Effects of a high-fiber diet on symptoms of irritable bowel syndrome: a randomized clinical trial.
OBJECTIVE
We investigated the effects of dietary fiber on symptoms of irritable bowel syndrome.


METHODS
A single-blind randomized clinical trial was designed. Fifty-six subjects with irritable bowel syndrome were prospectively and randomly assigned to one of two groups: group 1 received a diet containing 10.4 g/d of fiber and group 2 received a diet containing 30.5 g/d of fiber. Patients' body weights, nutritional intakes as assessed with 3-d written food records, and symptom scores were assessed at baseline and at 3 mo.


RESULTS
There were no dropouts during the study. Total energy intake and the distribution of macronutrients were not significantly different between groups. Total dietary fiber intake did not reach recommended levels in either group but was higher in group 2 than in group 1 (25.95 +/- 2.12 g/d versus 6.06 +/- 2.7 g/d, P < 0.05). Initial fiber intake did not differ significantly between groups. Pain scores, bowel scores, and general scores improved in both groups (from baseline to 3 mo), and no significant differences were detected between groups.


CONCLUSIONS
A modest fiber intake in patients with irritable bowel syndrome relieved symptoms, but this therapeutic benefit of fiber may have been due to a placebo effect because the results were similar in the low-fiber group.
Institute of Endocrinology and Nutrition, Medical School, University of Valladolid, Spain.
Rocio
R
Aller
Daniel Antonio
DA
de Luis
Olatz
O
Izaola
Fernando
F
la Calle
Lourdes
L
del Olmo
Luis
L
Fernandez
Teresa
T
Arranz
J M
JM
González Hernandez
D000328:Adult; D001835:Body Weight / Q000502:physiology; D015930:Diet Records; D004043:Dietary Fiber / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000178:diet therapy*; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D010147:Pain Measurement / Q000379:methods; D015990:Placebo Effect; D011446:Prospective Studies; D016037:Single-Blind Method; D013997:Time Factors