Effect of prebiotic oligosaccharides on bowel habit and the gut microbiota in children with functional constipation (Inside study): study protocol for a randomised, placebo-controlled, multi-centre trial.

BACKGROUND: Functional constipation (FC) in children is a common gastrointestinal disorder with a worldwide-pooled prevalence of 9.5%. Complaints include infrequent bowel movements, painful defecation due to hard and/or large stools, faecal incontinence, and abdominal pain. Prebiotic oligosaccharides have been shown to relieve constipation symptoms in young adults and elderly. However, sufficient evidence is lacking linking additional prebiotic intake to improve symptoms in children with FC. We hypothesise that prebiotic oligosaccharides are able to relieve symptoms of constipation in young children as well. METHODS: In the present randomised, double-blind, placebo-controlled, multi-centre study, we will study the effects of two prebiotic oligosaccharides in comparison to placebo on constipation symptoms in children of 1-5 years (12 to 72 months) of age diagnosed with FC according to the Rome IV criteria for functional gastrointestinal disorders. The primary outcome measure will be change in stool consistency. Secondary outcomes include stool frequency and stool consistency in a number of cases (%). Tertiary outcomes include among others painful defecation, use of rescue medication, and quality of life. In addition, the impact on gut microbiome outcomes such as faecal microbiota composition and metabolites will be investigated. Participants start with a run-in period, after which they will receive supplements delivered in tins with scoops for 8 weeks, containing one of the two prebiotic oligosaccharides or placebo, followed by a 4-week wash-out period. DISCUSSION: This randomised double-blind, placebo-controlled multi-centre study will investigate the effectiveness of prebiotic oligosaccharides in children aged 1-5 years with FC. TRIAL REGISTRATION: ClinicalTrials.gov NCT04282551. Registered on 24 February 2020.

What are Normal Defecation Patterns in Healthy Children up to Four Years of Age? A Systematic Review and Meta-Analysis.

OBJECTIVE: To summarize available data on defecation frequency and stool consistency of healthy children up to age 4 in order to estimate normal references values. STUDY DESIGN: Systematic review including cross-sectional, observational, and interventional studies published in English, that reported on defecation frequency and/or stool consistency in healthy children 0-4 years old. RESULTS: Seventy-five studies were included with 16 393 children and 40 033 measurements of defecation frequency and/or stool consistency. Based on visual inspection of defecation frequency data, a differentiation was made between two age categories: young infants (0-14 weeks old) and young children (15 weeks-4 years old). Young infants had a mean defecation frequency of 21.8 per week (95 % CI, 3.9-35.2) compared with 10.9 (CI, 5.7-16.7) in young children (P < .001). Among young infants, human milk-fed (HMF) infants had the highest mean defecation frequency per week (23.2 [CI, 8.8-38.1]), followed by formula-fed (FF) infants (13.7 [CI 5.4-23.9]), and mixed-fed (MF) infants (20.7 [CI, 7.0-30.2]). Hard stools were infrequently reported in young infants (1.5%) compared with young children (10.5%), and a reduction in the frequency of soft/watery stools was observed with higher age (27.0% in young infants compared with 6.2% in young children). HMF young infants had softer stools compared with FF young infants. CONCLUSIONS: Young infants (0-14 weeks old) have softer and more frequent stools compared with young children (15 weeks-4 years old).

L-arabinose co-ingestion delays glucose absorption derived from sucrose in healthy men and women: a double-blind, randomised crossover trial.

Dietary interventions to delay carbohydrate digestion or absorption can effectively prevent hyperglycaemia in the early postprandial phase. L-arabinose can specifically inhibit sucrase. It remains to be assessed whether co-ingestion of L-arabinose with sucrose delays sucrose digestion, attenuates subsequent glucose absorption and impacts hepatic glucose output. In this double-blind, randomised crossover study, we assessed blood glucose kinetics following ingestion of a 200-ml drink containing 50 g of sucrose with 7·5 g of L-arabinose (L-ARA) or without L-arabinose (CONT) in twelve young, healthy participants (24 ± 1 years; BMI: 22·2 ± 0·5 kg/m2). Plasma glucose kinetics were determined by a dual stable isotope methodology involving ingestion of (U-13C6)-glucose-enriched sucrose, and continuous intravenous infusion of (6,6-2H2)-glucose. Peak glucose concentrations reached 8·18 ± 0·29 mmol/l for CONT 30 min after ingestion. In contrast, the postprandial rise in plasma glucose was attenuated for L-ARA, because peak glucose concentrations reached 6·62 ± 0·18 mmol/l only 60 min after ingestion. The rate of exogenous glucose appearance for L-ARA was 67 and 57 % lower compared with CONT at t = 15 min and 30 min, respectively, whereas it was 214 % higher at t = 150 min, indicating a more stable absorption of exogenous glucose for L-ARA compared with CONT. Total glucose disappearance during the first hour was lower for L-ARA compared with CONT (11 ± 1 v. 17 ± 1 g, P < 0·0001). Endogenous glucose production was not differentially affected at any time point (P = 0·27). Co-ingestion of L-arabinose with sucrose delays sucrose digestion, resulting in a slower absorption of sucrose-derived glucose without causing adverse effects in young, healthy adults.

Fiber mixture-specific effect on distal colonic fermentation and metabolic health in lean but not in prediabetic men.

Infusions of the short-chain fatty acid (SCFA) acetate in the distal colon improved metabolic parameters in men. Here, we hypothesized that combining rapidly and slowly fermentable fibers will enhance distal colonic acetate production and improve metabolic health. In vitro cultivation studies in a validated model of the colon were used to identify fiber mixtures that yielded high distal colonic acetate production. Subsequently, in two randomized crossover studies, lean and prediabetic overweight/obese men were included. In one study, participants received supplements of either long-chain inulin+resistant starch (INU+RS), INU or maltodextrin (PLA) the day prior to a clinical investigation day (CID). The second trial studied beta glucan+RS (BG+RS) versus BG and PLA. During each CID, breath hydrogen, indirect calorimetry, plasma metabolites/hormones were assessed during fasting and postprandial conditions. Additionally, fecal microbiota composition and SCFA were determined. In prediabetic men, INU+RS increased plasma acetate compared to INU or PLA (P < .05), but did not affect metabolic parameters. In lean men, INU+RS increased breath hydrogen and fasting plasma butyrate, which was accompanied by increased energy expenditure, carbohydrate oxidation and PYY and decreased postprandial glucose concentrations (all P < .05) compared to PLA. BG+RS increased plasma butyrate compared to PLA (P < .05) in prediabetic individuals, but did not affect other fermentation/metabolic markers in both phenotypes. Fiber-induced shifts in fecal microbiota were individual-specific and more pronounced with INU+RS versus BG+RS. Administration of INU+RS (not BG+RS) the day prior to investigation improved metabolic parameters in lean but not in prediabetic individuals, demonstrating that effects were phenotype- and fiber-specific. Further research should study whether longer-term supplementation periods are required to elicit beneficial metabolic health in prediabetic individuals. Trial registration numbers: Clinical trial No. NCT03711383 (Inulin study) and Clinical trial No. NCT03714646 (Beta glucan study).

The Modified Bristol Stool Form Scale: A Reliable and Valid Tool to Score Stool Consistency in Dutch (Non)Toilet-trained Toddlers.

OBJECTIVE: The aim of the study was to assess whether the modified Bristol Stool Form Scale (m-BSFS) is reliable, valid and user-friendly to use by parents, grandparents, and day childcare employees to evaluate stool consistency in toilet and nontoilet-trained toddlers in the Netherlands. STUDY DESIGN: Translation to Dutch and validity of the m-BSFS (scoring 32 general stool pictures) for 1 to 3 year old toddlers (n = 89) was evaluated by parents, grandparents, and day childcare employees. A subgroup of participants scored an additional 7 pictures of stools in a diaper to validate the m-BSFS for non-toilet-trained toddlers (n = 16). To determine inter-rater reliability, 2-way random effects single-rater intraclass correlation coefficient (ICC)consistency was used. Intra-rater reliability was measured by Cohen kappa (κ) by rating the same pictures in random order twice, with at least 1 week between the first and second scoring. RESULTS: Inter- and intra-rater reliability of the m-BSFS were above recommended minimal standards of 0.61 for the 32 general stool pictures as well as for the 7 pictures of stools in a diaper. ICCconsistency for the general stool pictures of the first and second ratings were 0.71 (n = 89) and 0.79 (n = 77), respectively, with a κ of 0.71 (n = 77). ICCconsistency for the stools in diaper pictures of the first and second ratings were 0.93 (n = 16) and 0.93 (n = 15), respectively, with a κ of 0.77 (n = 15). CONCLUSIONS: The m-BSFS is reliable, valid and user-friendly to use by Dutch-speaking parents, grandparents, and day childcare workers to evaluate stool consistency in both toilet- and nontoilet-trained toddlers in the Netherlands.

Flexibility of Gut Microbiota in Ageing Individuals during Dietary Fiber Long-Chain Inulin Intake.

SCOPE: During ageing, dysbiosis in the intestinal microbiota may occur and impact health. There is a paucity of studies on the effect of fiber on the elderly microbiota and the flexibility of the aged microbiota upon prebiotic intake. It is hypothesized that chicory long-chain inulin consumption can change microbiota composition, microbial fermentation products, and immunity in the elderly. METHODS AND RESULTS: A double-blind, placebo-controlled trial is performed in healthy individuals (55-80 years), in which microbiota composition is studied before, during, and after two months of chicory long-chain inulin consumption. Fecal short chain fatty acid concentrations, T cell subsets, and antibody responses against a Hepatitis B (HB) vaccine are measured as well. Inulin consumption modified the microbiota composition, as measured by 16S rRNA sequencing. Participants consuming inulin have higher microbial diversity and a relatively higher abundance of the Bifidobacterium genus, as well as Alistipes shahii, Anaerostipes hadrus, and Parabacteroides distasonis. While the immune responses remain unchanged, the isobutyric acid levels, an undesired fermentation product, tend to be lower in the inulin group. CONCLUSIONS: Overall, it is shown that the gut microbiota composition is still sensitive to chicory long-chain inulin induced changes in an ageing population, although this did not translate into an improved immune response to an HB vaccine.

Effect of chicory inulin-type fructan-containing snack bars on the human gut microbiota in low dietary fiber consumers in a randomized crossover trial.

BACKGROUND: The low intake of dietary fiber compared to recommended amounts has been referred to as the dietary fiber gap. The addition of fiber to snack foods could favorably alter gut microbiota and help individuals meet intake recommendations. OBJECTIVES: Our objective was to examine the effect of low- and moderate-dose fiber-containing snack bars, comprising mainly chicory root inulin-type fructans (ITF), on gut microbiota in healthy adults with habitual low dietary fiber intake using 16S ribosomal RNA-based approaches. METHODS: In 2 separate 4-wk, placebo-controlled, double-blind, crossover trials, 50 healthy adults with low dietary fiber intake were randomly assigned to receive isocaloric snack bars of either moderate-dose fiber (7 g/d) or control in Trial 1 (n = 25) or low-dose fiber (3 g/d) or control in Trial 2 (n = 25), with 4-wk washout periods. Fecal microbiota composition and inferred function, fecal SCFA concentration, gastrointestinal (GI) symptoms, dietary intake, and quality of life were measured. RESULTS: Compared with the control group, the moderate-dose group showed significant differences across multiple microbial taxa, most notably an increased relative abundance of the Bifidobacterium genus from (mean ± SEM) 5.3% ± 5.9% to 18.7% ± 15.0%. With low-dose ITF, significant increases in Bifidobacterium were no longer present after correction for multiple comparisons but targeted analysis with qPCR showed a significant increase in Bifidobacterium. Predictive functional profiling identified changes in predicted function after intake of the moderate- but not the low-dose bar. Fecal SCFAs were affected by time but not treatment. There were no between-group differences in GI symptoms. Importantly, fiber intake increased significantly with the moderate- and low-dose bars. CONCLUSIONS: In healthy adults, adding 3 or 7 g ITF to snack bars increased Bifidobacterium, a beneficial member of the gut microbial community. The addition of ITF to food products could help reduce the dietary fiber gap prevalent in modern life.This trial was registered at clinicaltrials.gov as NCT03042494.

Changes in stool frequency following chicory inulin consumption, and effects on stool consistency, quality of life and composition of gut microbiota.

Inulin is a soluble dietary fibre, also classified as a prebiotic, extracted from chicory roots. The present study aimed to determine the effect of consumption of native chicory inulin on the stool frequency of middle-aged to older adults (40-75 years old) with uncomfortably but not clinically relevant low stool frequency, specified as two to four days without bowel movements per week. Two randomised, double blind, placebo-controlled crossover trials were conducted using similar protocols in differing populations. Trial A was conducted in Amsterdam, The Netherlands and subsequently Trial B was conducted in Newcastle, United Kingdom. Both trials involved supplementation for 5 weeks with 10 g per day of inulin or placebo, a washout period of 2 weeks, and then crossed over to receive the other treatment. In Trial B, faecal gut microbiota composition was assessed using 16S rRNA gene sequencing. In Trial A, which 10 volunteers completed, the stool frequency was significantly increased to an average 4.9 ±â€¯0.23 (SEM) times per week during inulin periods versus 3.6 ±â€¯0.25 in the periods with placebo (p = 0.01). In contrast, in Trial B which 20 volunteers completed, there was no significant effect of the inulin on stool frequency (7.5 ±â€¯2.1 times per week with inulin, 8.1 ±â€¯3.0 with placebo, p = 0.35). However, many subjects in Trial B had a stool frequency >5 per week also for the placebo period, in breach of the inclusion criteria. Combining the data of 16 low stool frequency subjects from Trials A and B showed a significant effect of inulin to increase stool frequency from 4.1 to 5.0 per week (p = 0.032). Regarding secondary outcomes, stool consistency was significantly softer with inulin treatment compared to placebo periods, it increased 0.29 on the Bristol stool scale (p = 0.008) when data from all subjects of Trials A and B were combined. No other differences in bowel habit parameters due to inulin consumption were significant. None of the differences in specific bacterial abundance, alpha or beta diversity were significant, however the trends were in directions consistent with published studies on other types of inulin. We conclude that 10 g per day of native chicory inulin can increase stool frequency in subjects with low stool frequency.

The effect of prebiotic fortified infant formulas on microbiota composition and dynamics in early life.

Gastrointestinal (GI) microbiota composition differs between breastfed and formula-fed infants. Today's infant formulas are often fortified with prebiotics to better mimic properties of human milk with respect to its effect on GI microbiota composition and function. We used Illumina HiSeq sequencing of PCR-amplified 16S rRNA gene fragments to investigate the composition of faecal microbiota in 2-12 week old infants receiving either breastmilk, infant formulas fortified with prebiotics, or mixed feeding. We compared these results with results from infants fed traditional formulas used in the Netherlands in 2002-2003, which contained no added prebiotics. We showed that today's formulas supplemented with either scGOS (0.24-0.50 g/100 ml) or scGOS and lcFOS (at a 9:1 ratio; total 0.6 g/100 ml) had a strong bifidogenic effect as compared to traditional formulas, and they also resulted in altered patterns of microbial colonisation within the developing infant gastrointestinal tract. We identified three microbial states (or developmental stages) in the first 12 weeks of life, with a gradual transition pattern towards a bifidobacteria dominated state. In infants receiving only fortified formulas, this transition towards the bifidobacteria dominated state was accelerated, whereas in infants receiving mixed feeding the transition was delayed, as compared to exclusively breastfed infants.

The effect of fiber and prebiotics on children's gastrointestinal disorders and microbiome.

INTRODUCTION: The bacteria received upon birth are the start of colonization of the approximately 1014 bacteria that are present in the mature human gastrointestinal tract, better known as the microbiota. The gut microbiota is implicated in gastrointestinal health, nutrient metabolism and benefits such as prevention of infection. Dietary fiber, including prebiotics, escape digestion in the small intestine and reach the colon intact, where they are partially or completely fermented by the gut microbiota. Areas covered: The possible interactions between dietary fiber, prebiotics and microbiota are discussed as well as how this relates to functional gastrointestinal disorders. During the first years of life the microbiota have not yet reached a stable state and is sensitive to disturbance by environmental factors. An imbalance in the microbiota early in life is found to be associated with several functional gastrointestinal disorders such as colic, functional abdominal pain, irritable bowel syndrome and constipation. Expert commentary: A better understanding of how gut microbial changes in early-life can impact gastrointestinal health might lead to new treatments or disease prevention. Nutritional strategies with fiber or prebiotics may support health due to modification of colonic microbiota composition and metabolic activity, for example by growth stimulation of Bifidobacterium and Lactobacillus.

Fructans in the first 1000 days of life and beyond, and for pregnancy.

Inulin-based prebiotics are non-digestible polysaccharides that influence the composition of the gut microbiota in infants and children, notably eliciting a bifidogenic effect with high short chain fatty acid levels. Inulin, a generic term that comprises ß-(2,1)-linked linear fructans, is typically isolated from the chicory plant root, and derivatives such as oligofructose and long chain inulin appear to have different physiological properties. The first 1000 days of a child's life are increasingly recognized as a critical timeframe for health also into adulthood, whereby nutrition plays a key role. There is an ever increasing association between nutrition and gut microbiota composition and development, with life health status of an individual. This review summarizes the latest knowledge in the infant gut microbiota from preterms to healthy newborns, as well as in malnourished children in developing countries. The impact of inulin or mixtures thereof on infants, toddlers and young children with respect to intestinal function and immunity in general, is reviewed. Possible benefits of prebiotics to support the gut microbiome of malnourished infants and children, especially those with infections in the developing world, are considered, as well as for the pregnant mothers health. Importantly, novel insights in metabolic programming are covered, which are being increasing recognized for remarkable impact on long term offspring health, and eventual potential beneficial role of prebiotic inulins. Overall increasing findings prompt the potential for gut microbiota-based therapy to support health or prevent the development of certain diseases from conception to adulthood where inulin prebiotics may play a role.

Prebiotics: why definitions matter.

The prebiotic concept was introduced twenty years ago, and despite several revisions to the original definition, the scientific community has continued to debate what it means to be a prebiotic. How prebiotics are defined is important not only for the scientific community, but also for regulatory agencies, the food industry, consumers and healthcare professionals. Recent developments in community-wide sequencing and glycomics have revealed that more complex interactions occur between putative prebiotic substrates and the gut microbiota than previously considered. A consensus among scientists on the most appropriate definition of a prebiotic is necessary to enable continued use of the term.

Community member and faith leader perspectives on the process of building trusting relationships between communities and researchers.

In the first phase of this research, we conducted, audio-recorded, and transcribed seven focus groups with more than 50 English- or Spanish-speaking women of childbearing age. Qualitative analysis revealed the following themes: (1) expectation that participation would involve relationships based on trust that is built over time and impacted by cultural factors; (2) perceived characteristics of research staff that would help facilitate the development of trusting relationships; (3) perceptions about the location of the visits that may affect trust; (4) perceptions of a research study and trust for the institution conducting the study may affect trust; (5) connecting the study to larger communities, including faith communities, could affect trust and willingness to participate. In the second phase of this research, we conducted, recorded, transcribed, and analyzed interviews with leaders from diverse faith communities to explore the potential for research partnerships between researchers and faith communities. In addition to confirming themes identified in focus groups, faith leaders described an openness to research partnerships between the university and faith communities and considerations for the formation of these partnerships. Faith leaders noted the importance of finding common ground with researchers, establishing and maintaining trusting relationships, and committing to open, bidirectional communication.

Interactions of black tea polyphenols with human gut microbiota: implications for gut and cardiovascular health.

Epidemiologic studies have convincingly associated consumption of black tea with reduced cardiovascular risk. Research on the bioactive molecules has traditionally been focused on polyphenols, such as catechins. Black tea polyphenols (BTPs), however, mainly consist of high-molecular-weight species that predominantly persist in the colon. There, they can undergo a wide range of bioconversions by the resident colonic microbiota but can in turn also modulate gut microbial diversity. The impact of BTPs on colon microbial composition can now be assessed by microbiomics technologies. Novel metabolomics platforms coupled to de novo identification are currently available to cover the large diversity of BTP bioconversions by the gut microbiota. Nutrikinetic modeling has been proven to be critical for defining nutritional phenotypes related to gut microbial bioconversion capacity. The bioactivity of circulating metabolites has been studied only to a certain extent. Bioassays dedicated to specific aspects of gut and cardiovascular health have been used, although often at physiologically irrelevant concentrations and with limited coverage of relevant metabolite classes and their conjugated forms. Evidence for cardiovascular benefits of BTPs points toward antiinflammatory and blood pressure-lowering properties and improvement in platelet and endothelial function for specific microbial bioconversion products. Clearly, more work is needed to fill in existing knowledge gaps and to assess the in vitro and in vivo bioactivity of known and newly identified BTP metabolites. It is also of interest to assess how phenotypic variation in gut microbial BTP bioconversion capacity relates to gut and cardiovascular health predisposition.

Application of state-of-art sequencing technologies to indigenous food fermentations.

Fermented foods and beverages are an integral part of the human diet globally. Understanding the microbial interactions within these fermenting ecosystems is required to deliver safe products with desirable consumer properties, and moreover, maintenance of these traditions. Effective tools are required for documentation of cultures in traditional and artisanal fermented products, for sensory quality and safety improvements, in some cases for starter culture design for commercialization and potentially for supporting sustainable food systems. Here we trace the developments of sequence-based molecular technologies for investigating the diversity and functionality of microbiota in traditional or indigenous fermented foods and beverages. The opportunities of phylobiomics, metagenomics and metatranscriptomics to enrich our knowledge of fermenting microbial ecosystems are presented.

Maternal perspectives on the return of genetic results: context matters.

The objectives of this study were to study maternal preferences for the return of their child's genetic results and to describe the experiences, perceptions, attitudes, and values that are brought to bear when individuals from different racial and cultural backgrounds consider participating in genetic research. We recruited women with diverse sociodemographic profiles to participate in seven focus groups. Twenty-eight percent of participants self-identified as Hispanic; 49% as White, non-Hispanic; and 21% as Asian or Asian American. Focus groups were conducted in English or Spanish and were audio-recorded and transcribed verbatim. Transcripts were analyzed using qualitative thematic methods. Results indicated that preferences and decisions regarding the return of results may depend on both research and individual contextual factors. Participants understood the return of results as a complex issue, where individual and cultural differences in preferences are certain to arise. Another key finding was that participants desired an interpersonal, dynamic, flexible process that accommodated individual preferences and contextual differences for returning results. Our findings indicate a need to have well-developed systems for allowing participants to make and change over time their choices regarding the return of their child's genetic results.

Predicting response to reassurances and uncertainties in bioterrorism communications for urban populations in New York and California.

Recent national plans for recovery from bioterrorism acts perpetrated in densely populated urban areas acknowledge the formidable technical and social challenges of consequence management. Effective risk and crisis communication is one priority to strengthen the U.S.'s response and resilience. However, several notable risk events since September 11, 2001, have revealed vulnerabilities in risk/crisis communication strategies and infrastructure of agencies responsible for protecting civilian populations. During recovery from a significant biocontamination event, 2 goals are essential: (1) effective communication of changing risk circumstances and uncertainties related to cleanup, restoration, and reoccupancy; and (2) adequate responsiveness to emerging information needs and priorities of diverse populations in high-threat, vulnerable locations. This telephone survey study explored predictors of public reactions to uncertainty communications and reassurances from leaders related to the remediation stage of an urban-based bioterrorism incident. African American and Hispanic adults (N=320) were randomly sampled from 2 ethnically and socioeconomically diverse geographic areas in New York and California assessed as high threat, high vulnerability for terrorism and other public health emergencies. Results suggest that considerable heterogeneity exists in risk perspectives and information needs within certain sociodemographic groups; that success of risk/crisis communication during recovery is likely to be uneven; that common assumptions about public responsiveness to particular risk communications need further consideration; and that communication effectiveness depends partly on preexisting values and risk perceptions and prior trust in leaders. Needed improvements in communication strategies are possible with recognition of where individuals start as a reference point for reasoning about risk information, and comprehension of how this influences subsequent interpretation of agencies' actions and communications.

Diverse perceptions of the informed consent process: implications for the recruitment and participation of diverse communities in the National Children's Study.

We examined the experiences, perceptions, and values that are brought to bear when individuals from different ethnic and cultural backgrounds consider participating in health research. Fifty-three women from Latino, Asian American, Middle Eastern, or Non-Latino, White backgrounds participated in seven English or Spanish focus groups facilitated by trained investigators using a standard protocol. Investigators described the National Children's Study (NCS) and then asked questions to elicit potential concerns, expectations, and informational needs. Group sessions were audio-recorded, transcribed verbatim, and analyzed using qualitative thematic methods. A major theme that emerged during focus groups was participant self-identification as a member of a cultural group or community when raising issues that would influence their decision to participate in research. A related theme was the belief by some that communities may differ in the ease of participation in the NCS. Identified themes related to the informed consent process included perceived risks, anticipated burden, perceived benefits, informational needs, and decision-making strategies. Although themes were shared across groups, there were cultural differences within themes. Findings indicated that individuals from diverse backgrounds may have different perspectives on and expectations for the research process. To effectively recruit representative samples, it will be important to address a range of issues relevant for informed consent and to consider the impact of participation on both individuals and communities.

The fecal bifidobacterial transcriptome of adults: a microarray approach.

Bifidobacteria are a predominant group present among adult human intestinal microbiota and are considered to be beneficial to host health. Both the dynamics and functional activity of bifidobacteria from the intestinal tract of four adults, following ingestion of a mix consisting of short chain galactooligosaccharides, long chain fructooligosaccharides and acidic oligosaccharides from pectin hydrolysate (GFP), was investigated. The percentage of total bifidobacteria, monitored by quantitative real time PCR, was not significantly altered but marked species-specific changes occurred in all individuals over time, indicating a dynamic bifidobacterial community. Insight into the functional activity of the bifidobacteria was acquired using a clone library-based microarray comprising the genomes of various bifidobacteria to reveal the bifidobacterial transcriptome within the fecal community. Total RNA from the fecal microbial community was hybridized to the microarray and 310 clones were selected for sequencing which revealed genes belonging to a wide range of functional groups demonstrating substantial metabolic activity. While the intake of GFP did not have a significant effect on the overall change in gene expression, 82 genes showed a significant change. Most of the predicted genes were involved in metabolism of carbohydrates of plant origin, house keeping functions such as DNA replication and transcription, followed by membrane transport of a wide variety of substrates including sugars and metals and amino acid metabolism. Other genes were involved in transport, nucleotide metabolism, amino acid metabolism, environmental information processing and cellular processes and signalling. A smaller number of genes were involved in general metabolism, glycan metabolism, energy metabolism, lipid metabolism and cell surface. These results support the notion that bifidobacteria utilize mainly indigestible polysaccharides as their main source of energy and biosynthesis of cellular components.