Constipation during pregnancy: dietary fibre intake and the effect of fibre supplementation. Randomised-controlled trial of a fibre supplement on the symptoms of irritable bowel syndrome. A dietary fiber mixture versus lactulose in the treatment of childhood constipation: a double-blind randomized controlled trial. Laxatives in the treatment of constipation in pregnant and breast-feeding mothers. Irritable bowel syndrome: assessment of psychological disturbance and its influence on the response to fibre supplementation. A controlled trial of a high dietary fibre intake in pregnancy--effects on plasma glucose and insulin levels. Is bran efficacious in irritable bowel syndrome? A double blind placebo controlled crossover study. Lack of effect of a high-fiber cereal supplement on the recurrence of colorectal adenomas. Phoenix Colon Cancer Prevention Physicians' Network. Differing effects of low and high bulk maternal dietary supplements during pregnancy.
Forty women who complained of constipation during the third trimester of pregnancy completed 14-day weighed diet records and bowel function charts over a 4-week period. After 2 weeks of baseline observation the women were randomly allocated into three groups which were asked to take 10 g dietary fibre supplements per day in the form of either a corn-based biscuit (Group A), or as wheat bran (Gp B), or to continue without intervention (Gp C). Mean (+/- s.e.m.) daily dietary fibre intake in the first 2 weeks was similar to that in the general population, at 20.4 +/- 1.2 g, for the whole group, and 21.1 +/- 1.6 g for the 26 women who said they had already increased their dietary fibre intakes in attempts to relieve their symptoms. In the final 2 weeks changes in fibre intakes were: Gp A, mean increase 7.2 +/- 1.0 g per day (P less than 0.001); Gp B, mean increase 9.1 +/- 1.6 g per day (P less than 0.001); Gp C mean decrease 3.50 +/- 1.6 g per day (P less than 0.005). These changes were accompanied by an increase in the number of bowel movements and a change to a softer stool consistency in Gps A and B, with no changes in number of bowel movements or stool consistency in Gp C. The aim of this study was to assess the effect of coarse wheat bran on specific bowel function parameters and symptoms in patients with irritable bowel syndrome (IBS). A longitudinal, prospective, randomised, placebo-controlled trial was undertaken. The duration of treatment was eight to 12 weeks and this consisted of 10-20 g/day of coarse wheat bran or a low fibre placebo taken in addition to the normal diet. Twenty-eight outpatients fulfilling the Rome criteria for constipation-predominant IBS were recruited to the trial (14 in the treatment group; 14 in the placebo group). Twelve people completed the trial in the treatment group and ten in the placebo group. The main outcome measures included changes in symptoms recorded in a diary, changes in objective measurements of bowel function and subjective overall feelings of improvement. The bran group significantly increased their non-starch polysaccharide (NSP) intake over that of the placebo group (p < 0.05). Mean stool wet weight increased significantly more in the bran group than in the placebo group (p < 0.05), but other bowel function measurements and all recorded symptoms were not different. Many patients reported changes in bowel habit that were not reflected in the objective measurements. The addition of coarse wheat bran to the diet increased NSP ingestion and stool wet weight in this group of IBS patients, but no evidence was obtained that such treatment was of benefit to these patients, other than a placebo effect on symptoms. Constipation is a common problem in children. As first-line treatment, increased dietary fiber is often advocated. To our knowledge, however, no large studies evaluating the effect of dietary fibers in childhood constipation have been published.
                A randomized, double-blind, prospective controlled study was performed. Patients received either a fiber mixture or lactulose in a yogurt drink. After a baseline period of 1 week, patients were treated for 8 weeks followed by 4 weeks of weaning. Polyethylene glycol 3350 was added if no clinical improvement was observed after 3 weeks. Using a standardized bowel diary, parents recorded defecation frequency during the treatment period. In addition, incontinence frequency, stool consistency, presence of abdominal pain and flatulence, necessity for step-up medication, and dry weight of feces were recorded, as were adverse effects.
                A total of 147 children were eligible; 12 children wished not to participate. Of the remaining children, 65 were randomized to treatment with fiber mixture and 70 to treatment with lactulose. In all, 97 children completed the study. No difference was found between the groups after the treatment period concerning defecation frequency (P = 0.481) and fecal incontinence frequency (P = 0.084). However, consistency of stools was softer in the lactulose group (P = 0.01). Abdominal pain and flatulence scores were comparable (P = 0.395 and P = 0.739, respectively). The necessity of step-up medication during the treatment period was comparable (P = 0.996), as were taste scores (P = 0.657). No serious adverse effects were registered.
                A fluid fiber mixture and lactulose give comparable results in the treatment of childhood constipation. nan This study describes the effect of fibre supplementation on the gastrointestinal symptoms and general wellbeing of patients with constipated irritable bowel syndrome. In a single centre, double blind, placebo controlled trial of 3 months duration, a daily supplement of 4.1 g fibre produced no greater change in gastrointestinal symptoms than placebo. Pretreatment constipation was related to baseline fibre intake. Overall outcome was the same in treated and control groups; a considerable placebo response was evident. This level of fibre supplementation is not a useful treatment; improving neither constipation nor other symptoms. At the outset pain severity correlated with depression score on psychometric testing. Those who felt better at the end of the study scored significantly lower for depression at outset than those who felt no better. In irritable bowel syndrome a depressive emotional state profile is a powerful determinant of outcome, shaping the response to treatment, which includes a considerable placebo element. Non-obese women in the second half of pregnancy were randomised into a control group receiving standard dietary advice and a group advised to make high fibre whole-food substitutions in their diets at every opportunity. Glucose and insulin profiles were performed over 24-h periods at 29 and 35 weeks gestation when the diets were equivalent in available carbohydrate, protein and fat, but the control group ingested 12.4 g dietary fibre/24 h and the high fibre group 51.4 g/24 h. Glucose homeostasis was similar in both groups but there was a significant attenuation of post-prandial insulin secretion in the high fibre group. It is suggested that the characteristic post-prandial peaks of plasma insulin observed in Western pregnant women are an unphysiological response to dietary fibre depletion. Twenty eight patients with classical irritable bowel syndrome completed a double blind placebo controlled crossover trial in which they added to their normal diet a daily supplement of either 12 bran biscuits (1 = 1.3 g fibre) or 12 placebo biscuits (1 = 0.23 g fibre). Each biscuit was given for three months in random order with crossover to the alternative biscuit at three months. After the initial three months therapy, there was a significant symptomatic improvement compared with pretreatment in both the bran treated (p less than 0.01) and placebo treated groups (p less than 0.01), but there was no significant difference in symptom scores between these two groups. There was no further improvement in either group after the second three months treatment with the alternative therapy. When crossover data for all 28 subjects were combined, symptoms scores after three months bran therapy and after three months placebo therapy did not differ significantly. Twenty four patients completed three day stool collections in both treatment periods. When the symptomatic response to bran among 15 subjects in whom stool weights rose on bran was compared with that among nine subjects whose stool weights were static or fell on the bran, it was shown that symptomatic improvement was independent of an increase in stool weight. These data suggest that in irritable bowel syndrome, especially that associated with abdominal pain, the beneficial effects of bran are due to a placebo response which is independent of an increase in stool weight. The risks of colorectal cancer and adenoma, the precursor lesion, are believed to be influenced by dietary factors. Epidemiologic evidence that cereal fiber protects against colorectal cancer is equivocal. We conducted a randomized trial to determine whether dietary supplementation with wheat-bran fiber reduces the rate of recurrence of colorectal adenomas.
                We randomly assigned 1429 men and women who were 40 to 80 years of age and who had had one or more histologically confirmed colorectal adenomas removed within three months before recruitment began to a supervised program of dietary supplementation with either high amounts (13.5 g per day) or low amounts (2 g per day) of wheat-bran fiber. The primary end point was the presence or absence of new adenomas at the time of follow-up colonoscopy. Subjects and physicians, including colonoscopists, were unaware of the group assignments.
                Of the 1303 subjects who completed the study, 719 had been randomly assigned to the high-fiber group and 584 to the low-fiber group. The median times from randomization to the last follow-up colonoscopy were 34 months in the high-fiber group and 36 months in the low-fiber group. By the time of the last follow-up colonoscopy, at least one adenoma had been identified in 338 subjects in the high-fiber group (47.0 percent) and in 299 subjects in the low-fiber group (51.2 percent). The multivariate adjusted odds ratio for recurrent adenoma in tile high-fiber group, as compared with the low-fiber group, was 0.88 (95 percent confidence interval, 0.70 to 1.11; P=0.28), and the relative risk of recurrence according to the number of adenomas, in the high-fiber group as compared with the low-fiber group, was 0.99 (95 percent confidence interval, 0.71 to 1.36; P=0.93).
                As used in this study, a dietary supplement of wheat-bran fiber does not protect against recurrent colorectal adenomas. The study attempted to determine if the bulk of dietary supplements given to pregnant women after midgestation affects fetal growth. 127 Zulu women were randomly assigned to four groups, two of which received daily food supplements designed to raise their energy, protein and vitamin intakes to levels recommended by the U.S. Food and Nutrition Board. One of these supplements had a high bulk, the other a low bulk. The third supplement contained only zinc and the fourth a placebo. Women in all four groups had a similar weight gain and length of gestation. Birth weights were from 6.5 to 9.5% greater with the low bulk than with the other supplements.
Dietary supplements of fibre in the form of bran or wheat fibre are likely to help women experiencing constipation in pregnancy. If the problem fails to resolve, stimulant laxatives are likely to prove more effective.