Wheat fiber and laxation: dose response and equilibration time.

We studied the dose response to soft white winter wheat fiber on fecal output in a group of healthy volunteers whose breakfasts consisted of wheat fiber cereals in amounts that provided 0.3 g, 5.6 g, 9.5 g, 11.2 g, 19.0 g, and 28.4 g dietary fiber per day for 14 days; no other aspects of their diet were altered. A linear dose response was observed between the six levels of fiber intake (r = 0.983, p less than 0.01) with a 1-g increase in wheat fiber, producing a mean 2.7-g increase in fecal weight. This increase was independent of the initial daily fecal weight of the volunteer (mean 117 +/- 64 g/day, range 5-297 g/day, n = 73). The maximum increase in fecal output due to cereal fiber was reached after the first week on the supplement. These data support the use of graded amounts of cereal fiber in the management of constipation.