Effects of cereal fiber on bowel function: A systematic review of intervention trials

Table 2 Fiber intakes and effects on total stool weight, dry stool weight, percentage water in stool, stool frequency, and transit time

	Source of intact cereal dietary fiber
	Wheat	Barley	Corn
Total stool weight
Observations, n	75	3	4
Fiber (g/d), mean ± SD or range	15.2 ± 8.3	10.2-23	6.0-42
Total effect (g/d), mean ± SD or range	65.4 ± 37.8	49.6-65	1.2-96.3
Average fecal bulking index, Δ in g/d stool weight per g/d fiber	4.7 ± 2.7	3.6 ± 2.4	2.1 ± 1.5
Fecal bulking index by regression, Δ in g/d stool weight per g/d fiber	3.67 ± 0.09b	-	-
	(3.50-3.84)
Dry stool weight
Observations, n	40	1	3
Fiber (g/d), mean ± SD or range	14.7 ± 8.5	-	6-42
Total effect (g/d), mean ± SD or range	14.4 ± 9.4	-	4.8-31
Fecal bulking index by regression, Δ in g/d stool weight per g/d fiber	0.75 ± 0.03b	-	0.7-0.9
	(0.69-0.82)
Fecal water
Observations, n	30	3	2
Fiber (g/d), mean ± SD or range	16.0 ± 7.4	10.2-23	-
Total effect by regression (∆% water), mean ± SD or range	1.5 ± 2.1	-1.8-10	-
Stool frequency
Observations, n	34	2	2
Fiber (g/d), mean ± SD or range	13.6 ± 6.4	-	-
Total effect (times/d), mean ± SD or range	0.34 ± 0.23	-	-
Frequency index by regression, Δ in times/d per g/d fiber	0.004 ± 0.002a	-	-
	(0.003-0.078)
Transit time
Observations, n	52	0	0
Fiber (g/d), mean ± SD	14.8 ± 8,4	-	-
Δ in h per g/d fiber by regression (those with initial transit time between 24-48 h)	0.78 ± 0.13b	-	-
	(0.53-1.04)
Δ in h per g/d fiber by regression (those with initial transit time between 48-96 h)	-0.75 ± 0.04b	-	-
	(-0.84- -0.67)

^aP < 0.05,

^bP < 0.01 vs control.