Effects of cereal fiber on bowel function: A systematic review of intervention trials

Agave tequilana Fructans Versus Psyllium plantago for Functional Constipation : Randomized Double-blind Clinical Trial

GOAL

The aim of this study was to evaluate the efficacy of supplementation with Agave tequilana Weber blue variety fructans (Predilife) in the improvement of symptoms in functional constipation.

BACKGROUND

Fiber supplementation is the first-line treatment for constipation. Fibers-like fructans have a known prebiotic effect.

MATERIALS AND METHODS

A randomized, double-blind, study comparing agave fructans (AF) against psyllium plantago (PP). Four groups were randomized. Group 1: AF 5 g (Predilife), group 2: AF 10 g (Predilife), group 3: AF 5 g (Predilife)+10 g maltodextrin (MTDx), and group 4: PP 5 g+10 g MTDx. The fiber was administered once daily for 8 weeks. All fibers were similarly flavored and packaged. Patients kept their usual diet and fiber sources were quantified. Responders were defined as ≥1 complete spontaneous bowel movement from baseline to 8 weeks. Adverse events were reported. The study was registered in Clinicaltrials.gov with registration number NCT04716868.

RESULTS

Seventy-nine patients were included (group 1: 21, group 2: 18, group 3: 20, and group 4: 20), of which 62 (78.4%) were women. The responders were similar across groups (73.3%, 71.4%, 70.6%, and 69%, P >0.050). After 8 weeks, all groups significantly increased complete spontaneous bowel movements, showing the greatest increase in spontaneous bowel movements in group 3 ( P =0.008). All groups improved in symptoms, stool consistency, and quality of life. Diet and fiber intake were similar between groups. Adverse events were mild and similar between groups.

CONCLUSIONS

AF (Predilife) are as effective at different doses and combined with MTDx as PP and are a feasible option for the treatment of functional constipation.

Dietary Fibre for the Prevention of Post-Pancreatitis Diabetes Mellitus: A Review of the Literature and Future Research Directions

Post-pancreatitis diabetes mellitus-the most common sequela of pancreatitis-leads to poorer glycaemic control compared with type 2 diabetes. Because post-pancreatitis diabetes mellitus is an exemplar of secondary diabetes (with a clear underlying cause), much post-pancreatitis diabetes mellitus is preventable or treatable early. Earlier literature established the important role of dietary fibre in reducing plasma glucose in individuals with type 2 diabetes. The present review benchmarks available evidence on the role of habitual dietary fibre intake in pancreatitis and post-pancreatitis diabetes mellitus. It also paves the way for future research on the use of dietary fibre in the post-pancreatitis setting.

Effects of Wholegrain Compared to Refined Grain Intake on Cardiometabolic Risk Markers, Gut Microbiota, and Gastrointestinal Symptoms in Children: A Randomized Crossover Trial

BACKGROUND

Wholegrain intake is associated with lower risk of cardiometabolic diseases in adults, potentially via changes in the gut microbiota. Although cardiometabolic prevention should start early, we lack evidence on the effects in children.

OBJECTIVES

This study investigated the effects of wholegrain oats and rye intake on serum low-density lipoprotein (LDL) cholesterol and plasma insulin (coprimary outcomes), other cardiometabolic markers, body composition, gut microbiota composition and metabolites, and gastrointestinal symptoms in children with high body mass index (BMI).

METHODS

In a randomized crossover trial, 55 healthy Danish 8- to 13-y-olds received wholegrain oats and rye ("WG") or refined grain ("RG") products ad libitum for 8 wk in random order. At 0, 8, and 16 wk, we measured anthropometry, body composition by dual-energy absorptiometry, and blood pressure. Fasting blood and fecal samples were collected for analysis of blood lipids, glucose homeostasis markers, gut microbiota, and short-chain fatty acids. Gut symptoms and stool characteristics were determined by questionnaires. Diet was assessed by 4-d dietary records and compliance by plasma alkylresorcinols (ARs).

RESULTS

Fifty-two children (95%) with a BMI z-score of 1.5 ± 0.6 (mean ± standard deviation) completed the study. They consumed 108 ± 38 and 3 ± 2 g/d wholegrain in the WG and RG period, which was verified by a profound difference in ARs (P < 0.001). Compared with RG, WG reduced LDL cholesterol by 0.14 (95% confidence interval: -0.24, -0.04) mmol/L (P = 0.009) and reduced total:high-density lipoprotein cholesterol (P < 0.001) and triacylglycerol (P = 0.048) without altering body composition or other cardiometabolic markers. WG also modulated the abundance of specific bacterial taxa, increased plasma acetate, propionate, and butyrate and fecal butyrate and reduced fatigue with no other effects on gut symptoms.

CONCLUSION

High intake of wholegrain oats and rye reduced LDL cholesterol and triacylglycerol, modulated bacterial taxa, and increased beneficial metabolites in children. This supports recommendations of exchanging refined grain with wholegrain oats and rye among children. This trial was registered at clinicaltrials.gov as NCT04430465.

Dietary fiber - a scoping review for Nordic Nutrition Recommendations 2023

Dietary fiber is a term crudely defined as carbohydrates (CHOs) that escape digestion and uptake in the small intestine. Lignin, which is not a CHO, is also a part of the dietary fiber definition. Dietary fibers come in different sizes and forms, with a variety of combinations of monomeric units. Health authorities worldwide have for many years recommended a diet rich in dietary fibers based on consistent findings that dietary fibers are associated with reduced incidences of major non-communicable diseases, including obesity, type 2 diabetes, cardiovascular disease, and colorectal cancer. Most fibers come from common edible foods from the plant kingdom, but fibers are also found in food additives, supplements, and breast milk. The recommended intake in Nordic Nutrition Recommendations 2012 (NNR2012) is 25 g/d for women and 35 g/d for men, whereas the actual intake is significantly lower, ranging from 16 g/d to 22 g/d in women and 18 g/d to 26 g/d in men. New studies since NNR2012 confirm the current view that dietary fiber is beneficial for health, advocating intakes of at least 25 g/day.

Effect of Adding Pulses to Replace Protein Foods and Refined Grains in Healthy Dietary Patterns

Pulses are dry seeds of legumes which are high in fiber and contain plant protein and several important macronutrients. Our aim was to model the nutritional effects of substituting servings of protein foods and/or refined grains with servings of beans and peas in the Healthy U.S.-Style Pattern identified in the Dietary Guidelines for Americans, 2020-2025. Dietary modeling was accomplished by substituting nutrients of protein foods and/or refined grains with nutrients of the USDA's beans and peas (pulses) composite in the 2000 kcal Healthy U.S.-Style Pattern. A 10% or more change was used as an indicator of meaningful differences. Cost implications were computed by adding the cost of pulses and subtracting the cost of protein foods/refined grains according to the modeling scenario. The substitution of 6-8 oz/week protein foods with 1.5-2.0 cups/week pulses increased fiber and decreased cholesterol. Higher amounts of pulses replacing refined grains or combinations of protein foods and refined grains generally increase fiber, iron, magnesium, potassium, and copper depending on the modeling scenarios. All modeling scenarios of substituting the servings of protein foods alone or in combination with refined grains with the servings of pulses were associated with cost savings. Our results suggest that encouraging increased pulse consumption may be an effective strategy for improving diet.

[Prospects of dietary fibers food fortification for the treatment and prevention of gastrointestinal diseases: A review]

Epidemiological studies have proven the connection between high consumption of dietary fiber and a reduction in the risk of many diseases. In clinical trials, the possibility of functional regulation of the intestine and intestinal microbiome by dietary fibers has been revealed, which may be significant in certain diseases of the digestive system. This review provides information on the relationship between the physico-chemical properties and functional characteristics of dietary fibers, discusses evidence of the effectiveness of their use in the treatment of diseases of the digestive system, discusses the need to enrich food with dietary fibers.

Pea hull fiber supplementation does not modulate uremic metabolites in adults receiving hemodialysis: a randomized, double-blind, controlled trial

Background

Fiber is a potential therapeutic to suppress microbiota-generated uremic molecules. This study aimed to determine if fiber supplementation decreased serum levels of uremic molecules through the modulation of gut microbiota in adults undergoing hemodialysis.

Methods

A randomized, double-blinded, controlled crossover study was conducted. Following a 1-week baseline, participants consumed muffins with added pea hull fiber (PHF) (15 g/d) and control muffins daily, each for 4 weeks, separated by a 4-week washout. Blood and stool samples were collected per period. Serum p-cresyl sulfate (PCS), indoxyl sulfate (IS), phenylacetylglutamine (PAG), and trimethylamine N-oxide (TMAO) were quantified by LC-MS/MS, and fecal microbiota profiled by 16S rRNA gene amplicon sequencing and specific taxa of interest by qPCR. QIIME 2 sample-classifier was used to discover unique microbiota profiles due to the consumption of PHF.

Results

Intake of PHF contributed an additional 9 g/d of dietary fiber to the subjects' diet due to compliance. No significant changes from baseline were observed in serum PCS, IS, PAG, or TMAO, or for the relative quantification of Akkermansia muciniphila, Faecalibacterium prausnitzii, Bifidobacterium, or Roseburia, taxa considered health-enhancing. Dietary protein intake and IS (r = -0.5, p = 0.05) and slow transit stool form and PCS (r = 0.7, p < 0.01) were significantly correlated at baseline. PHF and control periods were not differentiated; however, using machine learning, taxa most distinguishing the microbiota composition during the PHF periods compared to usual diet alone were enriched Gemmiger, Collinsella, and depleted Lactobacillus, Ruminococcus, Coprococcus, and Mogibacteriaceae.

Conclusion

PHF supplementation did not mitigate serum levels of targeted microbial-generated uremic molecules. Given the high cellulose content, which may be resistant to fermentation, PHF may not exert sufficient effects on microbiota composition to modulate its activity at the dose consumed.

Effects of a wholegrain-rich diet on markers of colonic fermentation and bowel function and their associations with the gut microbiome: a randomised controlled cross-over trial

Background

Diets rich in whole grains are associated with health benefits. Yet, it remains unclear whether the benefits are mediated by changes in gut function and fermentation.

Objective

We explored the effects of whole-grain vs. refined-grain diets on markers of colonic fermentation and bowel function, as well as their associations with the gut microbiome.

Methods

Fifty overweight individuals with increased metabolic risk and a high habitual intake of whole grains (~69 g/day) completed a randomised cross-over trial with two 8-week dietary intervention periods comprising a whole-grain diet (≥75 g/day) and a refined-grain diet (<10 g/day), separated by a washout period of ≥6  weeks. A range of markers of colonic fermentation and bowel function were assessed before and after each intervention.

Results

The whole-grain diet increased the levels of faecal butyrate (p = 0.015) and caproate (p = 0.013) compared to the refined-grain diet. No changes in other faecal SCFA, BCFA or urinary levels of microbial-derived proteolytic markers between the two interventions were observed. Similarly, faecal pH remained unchanged. Faecal pH did however increase (p = 0.030) after the refined-grain diet compared to the baseline. Stool frequency was lower at the end of the refined-grain period compared to the end of the whole-grain diet (p = 0.001). No difference in faecal water content was observed between the intervention periods, however, faecal water content increased following the whole-grain period compared to the baseline (p = 0.007). Dry stool energy density was unaffected by the dietary interventions. Nevertheless, it explained 4.7% of the gut microbiome variation at the end of the refined-grain diet, while faecal pH and colonic transit time explained 4.3 and 5%, respectively. Several butyrate-producers (e.g., Faecalibacterium, Roseburia, Butyriciococcus) were inversely associated with colonic transit time and/or faecal pH, while the mucin-degraders Akkermansia and Ruminococcaceae showed the opposite association.

Conclusion

Compared with the refined-grain diet, the whole-grain diet increased faecal butyrate and caproate concentrations as well as stool frequency, emphasising that differences between whole and refined grains affect both colonic fermentation and bowel habits.

Associations between diet and incidence risk of lung cancer: A Mendelian randomization study

Background

Observational studies have revealed associations between diet and lung cancer. However, it is unclear whether the association is disturbed by confounding factors. We used a two-sample Mendelian randomization (MR) method to characterize the associations between diet and the lung cancer risk (including 3 subtypes: lung adenocarcinoma (LA), squamous cell lung carcinoma (SqCLC), and small cell lung cancer (SCLC)).

Materials and methods

Data on 20 diets were screened from the UK Biobank. Lung cancer data came from a large meta-analysis of 85,716 individuals. The inverse-variance weighted method was used as the main analysis. Sensitivity analysis was also used to explain the different multiplicity patterns of the final model.

Results

Our results showed significant evidence that 3 diets were associated with lung cancer [odds ratio (OR): 0.271, 95% confidence interval (CI): 0.150–0.488, p = 1.46 × 10−4, dried fruit; OR: 3.010, 95% CI: 1.608–5.632, p = 5.70 × 10−4, beer] and SqCLC (OR: 0.135, 95% CI: 0.062–0.293, p = 2.33 × 10−5, dried fruit; OR: 0.485, 95% CI: 0.328–0.717, p = 2.9 × 10−4, cheese). There were also suggestive correlations between 5 dietary intakes and lung cancer (OR: 0.441, 95% CI: 0.250–0.778, p = 0.008, cereal; OR: 2.267, 95% CI: 1.126–4.564, p = 0.022, beef), LA (OR: 0.494, 95% CI: 0.285–0.858, p = 0.012, dried fruit; OR: 3.536, 95% CI: 1.546–8.085, p = 0.003, beer) and SCLC (OR: 0.006, 95% CI: 0.000–0.222, p = 0.039, non-oily fish; OR: 0.239, 95% CI: 0.086–0.664, p = 0.006, dried fruit). No other association between diet and lung cancer was observed.

Conclusion

Our study preliminary found that cheese, dried fruit, and beer intake were significantly associated with the risk of lung cancer or its subtypes, while cereal, beef, and non-oily fish intake were suggestively associated with the risk of lung cancer or its subtypes. Well-designed prospective studies are still needed to confirm our findings in the future.

Advancing human gut microbiota research by considering gut transit time

Accumulating evidence indicates that gut transit time is a key factor in shaping the gut microbiota composition and activity, which are linked to human health. Both population-wide and small-scale studies have identified transit time as a top covariate contributing to the large interindividual variation in the faecal microbiota composition. Despite this, transit time is still rarely being considered in the field of the human gut microbiome. Here, we review the latest research describing how and why whole gut and segmental transit times vary substantially between and within individuals, and how variations in gut transit time impact the gut microbiota composition, diversity and metabolism. Furthermore, we discuss the mechanisms by which the gut microbiota may causally affect gut motility. We argue that by taking into account the interindividual and intraindividual differences in gut transit time, we can advance our understanding of diet-microbiota interactions and disease-related microbiome signatures, since these may often be confounded by transient or persistent alterations in transit time. Altogether, a better understanding of the complex, bidirectional interactions between the gut microbiota and transit time is required to better understand gut microbiome variations in health and disease.

Dietary fibers with low hydration properties exacerbate diarrhea and impair intestinal health and nutrient digestibility in weaned piglets

Background

This study aimed to investigate the hydration properties of different-source fibrous materials by comparing their water-binding capacity (WBC), water swelling capacity (WSC), viscosity, and in vivo effects of selected samples on growth performance, nutrient digestibility, diarrhea, and intestinal health in weaned piglets.

Methods

A total of 13 commercially available fibrous materials were first compared in chemical composition and in vitro hydration property. Subsequently, 40 weaned piglets were randomized to five experimental dietary groups (8 piglets per group): control diet (a basal diet without dietary fiber, CON), basal diet supplemented with 5% microcrystalline cellulose (MCC), 5% wheat bran (WB), 5% Moringaoleifera leaf powder (MOLP), or 5% sugar beet pulp (SBP), followed by analyzing their growth performance and diarrhea rate in a 28-d experiment. After the feeding experiment, anaesthetized piglets were killed, and their intestinal and colon content or plasma samples were analyzed in nutrient digestibility, intestinal morphology, intestinal barrier, short-chain fatty acids (SCFAs), and bacterial population.

Results

In vitro studies showed low hydration properties for WB and MCC, while medium hydration properties for MOLP and SBP. In vivo studies indicated that compared with medium hydration property groups, low hydration property groups showed (1) exacerbated diarrhea, impaired intestinal health, and reduced apparent fecal digestibility of dry matter, gross energy, acid detergent fiber, and neutral detergent fiber; (2) decreased SCFAs concentration and relative levels of Lactobacillus and Bifidobacterium, but increased levels of Escherichia coli and Brachyspira hyodysenteriae in colon contents. Additionally, SBP showed optimal performance in reducing diarrhea and increasing SCFAs production. Correlation analysis revealed a positive correlation of fiber hydration properties with in vitro SCFAs production, and diarrhea index and nutrient digestibility were negatively and positively correlated with SCFAs levels in the colon contents of weaned piglets, respectively.

Conclusions

Different-source dietary fibers varied in their hydration properties and impacts on diarrhea, microbial composition and SCFAs production in weaned piglets. WB and MCC could exacerbate diarrhea and impair nutrient digestibility, probably because their low hydration properties were detrimental to gut microbial homeostasis and fermentation. Our findings provide new ideas for rational use of fiber resources in weaned piglets.

Short-Term Effect of Additional Daily Dietary Fibre Intake on Appetite, Satiety, Gastrointestinal Comfort, Acceptability, and Feasibility

Background: There is evidence that high-fibre diets have significant health benefits, although the effect of increasing fibre on individuals’ appetite, satiety, and gastrointestinal comfort is not well established, nor is its acceptability and feasibility. Methods: This mixed-methods feasibility randomised control trial included 38 participants allocated to one of three conditions: FibreMAX (two daily servings of 25 g of BARLEYmax^®), FibreGRAD (two daily servings with the amount of fibre gradually increased), and Control (two daily servings totalling 25 g of placebo product). Participants completed a food diary at baseline. The Hunger and Fullness Questionnaire and questions regarding gastrointestinal response were completed at baseline and at the end of each week. Participants completed the acceptability of intervention measure and engaged in a semi-structured interview, following trial completion. Results: The qualitative data suggested that increased fibre influenced appetite and fullness perceptions. Baseline fibre consumption and the method of increased fibre increase did not influence our findings. The qualitative results also indicated that the fibre intake was perceived as beneficial to well-being; it influenced feelings of hunger and caused some minor acute gastrointestinal symptoms that dissipated after a short adaption period. Conclusion: This study suggests that increasing fibre intake through BARLEYmax^® is a safe intervention that is acceptable to participants.

The impact of almonds and almond processing on gastrointestinal physiology, luminal microbiology, and gastrointestinal symptoms: a randomized controlled trial and mastication study

BACKGROUND

Almonds contain lipid, fiber, and polyphenols and possess physicochemical properties that affect nutrient bioaccessibility, which are hypothesized to affect gut physiology and microbiota.

OBJECTIVES

To investigate the impact of whole almonds and ground almonds (almond flour) on fecal bifidobacteria (primary outcome), gut microbiota composition, and gut transit time.

METHODS

Healthy adults (n = 87) participated in a parallel, 3-arm randomized controlled trial. Participants received whole almonds (56 g/d), ground almonds (56 g/d), or an isocaloric control in place of habitual snacks for 4 wk. Gut microbiota composition and diversity (16S rRNA gene sequencing), SCFAs (GC), volatile organic compounds (GC-MS), gut transit time (wireless motility capsule), stool output and gut symptoms (7-d diary) were measured at baseline and endpoint. The impact of almond form on particle size distribution (PSD) and predicted lipid release was measured (n = 31).

RESULTS

Modified intention-to-treat analysis was performed on 79 participants. There were no significant differences in mean ± SD abundance of fecal bifidobacteria after consumption of whole almonds (8.7% ± 7.7%), ground almonds (7.8% ± 6.9%), or control (13.0% ± 10.2%; q = 0.613). Consumption of almonds (whole and ground pooled) resulted in higher mean ± SD butyrate (24.1 ± 15.0 μmol/g) than control (18.2 ± 9.1 μmol/g; P = 0.046). There was no effect of almonds on gut microbiota at the phylum level or diversity, gut transit time, stool consistency, or gut symptoms. Almond form (whole compared with ground) had no effect on study outcomes. Ground almonds resulted in significantly smaller PSD and higher mean ± SD predicted lipid release (10.4% ± 1.8%) than whole almonds (9.3% ± 2.0%; P = 0.017).

CONCLUSIONS

Almond consumption has limited impact on microbiota composition but increases butyrate in adults, suggesting positive alterations to microbiota functionality. Almonds can be incorporated into the diet to increase fiber consumption without gut symptoms.This trial was registered at clinicaltrials.gov as NCT03581812.

Extruded Wheat Bran Consumption Increases Serum Short-Chain Fatty Acids but Does Not Modulate Psychobiological Functions in Healthy Men: A Randomized, Placebo-Controlled Trial

Background

Incorporation of wheat bran (WB) into food products increases intake of dietary fiber, which has been associated with improved mood and cognition and a lower risk for psychiatric disorders such as depression, with short-chain fatty acids (SCFAs) as candidate mediators of these effects. Modifying WB using extrusion cooking increases SCFA production in vitro relative to unmodified WB.

Objective

The aim of this study was to evaluate the effects of extruded WB on psychobiological functioning and the mediating role of SCFAs.

Methods

In a randomized, triple-blind, placebo-controlled trial, 69 healthy male participants consumed 55 g of breakfast cereal containing either extruded WB or placebo daily for 28 days. At pre- and post-intervention visits, the cortisol response to experimentally induced stress was measured as a primary outcome. In addition, serum SCFAs and brain-derived neurotrophic factors were quantified as potential mediators. Secondary psychobiological outcomes included subjective stress responses, responses to experimentally induced fear, cortisol awakening response, heart rate variability, and retrospective subjective mood ratings. Intestinal permeability, fecal SCFAs, and stool consistency were measured as secondary biological outcomes.

Results

Extruded WB increased serum acetate and butyrate (p < 0.05). None of the primary or secondary outcomes were affected by the intervention. Participants who consumed a placebo exhibited an increase in the percentage of fecal dry weight but did not report increased constipation. Despite these statistically significant effects, these changes were small in magnitude.

Conclusions

Extruded WB consumption increased serum short-chain fatty acids but did not modulate psychobiological functions in healthy men. Effective modulation of psychobiological functions may require greater increases in SCFAs than those achieved following extruded WB consumption. Rather than attempting to induce health benefits with a single fiber-rich food, combinations of different fibers, particularly highly fermentable ones, might be needed to further increase SCFA production and uptake in the systemic circulation to observe an effect on psychobiological processes.

Predictors of Gastrointestinal Transit Times in Colon Capsule Endoscopy

INTRODUCTION

Optimizing the accuracy of colon capsule endoscopy (CCE) requires high completion rates. To prevent incomplete CCE, we aimed to identify predictors associated with slow CCE transit times.

METHODS

In this population-based study, participants received CCE with a split-dose polyethylene glycol bowel preparation and booster regimen (0.5 L oral sulfate solution and 10 mg metoclopramide if capsule remained in stomach for > 1 hour). The following predictors were assessed: age, sex, body mass index (BMI), smoking, coffee and fiber intake, diet quality, physical activity, dyspeptic complaints, stool pattern, history of abdominal surgery, medication use, and CCE findings. Multivariable logistic and linear regressions with backward elimination were performed.

RESULTS

We analyzed 451 CCE procedures with a completion rate of 51.9%. The completion rate was higher among older participants (odds ratio [OR] 1.54, 95% confidence interval [CI] 1.04-2.28, P = 0.03) and participants with a changed stool pattern (OR 2.27, 95% CI 1.20-4.30, P = 0.01). Participants with a history of abdominal surgery had a lower completion rate (OR 0.54, 95% CI 0.36-0.80, P = 0.003). Participants with higher BMI had faster stomach, small bowel, and total transit times (β = -0.10, P = 0.01; β = -0.14, P = 0.001; β = -0.12, P = 0.01). A faster small bowel transit was found in participants with a changed stool pattern (β = -0.08, P = 0.049) and the use of metoclopramide (β = -0.14, P = 0.001). Participants with high fiber intake had a slower colonic transit (β = 0.11, P = 0.03).

DISCUSSION

Younger age, unchanged stool pattern, history of abdominal surgery, low BMI, and high fiber intake resulted in slower CCE transit times and lower completion rates. In future practice, these factors can be considered to adjust preparation protocols.

Association between Dietary Factors and Constipation in Adults Living in Luxembourg and Taking Part in the ORISCAV-LUX 2 Survey

Constipation, a disorder of bowel movements, is among the most frequent gastrointestinal complaints in Western countries. Dietary constituents such as inadequate fiber intake have been related to constipation, but discrepancies exist in the findings regarding dietary factors. This study investigated the association between dietary patterns and bowel movements in adults living in Luxembourg. Data from 1431 participants from ORISCAV-LUX 2 (a cross-sectional survey) who completed a 174-item food frequency questionnaire (FFQ) were analyzed. A questionnaire-based constipation score was assessed by a validated scoring system. Confounders such as physical activity and serum/urine indicators were assessed. Women had higher constipation scores than men (p < 0.001). In food group-based regression models, a negative association was found between higher constipation score and intake of grains (Beta = −0.62, 95%CI: −1.18, −0.05) and lipid-rich foods (Beta = −0.84, 95%CI: −1.55, −0.13), while a positive association was found for sugary products (Beta = 0.54, 95%CI: 0.11, 0.97) (p < 0.05). In a nutrient-based regression model, a positive association was found between constipation score and total energy (Beta = 5.24, 95%CI: 0.37, 10.11) as well as sodium intake (Beta = 2.04, 95%CI: 0.21, 3.87), and a negative one was found for total fats (Beta = −4.17, 95%CI: −7.46, −0.89) and starch (Beta = −2.91, 95%CI: −4.47, −1.36) (p < 0.05). Interestingly, neither fruits and vegetables or dietary fiber were significantly associated with constipation. Thus, grains, lipid-rich foods, total fats and starch were associated with a lower constipation score, while sugary products, sodium, and higher energy intake were correlated with higher constipation.

Understanding the physiology of human defaecation and disorders of continence and evacuation

The act of defaecation, although a ubiquitous human experience, requires the coordinated actions of the anorectum and colon, pelvic floor musculature, and the enteric, peripheral and central nervous systems. Defaecation is best appreciated through the description of four phases, which are, temporally and physiologically, reasonably discrete. However, given the complexity of this process, it is unsurprising that disorders of defaecation are both common and problematic; almost everyone will experience constipation at some time in their life and many will develop faecal incontinence. A detailed understanding of the normal physiology of defaecation and continence is critical to inform management of disorders of defaecation. During the past decade, there have been major advances in the investigative tools used to assess colonic and anorectal function. This Review details the current understanding of defaecation and continence. This includes an overview of the relevant anatomy and physiology, a description of the four phases of defaecation, and factors influencing defaecation (demographics, stool frequency/consistency, psychobehavioural factors, posture, circadian rhythm, dietary intake and medications). A summary of the known pathophysiology of defaecation disorders including constipation, faecal incontinence and irritable bowel syndrome is also included, as well as considerations for further research in this field.

Recent advances in utilization of pectins in biomedical applications: a review focusing on molecular structure-directing health-promoting properties

The numerous health benefits of pectins justify their inclusion in human diets and biomedical products. This review provides an overview of pectin extraction and modification methods, their physico-chemical characteristics, health-promoting properties, and pharmaceutical/biomedical applications. Pectins, as readily available and versatile biomolecules, can be tailored to possess specific functionalities for food, pharmaceutical and biomedical applications, through judicious selection of appropriate extraction and modification technologies/processes based on green chemistry principles. Pectin's structural and physicochemical characteristics dictate their effects on digestion and bioavailability of nutrients, as well as health-promoting properties including anticancer, immunomodulatory, anti-inflammatory, intestinal microflora-regulating, immune barrier-strengthening, hypercholesterolemia-/arteriosclerosis-preventing, anti-diabetic, anti-obesity, antitussive, analgesic, anticoagulant, and wound healing effects. HG, RG-I, RG-II, molecular weight, side chain pattern, and degrees of methylation, acetylation, amidation and branching are critical structural elements responsible for optimizing these health benefits. The physicochemical characteristics, health functionalities, biocompatibility and biodegradability of pectins enable the construction of pectin-based composites with distinct properties for targeted applications in bioactive/drug delivery, edible films/coatings, nano-/micro-encapsulation, wound dressings and biological tissue engineering. Achieving beneficial synergies among the green extraction and modification processes during pectin production, and between pectin and other composite components in biomedical products, should be key foci for future research.

[Low intake of dietary fibers among the elderly: 2014/2015 ISACAMP population-based study]

The scope of this article is to evaluate the prevalence of inadequate dietary fiber intake and associated factors among elderly adults. A cross-sectional population-based study evaluating participants from the Health Survey of the City of Campinas (ISACAMP) was conducted in 2014/2015, with 1,074 elderly individuals (≥60 years). Dietary fiber intake was obtained using a 24-hour recall, and the prevalence of inadequate fibers was estimated according to the cut-off point of the Institute of Medicine (30 g/day for men and 21 g/day for women). The factors evaluated were sociodemographic conditions (sex, age, schooling, income, marital status), health (number of reported diseases) and lifestyle (physical activity, smoking and alcohol consumption). The prevalence of inadequate dietary fiber intake was 86.6%, being higher in men (RP=1.10), single or divorced (RP=1.09) and physically inactive (PR=1.07). Elderly adults with higher incomes and who reported having 1 to 2 chronic non-communicable diseases had a higher intake of fibers. The high prevalence of inadequate dietary fiber intake in the elderly adults indicates that health and nutrition actions should be developed to ensure adequate dietary intake of these compounds.

Acidic pH enhances butyrate production from pectin by faecal microbiota

Environmental pH and gut transit rate are the key factors determining the dynamics of colonic microbiota. In this study, the effect of changing pH on the composition and metabolism of pooled faecal microbiota was elucidated at physiologically relevant dilution rates Dhigh = 0.2 and Dlow = 0.05 1/h. The results showed the best adaptability of Bacteroides ovatus within the pH range 6.0-8.0 at both dilution rates. The butyrate producing Faecalibacterium and Coprococcus comes were extremely sensitive to pH > 7.5, while the abundance of Akkermansia muciniphila increased significantly at pH >7 at Dhigh, causing a pH-dependant shift in the dynamics of mucin degrading species. Increased gas formation was observed at pH < 6.5. Substantially more CO2 was produced at Dlow than at Dhigh (18-29 vs 12-23 mmol per L medium, respectively). Methane was produced only at Dlow and pH > 7, consistent with the simultaneous increased abundance of Methanobrevibacter smithii. Our study confirmed the importance of pH in the development of faecal microbiota in pectin-supplemented medium. Fermentation of other dietary fibres can be studied using the same approach. The significance of pH should be more emphasized in gut research and diagnostics.

Healthy Aging-Nutrition Matters: Start Early and Screen Often

The amount of time spent in poor health at the end of life is increasing. This narrative review summarizes consistent evidence indicating that healthy dietary patterns and maintenance of a healthy weight in the years leading to old age are associated with broad prevention of all the archetypal diseases and impairments associated with aging including: noncommunicable diseases, sarcopenia, cognitive decline and dementia, osteoporosis, age-related macular degeneration, diabetic retinopathy, hearing loss, obstructive sleep apnea, urinary incontinence, and constipation. In addition, randomized clinical trials show that disease-specific nutrition interventions can attenuate progression-and in some cases effectively treat-many established aging-associated conditions. However, middle-aged and older adults are vulnerable to unhealthy dietary patterns, and typically consume diets with inadequate servings of healthy food groups and essential nutrients, along with an abundance of energy-dense but nutrient-weak foods that contribute to obesity. However, based on menu examples, diets that are nutrient-dense, plant-based, and with a moderately low glycemic load are better equipped to meet the nutritional needs of many older adults than current recommendations in US Dietary Guidelines. These summary findings indicate that healthy nutrition is more important for healthy aging than generally recognized. Improved public health messaging about nutrition and aging, combined with routine screening and medical referrals for age-related conditions that can be treated with a nutrition prescription, should form core components of a national nutrition roadmap to reduce the epidemic of unhealthy aging.

Health benefits of whole grain: effects on dietary carbohydrate quality, the gut microbiome, and consequences of processing

Grains are important sources of carbohydrates in global dietary patterns. The majority of these carbohydrates, especially in refined-grain products, are digestible. Most carbohydrate digestion takes place in the small intestine where monosaccharides (predominantly glucose) are absorbed, delivering energy to the body. However, a considerable part of the carbohydrates, especially in whole grains, is indigestible dietary fibers. These impact gut motility and transit and are useful substrates for the gut microbiota affecting its composition and quality. For the most part, the profile of digestible and indigestible carbohydrates and their complexity determine the nutritional quality of carbohydrates. Whole grains are more complex than refined grains and are promoted as part of a healthy and sustainable diet mainly because the contribution of indigestible carbohydrates, and their co-passenger nutrients, is significantly higher. Higher consumption of whole grain is recommended because it is associated with lower incidence of, and mortality from, CVD, type 2 diabetes, and some cancers. This may be due in part to effects on the gut microbiota. Although processing of cereals during milling and food manufacturing is necessary to make them edible, it also offers the opportunity to still further improve the nutritional quality of whole-grain flours and foods made from them. Changing the composition and availability of grain carbohydrates and phytochemicals during processing may positively affect the gut microbiota and improve health.

Dietary Fiber Is Essential to Maintain Intestinal Size, L-Cell Secretion, and Intestinal Integrity in Mice

Dietary fiber has been linked to improved gut health, yet the mechanisms behind this association remain poorly understood. One proposed mechanism is through its influence on the secretion of gut hormones, including glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2). We aimed to: 1) investigate the impact of a fiber deficient diet on the intestinal morphological homeostasis; 2) evaluate L-cell secretion; and 3) to ascertain the role of GLP-1, GLP-2 and Takeda G protein-receptor-5 (TGR5) signaling in the response using GLP-1 receptor, GLP-2 receptor and TGR5 knockout mice. Female C57BL/6JRj mice (n = 8) either received a standard chow diet or were switched to a crude fiber-deficient diet for a short (21 days) and long (112 days) study period. Subsequent identical experiments were performed in GLP-1 receptor, GLP-2 receptor and TGR5 knockout mice. The removal of fiber from the diet for 21 days resulted in a decrease in small intestinal weight (p < 0.01) and a corresponding decrease in intestinal crypt depth in the duodenum, jejunum and ileum (p < 0.001, p < 0.05, and p < 0.01, respectively). Additionally, colon weight was decreased (p < 0.01). These changes were associated with a decrease in extractable GLP-1, GLP-2 and PYY in the colon (p < 0.05, p < 0.01, and p < 0.01). However, we could not show that the fiber-dependent size decrease was dependent on GLP-1 receptor, GLP-2 receptor or TGR5 signaling. Intestinal permeability was increased following the removal of fiber for 112 days. In conclusion, our study highlights the importance of dietary fiber to maintain intestinal weight, colonic L-cell secretion and intestinal integrity.

Dietary fibre in gastrointestinal health and disease

Epidemiological studies have consistently demonstrated the benefits of dietary fibre on gastrointestinal health through consumption of unrefined whole foods, such as wholegrains, legumes, vegetables and fruits. Mechanistic studies and clinical trials on isolated and extracted fibres have demonstrated promising regulatory effects on the gut (for example, digestion and absorption, transit time, stool formation) and microbial effects (changes in gut microbiota composition and fermentation metabolites) that have important implications for gastrointestinal disorders. In this Review, we detail the major physicochemical properties and functional characteristics of dietary fibres, the importance of dietary fibres and current evidence for their use in the management of gastrointestinal disorders. It is now well-established that the physicochemical properties of different dietary fibres (such as solubility, viscosity and fermentability) vary greatly depending on their origin and processing and are important determinants of their functional characteristics and clinical utility. Although progress in understanding these relationships has uncovered potential therapeutic opportunities for dietary fibres, many clinical questions remain unanswered such as clarity on the optimal dose, type and source of fibre required in both the management of clinical symptoms and the prevention of gastrointestinal disorders. The use of novel fibres and/or the co-administration of fibres is an additional therapeutic approach yet to be extensively investigated.

Whole Grains, Refined Grains, and Cancer Risk: A Systematic Review of Meta-Analyses of Observational Studies

PubMed, Web of Science, and the Cochrane Database of Systematic Reviews were searched for meta-analyses that provided risk estimates (±95% confidence intervals) for associations between intakes of whole and refined grains and risk of total and site-specific cancer. The preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed. Only meta-analyses that included whole grains and refined grains as separate food groups, and not as part of dietary patterns, were included. A total of 17 publications were identified that met inclusion criteria. Within these, results from a total of 54 distinct meta-analyses were reported for whole grains and 5 meta-analyses for refined grains. For total cancer mortality, 7 meta-analyses of cohort studies indicated that whole grain intake was associated with 6% to 12% lower risk in comparison of highest vs. lowest intake groups, and 3% to 20% lower risk for doses ranging from 15 to 90 g/day. For site-specific cancers, meta-analyses indicated that whole grain intake was consistently associated with lower risks of colorectal, colon, gastric, pancreatic, and esophageal cancers. Limited data were available for refined grains, with only 4 publications providing risk estimates, and only 1 of the meta-analyses included more than 3 studies. High intake of refined grains was associated with increased risk of colon and gastric cancer. By contrast, in the only dose-response meta-analysis, each 90 g/day consumption of refined grains was associated with a 6% lower risk of total cancer. In addition to the limited number of published meta-analyses on refined grains, results were also weakened due to the fact that refined grains were frequently defined to include both staple grain foods and indulgent grain foods, and the majority of studies included in the meta-analyses provided no specific definition of refined grains. Overall, meta-analyses of cohort and case-control studies consistently demonstrate that whole grain intake is associated with lower risk of total and site-specific cancer, and support current dietary recommendations to increase whole grain consumption. By contrast, the relationship between refined grain intake and cancer risk is inconclusive.

C, Holst JJ, Zoetendal EG, Smidt H, Troost F, Schaap FG, Damink SO, Jocken JWE, Lenaerts K, Masclee AAM, Blaak EE. Effect of wheat bran derived prebiotic supplementation on gastrointestinal transit, gut microbiota, and metabolic health: a randomized controlled trial in healthy adults with a slow gut transit

Acute intake of the wheat bran extract Arabinoxylan-Oligosaccharide (AXOS) modulates the gut microbiota, improves stool characteristics and postprandial glycemia in healthy humans. Yet, little is known on how long-term AXOS intake influences gastrointestinal (GI) functioning, gut microbiota, and metabolic health. In this randomized, placebo-controlled, double-blind study, we evaluated the effects of AXOS intake on GI function and metabolic health in adults with slow GI transit without constipation. Forty-eight normoglycemic adults were included with whole-gut transit time (WGTT) of >35 h receiving either 15 g/day AXOS or placebo (maltodextrin) for 12-wks. The primary outcome was WGTT, and secondary outcomes included stool parameters, gut permeability, short-chain fatty acids (SCFA), microbiota composition, energy expenditure, substrate oxidation, glucose, insulin, lipids, gut hormones, and adipose tissue (AT) function. WGTT was unchanged, but stool consistency softened after AXOS. 12-wks of AXOS intake significantly changed the microbiota by increasing Bifidobacterium and decreasing microbial alpha-diversity. With a good classification accuracy, overall microbiota composition classified responders with decreased WGTT after AXOS. The incretin hormone Glucagon-like protein 1 was reduced after AXOS compared to placebo. Energy expenditure, plasma metabolites, AT parameters, SCFA, and gut permeability were unchanged. In conclusion, intake of wheat bran extract increases fecal Bifidobacterium and softens stool consistency without major effects on energy metabolism in healthy humans with a slow GI transit. We show that overall gut microbiota classified responders with decreased WGTT after AXOS highlighting that GI transit and change thereof were associated with gut microbiota independent of Bifidobacterium. NCT02491125.

Effects of Low and High FODMAP Diets on Human Gastrointestinal Microbiota Composition in Adults with Intestinal Diseases: A Systematic Review

A diet high in non-digestible carbohydrates is known to promote health, in part through its effect on the gut microbiome. While substantially proven for healthy individuals, these effects are more ambiguous in subjects with intestinal diseases. At the same time, a diet low in these fermentable carbohydrates, the low FODMAP (acronym for Fermentable Oligo-, Di-, Mono-saccharides, And Polyols) diet, is gaining popularity as a treatment option for symptom relief in irritable bowel syndrome and inflammatory bowel disease. There are, however, several indications that this diet induces effects opposite to those of prebiotic supplementation, resulting in gut microbiome changes that might be detrimental. Here, we provide a systematic review of the effects of low and high FODMAP diets on human gastrointestinal microbiota composition in adults with intestinal diseases, through literature screening using the databases PubMed, Embase, and Web of Science. We summarize study findings on dietary impact in patients, including the effect on bacterial taxa and diversity. In general, similar to healthy subjects, restricting non-digestible carbohydrate intake in patients with intestinal diseases has opposite effects compared to prebiotic supplementation, causing a reduction in bifidobacteria and an increase in bacteria associated with dysbiosis. Future studies should focus on assessing whether the induced microbial changes persist over time and have adverse effects on long-term colonic health.

Increasing dietary fibre intake in healthy adults using personalised dietary advice compared with general advice: a single-blind randomised controlled trial

Objective:

A high-fibre diet is associated with a lower risk for diseases. However, few adults meet the dietary fibre recommendation. Therefore, the effects and acceptance of an algorithm-generated personalised dietary advice (PDA) compared with general advice (GA) on fibre intake were investigated.

Design:

A 6-week, single-blind randomised controlled trial with a 3-month follow-up.

Setting:

PDA was based on habitual intake and provided fibre-rich alternatives using a website; GA contained brochures. Dietary intake was assessed at baseline, week 1, week 6 and 3-month follow-up. Both groups evaluated their advice at week 6. All participants had access to PDA from week 7 until 3-month follow-up.

Participants:

Two groups of healthy adults: PDA (n 34) and GA (n 47). For 3-month follow-up analysis, participants were re-divided into visitors (n 52) and non-visitors (n 26) of the PDA.

Results:

At week 6, energy intake remained stable in both groups, but fibre intake per 1000 kcal increased non-significantly in both groups (PDA = Δ0·5 ± 2·8; GA = Δ0·8 ± 3·1, P = 0·128). Importantly, a significantly higher percentage of PDA participants adhered to the recommendation compared with week 1 (PDA = 21 % increase; GA = 4 % increase, P ≤ 0·001). PDA participants evaluated the advice significantly better compared with GA participants. At 3-month follow-up, fibre intake increased compared with baseline (visitors = Δ2·2 ± 2·6, P < 0·001; non-visitors = Δ1·5 ± 1·9, P = 0·001), but was insignificantly different between groups. Visitors had a decrease and non-visitors had an increase in energy intake (visitors =Δ − 132 ± 525; non-visitors = Δ109 ± 507, P = 0·055).

Conclusions:

The algorithm-generated PDA was well accepted and stimulated adherence to the recommendations more than GA, indicating to be a suitable and cost-efficient method for improving dietary fibre intake in healthy adults.

Best management of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction which can have a considerable impact on quality of life. Following diagnosis, timely and evidence-based management is vital to the care of patients with IBS, aiming to improve outcomes, and enhance patient satisfaction. Good communication is paramount, and clinicians should provide a clear explanation about the disorder, with a focus on exploring the patient's own beliefs about IBS, and a discussion of any concerns they may have. It should be emphasised that symptoms are often chronic, and that treatment, while aiming to improve symptoms, may not relieve them completely. Initial management should include simple lifestyle and dietary advice, discussion of the possible benefit of some probiotics, and, if this is unsuccessful, patients can be referred to a dietician for consideration of a low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) diet. Antispasmodics and peppermint oil can be used first-line for the treatment of abdominal pain. If patients fail to respond, central neuromodulators can be used second-line; tricyclic antidepressants should be preferred. Loperamide and laxatives can be used first-line for treating diarrhoea and constipation, respectively. Patients with constipation who fail to respond to laxatives should be offered a trial of linaclotide. For patients with diarrhoea, the 5-hydroxytryptamine-3 receptor agonists alosetron and ramosetron appear to be the most effective second-line drugs. Where these are unavailable, ondansetron is a reasonable alternative. If medical treatment is unsuccessful, patients should be referred for psychological therapy, where available, if they are amenable to this. Cognitive behavioural therapy and gut-directed hypnotherapy are the psychological therapies with the largest evidence base.

Effects of rice-based and wheat-based diets on bowel movements in young Korean women with functional constipation

Background

Although several studies have reported the effects that dietary fiber intake from different types of grains and fiber components have on bowel movements, insufficient attention has been paid to comparing and evaluating the effects of rice-based and wheat-based diets. This study compared and evaluated the effects of ingesting rice-based (brown rice-based diet: BRD; white rice-based diet: WRD) and wheat-based diet (WD) on the bowel movements of young women with functional constipation.

Method

Based on an open, randomized, controlled, and parallel design, 39 subjects were assigned to BRD, WRD, and WD groups (13 in each group). Each participant had received three types of experimental diets over the course of 4 weeks and we recommended that the subjects eat only the test diet provided during the study. Primary outcomes (total colon transit time TCTT) and secondary outcomes (bowel movements, short-chain fatty acid content, and fecal enzyme activity) were compared before and after the 4-week intervention period.

Results

After the 4-week study, the rice-based diet (BRD and WRD) groups and the WD group had a statistically significant difference in TCTT (p = 0.028). The TCTT of the BRD group was significantly reduced (p = 0.028) compared with the WRD group (−16.5 ± 8.1 vs +6.8 ± 2.1), and the TCTT of the WD group was also significantly reduced (p = 0.022) compared with that of the WRD group (−17.1 ± 11.9 vs +6.8 ± 2.1).

Conclusion

Among women with functional constipation, the BRD and WD both improved bowel function by reducing TCTT and increasing the number of bowel movements compared with the WRD group.

Effects of copper hydroxychloride and distillers dried grains with solubles on intestinal microbial concentration and apparent ileal and total tract digestibility of energy and nutrients by growing pigs1

An experiment was conducted to test the hypothesis that Cu hydroxychloride improves nutrient digestibility and alters the concentration of microbial protein in the small intestine or large intestine by pigs fed a corn-soybean meal diet or a diet based on corn, soybean meal, and distillers dried grains with solubles (DDGS). Twenty-four barrows (33.3 ± 3.4 kg) that had a T-cannula installed in the distal ileum were allotted to a 2 × 2 factorial design with 2 levels of DDGS (0% or 45%) and 2 levels of supplemental Cu from Cu hydroxychloride (0 or 150 mg/kg). A 2-period switch back design with the 4 diets and 6 replicate pigs per diet in each period was used resulting in 12 replicate pigs per diet for the 2 periods. The initial 9 d of each period was considered an adaptation period to the experimental diets. For each period, feces were collected on days 10, 11, and 12, and ileal digesta were collected for 8 h on days 13 and 14. Results indicated that inclusion of 45% DDGS to diets reduced (P < 0.05) the apparent ileal digestibility (AID) of AA and the AID and the apparent total tract digestibility (ATTD) of dry matter, gross energy, and crude protein. In contrast, inclusion of DDGS to diets increased (P < 0.05) the AID and the ATTD of acid hydrolyzed ether extract and the concentration of microbial protein in the hindgut (P < 0.05). However, the total concentration of volatile fatty acids (VFA) in ileal digesta and in feces from pigs fed the DDGS diets were not different from concentrations in pigs fed diets without DDGS. The AID and ATTD of dry matter, gross energy, and crude protein were not affected by dietary Cu concentrations, but the AID and ATTD of acid hydrolyzed ether extract were greater (P < 0.05) in diets supplemented with Cu hydroxychloride compared with diets without Cu hydroxychloride. There was also a reduction (P < 0.05) in the concentration of microbial protein and a tendency for a reduction (P < 0.10) in the total concentration of VFA in feces when diets were supplemented with Cu hydroxychloride. In conclusion, supplementation of Cu hydroxychloride to diets improved AID and ATTD of acid hydrolyzed ether extract and reduced the concentration of microbial protein in the large intestine and this effect was observed in diets containing DDGS as well as in diets without DDGS.

Microplastics in Sea Turtles, Marine Mammals and Humans: A One Environmental Health Perspective

Microplastics are ubiquitous pollutants in the marine environment and a health concern. They are generated directly for commercial purposes or indirectly from the breakdown of larger plastics. Examining a toxicological profile for microplastics is a challenge due to their large variety of physico-chemical properties and toxicological behavior. In addition to their concentration, other parameters such as polymer type, size, shape and color are important to consider in their potential toxicity. Microplastics can adsorb pollutants such as polycyclic aromatic hydrocarbons (PAHs) or metals on their surface and are likely to contain plastic additives that add to their toxicity. The observations of microplastics in seafood increased concern for potential human exposure. Since literature considering microplastics in humans is scarce, using a One Environmental Health approach can help better inform about potential human exposures. Marine mammals and sea turtles are long-lived sentinel species regularly used for biomonitoring the health status of the ocean and share trophic chain and habitat with humans. This review considers the available research regarding microplastic and plastic fiber exposures in humans, marine mammals and turtles. Overall, across the literature, the concentration of microplastics, size, color, shape and polymer types found in GI tract and feces from sea turtles, marine mammals and humans are similar, showing that they might be exposed to the same microplastics profile. Additionally, even if ingestion is a major route of exposure due to contaminated food and water, dermal and inhalation studies in humans have provided data showing that these exposures are also health concerns and more effort on these routes of exposures is needed. In vitro studies looked at a variety of endpoints showing that microplastics can induce immune response, oxidative stress, cytotoxicity, alter membrane integrity and cause differential expression of genes. However, these studies only considered three polymer types and short-term exposures, whereas, due to physiological relevance, prolonged exposures might be more informative.

Effects of Extrinsic Wheat Fiber Supplementation on Fecal Weight; A Randomized Controlled Trial

Higher fiber intake may confer beneficial effects on health. Our objective was to investigate the impact of 10 g extrinsic wheat fiber on fecal bulk. Therefore, we performed two randomized intervention studies in which we provided extrinsic wheat fiber-enriched products or appropriate control products for five days together with normal diet. In one trial, 10 participants received fiber-enriched food products, whereas in the second study, 19 participants supplemented their daily diet with fiber-enriched drinks. The main outcome variable of this intervention was fecal bulk. Other outcomes were gut microbiota composition, short chain fatty acids in feces, and stool consistency and frequency. Fecal wet weight was significantly increased (p < 0.02) with extrinsic wheat fiber-enriched foods. In contrast, ingestion of extrinsic wheat fiber in the form of drinks did not significantly change fecal wet weight. In both groups, fecal dry weight was not altered upon extrinsic wheat fiber supplementation. However, the intake of fiber-enriched foods resulted in higher acetic acid levels in feces compared to fiber-enriched drinks. Regarding gut microbiota profiles, extrinsic wheat fiber-enriched food products were not associated with substantial alterations. In conclusion, 10 g extrinsic wheat fiber added to a normal diet increased fecal bulk if administered in a solid food matrix, but not if applied in the form of drinks. DRKS, DRKS00015792.Registered 30 October 2018.

Role of dietary fibre in older adults with asymptomatic (AS) or symptomatic uncomplicated diverticular disease (SUDD): Systematic review and meta-analysis

Dietary fibre and probiotics may play a role in the management of diverticular disease. This systematic review synthesises the evidence on the effects of dietary fibre modifications, with or without the use of probiotics, on the incidence in older adults of asymptomatic (AS) or symptomatic uncomplicated diverticular disease (SUDD), as well as on gastrointestinal function and symptoms. Five electronic databases were searched for studies through to December 2018. The body of evidence was appraised using the Cochrane Risk of Bias tool and GRADE. Nine studies were included, with mean sample ages ranging from 57 to 70 years, and three meta-analyses were performed. Only one study, with high risk of bias, measured the effect of dietary fibre on the incidence of diverticulitis. Dietary fibre supplementation improved stool weight (MD: 42 g/day, P < 0.00001; GRADE level of evidence: low), but had no significant effect on gastrointestinal symptoms (SMD: -0.13, P = 0.16; GRADE level of evidence: low) or stool transit time (MD: -3.70, P = 0.32 GRADE level of evidence: low). There was "very low" confidence for the body of evidence supporting symbiotics for AS or SUDD. A high dietary fibre intake, in line with dietary guidelines, may improve gastrointestinal function and is recommended in patients with AS or SUDD. Dietary fibre supplementation should be considered on an individualised basis to improve bowel function, while any recommendation on symbiotic supplements requires further well-designed research. Future studies should also measure the impact on the incidence of diverticulitis.

Effect of rice bran fermented with Saccharomyces cerevisiae and Lactobacillus plantarum on gut microbiome of mice fed high-sucrose diet

To clarify the effect of rice bran (RB) and fermented RB (FRB) in a high-sucrose and low-dietary fibre diet on the gut microbiome, the in vitro bile acid-lowering capacity and caecal microbiota of ICR mice fed with 20% RB or FRB diets for two weeks were determined. The caecal microbiome was analysed by 16S rRNA gene amplicon sequencing. The in vitro bile acid-lowering capacity was high for FRB. In mouse experiments, triacylglycerol and total cholesterol were generally lower with FRB, although the faecal frequency was highest in mice fed with RB. The Shannon-Wiener and Simpson's indices for alpha-diversity in the microbiome of mice fed with RB and FRB, were higher than mice fed the control diet. At the phylum level in the caecal microbiome, Firmicutes and Bacteroidetes were high with FRB and RB, respectively. At the operational taxonomic unit level, some bacterial groups related to diabetes and gut toxicity, such as Lachnospiraceae and Enterorhabdus mucosicola, were high for RB but not for FRB diets. These results suggest that FRB, rather than RB, intake improve the intestinal environment and blood lipid condition.

Rice Cultivation without Synthetic Fertilizers and Performance of Microbial Fuel Cells (MFCs) under Continuous Irrigation with Treated Wastewater

To obtain a high rice yield and quality for animal feed without synthetic fertilizers, an experiment with bench-scale apparatus was conducted by applying continuous irrigation with treated municipal wastewater (TWW). Uniform rice seedlings of a high-yield variety (Oryza sativa L., cv. Bekoaoba) were transplanted in five treatments to examine different TWW irrigation directions (“bottom-to-top” and “top-to-top” irrigation) and fertilization practices (with and without P-synthetic fertilizers) as well as one control that simulated the irrigation and fertilization management of normal paddy fields. The highest rice yield (14.1 t ha−1), shoot dry mass (12.9 t ha−1), and protein content in brown rice (14.6%) were achieved using bottom-to-top irrigation, although synthetic fertilizers were not applied. In addition, this subsurface irrigation system could contribute to environmental protection by removing 85–90% of nitrogen from TWW more effectively than the top-to-top irrigation, which showed a removal efficiency of approximately 63%. No accumulation of heavy metals (Fe, Mn, Cu, Zn, Cd, Ni, Pb, Cr, and As) in the paddy soils was observed after TWW irrigation for five months, and the contents of these metals in the harvested brown rice were lower than the permissible limits recommended by international standards. A microbial fuel cell system (MFC) was installed in the cultivation system using graphite-felt electrodes to test the capacity of electricity generation; however, the electricity output was much lower than that reported in normal paddy fields. Bottom-to-top irrigation with TWW can be considered a potential practice to meet both water and nutrient demand for rice cultivation in order to achieve a very high yield and nutritional quality of cultivated rice without necessitating the application of synthetic fertilizers.

Extrinsic wheat fibre consumption enhances faecal bulk and stool frequency; a randomized controlled trial

The beneficial effect of wheat fibres on faecal bulk and stool pattern has mainly been observed with intact wheat fibres. This study investigates the effect of extrinsic wheat fibre (VITACEL® wheat fibre), which can be easily incorporated in many food products, on faecal bulk, stool pattern, gastrointestinal complaints, satiety and food liking. In a double-blind randomized crossover trial, healthy male volunteers received meal boxes for 10 days, containing various food products enriched with extrinsic wheat fibre (∼20 grams of additional fibre per day) or control food products containing conventional levels of fibre with similar taste, appearance and caloric values. Meal boxes were integrated in the normal dietary pattern. Stool frequency, stool consistency, gastrointestinal complaints, satiety and product liking were assessed daily, and the last 5 days of each intervention, participants collected all their faeces to analyse faecal bulk. We found that consumption of extrinsic wheat fibre-enriched products significantly enhanced faecal bulk; faecal wet and dry weight showed a 1.41 ± 0.1 and 1.55 ± 0.1 times increase compared to control, respectively (p < 0.01). Extrinsic wheat fibre intervention furthermore increased stool frequency (1.3 ± 0.1 defecations per day compared to 1.1 ± 0.1 defecations per day during control diet, p < 0.05), but did not affect stool consistency, satiety, gastrointestinal complaints or product liking. So, increased consumption of extrinsic wheat fibre enhances faecal bulk and stool frequency. As this extrinsic wheat fibre can be easily incorporated in many food products without affecting appearance or taste, it might facilitate the increase of overall fibre intake and subsequently improve (intestinal) health.

Dietary Factors in Sulfur Metabolism and Pathogenesis of Ulcerative Colitis

The biogeography of inflammation in ulcerative colitis (UC) suggests a proximal to distal concentration gradient of a toxin. Hydrogen sulfide (H₂S) has long been considered one such toxin candidate, and dietary sulfur along with the abundance of sulfate reducing bacteria (SRB) were considered the primary determinants of H₂S production and clinical course of UC. The metabolic milieu in the lumen of the colon, however, is the result of a multitude of factors beyond dietary sulfur intake and SRB abundance. Here we present an updated formulation of the H₂S toxin hypothesis for UC pathogenesis, which strives to incorporate the interdependency of diet composition and the metabolic activity of the entire colon microbial community. Specifically, we suggest that the increasing severity of inflammation along the proximal-to-distal axis in UC is due to the dilution of beneficial factors, concentration of toxic factors, and changing detoxification capacity of the host, all of which are intimately linked to the nutrient flow from the diet.

Effect of High Fiber Cereal Intake on Satiety and Gastrointestinal Symptoms during Ramadan

(1) Background: Fasting during Ramadan involves large changes in daily eating patterns which strongly impacts the daily biorhythm and challenges the regular function of the digestive tract. The aim of this study was to assess satiety, bowel habits, body composition, blood glycaemia, and blood lipidemia after the consumption of high fiber cereal at dawn (Sohor) during the month of Ramadan; (2) Methods: A two-arm randomized, controlled, single-blinded, parallel-design study was conducted in Ramadan month. Participants were randomized to consume either 90 g of high fiber cereal (11 g fiber/90 g) at Sohor for 20 consecutive days (intervention group, n = 45) or to maintain their habitual diet intake (control group; n = 36); (3) Results: The intervention group reported higher satiety rating scores, improved bowel habits and reduced bloating frequency after the 20-day intervention. Significantly higher intake of carbohydrates and dietary fiber were observed in the intervention group. Total cholesterol and low density lipoprotein (LDL) cholesterol were significantly lower among the intervention group compared to the control group (p-value = 0.043, and p-value = 0.033, respectively) at the end of the intervention. No significant differences in body weight, body fat percentage, waist circumference, body mass index, blood glucose, high density lipoprotein (HDL) cholesterol, and triglycerides were observed between the two groups; (4) Conclusions: Consuming high fiber cereal had a positive effect on health and well-being during the month of Ramadan with better satiety, improved bowel functions, and improved blood lipids.

Modifying wheat bran to improve its health benefits

Consumption of wheat bran (WB) has been associated with improved gastrointestinal health and a reduced risk for colorectal cancer, cardiovascular diseases and metabolic disorders. These benefits are likely mediated by a combination of mechanisms, including colonic fermentation of the WB fiber, fecal bulking and the prevention of oxidative damage due to its antioxidant capacities. The relative importance of those mechanisms is not known and may differ for each health effect. WB has been modified by reducing particle size, heat treatment or modifying tissue composition to improve its technological properties and facilitate bread making processes. However, the impact of those modifications on human health has not been fully elucidated. Some modifications reinforce whereas others attenuate the health effects of coarse WB. This review summarizes available WB modifications, the mechanisms by which WB induces health benefits, the impact of WB modifications thereon and the available evidence for these effects from in vitro and in vivo studies.

Effects of β-Fructans Fiber on Bowel Function: A Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was to assess the effects of β-fructan supplementation on bowel function in healthy volunteers and patients. The search process was based on the selection of publications listed in the Pubmed and EUPMC database until December 2017, plus two unpublished studies, to identify studies evaluating the impact of β-fructans on bowel movement and stool parameters. Forty-seven publications were selected for inclusion. Primary parameter was frequency of bowel movements, evaluated by the number of defecations per day during the study period. Secondary outcomes were stool consistency, stool dry and wet weights, and transit time. Short-chain (DP < 10) β-fructans contributed to increased stool frequency (0.36 defecation +/- 0.06 per day; p < 0.001), while no significant effect was reported with long-chain (DP ≥ 10) β-fructans (-0.03 +/- 0.11, p = 0.82). A minimal increase in stool wet weight was also statistically demonstrated with short-chain β-fructans. Moreover, the meta-analysis highlighted significant differences in stool consistency in contrast to fecal dry weight after β-fructan supplementation. This systematic review and meta-analysis indicates that short-chain β-fructan supplementation has a positive effect on bowel function by significantly increasing the frequency of bowel movements.

Effect of Wheat Bran on Fecal Butyrate-Producing Bacteria and Wheat Bran Combined with Barley on Bacteroides Abundance in Japanese Healthy Adults

Wheat bran (WB) is rich in insoluble arabinoxylan, while BARLEYmax (BM) is a barley line that is rich in fructan, resistant starch, and β-glucan. In the present study, we investigated which of these two fiber sources would produce more favorable changes in the fecal variables of healthy subjects. Sixty healthy subjects were randomly divided into four groups (n = 15 per group) and fed twice daily for 4 weeks with baked cereal bars containing neither WB nor BM (WB−BM−), WB without BM (WB+BM−), BM without WB (WB−BM+), or WB and BM (WB+BM+). At baseline and after 4 weeks, the fecal microbiota composition and the concentrations of short-chain fatty acids were measured. A significant interactive effect of WB and BM on the abundance of genus Bacteroides was observed at week 4. The abundance of butyrate-producing bacteria and the fecal concentration of n-butyrate were significantly higher in the WB+ groups than in the WB− groups. In conclusion, WB was associated with elevated fecal concentrations of short-chain fatty acids including butyrate owing to an increase in the abundance of butyrate-producing bacteria. Additionally, the combination of WB and BM was associated with an increase in the abundance of genus Bacteroides. Therefore, both WB alone and WB combined with BM favorably influenced the fecal variables of healthy subjects.

Switching from a high-fat cellulose diet to a high-fat pectin diet reverses certain obesity-related morbidities

Background

Reducing caloric intake is a proven intervention for mitigating and modulating morbidities associated with overnutrition. Caloric restriction is difficult to affect clinically, therefore, dietary interventions that ameliorate the adverse consequences of overnutrition in the presence of a high-calorie diet would be of value.

Methods

Mice were fed an obesogenic diet containing 60% fat + 10% cellulose (HFC), or a control diet containing 10% fat + 10% cellulose (LFC) for 12 wks. Subgroups of mice were then switched from HFC to each of the following diets for an additional 5 wks: 1) 60% fat + 10% pectin (HFP), 2) LFC or 3) 10% fat + 10% pectin (LFP). To test for statistical differences, one-way or two-way ANOVAs were used with or without repeated measurements as needed.

Results

In comparison to HFC, HFP prevented additional weight gain while LFC and LFP triggered weight loss of 22.2 and 25.4%, respectively. Mice continued on HFC experienced a weight increase of 26% during the same 5 wk. interval. After 12 wks, HFC decreased mouse locomotion by 18% when compared to control diet, but a diet switch to LFC or LFP restored mouse movement. Importantly, HFP, LFC, and LFP reduced fasting blood glucose when compared to HFC. Likewise, HFP, LFC and LFP improved glucose tolerance and decreased fatty liver by 37.9, 49.8, 53.6 and 20.2%, 37.2, 43.7%, respectively.

Conclusions

Taken together, the results indicate that the dietary fiber pectin can mitigate some adverse consequences of overnutrition even in the presence of high-fat.

Effects of resistant maltodextrin on bowel movements: a systematic review and meta-analysis

It is well known that dietary fiber helps to relieve and prevent constipation, and there are a number of scientific papers, including systematic reviews and meta-analyses on the effects of naturally derived dietary fiber on bowel movements. In recent years, there has been an increase in the manufacture of dietary fiber ingredients obtained from food raw materials, and these are now commonly available in the market. Resistant maltodextrin (RMD), a soluble dietary fiber, is manufactured from starch, and industrially produced soluble dietary fiber is used worldwide. While there are many reports on the effects of RMD on bowel movements, no systematic review or meta-analysis has been reported. We conducted a systematic review and meta-analysis to clarify the effect of RMD on bowel movements based on stool frequency and stool volume. We also investigated the subjective evaluation of RMD effects on bowel movements. Of a total of 314 potentially relevant articles, 28 articles met the eligibility criteria, and 29 randomized controlled trials were identified. As a result of integration analyses, we found that the intake of RMD significantly increased stool volume and stool frequency compared with placebo intake. Furthermore, RMD intake tended to improve sensation of complete/incomplete evacuation. In conclusion, the evidence suggests that RMD has a positive effect on bowel movements, contributing to normal bowel function. This finding will help in the development of new criteria for choice of dietary fiber in the process of developing food products.

In Vitro Bioavailability of Calcium, Magnesium, Iron, Zinc, and Copper from Gluten-Free Breads Supplemented with Natural Additives

The aim of this study was to measure the content of calcium, magnesium, iron, zinc, and copper and determine the bioavailability of these ingredients in gluten-free breads fortified with milk and selected seeds. Due to the increasing prevalence of celiac disease and mineral deficiencies, it has become necessary to produce food with higher nutritional values which maintains the appropriate product characteristics. This study was designed for gluten-free breads fortified with milk and seeds such as flax, poppy, sunflower seeds, pumpkin seeds or nuts, and flour with amaranth. Subsequently, digestion was performed in vitro and the potential bioavailability of the minerals was measured. In the case of calcium, magnesium, iron, and copper, higher bioavailability was observed in rice bread, and, in the case of copper and zinc, in buckwheat bread. This demonstrated a clear increase in bioavailability of all the minerals when the bread were enriched. However, satisfactory results are obtained only for the individual micronutrients.

Gastrointestinal Transit Time, Glucose Homeostasis and Metabolic Health: Modulation by Dietary Fibers

Gastrointestinal transit time may be an important determinant of glucose homeostasis and metabolic health through effects on nutrient absorption and microbial composition, among other mechanisms. Modulation of gastrointestinal transit may be one of the mechanisms underlying the beneficial health effects of dietary fibers. These effects include improved glucose homeostasis and a reduced risk of developing metabolic diseases such as obesity and type 2 diabetes mellitus. In this review, we first discuss the regulation of gastric emptying rate, small intestinal transit and colonic transit as well as their relation to glucose homeostasis and metabolic health. Subsequently, we briefly address the reported health effects of different dietary fibers and discuss to what extent the fiber-induced health benefits may be mediated through modulation of gastrointestinal transit.

Substituting whole grains for refined grains in a 6-wk randomized trial favorably affects energy-balance metrics in healthy men and postmenopausal women

Background: The effect of whole grains on the regulation of energy balance remains controversial.Objective: We aimed to determine the effects of substituting whole grains for refined grains, independent of body weight changes, on energy-metabolism metrics and glycemic control.Design: The study was a randomized, controlled, parallel-arm controlled-feeding trial that was conducted in 81 men and postmenopausal women [49 men and 32 women; age range: 40-65 y; body mass index (in kg/m²): <35.0]. After a 2-wk run-in period, participants were randomly assigned to consume 1 of 2 weight-maintenance diets for 6 wk. Diets differed in whole-grain and fiber contents [mean ± SDs: whole grain-rich diet: 207 ± 39 g whole grains plus 40 ± 5 g dietary fiber/d; refined grain-based diet: 0 g whole grains plus 21 ± 3 g dietary fiber/d] but were otherwise similar. Energy metabolism and body-composition metrics, appetite, markers of glycemic control, and gut microbiota were measured at 2 and 8 wk.Results: By design, body weight was maintained in both groups. Plasma alkylresorcinols, which are biomarkers of whole-grain intake, increased in the whole grain-rich diet group (WG) but not in the refined grain-based diet group (RG) (P-diet-by-time interaction < 0.0001). Beta ± SE changes (ΔWG compared with ΔRG) in the resting metabolic rate (RMR) (43 ± 25 kcal/d; P = 0.04), stool weight (76 ± 12 g/d; P < 0.0001), and stool energy content (57 ± 17 kcal/d; P = 0.003), but not in stool energy density, were higher in the WG. When combined, the favorable energetic effects in the WG translated into a 92-kcal/d (95% CI: 28, 156-kcal/d) higher net daily energy loss compared with that of the RG (P = 0.005). Prospective consumption (P = 0.07) and glycemia after an oral-glucose-tolerance test (P = 0.10) trended toward being lower in the WG than in the RG. When nonadherent participants were excluded, between-group differences in stool energy content and glucose tolerance increased, and between-group differences in the RMR and prospective consumption were not statistically significant.Conclusion: These findings suggest positive effects of whole grains on the RMR and stool energy excretion that favorably influence energy balance and may help explain epidemiologic associations between whole-grain consumption and reduced body weight and adiposity. This trial was registered at clinicaltrials.gov as NCT01902394.