Tolerance and the effect of high doses of wheat bran extract, containing arabinoxylan–oligosaccharides, and oligofructose on faecal output: a double-blind, randomised, placebo-controlled, cross-over trial (original) (raw)
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British Journal of Nutrition, 2012
Wheat bran extract (WBE) is a food-grade soluble fibre preparation that is highly enriched in arabinoxylan oligosaccharides. In this placebo-controlled cross-over human intervention trial, tolerance and effects on colonic protein and carbohydrate fermentation were studied. After a 1-week run-in period, sixty-three healthy adult volunteers consumed 3, 10 and 0 g WBE/d for 3 weeks in a random order, with 2 weeks' washout between each treatment period. Fasting blood samples were collected at the end of the run-in period and at the end of each treatment period for analysis of haematological and clinical chemistry parameters. Additionally, subjects collected a stool sample for analysis of microbiota, SCFA and pH. A urine sample, collected over 48 h, was used for analysis of p-cresol and phenol content. Finally, the subjects completed questionnaires scoring occurrence frequency and distress severity of eighteen gastrointestinal symptoms. Urinary p-cresol excretion was significantly decreased after WBE consumption at 10 g/d. Faecal bifidobacteria levels were significantly increased after daily intake of 10 g WBE. Additionally, WBE intake at 10 g/d increased faecal SCFA concentrations and lowered faecal pH, indicating increased colonic fermentation of WBE into desired metabolites. At 10 g/d, WBE caused a mild increase in flatulence occurrence frequency and distress severity and a tendency for a mild decrease in constipation occurrence frequency. In conclusion, WBE is well tolerated at doses up to 10 g/d in healthy adults volunteers. Intake of 10 g WBE/d exerts beneficial effects on gut health parameters.
Effect of wheat bran in treatment of chronic nonorganic constipation
Digestive Diseases and Sciences, 1995
After a two-week basal period, 24 patients were randomly allocated to receive, with a crossover double-blind design, for two consecutive four-week periods, bran (20 g/24 hr) or placebo. The daily intake of water and dietary fibers was standardized. Symptomatology, oroanal transit time, bowel frequency, and stool weight were assessed in basal conditions and at week 4 and 8 of the treatment. Oroanal transit time decreased and bowel frequency and stool weight increased significantly during both bran and placebo administration in comparison with basal period. Bran treatment was more effective than placebo in improving bowel frequency and oroanal transit. During bran treatment oroanal transit time became normal only in patients with slow colonic transit and not in those with slow rectal transit. Neither the occurrence nor the severity of the most frequent accompanying symptoms of chronic constipation differed significantly between placebo and bran treatments. KEY WORDS: constipation; dietary fibers. Dietary fibers, and particulary wheat bran, is widely advocated as a first-line treatment in patients complaining of constipation. This therapeutic approach has been confirmed by clinical studies that showed a beneficial effect of bran on constipated patients with irritable bowel syndrome (1-3) or diverticular disease (4-8). However with the exception of only two noncontrolled studies (9, 10), no proper clinical trials have been carried out in patients with chronic nonorganic constipation (CNOC). In the present crossover, double-blind controlled trial the effects of wheat bran on large bowel transit time, bowel frequency, stool weight, and symptom-Manuscript
Journal of Pediatric Gastroenterology and Nutrition, 2014
We assessed whether wheat bran extract (WBE) containing arabinoxylan-oligosaccharides (AXOS) elicited a prebiotic effect and modulated gastrointestinal (GI) parameters in healthy preadolescent children upon consumption in a beverage. Methods: This double-blind randomized placebo-controlled crossover trial evaluated the effects of consuming WBE at 0 (control) or 5.0 g/day for 3 weeks in 29 healthy children (8-12 years). Fecal levels of microbiota, shortchain fatty acids, branched-chain fatty acids, ammonia, moisture, and fecal pH were assessed at the end of each treatment and at the end of a 1-week runin (RI) period. In addition, the subjects completed questionnaires scoring distress severity of 3 surveyed GI symptoms. Finally, subjects recorded defecation frequency and stool consistency. Results: Nominal fecal bifidobacteria levels tended to increase after 5 g/day WBE consumption (P ¼ 0.069), whereas bifidobacteria expressed as percentage of total fecal microbiota was significantly higher upon 5 g/day WBE intake (P ¼ 0.002). Additionally, 5 g/day WBE intake induced a significant decrease in fecal content of isobutyric acid and isovaleric acid (P < 0.01), markers of protein fermentation. WBE intake did not cause a change in distress severity of the 3 surveyed GI symptoms (flatulence, abdominal pain/cramps, and urge to vomit) (P > 0.1). Conclusions: WBE is well tolerated at doses up to 5 g/day in healthy preadolescent children. In addition, the intake of 5 g/day exerts beneficial effects on gut parameters, in particular an increase in fecal bifidobacteria levels relative to total fecal microbiota, and reduction of colonic protein fermentation.
British Journal of Nutrition, 2014
Wheat bran extract (WBE), containing arabinoxylan-oligosaccharides that are potential prebiotic substrates, has been shown to modify bacterial colonic fermentation in human subjects and to beneficially affect the development of colorectal cancer (CRC) in rats. However, it is unclear whether these changes in fermentation are able to reduce the risk of developing CRC in humans. The aim of the present study was to evaluate the effects of WBE on the markers of CRC risk in healthy volunteers, and to correlate these effects with colonic fermentation. A total of twenty healthy subjects were enrolled in a double-blind, cross-over, randomised, controlled trial in which the subjects ingested WBE (10 g/d) or placebo (maltodextrin, 10 g/d) for 3 weeks, separated by a 3-week washout period. At the end of each study period, colonic handling of NH3 was evaluated using the biomarker lactose[15N, 15N′]ureide, colonic fermentation was characterised through a metabolomics approach, and the predominant...
The influence of a diet rich in wheat fibre on the human faecal flora
Journal of Medical Microbiology, 1976
MANY of the diseases peculiar to western civilisation have been ascribed to the removal from the diet of the major part of the fibre of the wheat grain. It has been suggested that this part of the wheat grain, known as bran, is of specific value in the prevention of various diseases including large bowel cancer (Burkitt, 1971). The prophylactic influence of bran is ascribed to its effects on intestinal transit, faecal bulk and the faecal flora. The effect of bran on intestinal transit and faecal bulk has been previously documented (Cowgill and Anderson, 1932; Harvey, Pomare and Heaton, 1973). In this paper we describe the effect of bran on the faecal flora. MATERIALS AND METHODS Plan of Study. Four healthy male medical students (nos. 1-4) aged 22-25 took part in the study. The protocol was fully explained to each subject and had been approved by the ethical committee of the Central Middlesex Hospital. For 6 weeks the subjects ate a carefully prepared metabolic diet whilst living in a hostel in the hospital grounds and carrying out their normal occupations. The basic diet was a 2902 K cal. low-fibre diet of normal " western " composition comprising 351 g of carbohydrate, 122 g of fat and 88 g of protein, and it contained 3-6 g of crude fibre. This was fed for 3 weeks; for the other 3-week period the fibre content of the diet was increased (high fibre diet) by substituting an equal weight of wholemeal bread for the white bread (120 g), All-bran for cornflakes (25 g), bran biscuits for Nice biscuits (52 g), and by adding 30 g of bran (Allison's Bran +). The high-fibre diet supplied 2775 K cal. as 339 g of carbohydrate, 11 5 g of fat and 97 g of protein, and it contained 11.7 g of crude fibre. Apart from the substitutions, the two diets were identical. Data were not available for the dietaryfibre (as opposed to crude-fibre) content of all the items, but this information was obtained for the four items changed in the two diets by the method of Southgate (1969). From this it was calculated that the high-fibre diet contained an additional 36 g of dietary fibre. Subjects nos. 1-2 took the low-fibre diet first and subjects nos. 3-4 the high-fibre diet first. Further details of the diets are given by Jenkins, Hill and Cummings (1975). Throughout the 6-week period and for 1 further week the subjects collected their faeces. Each stool was collected separately into a plastic bag fixed over a toilet. Mean transit time (MTT) was measured during the third week of each diet period by giving a single dose of 25 opaque pellets with breakfast and determining their presence in the collected stools radiographically. Preservation of specimens. From a freshly passed stool, 0.5 g of faeces was mixed with 4.5 ml of glycerol broth 10% (v/v) in a 10-ml screw-capped bottle. The suspension was
American Journal of Clinical Nutrition
Wheat bran (WB) increases fecal bulk and hastens colonic transit, whereas resistant starch (RS) has effects on colonic fermentation, including increasing concentrations of butyrate. We hypothesized that a diet combining WB with RS would produce more favorable changes in fecal variables (eg, fecal bulk, rapid transit time, lower pH, and higher butyrate) than would WB alone. This was a randomized crossover block-design study for which 20 volunteers with a family history of colorectal cancer were recruited. The study included 3 diets: control, WB (12 g fiber/d), and WBRS (12 g WB fiber/d plus 22 g RS/d), each continued for 3 wk. In each diet, the major source of protein was lean red meat. During 5 consecutive days (days 15-19) of each dietary period, the subjects collected their total fecal output for analysis. The WB diet resulted in greater fecal output (by 23% and 21% for wet and dry weights, respectively) and a lesser transit time (-11 h) than did the control diet but did not have ...
Annals of Nutrition and Metabolism, 2010
Background: Average dietary fiber intake in the United States is roughly half of the recommended amount. As new dietary fiber products are introduced to increase fiber intake, it is critical to evaluate the physiological effects of such fibers. Aims: This study examined the effect of 4 fibers derived from maize or tapioca on fecal chemistry, gastrointestinal (GI) symptoms and serum markers of chronic disease. Methods: Twenty healthy subjects completed the single-blind crossover study in which 12 g/day of fiber (pullulan, Promitor™ Resistant Starch, soluble fiber dextrin or Promitor Soluble Corn Fiber) or placebo (maltodextrin) were consumed for 14 days followed by a 21-day washout. GI symptom surveys were completed (days 3 and 14), stools were collected (days 11–14), diet was recorded (days 12–14) and fasting blood samples were obtained (day 15). Results: The 4 test fibers were well tolerated, with mild to moderate GI symptoms. Total short-chain fatty acid (SCFA) concentrations did ...