Effects of cereal fiber on bowel function: A systematic review of intervention trials.
OBJECTIVE
To comprehensively review and quantitatively summarize results from intervention studies that examined the effects of intact cereal dietary fiber on parameters of bowel function.


METHODS
A systematic literature search was conducted using PubMed and EMBASE. Supplementary literature searches included screening reference lists from relevant studies and reviews. Eligible outcomes were stool wet and dry weight, percentage water in stools, stool frequency and consistency, and total transit time. Weighted regression analyses generated mean change (± SD) in these measures per g/d of dietary fiber.


RESULTS
Sixty-five intervention studies among generally healthy populations were identified. A quantitative examination of the effects of non-wheat sources of intact cereal dietary fibers was not possible due to an insufficient number of studies. Weighted regression analyses demonstrated that each extra g/d of wheat fiber increased total stool weight by 3.7 ± 0.09 g/d (P < 0.0001; 95%CI: 3.50-3.84), dry stool weight by 0.75 ± 0.03 g/d (P < 0.0001; 95%CI: 0.69-0.82), and stool frequency by 0.004 ± 0.002 times/d (P = 0.0346; 95%CI: 0.0003-0.0078). Transit time decreased by 0.78 ± 0.13 h per additional g/d (P < 0.0001; 95%CI: 0.53-1.04) of wheat fiber among those with an initial transit time greater than 48 h.


CONCLUSIONS
Wheat dietary fiber, and predominately wheat bran dietary fiber, improves measures of bowel function.
Jan de Vries, De Vries Nutrition Solutions Inc., 7213 CE Gorssel, The Netherlands.
Jan
J
de Vries
Jan de Vries, De Vries Nutrition Solutions Inc., 7213 CE Gorssel, The Netherlands.
Paige E
PE
Miller
Jan de Vries, De Vries Nutrition Solutions Inc., 7213 CE Gorssel, The Netherlands.
Kristin
K
Verbeke
D002986:Clinical Trials as Topic; D003672:Defecation; D004043:Dietary Fiber; D002523:Edible Grain; D005247:Feeding Behavior; D041981:Gastrointestinal Tract / Q000502:physiology*; D005772:Gastrointestinal Transit; D006304:Health Status; D006801:Humans; D008019:Life Style
Bowel function; Cereal; Comprehensive review; Dietary fiber; Wheat bran