofructose substantially
increased GI symptoms compared to control.
Doses up to 10 g/day of native inulin and up to 5 g/day of oligofructose were well-tolerated
in healthy, young adults.