Fiber and colorectal diseases: Separating fact from fiction

Association of dietary fibre intake with subsequent fasting glucose levels and indicators of adiposity in school-age Japanese children

OBJECTIVE

To evaluate the relationships of fibre intake with subsequent BMI sd-score, waist-to-height ratio and serum fasting glucose levels among school-age Japanese children.

DESIGN

This is a prospective study of school-age Japanese children. Participants were followed from 6-7 to 9-10 years of age (follow-up rate: 92·0 %). Fibre intake was assessed using a validated FFQ. Serum fasting glucose was measured by a hexokinase enzymatic method. Using a general linear model, the associations between dietary fibre intake at baseline and BMI sd-score, waist-to-height ratio, and serum levels of fasting glucose at follow-up were evaluated after considering potential confounding factors.

SETTING

Public elementary schools in a city in Japan.

PARTICIPANTS

A total of 2784 students.

RESULTS

The estimated means for fasting glucose at 9-10 years of age were 86·45, 85·68, 85·88 and 85·58 mg/dl in the lowest, second, third and highest quartile of fibre intake at 6-7 years of age, respectively (P = 0·033, trend P = 0·018). Higher fibre intake at 6-7 years of age was associated with lower waist-to-height ratio at 9-10 years of age (trend P = 0·023). The change in fibre intake was inversely associated with concurrent change of BMI sd-score (trend P = 0·044).

CONCLUSION

These results suggest that dietary fibre intake may be potentially effective to limit excess weight gain and lower glucose levels during childhood.

Chia seeds (Salvia hispanica L.): A therapeutic weapon in metabolic disorders

The growth of functional components containing agricultural foods is enhancing because these components aid the human body against different chronic diseases. Currently, chia seeds basically belong to the mint family and are edible seeds of Salvia hispanica. These seeds are composed of different functional components including fiber, polyphenols, antioxidants, omega-3 fatty acid vitamins, minerals, and peptides. Besides, these seeds are also a good source of vegetable protein, unsaturated fat, carbohydrates, and ash. Chia seed components are helpful in cardiovascular disease (CVD) by reducing blood pressure, platelet aggregation, cholesterol, and oxidation. In GI-tract-related diseases like diabetes and constipation, chia fiber reduces the blood glucose level and provides bulk to stool. However, antioxidants and polyphenols are protected beta cells of the pancreas from inflammation. These components are protected from the cell damage of the different body parts, which can provide help in different types of cancer including breast, colorectal, liver, and pancreatic. Conclusively, some pervious studies approved that chia seed components are played important role in chronic diseases.

Animal models of cathartic colon

The incidence of cathartic colon has been increasing, but satisfactory treatments are still lacking. In order to study the pathological mechanisms of the disorder and identify effective treatment methods, researchers have established different animal models of cathartic colon. This minireview briefly summarizes several common cathartic colon animal models, induced with anthraquinone laxatives such as rhubarb, total anthraquinone, rhein, and emodin, or induced with diphenylmethane laxatives such as phenolphthalein. The advantages and limitations of these models are evaluated and analyzed. We hope that this review will facilitate the selection of suitable models and improve relevant modeling methods. We anticipate the development of more convenient and stable models that can reflect the characteristics of cathartic colon in humans, and serve as useful tools for further studies.

Acceptance of a New Food Enriched in β-Glucans among Adolescents: Effects of Food Technology Neophobia and Healthy Food Habits

The aim of the present study was to evaluate adolescents’ acceptability of a novel flat bread modified by substituting a part of the wheat flour content with a Pleurotus ostreatus powder rich in β-glucans, which can potentially provide health benefits. The effects of food technology neophobia and adolescents’ food habits on hedonic perception of the developed product was also investigated. Two hundred and two adolescents (age range: 13–18 years; girls: 49.5%; boys: 50.5%) evaluated their liking of two flat breads, one with mushroom powder added and one control sample with only wheat flour. Sample acceptance was studied in relation to age, gender, neophobic traits and healthy food habits. The results showed that, even if the sample with mushroom powder added was generally well accepted, there were different hedonic responses among adolescents according to their food technology neophobia level and healthy habits. In particular, adolescents with a low food technology neophobia level and healthy eating behavior mostly appreciated the sample with mushroom powder added, whereas subjects with neophobic and unhealthy eating behavior gave comparable hedonic scores to the two samples. Moreover, a negative correlation was found between food technology neophobia level and healthy food habits. In conclusion, it is possible to develop a β-glucan-enriched product appreciated by adolescents using a sustainable ingredient. The developed product may be used to achieve the daily recommended intake of β-glucans by adolescents.

The Mexican consensus on the diagnosis and treatment of diverticular disease of the colon

Since the publication of the 2008 guidelines on the diagnosis and treatment of diverticular disease of the colon by the Asociación Mexicana de Gastroenterología, significant advances have been made in the knowledge of that disease. A systematic review of articles published in the medical literature from January 2008 to July 2018 was carried out to revise and update the 2008 guidelines and provide new evidence-based recommendations. All high-quality articles in Spanish and English published within that time frame were included. The final versions of the 43 statements accepted in the three rounds of voting, utilizing the Delphi method, were written, and the quality of evidence and strength of the recommendations were established for each statement, utilizing the GRADE system. The present consensus contains new data on the definition, classification, epidemiology, pathophysiology, and risk factors of diverticular disease of the colon. Special emphasis is given to the usefulness of computed tomography and colonoscopy, as well as to the endoscopic methods for controlling bleeding. Outpatient treatment of uncomplicated diverticulitis is discussed, as well as the role of rifaximin and mesalazine in the management of complicated acute diverticulitis. Both its minimally invasive alternatives and surgical options are described, stressing their indications, limitations, and contraindications. The new statements provide guidelines based on updated scientific evidence. Each statement is discussed, and its quality of evidence and the strength of the recommendation are presented.

Association of dietary fiber intake with general and abdominal obesity in children and adolescents: The Weight disorder survey of the CASPIAN-IV Study

BACKGROUND: Dietary fiber intake might have a protective role against obesity. The aim of this study is to explore the association of dietary fiber intake with general and abdominal obesity in Iranian children and adolescents. MATERIAL AND METHODS: This cross-sectional nationwide study was conducted on 5187 students aged 6–18 years, living in 30 provinces of Iran. They were selected randomly through cluster sampling method. Data on demographic and anthropometric indices including weight, height and waist circumference (WC) were collected by trained interviewers. A valid and reliable 168-item semi-quantitative food frequency questionnaire (FFQ) was used to assess student’s usual dietary intake including total dietary fiber. All dietary reports were converted to daily consumption (g/day) using household measures for different portion sizes. Food items were then converted to their nutrient content. Energy-adjusted dietary fiber intake (g/1000 kcal/day) was also calculated using the energy density method. Multivariate regression models were applied to explore the association between dietary fiber intake and anthropometric indices. RESULTS: The mean and standard deviation (SD) for age of participants were 11.40 (3.20) years. Of 5187 students, 52.6% were boys and 72.5% were from urban areas (participation rate: 79.7%). White bread (32.5%), white rice (17.1%) and potato (11.7%) were the most common sources of dietary fiber intake. Each 1 g/1000 Kcal increase in dietary fiber intake was significantly associated with lower weight and waist circumference (P = 0.006 and P = 0.008, respectively). CONCLUSION: Higher fiber intake was associated with lower anthropometric indices including weight and WC. Increased fiber intake should be encouraged for children and adolescents.

Effects of concentration of corn distillers dried grains with solubles and enzyme supplementation on cecal microbiota and performance in broiler chickens

With the increasing production of ethanol for biofuels, a by-product of corn-based ethanol fermentation, dried distillers grains with solubles (DDGS) is finding its way into the feed of agricultural animals including cattle, pigs, poultry, sheep, goats, aquaculture species and horses. Corn DDGS contains very high levels of non-starch polysaccharides and could be considered a good source of fibre. Despite knowledge of the role of the fibre in modulating intestinal microbiota and consequently influencing health, there is currently little information on the interactions between DDGS and intestinal microbiota. We assessed the changes in the cecal microbiota of broilers feed rations supplemented with DDGS (five concentrations: 0, 6, 12, 18 and 24% w/w) with and without presence of digestive enzymes. DDGS concentration was strongly positively correlated (P = 3.7e^-17, r = 0.74) with feed conversion efficiency (FCR), diminishing broiler performance with higher concentrations. Additionally, DDGS concentrations positively correlated with Richness index (P = 1.5e^-3, r = 0.5), increasing the number of detectable species in the cecum. Among the most affected genera, Faecalibacterium (P = 0.032, r = -0.34) and Streptococcus (P = 7.9e^-3, r = -0.39) were negatively correlated with DDGS, while Turicibacter (P = 2.8e^-4, r = 0.52) was positively correlated with the DDGS concentration. Enzymes showed minimal effect on cecal microbiota.

New insights into the pathogenesis and treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders (FGID), characterized by abdominal pain and a change in stool form that cannot be explained by structural abnormalities. Its prevalence ranges from 9 to 23% of the worldwide population. The pathophysiology of IBS is diverse and not well understood. Biopsychosocial concept assumes that the disease is a product of psychosocial factors and altered at multiple levels of gut physiology interactions. Some aetiological factors have been identified, yet. One of the most important is the disruption of brain-gut mutual communication that leads to visceral hypersensitivity. Also genetic and epigenetic factors are involved. Chronic stress may predispose to IBS as well as exacerbate its symptoms. Both quantitative and qualitative disorders of the gut microbiota are observed. There is also a relationship between the IBS symptoms and the intake of a specific type of food products. In the diarrhoea type of IBS the role of previous gastrointestinal infection is demonstrated. Recent studies have suggested that visceral hypersensitivity in patients with IBS may be secondary to the activation of the immune cells and low-grade inflammation. Clinical symptoms of IBS include abdominal pain and change in bowel habits as well as somatic and psychiatric comorbidities. IBS is diagnosed on the basis of Rome Diagnostic Criteria. Recently, their newest version (Rome IV) has been presented. The aim of this review is to summarize the past decade progress in IBS diagnosis, main pathophysiological aspects and therapeutic management strategy.

Logical hypothesis: Low FODMAP diet to prevent diverticulitis

Despite little evidence for the therapeutic benefits of a high-fiber diet for diverticulitis, it is commonly recommended as part of the clinical management. The ongoing uncertainty of the cause(s) of diverticulitis confounds attempts to determine the validity of this therapy. However, the features of a high-fiber diet represent a logical contradiction for colon diverticulitis. Considering that Bernoulli’s principle, by which enlarged diameter of the lumen leads to increased pressure and decreased fluid velocity, might contribute to development of the diverticulum. Thus, theoretically, prevention of high pressure in the colon would be important and adoption of a low FODMAP diet (consisting of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) may help prevent recurrence of diverticulitis.

Dietary fiber intake and its association with indicators of adiposity and serum biomarkers in European adolescents: the HELENA study

PURPOSE

To evaluate total, energy-adjusted dietary fiber (DF), water-soluble fiber (WSF), and water-insoluble fiber (WIF) intakes in European adolescents and to investigate their association with indicators of adiposity and serum biomarkers.

METHODS

This study, conducted from 2006 to 2007, included 1804 adolescents aged 12.5-17.5 years (47% males) from eight European cities completing two non-consecutive computerized 24-h dietary recalls. GLM multivariate analysis was used to investigate associations.

RESULTS

Mean DF intake (20 g/day) of the sample met the European Food Safety Authority recommendation, but was below those of the World Health Organization and of the Institute of Medicine. Total DF, WSF and WIF intakes were higher in males (P < 0.001), but following energy-adjustments significantly higher intakes were observed among females (P < 0.001). Bread and cereals contributed most to total DF, WSF and WIF intakes, followed by potatoes and grains, energy-dense but low-nutritious foods, fruits and vegetables. Moreover, energy-adjusted WSF and WIF were positively associated with body fat percentage (BF%), waist to height ratio and low-density lipoprotein cholesterol, while energy-adjusted WSF was inversely associated with serum fasting glucose (β = -0. 010, P = 0.020).

CONCLUSION

Total DF intakes are rather low in European adolescents. An inverse association with serum fasting glucose might indicate a possible beneficial role of DF in preventing insulin resistance and its concomitant diseases, even though DF intakes were positively associated with adolescents' BF%. Therefore, further longitudinal studies should elaborate on these potential beneficial effects of DF intake in the prevention of obesity and related chronic diseases.

Microencapsulated sodium butyrate administered to patients with diverticulosis decreases incidence of diverticulitis--a prospective randomized study

BACKGROUND

Microencapsulated sodium butyrate (MSB) has been previously associated with anti-inflammatory and regenerative properties regarding large bowel mucosa. We aimed to examine a role of MSB in patients with diverticulosis, hypothesizing its potential for reduction of diverticulitis episodes and diverticulitis prevention.

METHODS

Seventy-three patients with diverticulosis (diagnosed in colonoscopy or/and barium enema or/and CT colography) were recruited for the study and randomized. The investigated group was administered MSB 300 mg daily; the control group was administered placebo. After 12 months, a total of 52 patients completed the study and were subject to analysis (30 subjects and 22 controls). During the study, the number of episodes of diverticulitis (symptomatic diagnosis with acute pain, fever, and leukocytosis), hospitalizations, and surgery performed for diverticulitis were recorded. Additionally, a question regarding subjective improvement of symptoms reflected changes in quality of life during the analysis.

RESULTS

After 12 months, the study group noted a significantly decreased number of diverticulitis episodes in comparison to the control group. The subjective quality of life in the study group was higher than in the control group. There were no side effects of the MSB during the therapy.

CONCLUSIONS

MSB reduces the frequency of diverticulitis episodes, is safe, and improves the quality of life. It can play a role in the prevention of diverticulitis.

The risk of cancer in patients with benign anal lesions: a nationwide population-based study

OBJECTIVE

To evaluate the risk of cancer among patients diagnosed with hemorrhoids and benign anal inflammatory lesions.

METHODS

A population-based, retrospective cohort study was conducted that included patients diagnosed with hemorrhoids or benign inflammatory anal lesions (eg, anal fissure, fistula, and perianal abscesses) that were registered in the National Health Insurance Research Database in Taiwan between January 1, 2000 and December 31, 2010. Standardized incidence ratios (SIRs) were calculated to compare the cancer incidence of these patients to the general population.

RESULTS

During a median observation period of 6.23 years, 3080 cancers developed among 70,513 hemorrhoid patients, with a follow-up period of 438,425.6 person-years, entailing the SIR of 1.52 (95% confidence interval [CI], 1.47-1.58). Increased cancer risk (SIR 1.16; 95% CI, 1.11-1.21) was still noted even after excluding the first year of observation. Significant long-term risk for colorectal cancer (SIR 1.50; 95% CI, 1.35-1.66) and prostate cancer (SIR 1.40; 95% CI, 1.17-1.66) was observed after corrections were made for multiple comparisons. In contrast, there was no remarkable increase in cancer risk for patients with inflammatory anal lesions when cancers detected within the first year of diagnosis were excluded.

CONCLUSION

The presence of hemorrhoids is associated significantly with a long-term risk of developing colorectal cancer or prostate cancer. In contrast, benign inflammatory anal lesions do not appear to increase the risk of malignancy.

Plasma serotonin level in left-sided colonic diverticulosis: A pilot study

Neurotransmitters might participate in the development of diverticular disease. We measured fasting and postprandial serotonin levels in colonic diverticulosis patients and healthy volunteers. We demonstrated significantly lower maximal concentrations of serotonin in patients than the controls (respectively 109.8±61.4 and 251.3±44.1 ng/ml, p<0.001) as well as lower serotonin minimal values (respectively 38.4±21.8 and 124.6±41.4 ng/ml, p<0.001) and areas under time-course curves (respectively 288.8±139.8 and 739±167.4 ng/ml, p<0.001); significant difference between alternating pattern and normal bowel habit concerning fasting serotonin level, the hormone response to test meal (p=0.041) as well as minimal serotonin level (p=0.044). Bowel habit was also related to peak serotonin values following a test meal with 38.5 ng/ml in constipation, 139.5 ng/ml in diarrhea, 122.4 ng/ml in alternating pattern and 249 ng/ml in subjects with normal bowel habit (p=0.040) as well as AUC with 120.8 ng/ml in constipation, 416 ng/ml in diarrhea, 298 ng/ml in alternating pattern and 684 ng/ml in subjects with normal bowel habit (p=0.043). We demonstrated substantial differences in fasting serum serotonin levels as well as the hormone response to a test meal between colonic diverticulosis patients and healthy individuals, which seemed to be associated with abnormal bowel habits rather than presence of diverticula.

Stopping or reducing dietary fiber intake reduces constipation and its associated symptoms

AIM: To investigate the effect of reducing dietary fiber on patients with idiopathic constipation.

METHODS: Sixty-three cases of idiopathic constipation presenting between May 2008 and May 2010 were enrolled into the study after colonoscopy excluded an organic cause of the constipation. Patients with previous colon surgery or a medical cause of their constipation were excluded. All patients were given an explanation on the role of fiber in the gastrointestinal tract. They were then asked to go on a no fiber diet for 2 wk. Thereafter, they were asked to reduce the amount of dietary fiber intake to a level that they found acceptable. Dietary fiber intake, symptoms of constipation, difficulty in evacuation of stools, anal bleeding, abdominal bloating or abdominal pain were recorded at 1 and 6 mo.

RESULTS: The median age of the patients (16 male, 47 female) was 47 years (range, 20-80 years). At 6 mo, 41 patients remained on a no fiber diet, 16 on a reduced fiber diet, and 6 resumed their high fiber diet for religious or personal reasons. Patients who stopped or reduced dietary fiber had significant improvement in their symptoms while those who continued on a high fiber diet had no change. Of those who stopped fiber completely, the bowel frequency increased from one motion in 3.75 d (± 1.59 d) to one motion in 1.0 d (± 0.0 d) (P < 0.001); those with reduced fiber intake had increased bowel frequency from a mean of one motion per 4.19 d (± 2.09 d) to one motion per 1.9 d (± 1.21 d) on a reduced fiber diet (P < 0.001); those who remained on a high fiber diet continued to have a mean of one motion per 6.83 d (± 1.03 d) before and after consultation. For no fiber, reduced fiber and high fiber groups, respectively, symptoms of bloating were present in 0%, 31.3% and 100% (P < 0.001) and straining to pass stools occurred in 0%, 43.8% and 100% (P < 0.001).

CONCLUSION: Idiopathic constipation and its associated symptoms can be effectively reduced by stopping or even lowering the intake of dietary fiber.

Bulking agents, antispasmodics and antidepressants for the treatment of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder. The role of pharmacotherapy for IBS is limited and focused mainly on symptom control.

OBJECTIVES

The objective of this systematic review was to evaluate the efficacy of bulking agents, antispasmodics and antidepressants for the treatment of irritable bowel syndrome.

SEARCH STRATEGY

Computer assisted structured searches of MEDLINE, EMBASE, The Cochrane library, CINAHL and PsychInfo were conducted for the years 1966-2009. An updated search in April 2011 identified 10 studies which will be considered for inclusion in a future update of this review.

SELECTION CRITERIA

Randomized controlled trials comparing bulking agents, antispasmodics or antidepressants with a placebo treatment in patients with irritable bowel syndrome aged over 12 years were considered for inclusion. Only studies published as full papers were included. Studies were not excluded on the basis of language. The primary outcome had to include improvement of abdominal pain, global assessment or symptom score.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from the selected studies. Risk Ratios (RR) and Standardized Mean Differences (SMD) with 95% confidence intervals (CI) were calculated. A proof of practice analysis was conducted including sub-group analyses for different types of  bulking agents, spasmolytic agents or antidepressant medication. This was followed by a proof of principle analysis where only the studies with adequate allocation concealment were included.

MAIN RESULTS

A total of 56 studies (3725 patients) were included in this review. These included 12 studies of bulking agents (621 patients), 29 of antispasmodics (2333 patients), and 15 of antidepressants (922 patients). The risk of bias was low for most items. However, selection bias is unclear for many of the included studies because the methods used for randomization and allocation concealment were not described. No beneficial effect for bulking agents over placebo was found for improvement of abdominal pain (4 studies; 186 patients; SMD 0.03; 95% CI -0.34 to 0.40; P = 0.87), global assessment (11 studies; 565 patients; RR 1.10; 95% CI 0.91 to 1.33; P = 0.32) or symptom score (3 studies; 126 patients SMD -0.00; 95% CI -0.43 to 0.43; P = 1.00). Subgroup analyses for insoluble and soluble fibres also showed no statistically significant benefit. Separate analysis of the studies with adequate concealment of allocation did not change these results. There was a beneficial effect for antispasmodics over placebo for improvement of abdominal pain (58% of antispasmodic patients improved compared to 46% of placebo; 13 studies; 1392 patients; RR 1.32; 95% CI 1.12 to 1.55; P < 0.001; NNT = 7), global assessment (57% of antispasmodic patients improved compared to 39% of placebo; 22 studies; 1983 patients; RR 1.49; 95% CI 1.25 to 1.77; P < 0.0001; NNT = 5) and symptom score (37% of antispasmodic patients improved compared to 22% of placebo; 4 studies; 586 patients; RR 1.86; 95% CI 1.26 to 2.76; P < 0.01; NNT = 3). Subgroup analyses for different types of antispasmodics found statistically significant benefits for cimteropium/ dicyclomine, peppermint oil, pinaverium and trimebutine. Separate analysis of the studies with adequate allocation concealment found a significant benefit for improvement of abdominal pain. There was a beneficial effect for antidepressants over placebo for improvement of abdominal pain (54% of antidepressants patients improved compared to 37% of placebo; 8 studies; 517 patients; RR 1.49; 95% CI 1.05 to 2.12; P = 0.03; NNT = 5), global assessment (59% of antidepressants patients improved compared to 39% of placebo; 11 studies; 750 patients; RR 1.57; 95% CI 1.23 to 2.00; P < 0.001; NNT = 4) and symptom score (53% of antidepressants patients improved compared to 26% of placebo; 3 studies; 159 patients; RR 1.99; 95% CI 1.32 to 2.99; P = 0.001; NNT = 4). Subgroup analyses showed a statistically significant benefit for selective serotonin releasing inhibitors (SSRIs) for improvement of  global assessment and for tricyclic antidepressants (TCAs) for improvement of abdominal pain and symptom score. Separate analysis of studies with adequate allocation concealment found a significant benefit for improvement of symptom score and global assessment. Adverse events were not assessed as an outcome in this review.

AUTHORS' CONCLUSIONS

There is no evidence that bulking agents are effective for treating IBS.  There is evidence that antispasmodics are effective for the treatment of IBS. The individual subgroups which are effective include: cimetropium/dicyclomine, peppermint oil, pinaverium and trimebutine. There is good evidence that antidepressants are effective for the treatment of IBS. The subgroup analyses for SSRIs and TCAs are unequivocal and their effectiveness may depend on the individual patient. Future research should use rigorous methodology and valid outcome measures.

Fibre intake among the Belgian population by sex–age and sex–education groups and its association with BMI and waist circumference

The objectives of the present study were to assess total dietary fibre intake and the main contributors to fibre intake in the Belgian population by sex–age and sex–education groups and to investigate its relationship with BMI and waist circumference (WC). The participants of the Belgian food consumption survey (2004) were randomly selected. Information about food intake was collected using two repeated, non-consecutive 24 h recall interviews. A total of 3083 individuals ( ≥ 15 years; 1546 men and 1537 women) completed both interviews. The main contributors to total fibre intake (17·8 g/d) were cereals and cereal products (34 %; 5·9 g/d), potatoes and other tubers (18·6 %; 3·3 g/d), fruits (14·7 %; 2·8 g/d) and vegetables (14·4 %; 2·6 g/d). Legume fibre intake was extremely low (0·672 %; 0·139 g/d). In all sex–age and sex–education groups, total fibre intake was below the recommendations of the Belgian Superior Health Council. Men (21 g/d) consumed significantly more fibre than women (17·3 g/d) (P < 0·001). Lower educated men and higher educated women reported the highest fibre intake. A significant inverse association was found between total fibre intake and WC (β = − 0·118, P < 0·001). Fruit-derived fibre was positively associated with WC (β = 0·731, P = 0·001). In summary, total fibre intake was inversely associated with WC, whereas fruit-derived fibre intake was positively associated with WC in the Belgian population.

Modification of anin vitromodel simulating the whole digestive process to investigate cellular endpoints of chemoprevention

In vitrogut fermentation systems are relevant tools to study health benefits of foodstuffs. Most of them are commonly used to investigate the degradation of nutrients or the development of gut flora. Using these models, strong cytotoxic effects of the resulting samples on cultured cells were observed. Hence, the aim of the present study was to develop a modifiedin vitrofermentation model that simulates the whole digestive tract and generates fermented samples that are suitable for testing in cell culture experiments. Wholemeal wheat flour (wwf) was digested and fermentedin vitrowith a fermentation model using different ox gall concentrations (41·6 and 0·6 g/l). The resulting fermentation supernatants (fs) were characterised for metabolites and biological effects in HT29 cells. The fermentation of wwf increased chemopreventive SCFA and decreased carcinogenic deoxycholic acid (DCA). The strong cytotoxic effects of the fs, which were partly due to cholic acid and DCA, were diminished by lowering the ox gall concentration, allowing the use of the samples in cell culture experiments. In conclusion, anin vitrodigestion model, which can be used to study the effects of foodstuffs on chemoprevention and gut health in colon cells, is introduced and its physiological relevance is demonstrated.

Fermentation supernatants of wheat ( Triticum aestivum L.) aleurone beneficially modulate cancer progression in human colon cells

Wheat aleurone contains high amounts of dietary fibers that are fermented by the microflora, resulting in the formation of short-chain fatty acids (SCFA), which are recognized for their chemopreventive potential. This study investigated the effects of fermented aleurone on growth, apoptosis, differentiation, and expression of several genes using two different human colon cell lines (LT97 and HT29). In LT97 cells, the fermentation supernatant (fs) aleurone reduced significantly the cell growth (EC(50) after 48 h = 7.6-8.3%), whereas the level of apoptotic cells was significantly increased (2.1-2.3-fold). Differentiation was enhanced in HT29 cells (1.8-fold) more than in LT97 cells (1.6-fold). Cell growth and apoptosis-related genes, namely WNT2B and p21, were induced by the fs (LT97, 1.7-3.3-fold; HT29, 7.9-22.2-fold). In conclusion, fermented wheat aleurone is able to act as a secondary chemopreventive agent by modulating parameters of cell growth and survival, whereas cells of an early transformation stage are more sensitive.

Conversion of dehydrodiferulic acids by human intestinal microbiota

Plant cell wall associated dehydrodiferulic acids (DFA) are abundant components of cereal insoluble dietary fibers ingested by humans. The ability of human intestinal microbiota to convert DFA was studied in vitro by incubating 8-O-4- and 5-5-coupled DFA with fecal suspensions. 8-O-4-DFA was completely degraded by the intestinal microbiota of the majority of donors, yielding homovanillic acid, 3-(3,4-dihydroxyphenyl)propionic acid, and 3,4-dihydroxyphenylacetic acid as the main metabolites. The transient formation of ferulic acid and presumably 3-(3-hydroxy-4-methoxyphenyl)pyruvic acid suggests an initial cleavage of the ether bond. In contrast to 8-O-4-DFA, the 5-5-coupled DFA was not cleaved into monomers by any of the fecal suspensions. Only the side chains were hydrogenated and the methoxy groups were demethylated. The cleavage of DFA by human intestinal microbiota, which depended on their coupling type, may affect both the bioavailability of DFA and the degradability of DFA-coupled fiber in the gut.