Kiwifruit-derived supplements increase stool frequency in healthy adults: a randomized, double-blind, placebo-controlled study

The effectiveness and safety of natural food and food-derived extract supplements for treating functional gastrointestinal disorders-current perspectives

Functional gastrointestinal disorders (FGIDs) were highly prevalent and involve gastrointestinal discomfort characterized by non-organic abnormalities in the morphology and physiology of the gastrointestinal tract. According to the Rome IV criteria, irritable bowel syndrome and functional dyspepsia are the most common FGIDs. Complementary and alternative medicines are employed by increasing numbers of individuals around the world, and they include herbal and dietary supplements, acupuncture, and hypnosis. Of these, herbal and dietary supplements seem to have the greatest potential for relieving FGIDs, through multiple modes of action. However, despite the extensive application of natural extracts in alternative treatments for FGIDs, the safety and effectiveness of food and orally ingested food-derived extracts remain uncertain. Many randomized controlled trials have provided compelling evidence supporting their potential, as detailed in this review. The consumption of certain foods (eg, kiwifruit, mentha, ginger, etc) and food ingredients may contribute to the alleviation of symptoms associated with FGID,. However, it is crucial to emphasize that the short-term consumption of these components may not yield satisfactory efficacy. Physicians are advised to share both the benefits and potential risks of these alternative therapies with patients. Furthermore, larger randomized clinical trials with appropriate comparators are imperative.

The effect of food, vitamin, or mineral supplements on chronic constipation in adults: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Over-the-counter supplements are commonly used to manage chronic constipation; however, their efficacy remains unclear. We aimed to investigate the effect of food, vitamin or mineral supplements on stool output, gut transit time, symptoms, and quality of life in adults with chronic constipation via a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

Studies were identified using electronic databases, backward citation, and hand-searching abstracts. RCTs reporting administration of food supplements (e.g., fruit extract supplements), vitamin or mineral supplements in adults with chronic constipation were included. Studies administering whole foods (e.g., fruits) were excluded. Risk of bias (RoB) was assessed with Cochrane RoB 2.0. Relative risks (RR), mean differences (MD), or standardized mean differences (95% confidence intervals [CI]) were calculated using a random-effects model.

KEY RESULTS

Eight RCTs (787 participants) were included, investigating kiwifruit (n = 3 RCTs), senna (n = 2), magnesium oxide (n = 2), Ziziphus jujuba (n = 1), and Malva Sylvestris (n = 1) supplements. Kiwifruit supplements did not impact stool frequency (MD 0.24 bowel movements/week [-0.32, 0.80]; p = 0.40) or consistency (MD -0.11 Bristol points [-0.31, 0.09], p = 0.29). Overall, 61% responded to senna and 28% to control; however, this did not reach statistical significance (RR 2.78, [0.93, 8.27]; p = 0.07). Overall, 68% responded to magnesium oxide and 19% to control (RR 3.32 [1.59, 6.92]; p = 0.001). Magnesium oxide improved stool frequency (MD 3.72 bowel movements/week [1.41, 6.03]; p = 0.002) and consistency (MD 1.14 Bristol points [0.48, 1.79]; p = 0.0007).

CONCLUSIONS AND INFERENCES

Magnesium oxide supplements are effective at improving cardinal symptoms of chronic constipation. Senna and kiwifruit supplements did not impact symptoms; however, findings were based on a small number of studies. Further research is required to investigate the effect of food supplements (e.g., kiwifruit supplements), as well as their whole food equivalents (e.g., whole kiwifruits) in chronic constipation.

Gut Microbiome-Brain Alliance: A Landscape View into Mental and Gastrointestinal Health and Disorders

Gut microbiota includes a vast collection of microorganisms residing within the gastrointestinal tract. It is broadly recognized that the gut and brain are in constant bidirectional communication, of which gut microbiota and its metabolic production are a major component, and form the so-called gut microbiome-brain axis. Disturbances of microbiota homeostasis caused by imbalance in their functional composition and metabolic activities, known as dysbiosis, cause dysregulation of these pathways and trigger changes in the blood-brain barrier permeability, thereby causing pathological malfunctions, including neurological and functional gastrointestinal disorders. In turn, the brain can affect the structure and function of gut microbiota through the autonomic nervous system by regulating gut motility, intestinal transit and secretion, and gut permeability. Here, we examine data from the CAS Content Collection, the largest collection of published scientific information, and analyze the publication landscape of recent research. We review the advances in knowledge related to the human gut microbiome, its complexity and functionality, its communication with the central nervous system, and the effect of the gut microbiome-brain axis on mental and gut health. We discuss correlations between gut microbiota composition and various diseases, specifically gastrointestinal and mental disorders. We also explore gut microbiota metabolites with regard to their impact on the brain and gut function and associated diseases. Finally, we assess clinical applications of gut-microbiota-related substances and metabolites with their development pipelines. We hope this review can serve as a useful resource in understanding the current knowledge on this emerging field in an effort to further solving of the remaining challenges and fulfilling its potential.

The Mediterranean Diet in Paediatric Gastrointestinal Disorders

The Mediterranean diet is considered one of the healthiest dietary patterns worldwide, thanks to a combination of foods rich mainly in antioxidants and anti-inflammatory nutrients. Many studies have demonstrated a strong relationship between the Mediterranean diet and some chronic gastrointestinal diseases. The aim of this narrative review was to analyse the role of the Mediterranean diet in several gastrointestinal diseases, so as to give a useful overview on its effectiveness in the prevention and management of these disorders.

Kiwifruit and Kiwifruit Extracts for Treatment of Constipation: A Systematic Review and Meta-Analysis

INTRODUCTION

This systematic review aimed to summarize evidence to determine the effectiveness of kiwifruit or kiwifruit extracts in the treatment of constipation.

METHODS

Electronic databases were searched from inception to May 2022 without any age or language limitations. Eligible studies enrolled participants with constipation who were randomized to receive kiwifruit or kiwifruit extracts vs. any nonkiwifruit control. Standardized mean difference (SMD) and mean difference (MD) with confidence intervals (CI) were determined for the following outcomes: frequency of spontaneous bowel movements (SBM), abdominal pain and straining, as well as stool type as determined by the Bristol Stool Scale (BSS). The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach was used to rate the certainty of evidence. Our review was registered on PROSPERO (CRD42021239397).

RESULTS

Seven RCTs, including 399 participants (82% female; mean age: 42 years (SD 14.6)), were included. Compared with placebo (n = 95), kiwifruit extracts might increase the weekly frequency of SBM (MD: 1.36; 95% CI: -0.44, 3.16) with low certainty of evidence; moreover, it had an uncertain effect on BSS (SMD: 1.54; 95% CI: -1.33, 4.41) with very low certainty of evidence. Additionally, compared with placebo (n = 119), kiwifruit or its extracts reduced abdominal pain (SMD: -1.44, 95% CI -2.83, -1.66) with moderate certainty of the evidence and improved frequency of straining (SMD: -0.29; 95% CI: -1.03, 0.47). Compared with psyllium, kiwifruit may increase the weekly frequency of SBM (MD: 1.01; 95% CI: -0.02, 2.04) with moderate certainty evidence, and may increase the value on the BSS (indicating softer stools) (MD: 0.63; 95% CI: 0.01, 1.25)with low certainty of evidence. Compared to placebo, kiwifruit-encapsulated extracts may result in an increase in minor adverse events (relative risk: 4.58; 95% CI: 0.79, 26.4).

CONCLUSIONS

Among individuals with constipation, there is an overall low certainty of evidence indicating that kiwifruit may increase SBM when compared to placebo or psyllium. Although overall results are promising, establishing the role of kiwifruit in constipation requires large, methodologically rigorous trials. Protocol Registration: PROSPERO registration number CRD42021239397.

Habitual Green Kiwifruit Consumption Is Associated with a Reduction in Upper Gastrointestinal Symptoms: A Systematic Scoping Review

Kiwifruit have known positive effects on digestion. During clinical intervention trials using kiwifruit to improve constipation, upper gastrointestinal (GI) symptoms such as abdominal discomfort and pain, indigestion, and reflux were also alleviated. We aimed to evaluate the evidence for upper GI symptom relief by kiwifruit in clinical trials on participants with functional constipation (FC), irritable bowel syndrome with constipation (IBS-C), and healthy participants, and to elucidate which symptoms may be relieved and whether a difference exists between the effects of gold and green kiwifruit. We executed a systematic scoping review of 3 electronic databases from 1947 through January 2021 to identify clinical trials that reported effects of green or gold kiwifruit or kiwifruit compounds on upper GI symptoms as secondary outcomes in healthy participants or participants with FC or IBS-C. Studies were divided into those using the Gastrointestinal Symptom Rating Scale (GSRS) and those using alternative measurement tools. GSRS outcomes were pooled and statistically analyzed; non-GSRS outcomes were summarized. We identified 12 clinical trials with a total of 661 participants (124 controls, 537 receiving intervention) providing evidence for symptom relief of upper GI symptoms by kiwifruit intake. Only 5 of the 12 clinical trials used the GSRS to assess upper GI symptom relief. We found good evidence that green kiwifruit may reduce abdominal discomfort and pain, and some evidence that kiwifruit consumption may attenuate indigestion. Pooled GSRS outcome analysis indicates an average reduction of -0.85 (95% CI: -1.1, -0.57; Z = 6.1) in abdominal pain scores and -0.33 (95% CI: -0.52, -0.15; Z = -3.5) in indigestion scores with habitual kiwifruit consumption. While the number of studies reporting on upper GI symptom relief with a comparable measurement is limited, there is consistent evidence for the efficacy of kiwifruit on upper GI symptom relief. More research to strengthen the evidence is recommended.

Valorization of kiwi agricultural waste and industry by-products by recovering bioactive compounds and applications as food additives: A circular economy model

Currently, agricultural production generates large amounts of organic waste, both from the maintenance of farms and crops (agricultural wastes) and from the industrialization of the product (food industry waste). In the case of Actinidia cultivation, agricultural waste groups together leaves, flowers, stems and roots while food industry by-products are represented by discarded fruits, skin and seeds. All these matrices are now underexploited and so, they can be revalued as a natural source of ingredients to be applied in food, cosmetic or pharmaceutical industries. Kiwifruit composition (phenolic compounds, volatile compounds, vitamins, minerals, dietary fiber, etc.) is an outstanding basis, especially for its high content in vitamin C and phenolic compounds. These compounds possess antioxidant, anti-inflammatory or antimicrobial activities, among other beneficial properties for health, but stand out for their digestive enhancement and prebiotic role. Although the biological properties of kiwi fruit have been analyzed, few studies show the high content of compounds with biological functions present in these by-products. Therefore, agricultural and food industry wastes derived from processing kiwi are regarded as useful matrices for the development of innovative applications in the food (pectins, softeners, milk coagulants, and colorants), cosmetic (ecological pigments) and pharmaceutical industry (fortified, functional, nutraceutical, or prebiotic foods). This strategy will provide economic and environmental benefits, turning this industry into a sustainable and environmentally friendly production system, promoting a circular and sustainable economy.

Spanish Translation, Face Validity, and Reliability of the ICIQ-B Questionnaire with Colorectal Cancer Patients

Purpose To describe the English-to-Spanish translation process and preliminary psychometric analysis (face validity, cultural adaptation, and test-retest reliability) of the International Consultation on Incontinence Questionnaire – Bowels Module (ICIQ-B) among Chilean colorectal cancer patients.

Materials and Methods The face validity was studied with 10 colorectal cancer patients, and the test-retest reliability, with 15 patients, 1 month before and 6 months after cancer surgery.

Results Two rounds of translation/back translation resulted in a Spanish version. The English expression open your bowels was translated as defecar, as it is easily understandable in Spanish. The patients reported that the instrument was easy to answer, with clear instructions, and that it was adequate to appraise their health condition. The test-retest reliability was good (Spearman rho [ρ] ≥ 0.842); only item 15a, the Bristol Stool Scale, obtained a moderate correlation (ρ = 0.639). The patients reported a variety of symptoms, including increased bowel movements, nocturnal bowel movements, fecal urgency, and incontinence.

Conclusions The first Spanish version of the ICIQ-B was culturally adapted for Chilean colorectal cancer patients, and showed good test-retest reliability. It might be a reference for other Spanish-speaking countries and for patients with other conditions. The ICIQ-B is a robust comprehensive questionnaire for bowel function.

Green kiwifruit (lat. Actinidia deliciosa var. Hayward) and maintenance of normal defecation: evaluation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006

Following an application from Zespri International Limited, submitted for authorisation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Belgium, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to green kiwifruit (lat. Actinidia deliciosa var. Hayward) and maintenance of normal defecation. The scope of the application was proposed to fall under a health claim based on newly developed scientific evidence. The food proposed by the applicant as the subject of the health claim is green kiwifruit. The Panel considers that green kiwifruit (Actinidia deliciosa var. Hayward) is sufficiently characterised. The claimed effect proposed by the applicant is 'maintenance of normal defecation'. Maintenance of normal defecation is a beneficial physiological effect provided that it does not result in diarrhoea. All human intervention studies submitted had different limitations and could not be used on their own for the scientific substantiation of the claim. However, the results of six pertinent human intervention studies are consistent with respect to an effect of consuming daily between two and four green kiwifruits var. Hayward on an increase in stool frequency. Two out of four studies in which a validated instrument was used to assess stool consistency showed an effect also on stool consistency. There is evidence for a plausible mechanism by which kiwifruit could exert an effect on normal defecation. The consumption of kiwifruit in the studies did not result in diarrhoea. A cause and effect relationship has been established between the consumption of green kiwifruit (Actinidia deliciosa var. Hayward) and maintenance of normal defecation. The following wordings reflect the scientific evidence: 'consumption of kiwifruit contributes to the maintenance of normal defecation'. In order to obtain the claimed effect, two large green kiwifruits (i.e. around 200 g of kiwi flesh) should be consumed.

Efficacy and Safety of Over-the-Counter Therapies for Chronic Constipation: An Updated Systematic Review

INTRODUCTION

Constipation is commonly treated with over-the-counter (OTC) products whose efficacy and safety remain unclear. We performed a systematic review of OTC therapies for chronic constipation and provide evidence-based recommendations.

METHODS

We searched PubMed and Embase for randomized controlled trials of ≥4-week duration that evaluated OTC preparations between 2004 and 2020. Studies were scored using the US Preventive Services Task Force criteria (0-5 scale) including randomization, blinding, and withdrawals. The strengths of evidence were adjudicated within each therapeutic category, and recommendations were graded (A, B, C, D, and I) based on the level of evidence (level I, good; II, fair; or III, poor).

RESULTS

Of 1,297 studies identified, 41 met the inclusion criteria. There was good evidence (grade A recommendation) for the use of the osmotic laxative polyethylene glycol (PEG) and the stimulant senna; moderate evidence (grade B) for psyllium, SupraFiber, magnesium salts, stimulants (bisacodyl and sodium picosulfate), fruit-based laxatives (kiwi, mango, prunes, and ficus), and yogurt with galacto-oligosaccharide/prunes/linseed oil; and insufficient evidence (grade I) for polydextrose, inulin, and fructo-oligosaccharide. Diarrhea, nausea, bloating, and abdominal pain were common adverse events, but no serious adverse events were reported.

DISCUSSION

The spectrum of OTC products has increased and quality of evidence has improved, but methodological issues including variability in study design, primary outcome measures, trial duration, and small sample sizes remain. We found good evidence to recommend polyethylene glycol or senna as first-line laxatives and moderate evidence supporting fiber supplements, fruits, stimulant laxatives, and magnesium-based products. For others, further validation with more rigorously designed studies is warranted.

Exploratory Comparative Effectiveness Trial of Green Kiwifruit, Psyllium, or Prunes in US Patients With Chronic Constipation

INTRODUCTION

Psyllium and prunes are proven treatments for chronic constipation (CC). Asian studies suggest that kiwifruit may also benefit CC symptoms. We report a partially randomized, comparative effectiveness trial evaluating kiwifruit, psyllium, and prunes in US patients with CC.

METHODS

Adults with CC at a US medical center were randomized to 3 natural treatments. Eligible patients had ≤3 complete spontaneous bowel movements (CSBMs) per week and were partially randomized to green kiwifruit (2/d), prunes (100 g/d), or psyllium (12 g/d) for 4 weeks. The primary endpoint was the proportion of patients in each group reporting an increase of ≥1 CSBM per week compared with baseline for at least 2 of 4 treatment weeks. Key secondary outcomes included stool frequency, stool consistency, and straining assessed daily. Treatment satisfaction and adverse events (AEs) were also measured. Standard statistical methods were used, and a P < 0.05 was considered significant.

RESULTS

Seventy-nine patients with CC (mean age = 42.7 years, 87% female, and 77% white) were partially randomized. Complete data were available for 75 patients (kiwifruit 29, prunes 24, and psyllium 22). For the primary endpoint, proportions of CSBM responders were similar for the treatments. For secondary outcomes comparing treatment weeks 3 and 4 to baseline, there was a significant increase in weekly CSBM rate with all 3 treatments (P ≤ 0.003); stool consistency significantly improved with kiwifruit (P = 0.01) and prunes (P = 0.049); and straining significantly improved with kiwifruit (P = 0.003), prunes (P < 0.001), and psyllium (P = 0.04). Patients randomized to the kiwifruit group reported significant improvement in bloating scores (P = 0.02). AEs were most common with psyllium and least common with kiwifruit. At the end of treatment, a smaller proportion of patients were dissatisfied with kiwifruit compared with prunes or psyllium (P = 0.02).

DISCUSSION

Kiwifruit, prunes, and psyllium improve constipation symptoms in patients with CC. Kiwifruit was associated with the lowest rate of AEs and dissatisfaction with therapy.

Impact of Diet on Symptoms of the Irritable Bowel Syndrome

Irritable bowel syndrome (IBS), with its key features of abdominal pain and disturbed bowel habit, is thought by both patients and clinicians to be strongly influenced by diet. However, the complexities of diet have made identifying specific food intolerances difficult. Eating disorders can masquerade as IBS and may need specialist treatment. While typical food allergy is readily distinguished from IBS, the mechanisms of gut-specific adverse reactions to food are only just being defined. These may include gut-specific mast cell activation as well as non-specific activation by stressors and certain foods. Visceral hypersensitivity, in some cases mediated by mast cell activation, plays a key part in making otherwise innocuous gut stimuli painful. Rapidly fermented poorly absorbed carbohydrates produce gaseous distension as well as short-chain fatty acids and lowering of colonic pH which may cause symptoms in IBS patients. Limiting intake of these in low FODMAP and related diets has proven popular and apparently successful in many patients. Existing diet, colonic microbiota and their metabolic products may be helpful in predicting who will respond. Wheat intolerance may reflect the fact that wheat is often a major source of dietary FODMAPs. It may also be either a forme fruste of coeliac disease or non-specific immune activation. Wheat exclusion can be successful in some of these patients. More research is needed to fully understand the mechanisms of food intolerances and how to best ameliorate them in a personalised medicine approach to diet in IBS.

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.

Untargeted and Targeted Metabolomics and Tryptophan Decarboxylase In Vivo Characterization Provide Novel Insight on the Development of Kiwifruits (Actinidia deliciosa)

Kiwifruit (Actinidia deliciosa cv. Hayward) is a commercially important crop with highly nutritional green fleshy fruits. The post-harvest maturation of the fruits is well characterized, but little is known about the metabolic changes that occur during fruit development. Here we used untargeted metabolomics to characterize the non-volatile metabolite profile of kiwifruits collected at different time points after anthesis, revealing profound metabolic changes before the onset of ripening including the depletion of many classes of phenolic compounds. In contrast, the phytohormone abscisic acid accumulated during development and ripening, along with two indolamines (serotonin and its precursor tryptamine), and these were monitored in greater detail by targeted metabolomics. The role of indolamines in kiwifruit development is completely unknown, so we also characterized the identity of genes encoding tryptophan decarboxylase in A. deliciosa and its close relative A. chinensis to provide insight into the corresponding biological processes. Our results indicate that abscisic acid and indolamines fulfill unrecognized functions in the development and ripening of kiwifruits.

The nutritional and health attributes of kiwifruit: a review

PURPOSE

To describe the nutritional and health attributes of kiwifruit and the benefits relating to improved nutritional status, digestive, immune and metabolic health. The review includes a brief history of green and gold varieties of kiwifruit from an ornamental curiosity from China in the 19th century to a crop of international economic importance in the 21st century; comparative data on their nutritional composition, particularly the high and distinctive amount of vitamin C; and an update on the latest available scientific evidence from well-designed and executed human studies on the multiple beneficial physiological effects. Of particular interest are the digestive benefits for healthy individuals as well as for those with constipation and other gastrointestinal disorders, including symptoms of irritable bowel syndrome. The mechanisms of action behind the gastrointestinal effects, such as changes in faecal (stool) consistency, decrease in transit time and reduction of abdominal discomfort, relate to the water retention capacity of kiwifruit fibre, favourable changes in the human colonic microbial community and primary metabolites, as well as the naturally present proteolytic enzyme actinidin, which aids protein digestion both in the stomach and the small intestine. The effects of kiwifruit on metabolic markers of cardiovascular disease and diabetes are also investigated, including studies on glucose and insulin balance, bodyweight maintenance and energy homeostasis.

CONCLUSIONS

The increased research data and growing consumer awareness of the health benefits of kiwifruit provide logical motivation for their regular consumption as part of a balanced diet. Kiwifruit should be considered as part of a natural and effective dietary strategy to tackle some of the major health and wellness concerns around the world.

Polyphenol-rich Mango (Mangifera indica L.) Ameliorate Functional Constipation Symptoms in Humans beyond Equivalent Amount of Fiber

SCOPE

Chronic constipation is a common gastrointestinal condition associated with intestinal inflammation and considerably impaired quality of life, affecting about 20% of Americans. Dietary fiber and laxatives aid in its treatment but do not fully address all symptoms, such as intestinal inflammation. Mango (Mangifera indica L.), a fiber- and polyphenol-rich fruit may provide anti-inflammatory effects in constipation.

METHODS AND RESULTS

The 4 week consumption of mango fruit (300 g) or the equivalent amount of fiber is investigated in otherwise healthy human volunteers with chronic constipation who are randomly assigned to either group. Blood and fecal samples and digestive wellness questionnaires are collected at the beginning and end of the study. Results show that mango consumption significantly improve constipation status (stool frequency, consistency, and shape) and increase gastrin levels and fecal concentrations of short chain fatty acid (valeric acid) while lowering endotoxin and interleukin 6 concentrations in plasma.

CONCLUSION

In this pilot study, the consumption of mango improves symptoms and associated biomarkers of constipation beyond an equivalent amount of fiber. Larger follow-up studies would need to investigate biomarkers for intestinal inflammation in more detail.

Consumption of kiwifruit capsules increases Faecalibacterium prausnitzii abundance in functionally constipated individuals: a randomised controlled human trial

This study investigated the impact of ACTAZIN™ green (2400 and 600 mg) and Livaux™ (2400 mg) gold kiwifruit supplements on faecal microbial composition and metabolites in healthy and functionally constipated (FC) participants. The participants were recruited into the healthy group (n 20; one of whom did not complete the study) and the FC group (n 9), each of whom consumed all the treatments and a placebo (isomalt) for 4 weeks in a randomised cross-over design interspersed with 2-week washout periods. Modification of faecal microbiota composition and metabolism was determined by 16S rRNA gene sequencing and GC, and colonic pH was calculated using SmartPill^® wireless motility capsules. A total of thirty-two taxa were measured at greater than 1 % abundance in at least one sample, ten of which differed significantly between the baseline healthy and FC groups. Specifically, Bacteroidales and Roseburia spp. were significantly more abundant (P < 0·05) in the healthy group and taxa including Ruminococcaceae, Dorea spp. and Akkermansia spp. were significantly more abundant (P < 0·05) in the FC group. In the FC group, Faecalibacterium prausnitzii abundance significantly increased (P = 0·024) from 3·4 to 7·0 % following Livaux™ supplementation, with eight of the nine participants showing a net increase. Lower proportions of F. prausnitzii are often associated with gastrointestinal disorders. The discovery that Livaux™ supplementation increased F. prausnitzii abundance offers a potential strategy for improving gut microbiota composition, as F. prausnitzii is a butyrate producer and has also been shown to exert anti-inflammatory effects in many studies.

Effects of Cereal, Fruit and Vegetable Fibers on Human Fecal Weight and Transit Time: A Comprehensive Review of Intervention Trials

Cereal fibers are known to increase fecal weight and speed transit time, but far less data are available on the effects of fruits and vegetable fibers on regularity. This study provides a comprehensive review of the impact of these three fiber sources on regularity in healthy humans. We identified English-language intervention studies on dietary fibers and regularity and performed weighted linear regression analyses for fecal weight and transit time. Cereal and vegetable fiber groups had comparable effects on fecal weight; both contributed to it more than fruit fibers. Less fermentable fibers increased fecal weight to a greater degree than more fermentable fibers. Dietary fiber did not change transit time in those with an initial time of <48 h. In those with an initial transit time ≥48 h, transit time was reduced by approximately 30 min per gram of cereal, fruit or vegetable fibers, regardless of fermentability. Cereal fibers have been studied more than any other kind in relation to regularity. This is the first comprehensive review comparing the effects of the three major food sources of fiber on bowel function and regularity since 1993.