Wheat Bran Fiber Research Articles

Starch-vegetable fibre composites to protect food products

The influence of wheat bran content in biodegradable composites based on cassava starch and containing glycerol and potassium sorbate were studied. Films were produced by casting and three different fractions of wheat bran fibre were used: 1.5 mg, 13.5 mg and 27.1 mg/g of matrix. It was observed that the addition of wheat bran, which contains 40 g of water insoluble fibre per 100 g of bran, shifted the glycerol-rich phase glass transition temperature toward higher temperatures, broadening and diminishing in intensity the peak associated with this relaxation. This effect suggests that the presence of fibre led to an enhancement in the glycerol dispersion. At room temperature, an increase in fibre content did not affect density of the matrix but caused the increase of the storage modulus and the decrease of loss tangent, moisture content and water vapor permeability. Besides, the addition of fibres led to the increase of the yellow index. The improvement in water vapor barrier properties jointly with the enhancement of mechanical properties when fibre was present, lead to the idea that the composite developed can be used to protect food and extend its shelf life.

Plasma Insulin-Like Growth Factor I Is Inversely Associated with Colorectal Adenoma Recurrence: A Novel Hypothesis

The insulin-like growth factor I (IGF-I) axis has been proposed to be a significant factor in the development of certain cancers, including colorectal. However, results from epidemiologic studies suggest modest effects on colorectal cancer risk. Using cross-sectional and prospective study designs within the same cohort of men who had at least one adenoma at baseline, we investigated whether plasma IGF-I, IGF-I binding protein 1, and IGF-I binding protein 3 were associated with colorectal adenoma characteristics at baseline and whether their levels were related to odds for adenoma recurrence. Plasma levels of each marker were measured at baseline in 299 male participants in the Wheat Bran Fiber Trial, who were followed prospectively for recurrence of their adenomatous lesions. In cross-sectional analyses, plasma IGF-I was significantly positively associated with the presence of adenomas with any villous features (P = 0.04). In contrast, IGF-I levels were inversely associated with odds of colorectal adenoma recurrence, with adjusted odds ratios (95% confidence interval) of 0.55 (0.29-1.01) and 0.49 (0.26-0.91) for the second and third tertiles of IGF-I, respectively, compared with the first tertile (P(trend) = 0.02). The inverse association was stronger for advanced adenoma recurrence (P(trend) = 0.02) than for nonadvanced recurrence (P(trend) = 0.10). These results suggest that, once an adenoma is removed, higher IGF-I levels reduce the odds of the formation of new lesions in the colorectum.

Association Between Body Size and Colorectal Adenoma Recurrence

Obesity has been associated with increased risk for colorectal adenoma, although its role as a risk factor after polypectomy for recurrence is unclear. Therefore, we sought to evaluate the effect of anthropometric measures of obesity on adenoma after polypectomy. Subjects with baseline adenomas (n = 2465) and follow-up colonoscopy data were drawn from 2 randomized trials designed to prevent adenoma recurrence. Over a mean follow-up period of 3.1 years presence of a body mass index (BMI) > or = 30 kg/m2 was associated with a nonsignificant 17% increase in the odds for any adenoma recurrence among all subjects (odds ratio [OR], 1.17; 95% confidence interval [CI], 0.92-1.48). This result was confined to men (OR, 1.36; 95% CI, 1.01-1.83) and not observed for women (OR, 0.90; 95% CI, 0.60-1.33). Results for waist circumference did not reach statistical significance, although trends were similar to those for BMI. Analyses of the effects of obesity on more clinically significant lesions demonstrated that high BMI was a slightly stronger risk factor for advanced adenoma recurrences in men (OR, 1.62; 95% CI, 1.04-2.53) when compared with non-advanced lesions (OR, 1.26; 95% CI, 0.91-1.75). In addition, we observed an association for obesity and odds of adenoma recurrence among participants reporting a family history of colorectal cancer (OR, 2.25; 95% CI, 1.32-3.84) but not for those without (OR, 1.00; 95% CI, 0.77 to 1.31; P(int) = P = .008). Our results support obesity as a risk factor for subsequent short-interval (mean follow-up time 3.1 years) development of colorectal adenomas, particularly among men and persons with a family history of colorectal cancer. Furthermore, obesity in men appears to be strongly associated with the development of clinically advanced lesions.

Folate fortification, plasma folate, homocysteine and colorectal adenoma recurrence

In 1996, the US Food and Drug Administration mandated the fortification of grain products with folic acid, a nutrient that has been associated with lower risk of colorectal neoplasia. We assessed the relation of plasma folate and homocysteine and colorectal adenoma recurrence separately in 2 studies: the first involved an intervention of a cereal supplement that contained folic acid, wheat bran fiber (WBF), and the second was conducted primarily during postfortification of the food supply using ursodeoxycholic acid (UDCA). Analyses were stratified for multivitamin use. Results show that plasma folate and homocysteine concentrations were associated with adenoma recurrence among nonusers of multivitamins only. Among nonmultivitamin users, the odds ratio [OR] (95% confidence interval [CI]) for those in the highest versus the lowest folate quartile was 0.65 (0.40-1.06) for the WBF study and 0.56 (0.31-1.02) for the UDCA; likewise, individuals in the highest versus the lowest quartile of homocysteine had higher odds of adenoma recurrence, in both the WBF (OR = 2.25; 95% CI = 1.38-3.66) and UDCA (OR = 1.93; 95% CI = 1.07-3.49) populations. Analyses comparing multivitamin users to different plasma folate concentrations among nonusers show that odds of recurrence for supplement users was lower only when compared to nonusers who had lower concentrations. Our results show that higher plasma folate or lower homocysteine levels are associated with lower odds of recurrence among nonusers of multivitamins in both studies. Our finding, suggesting that multivitamins or supplemental folate only benefit individuals with lower plasma folate concentrations, should be taken into consideration when designing and interpreting results of intervention studies.

Both Wheat (Triticum aestivum) Bran Arabinoxylans and Gut Flora-Mediated Fermentation Products Protect Human Colon Cells from Genotoxic Activities of 4-Hydroxynonenal and Hydrogen Peroxide

Dietary fibers are fermented by the gut flora to yield short chain fatty acids (SCFAs), which inhibit the growth of tumor cells, induce glutathione S-transferases (GSTs), and protect cells from the genotoxic activity of 4-hydroxynonenal (HNE). Here, we investigated effects of wheat bran-derived arabinoxylans and fermentation products on these parameters of chemoprevention. Newly isolated water extractable (WeAx) and alkali extractable arabinoxylans (AeAx) were fermented under anaerobic conditions with human feces. Resulting fermentation supernatants (FSs) were analyzed for SCFAs and used to treat HT29 colon cancer cells. Cell growth, cytotoxicity, antigenotoxicity against hydrogen peroxide (H2O2) or HNE, and GST activity were determined. Nonfermented WeAx decreased H2O2-induced DNA damage by 64%, thus demonstrating chemoprotective properties by this nonfermented wheat bran fiber. The fermentation of WeAx and AeAx resulted in 3-fold increases of SCFA, but all FSs (including the control without arabinoxylans) inhibited the growth of the HT29 cells, reduced the genotoxicity of HNE, and enhanced the activity of GSTs (FS WeAx, 2-fold; FS AeAx, 1.7-fold; and control FS, 1.4-fold), which detoxify HNE. Thus, increases in SCFAs were not reflected by enhanced functional effects. The conclusion is that fermentation mixtures contain modulatory compounds that arise from the feces and might add to the effectiveness of SCFAs.

Fiber, sex, and colorectal adenoma: results of a pooled analysis

Evidence for an association between dietary fiber and colorectal neoplasia has been equivocal, and some data suggest that there may be sex differences in response to fiber. We sought to determine whether fiber affects colorectal adenoma recurrence differently in men and women by combining the study populations of 2 large clinical intervention trials: the Wheat Bran Fiber Trial and the Polyp Prevention Trial. Data from 3209 participants combined from 2 trials were analyzed with logistic regression models to examine the effect of a dietary intervention on colorectal adenoma recurrence in the pooled population as a whole and by sex. The adjusted odds ratio for adenoma recurrence for those in the intervention group of either the Wheat Bran Fiber Trial or the Polyp Prevention Trial was 0.91 (95% CI: 0.78, 1.06). For men, the intervention was associated with statistically significantly reduced odds of recurrence with an odds ratio of 0.81 (95% CI: 0.67, 0.98); for women, no significant association was observed. Using a likelihood-ratio test, we found a statistically significant interaction between intervention group and sex (P = 0.03). The results of the current analyses indicate that men may experience more benefit from dietary fiber than do women and may help to explain some of the discrepant results reported in the literature.

Polychlorinated biphenyl distribution and faecal excretion in rats fed wheat bran

Polychlorinated biphenyls (PCBs) are abundant and persistent environmental contaminants, which tend to accumulate through the food chain. Because of the toxic potential of these compounds, body burden should be kept as low as possible e.g. by taking dietary measures. In the present report, the effect of wheat bran consumption on absorption of dietary PCBs as well as on excretion of previously absorbed PCBs was investigated in rats. Moreover, the accumulation of 7 reference PCB congeners in liver and abdominal adipose tissue was studied. Faecal excretion of dietary PCBs was significantly higher in rats fed wheat bran compared to its placebo. As a result, apparent PCB digestibility was diminished, but not enough to significantly affect PCB accumulation in liver and abdominal adipose tissue. Furthermore, excretion of previously absorbed PCBs following switching of the rats to a control diet without added PCBs was enhanced by wheat bran fibre intake, although to a much lesser extent than excretion of PCBs originating directly from the diet. Consequently, stimulation of PCB clearance from liver and abdominal adipose tissue due to wheat bran consumption was not detectable. Although no preferential absorption of PCB congeners was observed, PCB patterns in tissues obviously differed from the dietary PCB pattern. This was mainly due to PCBs 52 and 101, which were metabolised in the body. Moreover, reduced levels of PCB 138 were found in liver, while PCB 28 and 138 were predominantly present in adipose tissue. The experiment also demonstrated that PCB redistribution from the liver to the adipose tissue occurs.

Can Selenium Prevent Colorectal Cancer? A Signpost From Epidemiology

The limited epidemiology published heretofore on associations between selenium and colorectal adenomas or cancer has been mixed, inconclusive, and based predominantly on small studies. The epidemiology studies have been about evenly split between those showing a statistically significant (1–5) or suggestive (6,7) protective association and those showing a null (8–11) or suggestive harmful (12,13) association between selenium and colorectal adenomas or cancer. The strongest (and only clinical) previous support for a possible protective effect of selenium intake came from a large, randomized controlled trial of selenium in preventing nonmelanoma skin cancer (14). This trial showed a statistically significant reduction of colorectal cancer as a secondary endpoint (relative risk [RR] 0.58, 95% confidence interval [CI] 0.18 to 0.95) that attenuated after longer follow-up (RR 0.45, 95% CI 0.19 to 1.08) (15). A marginally statistically significant overall reduction in colorectal adenomas, which became stronger in association with the lowest tertile of baseline selenium, was also observed again, as a secondary endpoint in the trial (16). In this issue of the Journal, Jacobs et al. report their pooled analysis of three randomized clinical trials of dietary or nutrient interventions in preventing colorectal adenomas (17). Individuallevel data from each of the Wheat Bran Fiber (WBF) Trial (18), the Polyp Prevention Trial (PPT) (19), and the Polyp Prevention Study (PPS) (20) were statistically reanalyzed to provide a more precise estimate of the association between plasma selenium concentration and adenoma risk than would be possible from any of the three studies alone. None of the trials tested selenium as an intervention. This pooled analysis, the largest epidemiologic investigation of the role of selenium in preventing colorectal neoplasia, indicates that individuals in the highest quartile of plasma selenium concentration (median 150 ng/mL) (plasma collected at enrollment for PPT and PPS and 1 year after randomization for WBF) had 34% lower odds (OR 0.66, 95% CI 0.50 to 0.87, Ptrend .006) of developing a new adenoma throughout the follow-up, compared with those in the lowest quartile of plasma selenium (median 113 ng/mL). Plasma selenium concentrations were not statistically significantly associated with adenoma size, location, or histology in the pooled analysis. There was a trend, however, of fewer advanced adenomas ( 1 cm in diameter and/or villous histology) in persons within the highest quartile of plasma selenium. This suggestion of activity in higher–cancer risk, advanced adenomas supports the promise of selenium for reducing colorectal cancer risk. The association of selenium with colorectal cancer development (and mortality) will be assessed as a prespecified secondary endpoint of the Selenium and Vitamin E [prostate] Cancer Prevention Trial (SELECT) currently under way in more than 35 000 men (21). Although the three source studies were mutually independent and executed prior to the pooling project, they had similar designs and outcomes that strengthened the pooled analysis. All participants were at high adenoma risk after recent colonoscopic adenoma resection; each of the three trials assessed colorectal adenoma endpoints in over 85% of its patients, at year 1 and either year 3 (WBF) or year 4 (PPT and PPS) after randomization; and each intervention did not statistically significantly alter the adenoma risk. The pooled analysis also had limitations, however, which were adequately discussed by the authors and included the possibility that some events (new adenomas) detected at year 1 were not actual events but preexisting adenomas missed at the index colonoscopy, varied blood collection times, and different methodologies used to determine plasma selenium concentrations. The biologic plausibility of the pooled analysis and earlier secondary clinical data is provided by consistent animal studies showing the activity of selenium in colorectal neoplasia (22–28) and by other data that address relevant selenium mechanisms. Selenium has effects on key cellular events of tumorigenesis, such as cell proliferation and apoptosis, and the possible complex mechanisms underlying these effects are emerging in increasing numbers (28–30). Important relevant selenium mechanisms may involve gene promoter methylation and polyunsaturated fatty acid metabolism. Cancer cells commonly have aberrant methylation patterns characterized by global hypomethylation coupled with hypermethylation of CpG islands that appear to contribute importantly to tumorigenesis (31). The enzyme DNA cytosine methyltransferase 1 (DNMT1) is increased in tumor progression in association with regional hypermethylation (31). Preclinical studies suggest that selenium inhibits DNMT1 in various cell lines, including the HCT116 and HT-29 human colonic carcinoma cell lines (22,32–34). Oxidative metabolism of the n-6 polyunsaturated fatty acids arachidonic and linoleic acids contributes importantly to colonic tumorigenesis (35), and current data suggest that selenium and arachidonic and linoleic acid metabolism are linked in colonic tumorigenesis. Selenomethionine inhibited growth in four hu-

Selenium and Colorectal Adenoma: Results of a Pooled Analysis

Secondary analyses of data from a large randomized clinical trial have suggested that intake of the trace element selenium reduces risk of colorectal neoplasia, but epidemiologic studies have not shown a consistent protective association. We conducted a combined analysis of data from three randomized trials--the Wheat Bran Fiber Trial, the Polyp Prevention Trial, and the Polyp Prevention Study--which tested the effects of various nutritional interventions for colorectal adenoma prevention among participants who recently had an adenoma removed during colonoscopy. Selenium concentrations were measured from blood specimens from a total of 1763 trial participants, and quartiles of baseline selenium were established from the pooled data. To estimate the association between baseline selenium and colorectal adenoma risk, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression modeling. All statistical tests were two-sided. Individual study results among participants whose blood selenium concentrations were in the highest versus the lowest quartile varied in magnitude (Polyp Prevention Trial: OR = 0.67, 95% CI = 0.43 to 1.05; P(trend) = .21; Wheat Bran Fiber Trial: OR = 0.66, 95% CI = 0.40 to 1.10; P(trend) = .13, and Polyp Prevention Study: OR = 0.57, 95% CI = 0.34 to 0.95, P(trend) = .04). Analyses of the pooled data showed that individuals whose blood selenium values were in the highest quartile (median = 150 ng/mL) had statistically significantly lower odds of developing a new adenoma compared with those in the lowest quartile (OR = 0.66, 95% CI = 0.50 to 0.87; P(trend) = .006). The inverse association between higher blood selenium concentration and adenoma risk supports previous findings indicating that higher selenium status may be related to decreased risk of colorectal cancer.

Wheat bran fiber supplementation and bone loss among older people

Objective The purpose of this study was to investigate the effect of wheat bran fiber (WBF) supplementation on bone loss in older people. Methods Two hundred thirty-seven men and women ages 40 to 80 y were included in this study. They constituted a subgroup of participants from a 3-y WBF intervention trial for preventing recurrence of colorectal adenomas. These participants were randomized into a high (13.5 g/d) or a low (2 g/d) WBF supplementation group. Bone mineral density at the forearm was measured by single photon absorptiometry at baseline and yearly during the intervention to monitor possible toxic effects of fiber supplementation on bone metabolism. Results Baseline characteristics of this subgroup of participants from the WBF trial were similar between the high and low supplementation groups. The annual amounts of bone loss at the radial third site were −0.017 ± 0.018 g/cm 2 and −0.013 ± 0.021 g/cm 2, respectively, for the low and high WBF groups; and the annual bone losses at the ultra-distal site were was −0.005 ± 0.020 g/cm 2 and −0.006 ± 0.027 g/cm 2, respectively, for the low and high WBF groups. After controlling for confounding factors, we found no significant differences in bone loss between groups ( P > 0.05). Conclusion WBF supplementation at the level given in this study may not have a significant effect on bone loss among older people.

Fiber from Fruit and Colorectal Neoplasia

Fiber from Fruit and Colorectal Neoplasia

Baseline Dietary Fiber Intake and Colorectal Adenoma Recurrence in the Wheat Bran Fiber Randomized Trial

The Wheat Bran Fiber (WBF) trial was a double-blind, high-fiber versus low-fiber phase III intervention trial in which participants were randomly assigned to receive a cereal fiber supplement of either 2.0 g/day or 13.5 g/day to assess whether a high-fiber supplement could decrease risk of recurrent colorectal adenomas. Although no effect of the supplement on polyp recurrence was observed, participants consumed a baseline average of 17.5 grams of fiber per day, which may have been sufficient to protect against adenoma recurrence. Therefore, we examined whether baseline fiber intake affected colorectal adenoma recurrence or modified the effect of treatment group in the WBF trial participants. Quartiles of baseline fiber intake were calculated on the basis of the distribution in the study population. Odds ratios (ORs) for adenoma recurrence were calculated using the lowest quartile of fiber intake as the reference. The effect of fiber from specific food sources on adenoma recurrence was also assessed. All statistical tests were two-sided. Adjusted ORs (95% confidence intervals) for adenoma recurrence were 0.79 (0.56 to 1.12), 0.76 (0.54 to 1.08), and 0.83 (0.57 to 1.19) for the second, third, and fourth quartiles, respectively. Fiber from the three primary food sources (fruits; breads, cereals and crackers; and vegetables) had no appreciable effect on adenoma recurrence. Baseline fiber intake also had little effect on adenoma recurrence when the population was stratified by treatment group. In addition, there was no interaction between treatment group and quartile of baseline fiber intake. No association was found between amount of fiber consumed at baseline and adenoma recurrence in the WBF trial participants. The baseline fiber intake, whether considered as a whole or from specific sources, did not modify the effect of treatment group.

Press Release: Higher-Than-Average Fiber Consumption Does Not Affect Results of Wheat Bran Fiber Trial

Press Release: Higher-Than-Average Fiber Consumption Does Not Affect Results of Wheat Bran Fiber Trial

The colonic response to genotoxic carcinogens in the rat: regulation by dietary fibre.

The apoptotic response to DNA damage appears to be an innate biological mechanism for protection against tumourigenesis. It is possible that agents that protect against colorectal cancer act by enhancing the apoptotic deletion of cells suffering DNA damage, with consequent removal of those with tumourigenic mutations. We examined the acute apoptotic response to genotoxic carcinogens ("AARGC") in colonic epithelium and the possibility that dietary fibres of different fermentability might regulate AARGC. To fully define the time-course and nature of AARGC in response to the carcinogen azoxymethane (AOM), a single injection of AOM (10 mg/kg) was given to rats and apoptosis monitored in the colon by light microscopy and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling staining over a 72 h period. Having defined the site and time of maximum response, two groups of eight rats were fed diets containing 10% wheat bran fibre (WB; fermentable) or 10% methylcellulose (MC; poorly fermentable) for 4 weeks. Colonic AARGC was compared by light microscopy; lumenal short chain fatty acids (SCFAs) and pH were measured as indicators of the fermentative environment. AOM-induced AARGC was maximal at 8 h and greater in distal compared with proximal colon. Apoptotic cells were situated predominantly in the lower half of the crypt, with the median at position 9 indicating involvement of daughter as well as stem cells. There was no "second wave" of apoptosis within 72 h as follows irradiation in small intestine. Distal colonic AARGC in rats fed WB was twice that in rats fed MC (P < 0.01). Compared with MC, WB significantly lowered lumenal pH and increased all SCFAs including butyrate, while proliferation did not differ between the fibres. Certainly, dietary fibres can regulate AARGC and further studies are warranted to determine if this biological effect is the way in which dietary factors regulate tumourigenesis. Lumenal generation of butyrate may enhance AARGC as butyrate is proapoptotic in vitro.

Dietary fibre for the prevention of colorectal adenomas and carcinomas.

Colorectal cancer (CRC) is a major cause of morbidity and mortality in industrialized countries. Experimental evidence has supported the hypothesis that dietary fibre may be protective for the development of CRC, although epidemiologic data have been inconclusive. We have conducted a systematic review and meta-analysis to assess the effect of dietary fibre on the incidence or recurrence of colorectal adenomas, the incidence of CRC, and the development of adverse events. We identified randomized controlled trials from Medline, Embase, and the Cochrane Controlled Trials Register up to Oct 2001 Randomized or quasi-randomized controlled trials were assessed. The population included all subjects that had adenomatous polyps but no previous history of colorectal cancer (CRC), a documented "clean colon" at baseline and repeated visualization of the colon/rectum after at least two years of follow-up. Dietary fibre was the intervention. The primary outcomes were the number of subjects with: a) at least one adenoma, b) more than one adenoma, c) at least one adenoma greater than or equal to 1 cm or d) a new diagnosis of CRC. The secondary outcome was the number of adverse events. Two reviewers independently extracted data, assessed trial quality and resolved discrepancies by consensus. The outcomes were reported as relative risks (RR) and risk difference (RD) with 95% confidence intervals (CI). If statistical significance was reached, the number need to treat (NNTT) or harm (NNTH) was reported. The study data were combined with the fixed effects model if it was clinically, methodologically, and statistically reasonable. Five studies with 4349 subjects met the inclusion criteria. The interventions were wheat bran fibre, ispaghula husk, or a comprehensive dietary intervention with high fibre whole food sources alone or in combination. When the data were combined there was no difference between the intervention and control groups for the number of subjects with at least one adenoma [RR 1.04 (95% CI 0.95,1.13); RD 0.01 (95% CI 0.02,0.04)]. As well, the combined results for the number of subjects with more than one adenoma [RR 1.02 (95% CI 0.89,1.17), RD 0.00 (-0.02,0.03)] or at least one adenoma 1 cm or greater [RR 0.94 (95% CI 0.77,1.15), RD -0.01 (-0.02,0.01)] were not statistically significant. Other primary and secondary outcomes and subanalyses by type of fibre intervention were not statistically or clinically significant. There is currently no evidence from RCTs to suggest that increased dietary fibre intake will reduce the incidence or recurrence of adenomatous polyps within a two to four year period.

Co-extrusion of Dietary Fiber and Milk Proteins in Expanded Corn Products

To improve the nutrient-density of snack products, milk proteins (casein, whey protein concentrate or whey protein isolate) and wheat fiber were co-extruded with corn meal flour, in a twin screw extruder under high shear and high temperature processing conditions. Co-extruding corn products and fiber resulted in the reduction of specific mechanical energy while increasing the expansion and breaking strength of the extrudate. Fiber added at 125 g/kg increased expansion and breaking strength. Whey products alone, at a concentration of 250 g/kg reduced expansion and water absorption properties, but the incorporation of fiber reversed this effect and improved expansion. The negative textural indicators associated with the inclusion of whey products can be improved significantly by adding wheat bran fiber at 125 g/kg. Adding fiber, improved specific mechanical energy (SME) along with product quality characteristics.

Effect of Wheat Bran Fiber and Bran Particle Size on Fat and Fiber Digestibility and Gastrointestinal Tract Measurements in the Rat

ABSTRACTThe effect of wheat bran (AACC hard red) and bran particle size on fat and fiber digestibility and gastrointestinal tract measurements were investigated with diets containing 5.7–10.7% dietary fiber. Fifty‐six male weanling Sprague‐Dawley rats were randomly assigned to four diets containing 5% cellulose (C5); 10.5% cellulose (C10); 21.5% coarse (2 mm) wheat bran (CB); or 22.2% fine (0.5 mm) wheat bran (FB) in a sixweek study. Dietary fiber digestibilities were significantly different (P &lt; 0.05) among treatment diets (CB &gt; FB &gt; C5 &gt; C10) but there was no effect in fat digestibility among treatments. High‐fiber diets fed to rats resulted in significantly greater wet and dry fecal weights than low‐fiber diets. Bran diets resulted in significantly higher fecal moisture than cellulose diets. Cecum lengths increased significantly with bran diets compared with cellulose diets. The CB diet resulted in significantly higher stomach weights than with cellulose diets. Stomachs were heavier and cecal lengths were greater with bran diets than with cellulose diets; however, a high‐cellulose diet resulted in increased colon weight. Except for higher fiber digestibility of coarse bran, bran particle size had no significant effects. Healthful effects of wheat bran may be associated with gastrointestinal morphology and function. Fecal bulking and decreased intestinal transit time can prevent constipation and may dilute or reduce absorption of toxic or carcinogenic metabolites, thus improving gastrointestinal health and lowering the risk of tumor development and cancer.

Adenoma characteristics as risk factors for recurrence of advanced adenomas

The link between adenoma characteristics at baseline colonoscopy and adenoma recurrence is poorly understood. We assessed whether the number, size, location, or histology of resected adenomas was related to the probability of recurrence of advanced lesions. Analyses were based on 1287 men and women in the wheat bran fiber (WBF) study, a randomized, double-blind trial of WBF as a means of decreasing the probability of adenoma recurrence over a period of 3 years. Multiple logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Recurrence of advanced adenomas (>1 cm or tubulovillous/villous histology) was higher among individuals with adenomas >1 cm compared with those with adenomas <0.5 cm (OR, 2.69; 95% CI, 1.34-5.42) and among those with proximal than those with distal adenomas (OR, 1.65; 95% CI, 1.02-2.67). No association was observed for adenoma number or histology. A shift in location from the distal colon and rectum at baseline (54.6%) to more proximal recurrent adenomas (45.2%), including advanced lesions (42.8%), was observed. Large or proximally located adenomas are important indicators of recurrence of advanced lesions. Because most recurrences were detected in the proximal colon, careful surveillance of this area is warranted.

Fermentation-related factors that underlie the effects of wheat bran and soluble fibre on distal colonic epithelium

Fermentation-related factors that underlie the effects of wheat bran and soluble fibre on distal colonic epithelium

Effect of wheat bran fiber supplement on colorectal adenoma recurrence

Effect of wheat bran fiber supplement on colorectal adenoma recurrence