Cereal products derived from wheat, sorghum, rice and oats alter the infant gut microbiota in vitro

Development of an infant colon simulating in vitro model, I-TIM-2, to study the effects of modulation strategies on the infant gut microbiome composition and function

The early life stages are critical for the development of the gut microbiome. Variables such as antibiotics exposure, birth-mode via Cesarean section, and formula feeding are associated with disruptions in microbiome development and are related to adverse health effects later in life. Studying the effects of microbiome-modulating strategies in infants is challenged by appropriate ethical constraints. Therefore, we developed I-TIM-2, an infant in vitro colonic model based on the validated, computer-controlled, dynamic model of the colon, TIM-2. The system, consisting of four separate compartments, was inoculated with feces from four healthy, primarily breastfed infants, displaying distinctive microbiome profiles. For each infant's fecal sample, a 96-h experiment was performed, with two compartments receiving an infant diet adapted medium and two compartments additionally receiving five human milk oligosaccharides (HMOs) in physiological concentrations and proportions. Bacterial composition was determined by shotgun metagenomics and qPCR. Concentrations of short-chain fatty acids (SCFAs) and HMOs were determined by LC-MS. Microbial diversity and high amounts of inoculum-derived species were preserved in the model throughout each experiment. Microbiome composition and SCFA concentrations were consistent with published data from infants. HMOs strongly modulated the microbiome composition by stimulating relative proportions of Bifidobacterium. This affected the metabolic output and resulted in an increased production of acetic and formic acid, characteristic of bifidobacterial HMO metabolism. In conclusion, these data demonstrate the development of a valid model to study the dynamics and modulations of the infant gut microbiome and metabolome.IMPORTANCEThe infant gut microbiome is intricately linked to the health of its host. This is partly mediated through the bacterial production of metabolites that interact with the host cells. Human milk shapes the establishment of the infant gut microbiome as it contains human milk sugars that select for primarily bifidobacteria. The establishment can be disrupted by modern interventions such as formula feeding. This can alter the microbiome composition and metabolite production profile, which can affect the host. In this article, we set up an infant in vitro colonic model to study microbiome interactions and functions. In this model, we investigated the effects of human milk sugars and their promotion of bifidobacteria at the expense of other bacteria. The model is an ideal system to assess the effects of various modulating strategies on the infant gut microbiome and its interactions with its host.

Breastfeeding and biomarkers of folate and cobalamin status in Norwegian infants: a cross-sectional study

Folate and vitamin B12 (cobalamin) are essential for growth and development. This cross-sectional study aims to describe folate and vitamin B12 status according to infant age and breastfeeding practices in Norwegian infants. Infants aged 0-12 months (n = 125) were recruited through public health clinics. We registered breastfeeding status and measured serum concentrations of folate, cobalamin, total homocysteine (tHcy), and methylmalonic acid (MMA). The associations between infant age, breastfeeding, and biomarker concentrations were estimated in regression models. The mean (SD) age was 24 (16) weeks, and 42% were exclusively breastfed, 38% were partially breastfed, and 21% were weaned. Overall, median (IQR) folate, cobalamin, tHcy, and MMA concentrations were 47 (35-66) nmol/L, 250 (178-368) pmol/L, 6.99 (5.69-9.27) µmol/L, and 0.35 (0.24-0.83) µmol/L, respectively. None of the infants were folate deficient, 15% were vitamin B12 deficient (< 148 pmol/L), and 23% had low vitamin B12 status (148-221 pmol/L). Elevated tHcy (> 6.5 μmol/L) and MMA (> 0.26 μmol/L) were found in 62% and 69% of the infants, respectively. Compared to weaned, exclusively or partially breastfed infants were younger and had 46% higher tHcy concentrations (P < 0.001), in addition to 47% and 39% lower cobalamin concentrations (P < 0.001), respectively. However, the observed biomarker concentrations appeared to be independent of infant age. In conclusion, low vitamin B12 status was prevalent and appeared to be more common in the younger exclusively breastfed compared to older weaned infants. The implications of low vitamin B12 status in infancy are unknown and require further investigation.

Food-breastmilk combinations alter the colonic microbiome of weaning infants: an in silico study

The introduction of solid foods to infants, also known as weaning, is a critical point for the development of the complex microbial community inhabiting the human colon, impacting host physiology in infancy and later in life. This research investigated in silico the impact of food-breastmilk combinations on growth and metabolite production by colonic microbes of New Zealand weaning infants using the metagenome-scale metabolic model named Microbial Community. Eighty-nine foods were individually combined with breastmilk, and the 12 combinations with the strongest influence on the microbial production of short-chain fatty acids (SCFAs) and branched-chain fatty acids (BCFAs) were identified. Fiber-rich and polyphenol-rich foods, like pumpkin and blackcurrant, resulted in the greatest increase in predicted fluxes of total SCFAs and individual fluxes of propionate and acetate when combined, respectively, with breastmilk. Identified foods were further combined with other foods and breastmilk, resulting in 66 multiple food-breastmilk combinations. These combinations altered in silico the impact of individual foods on the microbial production of SCFAs and BCFAs, suggesting that the interaction between the dietary compounds composing a meal is the key factor influencing colonic microbes. Blackcurrant combined with other foods and breastmilk promoted the greatest increase in the production of acetate and total SCFAs, while pork combined with other foods and breastmilk decreased the production of total BCFAs.IMPORTANCELittle is known about the influence of complementary foods on the colonic microbiome of weaning infants. Traditional in vitro and in vivo microbiome methods are limited by their resource-consuming concerns. Modeling approaches represent a promising complementary tool to provide insights into the behavior of microbial communities. This study evaluated how foods combined with other foods and human milk affect the production of short-chain fatty acids and branched-chain fatty acids by colonic microbes of weaning infants using a rapid and inexpensive in silico approach. Foods and food combinations identified here are candidates for future experimental investigations, helping to fill a crucial knowledge gap in infant nutrition.

Gastrointestinal Health Benefits of Sorghum Phenolics

Sorghum is considered a promising food security crop and remarkable rich source of bioactive components including phenolic acids, flavonoids, and tannins. Sorghum phenolics exhibited numerous protective effects against multiple chronic diseases. However, there is no review of the effects of sorghum phenolics on gastrointestinal (GI) health. Specifically, recent studies have highly suggested that sorghum phenolics can maintain gastrointestinal homeostasis and enhance microbial diversity and richness. Furthermore, sorghum phenolics showed GI anticancer effects in both in vitro and in vivo studies against colorectal and esophageal cancers. Treatment of GI related human cancer cell lines stimulated apoptosis and suppressed proliferation. Sorghum intake and extracts treatments reduced intestinal oxidative stress and inflammatory mediators in human and in vivo studies. In addition, understanding the role and mechanisms underlying gastrointestinal health benefits of sorghum phenolics is crucial to determine treatment strategies of different GI diseases.

Enhanced anti-inflammatory activity of chlorogenic acid via folic acid-TPGS-modified liposomes encapsulation: characterization and In vivo evaluation on colitis mice

Introduction

Chlorogenic acid (CGA) has been identified to possess salient anti-inflammatory, antioxidant, and anticancer attributes. However, its application is limited by its instability and low bioavailability. Liposomes have been considered effective pharmaceutical delivery vehicles due to their ability to continuously release loaded drugs, improve drug stability, and display good biocompatibility. They can be easily modified by other small molecules to acquire additional biological functions. In this study, we developed and characterized folic acid-TPGS-modified chlorogenic acid liposome (FTCLP) and evaluated its anti-inflammatory activity.

Methods

The successful encapsulation of CGA within FTCLP was confirmed through examination using electron microscopy, fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The in vitro release characteristics of FTCLP were evaluated using the dialysis bag membrane method. Meanwhile, a dextran sulfate sodium (DSS) -induced colitis model was employed to investigate the anti-inflammatory effect of FTCLP and its mechanism.

Results

The FTCLP exhibited an encapsulation efficiency (EE) of 84.85 ± 1.20% and a drug loading (DL) of 11.67 ± 0.04%. The particle size of FTCLP was determined to be 150.63 ± 0.71 nm, with a polydispersity index (PDI) of 0.198 ± 0.02 and a zeta potential of 2.61 ± 0.38 mV. The in vitro release profile followed the Higuchi model, indicating sustained-release characteristics. The in vivo study demonstrated that FTCLP treatment was effective in improving the symptoms of DSS-induced inflammatory response, as evidenced by mitigation of weight loss, reduction in the disease activity index (DAI) score, restoration of colon length, and attenuation of colon tissue damage. Furthermore, the levels of pro-inflammatory cytokines, including interferon-gamma (INF-γ), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6), were markedly diminished in both the serum and colon tissue. FTCLP was also observed to suppress the expression of INF-γ, IL-1β, IL-6, tumor necrosis factor-alpha (TNF-α), and nuclear factor kappa B (NF-κB) p65, while concomitantly upregulating the expression of Janus kinase (JAK) and signal transducer and activator of transcription 3 (STAT3). Besides, the administration of FTCLP was found to result in an increase in the abundance of Lactobacillaceae and Peptostreptococcaceae, while decreasing the abundance of Bacteroidaceae, Rikenellaceae, and Helicobacteraceae.

Conclusion

Following encapsulation of CGA within liposomes, FTCLP revealed favorable stability and sustained release properties, and enhanced the anti-inflammatory effects by modulating multiple inflammation-related biomarkers. FTCLP has the potential to be a safe and effective drug for targeted therapy of colitis.

Faecal bacterial communities differ amongst discrete foraging populations of dugongs along the east Australian coast

Gut bacterial communities play a vital role in a host's digestion and fermentation of complex carbohydrates, absorption of nutrients, and energy harvest/storage. Dugongs are obligate seagrass grazers with an expanded hindgut and associated microbiome. Here, we characterised and compared the faecal bacterial communities of dugongs from genetically distinct populations along the east coast of Australia, between subtropical Moreton Bay and tropical Cleveland Bay. Amplicon sequencing of fresh dugong faecal samples (n=47) revealed Firmicutes (62%) dominating the faecal bacterial communities across all populations. Several bacterial genera (Bacteroides, Clostridium sensu stricto 1, Blautia and Polaribacter) were detected in samples from all locations, suggesting their importance in seagrass digestion. Principal coordinate analysis showed the three southern-most dugong populations having different faecal bacterial community compositions from northern populations. The relative abundances of the genera Clostridium sensu stricto 13 and dgA-11 gut group were higher, but Bacteroides was lower, in the southern dugong populations, compared to the northern populations, suggesting potential adaptive changes associated with location. This study contributes to our knowledge of the faecal bacterial communities of dugongs inhabiting Australian coastal waters. Future studies of diet selection in relation to seagrass availability throughout the dugong's range will help to advance our understanding of the roles that seagrass species may play in affecting the dugong's faecal bacterial community composition.

Infant gastroesophageal reflux disease management consensus

AIM

Infant gastroesophageal reflux is mostly benign; however, when associated with complications like failure to thrive, it may be indicative of gastroesophageal reflux disease. There are currently several unmet needs pertaining to the management of infant gastroesophageal reflux (disease). Reflux in infants is mostly composed of breast milk or formula, so this population is significantly different to older children and adults. The objective of this Delphi consensus was to establish recommendations based on published literature and the experience of clinical experts in paediatric gastroenterology in the context of infant gastroesophageal reflux (disease).

METHODS

The Delphi methodology was used to obtain a consensus on 18 statements relating to clinical aspects of infant gastroesophageal reflux (disease).

RESULTS

The expert panel comprising paediatric gastroenterology clinical specialists reached a consensus for all statements by means of an online, anonymised voting system.

CONCLUSION

It was highlighted that there is generally low awareness of or adherence to guidelines in clinical practice and that acid suppression therapy should not be indicated for non-acid reflux, which constitutes a significant proportion of total gastroesophageal reflux episodes among infants. Furthermore, it was emphasised that there is an unmet medical need for therapy for some symptomatic infants with non-acid reflux disease.

New horizon to the world of gut microbiome: seeds germination

The second brain of humans has been known as the microbiome. The microbiome is a dynamic network composed of commensal bacteria, archaea, viruses, and fungi colonized in the human gastrointestinal tract. They play a vital role in human health by metabolizing components, maturation of the immune system, and taking part in the treatment of various diseases. Two important factors that can affect the gut microbiome's composition and/or function are the food matrix and methods of food processing. Based on scientific research, the consumption of whole grains can make positive changes in the gut microbiota. Seeds contain different microbiota-accessible substrates that can resist digestion in the upper gastrointestinal tract. Seed germination is one of the simplest and newest food processing approaches to improve seeds' bioavailability and overall nutritional value. During germination, the dormant hydrolytic seed's enzymes have been activated and then metabolize the macromolecules. The quality and quantity of bioactive compounds like prebiotics, fiber, phenolic compounds (PC), total free amino acids, and γ-aminobutyric acid (GABA) can increase even up to 4-10 folds in some cases. These components stimulate the survival and growth of healthful bacteria like probiotics and boost their activity. This effect depends on several parameters, e.g., germination environmental conditions. This review aims to provide up-to-date and latest research about promoting bioactive components during seed germination and investigating their impacts on gut microbiota to understand the possible direct and indirect effects of seed germination on the microbiome and human health.

A narrative review on dietary components and patterns and age-related macular degeneration

Age-related macular degeneration (AMD) is one of the most prevalent eye diseases among the ageing population worldwide. It is a leading cause of blindness in individuals over 55, particularly in industrialised Western countries. The prevalence of AMD increases with age, and genetic factors and environmental influences are believed to contribute to its development. Among the environmental factors, diet plays a significant role in AMD. This review explores the association between dietary components, dietary patterns and AMD. Various nutrients, non-nutrient substances and dietary models that have the potential to counteract oxidative stress and inflammation, which are underlying mechanisms of AMD, are discussed. Consuming fruits, vegetables, fish and seafood, whole grains, olive oil, nuts and low-glycaemic-index foods has been highlighted as beneficial for reducing the risk of AMD. Adhering to the Mediterranean diet, which encompasses these elements, can be recommended as a dietary pattern for AMD. Furthermore, the modulation of the gut microbiota through dietary interventions and probiotics has shown promise in managing AMD.

Surveys of eleven species of wild and zoo birds and feeding experiments in white-tailed eagles reveal differences in the composition of the avian gut microbiome based on dietary habits between and within species

The composition of the gut microbiome varies due to dietary habits. We investigated influences of diet on the composition of the gut microbiome using the feces of 11 avian species, which consumed grain-, fish- and meat-based diets. We analyzed gut microbiome diversity and composition by next-generation sequencing (NGS) of 16S ribosomal RNA. The grain-diet group had higher gut microbiome diversity than the meat- and fish-diet group. The ratio of Bacteroidetes and Firmicutes phyla was higher in the grain-diet group than in the meat- and fish-diet groups. The grain-diet group had a higher ratio of Veillonellaceae than the meat-diet group and a higher ratio of Eubacteriaceae than the fish-diet habit group. To clarify the influence of diet within the same species, white-tailed eagles (Haliaeetus albicilla, n=6) were divided into two groups, and given only deer meat or fish for approximately one month. The composition of the gut microbiome of individuals in both groups were analyzed by NGS. There were indications of fluctuation in the levels of some bacteria (Lactobacillus, Coriobacteriales, etc.) in each diet group. Moreover, one individual for each group which switched each diet in last week changed to each feature of composition of bacterial flora. The above results show that the composition of the gut microbiome differ depending on diet, even within the same species.

A Decade of Evidence of Sorghum Potential in the Development of Novel Food Products: Insights from a Bibliometric Analysis

Due to the increasing interest in sorghum for human nutrition, recent literature reviews highlight its nutrient and bioactive contents, potential health benefits and its 'gluten-free' feature. Moreover, a current view of research advances on sorghum-based food products is needed to help both food scientists and industry identify current trends and forward-looking approaches. Studies on homemade processing are still scarce. Thus, this review aimed to provide the latest information regarding the use of sorghum to develop ready-to-eat products or food ingredients based on studies published in the last decade (2012-2022), which then guided discussions on recent advances and prospects. The articles were identified by searching the Elsevier Scopus database. Sorghum has great potential as a functional and sustainable food that can be used in daily meals as a substitute for common cereals like wheat, rice and corn. The studies in the review show that it is possible to process sorghum in a wide variety of ways to obtain ready-to-eat products and ingredients for food products and preparations, such as popping, lamination, extrusion and wet cooking. The studies also show promising approaches to use sorghum in acceptable and nutrient-dense bakery and pasta products, highlighting their gluten-free versions. However, more efforts to make these novel food products available to consumers should be made.

Involvement of intestinal flora and miRNA into the mechanism of coarse grains improving type 2 diabetes: an overview

The prevalence of type 2 diabetes has been growing at an increasing rate worldwide. Dietary therapy is probably the easiest and least expensive method to prevent and treat diabetes. Previous studies have reported that coarse grains have anti-diabetic effects. Although considerable efforts have been made on the anti-diabetic function of different grains, the mechanisms of coarse grains on type 2 diabetes have not been systematically compared and summarized so far. Intestinal flora, reported as the main 'organ' of action underlying coarse grains, is an important factor in the alleviation of type 2 diabetes by coarse grains. Furthermore, microRNA (miRNA), as a new disease marker and 'dark nutrient', plays a likely influential role in cross-border communication among coarse grains, intestinal flora, and hosts. Given this context, this article reviews several possible mechanisms for the role of coarse grains on diabetes, incorporating resistance to inflammation and oxidative stress, repair of insulin signaling and β-cell dysfunction, and highlights the regulation of intestinal flora disorders and miRNAs expression, along with some novel insights. © 2022 Society of Chemical Industry.

Functional Fermented Milk with Fruit Pulp Modulates the In Vitro Intestinal Microbiota

The effect of putative probiotic fermented milk (FM) with buriti pulp (FMB) or passion fruit pulp (FMPF) or without fruit pulp (FMC) on the microbiota of healthy humans was evaluated. FM formulations were administered into a simulator of the human intestinal microbial ecosystem (SHIME^®) to evaluate the viability of lactic acid bacteria (LAB), microbiota composition, presence of short-chain fatty acids (SCFA), and ammonium ions. The probiotic LAB viability in FM was affected by the addition of the fruit pulp. Phocaeicola was dominant in the FMPF and FMB samples; Bifidobacterium was related to FM formulations, while Alistipes was associated with FMPF and FMB, and Lactobacillus and Lacticaseibacillus were predominant in FMC. Trabulsiella was the central element in the FMC, while Mediterraneibacter was the central one in the FMPF and FMB networks. The FM formulations increased the acetic acid, and a remarkably high amount of propionic and butyric acids were detected in the FMB treatment. All FM formulations decreased the ammonium ions compared to the control; FMPF samples stood out for having lower amounts of ammonia. The probiotic FM with fruit pulp boosted the beneficial effects on the intestinal microbiota of healthy humans in addition to increasing SCFA in SHIME^® and decreasing ammonium ions, which could be related to the presence of bioactive compounds.

Starch Digestion in Infants: An Update of Available In Vitro Methods-A Mini Review

Complementary feeding starts at around six months of age because neither breast milk nor formula assure the proper nutrition of infants. Therefore, along with breast milk, solid foods are gradually introduced, particularly cereal-based foods, which will provide starch as a new source of energy and nutrients. As a result, the need of an adequate in vitro digestion method to study the influence of different aspects of weaning period is unquestionable. This critical review summarizes the in vitro digestion methods available for the analysis of starch hydrolysis under infant conditions considering different features, namely, starch digestion, infant digestive conditions and in vitro models suitable for the study of starch digestion (static, semi-dynamic and dynamic). Key factors such as enzyme concentrations, transit time, oral, gastric and intestinal conditions and differences with current adult models, have been addressed. The need for standardized infant digestion models adapted to the complementary feeding period was discussed. Existing literature data demonstrate that more effort has to be done to improve the research on this issue, in order to obtain comparable results that would address a better understanding of the digestibility of different food nutrients under infant conditions facilitating the development of appropriate formulations that may assure proper infant nutrition.

Targeting gut microbiota-derived butyrate improves hepatic gluconeogenesis through the cAMP-PKA-GCN5 pathway in late pregnant sows

Short chain fatty acids (SCFAs) produced by gut microbiota affected hepatic glucose metabolism via the gut-liver axis. The present study aimed to investigate the effects of butyrate produced by gut microbiota on hepatic gluconeogenesis in late-pregnancy sows. A total of 240 primiparous sows in late pregnancy were tested for blood glucose using a glucose meter before feeding and grouped according to their blood glucose level as follows: 0-3.0 mmol L^-1 (low blood glucose group, LG group) and 3.1-5.0 mmol L^-1 (normal blood glucose group, NG group). Colonic SCFAs and microbiota, SCFAs in the portal vein and liver, and acetylation and phosphorylation levels in the liver samples were analyzed. Hepatocytes from pregnant sows were examined for the effect of butyrate on hepatic glucose gluconeogenesis. In vivo experiments showed that the reproductive performance, serum glucose metabolism index, colonic butyrate and butyrate-producing bacteria decreased in the LG group compared with the NG group. Correlation analysis found a positive correlation among colonic butyrate, butyrate-producing bacteria and the serum glucose metabolism index. Moreover, the hepatic cAMP concentration, PKA activity, GCN5 phosphorylation, and the expression of G6P and PEPCK were decreased and PGC1-α acetylation was increased in the LG group compared with the NG group. In vitro, sodium butyrate significantly stimulated the cAMP concentration, PKA activity, GCN5 phosphorylation, and the expression of G6P and PEPCK and inhibited PGC-1α acetylation in the LG group of hepatocytes from late-pregnancy sows. Interestingly, another in vivo experiment showed that dietary 1-kestose, a natural regulator of gut bacteria, significantly increased butyrate and butyrate-producing bacteria, and improved the reproductive performance and serum glucose metabolism index in late-pregnancy sows. Taken together, we found that targeting gut microbiota-derived butyrate could improve hepatic gluconeogenesis through the cAMP-PKA-GCN5 pathway in late-pregnancy sows.

The effects of dietary fibers from rice bran and wheat bran on gut microbiota: An overview

•

The physicochemical properties of DFs are related to their digestive behaviors.

•

DFs are degraded in the intestines due to the fermentation of gut microbiota.

•

DFs and their metabolites exert beneficial effects on gut microbiota.

•

The fermentation of DFs improve gut barrier function and immune function.

Whole grain is the primary food providing abundant dietary fibers (DFs) in the human diet. DFs from rice bran and wheat bran have been well documented in modulating gut microbiota. This review aims to summarize the physicochemical properties and digestive behaviors of DFs from rice bran and wheat bran and their effects on host gut microbiota. The physicochemical properties of DFs are closely related to their fermentability and digestive behaviors. DFs from rice bran and wheat bran modulate specific bacteria and promote SAFCs-producing bacteria to maintain host health. Moreover, their metabolites stimulate the production of mucus-associated bacteria to enhance the intestinal barrier and regulate the immune system. They also reduce the level of related inflammatory cytokines and regulate Tregs activation. Therefore, DFs from rice bran and wheat bran will serve as prebiotics, and diets rich in whole grain will be a biotherapeutic strategy for human health.

The nutritional profile and human health benefit of pigmented rice and the impact of post-harvest processes and product development on the nutritional components: A review

Pigmented rice has attracted considerable attention due to its nutritional value, which is in large conferred by its abundant content of phenolic compounds, considerable micronutrient concentrations, as well as its higher resistant starch and thereby slower digestibility properties. A wide range of phenolic compounds identified in pigmented rice exhibit biological activities such as antioxidant activity, anti-inflammatory, anticancer, and antidiabetic properties. Post-harvest processes significantly reduce the levels of these phytochemicals, but recent developments in processing methods have allowed greater retention of their contents. Pigmented rice has also been converted to different products for food preservation and to derive functional foods. Profiling a large set of pigmented rice cultivars will thus not only provide new insights into the phytochemical diversity of rice and the genes underlying the vast array of secondary metabolites present in this species but also provide information concerning their nutritional benefits, which will be instrumental in breeding healthier rice. The present review mainly focuses on the nutritional composition of pigmented rice and how it can impact human health alongside the effects of post-harvest processes and product development methods to retain the ambient level of phytochemicals in the final processed form in which it is consumed.

A Review of Health-Beneficial Properties of Oats

Oat is among the food crops and ancient grains cultivated and consumed worldwide. It is gaining in popularity owing to its nutritional composition and multifunctional benefits of select bioactive compounds. Beta-glucan is an important component of dietary fiber found in oat grains. It is the major active compound in oats with proven cholesterol-lowering and antidiabetic effects. Oats also provide substantial levels of other bioactive compounds such as phenolic acids, tocols, sterols, avenacosides, and avenanthramides. The consumption of oats has been determined to be beneficial for human health by promoting immunomodulation and improving gut microbiota. In addition, oat consumption assists in preventing diseases such as atherosclerosis, dermatitis, and some forms of cancer. While much has been published in relation to oat nutrients and oat fibers and their impact on major diseases, the oat industries and consumers may benefit from greater knowledge and understanding of clinical effects, range of occurrence, distribution, therapeutic doses and food functional attributes of other oat bioactives such as avenanthramides and saponins as well as other anti-inflammatory agents found in the cereal. This review focuses on the various studies relevant to the contribution of the consumption of oats and oat-based products in preventing human diseases and promoting human health.

Systematic Review of the Effects of Oat Intake on Gastrointestinal Health

BACKGROUND

Oats are a food source with multiple health benefits that could support beneficial bacterial groups and provide important bioactive compounds for the gut.

OBJECTIVES

This review explores the association between oat intake, gastrointestinal (GI) symptoms, and microbial community changes in individuals with celiac disease (CeD), irritable bowel syndrome (IBS), and inflammatory bowel disease (IBD) and without GI disease.

METHODS

Four databases and Google Scholar were systematically searched from inception until April 29, 2021. Clinical trials, observational studies, and in vitro studies with human gut-derived samples were included.

RESULTS

There were 84 articles [23 randomized controlled trials (RCTs), 21 nonrandomized trials, 8 observational studies, and 32 in vitro studies] included. Oat intake increased total bacterial count, Lactobacilli spp., and Bifidobacterium spp. in healthy individuals and those with CeD. There was an increased concentration of short-chain fatty acids and improved gut permeability with oat intake but with no significant quality-of-life difference. In some individuals with CeD, consumption of certain oat types was associated with worsening of GI symptoms. We found no studies reporting on IBS and only 3 for IBD. The quality of RCTs showed some concerns mostly in domains of randomization (73.9%), whereas the quality of evidence of non-RCTs, observational studies, and in vitro studies was satisfactory.

CONCLUSIONS

Oat intake was associated with the increase of beneficial bacterial groups in individuals without GI disease and those with CeD. Most studies showed no changes in GI symptoms with oat consumption. In vitro studies in CeD provide insight to oat-sensitive individuals and their GI mucosa, but the clinical studies remain limited, precluding our ability to draw firm conclusions. The prevalence of oat sensitivity in individuals with CeD should be further explored as this could improve clinical management and facilitate inclusion of oat in the diet for this population.

Shaping biofilm microbiomes by changing GAC location during wastewater anaerobic digestion

The addition of granular activated carbon (GAC) to up-flow anaerobic sludge blanket (UASB) reactors treating synthetic wastewater enhanced methane production by stimulating direct interspecies electron transfer (DIET). A modified UASB reactor with GAC packed in plastic carriers that allowed the GAC to float in the upper reactor zone achieved enhanced performance compared to a UASB reactor with GAC settled at the bottom of the reactor. Microbial communities in the biofilms developed on settled or floated GAC were compared. Methanosarcina (56.3-73.3%) dominated the floated-GAC biofilm whereas Methanobacterium (84.9-85.1%) was greatly enriched in the settled-GAC biofilm. Methanospirillum and Methanocorpusculum were enriched in the floated-GAC biofilm (8.8-19.8% and 5.1-9.5%, respectively), but only existed in low abundances in the settled-GAC biofilm (3.4-3.6% and 0-0.4%, respectively). The floated GAC developed bacterial communities with higher diversity and more syntrophic bacteria enrichments on its surface, including Geobacter, Smithella, and Syntrophomonas, than the settled-GAC biofilm. Common hydrogen-donating syntrophs and hydrogenotrophic archaea, Methanospirillum and Methanoregula, were identified as potential electro-active microorganisms related to DIET.

In vitro models of gut digestion across childhood: current developments, challenges and future trends

The human digestion is a multi-step and multi-compartment process essential for human health, at the heart of many issues raised by academics, the medical world and industrials from the food, nutrition and pharma fields. In the first years of life, major dietary changes occur and are concomitant with an evolution of the whole child digestive tract anatomy and physiology, including colonization of gut microbiota. All these phenomena are influenced by child exposure to environmental compounds, such as drugs (especially antibiotics) and food pollutants, but also childhood infections. Due to obvious ethical, regulatory and technical limitations, in vivo approaches in animal and human are more and more restricted to favor complementary in vitro approaches. This review summarizes current knowledge on the evolution of child gut physiology from birth to 3 years old regarding physicochemical, mechanical and microbial parameters. Then, all the available in vitro models of the child digestive tract are described, ranging from the simplest static mono-compartmental systems to the most sophisticated dynamic and multi-compartmental models, and mimicking from the oral phase to the colon compartment. Lastly, we detail the main applications of child gut models in nutritional, pharmaceutical and microbiological studies and discuss the limitations and challenges facing this field of research.

The sugar composition of the fibre in selected plant foods modulates weaning infants' gut microbiome composition and fermentation metabolites in vitro

Eight plant-based foods: oat flour and pureed apple, blackcurrant, carrot, gold- and green-fleshed kiwifruit, pumpkin, sweetcorn, were pre-digested and fermented with pooled inocula of weaning infants’ faecal bacteria in an in vitro hindgut model. Inulin and water were included as controls. The pre-digested foods were analysed for digestion-resistant fibre-derived sugar composition and standardised to the same total fibre concentration prior to fermentation. The food-microbiome interactions were then characterised by measuring microbial acid and gas metabolites, microbial glycosidase activity and determining microbiome structure. At the physiologically relevant time of 10 h of fermentation, the xyloglucan-rich apple and blackcurrant favoured a propiogenic metabolic and microbiome profile with no measurable gas production. Glucose-rich, xyloglucan-poor pumpkin caused the greatest increases in lactate and acetate (indicative of high fermentability) commensurate with increased bifidobacteria. Glucose-rich, xyloglucan-poor oats and sweetcorn, and arabinogalactan-rich carrot also increased lactate and acetate, and were more stimulatory of clostridial families, which are indicative of increased microbial diversity and gut and immune health. Inulin favoured a probiotic-driven consortium, while water supported a proteolytic microbiome. This study shows that the fibre-derived sugar composition of complementary foods may shape infant gut microbiome structure and metabolic activity, at least in vitro.

Safety considerations when managing gastro-esophageal reflux disease in infants

Introduction: Gastro-esophageal reflux disease (GERD) in infants is worldwide diagnosed with increasing frequency, resulting in an increasing number of infants exposed to treatment. In this review, we focus on the safety of therapeutic options. Areas covered: English articles were searched from 1990 until May 2020 in PubMed and Google Scholar. Evidence suggests that non-pharmacological treatment is often effective and safe. Guidelines restrict pharmacological treatment to acid-suppressive medication, which is associated with adverse effects, often related to gastro-intestinal dysbiosis and consequences of the latter. Aluminum-free alginates have some efficacy and are not associated with relevant adverse effects. Especially in infants, GERD is often nonacid related. Prokinetics are not recommended because of lack of efficacy and numerous adverse effects. Expert opinion: Pediatric trials are underpowered regarding adverse effects. The number of infants exposed to anti-secretory agents is increasing worldwide, often without indication. Informing healthcare providers about adverse effects of acid-secretory medication may contribute to a more rational use. Acid inhibiting agents such as alginates are a drug class associated with limited efficacy and devoid of serious adverse effects. Regarding prokinetics, the risk of adverse effects outweighs the benefit. Reassurance of parents and nutritional management of GERD in infants is effective and safe.

The Human Digestive Tract Is Capable of Degrading Gluten from Birth

The human gastrointestinal system has the capacity to metabolize dietary gluten. The capacity to degrade gliadin-derived peptide is present in humans from birth and increases during the first stages of life (up to 6–12 months of age). Fecal samples from 151 new-born and adult non-celiac disease (NCD) volunteers were collected, and glutenase and glianidase activities were evaluated. The capacity of total fecal proteins to metabolize 33-mer, 19-mer, and 13-mer gliadin peptides was also evaluated by high-performance liquid chromatography (HPLC). Feces from new-borns (meconium) showed glutenase and gliadinase activities, and peptidase activity against all three gliadin peptides. Maximal gluten degradative activity was observed in fecal samples from the youngest volunteers (0–12 months old). After the age of nine months, the gluten digestive capacity of gastrointestinal tract decreases and, from ±8 years old, individuals lose the ability to completely degrade toxic peptides. The gastrointestinal proteases involved in gluten digestion: elastase 2A, elastase 3B, and carboxipeptidase A1 are present from earlier stages of life. The human digestive tract contains the proteins capable of metabolizing gluten from birth, even before starting gluten intake. Humans are born with the ability to digest gluten and to completely degrade the potentially toxic gliadin-derived peptides (33-, 19-, and 13-mer).

Bioaminergic Responses in an In Vitro System Studying Human Gut Microbiota-Kiwifruit Interactions

Whole kiwifruit ('Hayward' and 'Zesy002') were examined for their bioaminergic potential after being subjected to in vitro gastrointestinal digestion and colonic fermentation. Controls included the prebiotic inulin and water, a carbohydrate-free vehicle. The dopamine precursor l-dihydroxyphenylalanine (L-DOPA) and the serotonin precursor 5-hydroxytryptophan were increased in the kiwifruit gastrointestinal digesta ('Hayward' > 'Zesy002') in comparison to the water digesta. Fermentation of the digesta with human fecal bacteria for 18 h modulated the concentrations of bioamine metabolites. The most notable were the significant increases in L-DOPA ('Zesy002' > 'Hayward') and γ-aminobutyric acid (GABA) ('Hayward' > 'Zesy002'). Kiwifruit increased Bifidobacterium spp. and Veillonellaceae (correlating with L-DOPA increase), and Lachnospira spp. (correlating with GABA). The digesta and fermenta were incubated with Caco-2 cells for 3 h followed by gene expression analysis. Effects were seen on genes related to serotonin synthesis/re-uptake/conversion to melatonin, gut tight junction, inflammation and circadian rhythm with different digesta and fermenta from the four treatments. These indicate potential effects of the substrates and the microbially generated organic acid and bioamine metabolites on intestinal functions that have physiological relevance. Further studies are required to confirm the potential bioaminergic effects of gut microbiota-kiwifruit interactions.

Short-Chain Fatty Acid Production by Gut Microbiota from Children with Obesity Differs According to Prebiotic Choice and Bacterial Community Composition

Pediatric obesity remains a public health burden and continues to increase in prevalence. The gut microbiota plays a causal role in obesity and is a promising therapeutic target. Specifically, the microbial production of short-chain fatty acids (SCFA) from the fermentation of otherwise indigestible dietary carbohydrates may protect against pediatric obesity and metabolic syndrome. Still, it has not been demonstrated that therapies involving microbiota-targeting carbohydrates, known as prebiotics, will enhance gut bacterial SCFA production in children and adolescents with obesity (age, 10 to 18 years old). Here, we used an in vitro system to examine the SCFA production by fecal microbiota from 17 children with obesity when exposed to five different commercially available over-the-counter (OTC) prebiotic supplements. We found microbiota from all 17 patients actively metabolized most prebiotics. Still, supplements varied in their acidogenic potential. Significant interdonor variation also existed in SCFA production, which 16S rRNA sequencing supported as being associated with differences in the host microbiota composition. Last, we found that neither fecal SCFA concentration, microbiota SCFA production capacity, nor markers of obesity positively correlated with one another. Together, these in vitro findings suggest the hypothesis that OTC prebiotic supplements may be unequal in their ability to stimulate SCFA production in children and adolescents with obesity and that the most acidogenic prebiotic may differ across individuals.IMPORTANCE Pediatric obesity remains a major public health problem in the United States, where 17% of children and adolescents are obese, and rates of pediatric "severe obesity" are increasing. Children and adolescents with obesity face higher health risks, and noninvasive therapies for pediatric obesity often have limited success. The human gut microbiome has been implicated in adult obesity, and microbiota-directed therapies can aid weight loss in adults with obesity. However, less is known about the microbiome in pediatric obesity, and microbiota-directed therapies are understudied in children and adolescents. Our research has two important findings: (i) dietary prebiotics (fiber) result in the microbiota from adolescents with obesity producing more SCFA, and (ii) the effectiveness of each prebiotic is donor dependent. Together, these findings suggest that prebiotic supplements could help children and adolescents with obesity, but that these therapies may not be "one size fits all."

Glycan Utilisation and Function in the Microbiome of Weaning Infants

Glycans are present exogenously in the diet, expressed and secreted endogenously by host cells, and produced by microbes. All of these processes result in them being available to the gut microbiome, firmly placing glycans at the interface of diet–microbe–host interactions. The most dramatic shift in dietary sources of glycans occurs during the transition from the milk-based neonatal diet to the diverse omnivorous adult diet, and this has profound effects on the composition of the gut microbiome, gene expression by microbes and host cells, mucin composition, and immune development from innate towards adaptive responses. Understanding the glycan-mediated interactions occurring during this transitional window may inform dietary recommendations to support gut and immune development during a vulnerable age. This review aims to summarise the current state of knowledge on dietary glycan mediated changes that may occur in the infant gut microbiome and immune system during weaning.

Clinical Aspects of Thickeners for Pediatric Gastroesophageal Reflux and Oropharyngeal Dysphagia

PURPOSE OF REVIEW

The purpose of this review is to discuss current knowledge and recent findings regarding clinical aspects of thickeners for pediatric gastroesophageal reflux and oropharyngeal dysphagia. We review evidence for thickener efficacy, discuss types of thickeners, practical considerations when using various thickeners, and risks and benefits of thickener use in pediatrics.

RECENT FINDINGS

Thickeners are effective in decreasing regurgitation and improving swallowing mechanics and can often be used empirically for the treatment of infants and young children. Adverse effects have been reported, but with careful consideration of appropriate thickener types, desired thickening consistency, and follow-up in collaboration with feeding specialists, most patients have symptomatic improvements. Thickeners are typically well tolerated and with few side effects, but close follow-up is needed to make sure patients tolerate thickeners and have adequate symptom improvement.

Longitudinal changes during pregnancy in gut microbiota and methylmercury biomarkers, and reversal of microbe-exposure correlations

OBJECTIVE

Gut microorganisms contribute to the metabolism of environmental toxicants, including methylmercury (MeHg). Our main objective was to investigate whether associations between biomarkers for prenatal MeHg exposure and maternal gut microbiota differed between early and late gestation.

METHODS

Maternal blood and stool samples were collected during early (8.3-17 weeks, n=28) and late (27-36 weeks, n=24) gestation. Total mercury and MeHg concentrations were quantified in biomarkers, and inorganic mercury was estimated by subtraction. The diversity and structure of the gut microbiota were investigated using 16S rRNA gene profiling (n = 52). Biomarkers were dichotomized, and diversity patterns were compared between high/low mercury concentrations. Spearman's correlation was used to assess bivariate associations between MeHg biomarkers (stool, blood, and meconium), and 23 gut microbial taxa (genus or family level, >1% average relative abundance).

RESULTS

Within-person and between-person diversity patterns in gut microbiota differed between early/late gestation. The overall composition of the microbiome differed between high/low MeHg concentrations (in blood and stool) during early gestation, but not late gestation. Ten (of 23) taxa were significantly correlated with MeHg biomarkers (increasing or decreasing); however, associations differed, depending on whether the sample was collected during early or late gestation. A total of 43% of associations (69/161) reversed the direction of correlation between early/late gestation.

CONCLUSIONS

The time point at which a maternal fecal sample is collected may yield different associations between gut microorganisms and MeHg biomarkers, which may be due in part to remodeling of maternal microbiota during pregnancy. Our results suggest the effectiveness of dietary interventions to reduce prenatal MeHg exposure may differ between early and late gestation.

Inulin Can Alleviate Metabolism Disorders in ob/ob Mice by Partially Restoring Leptin-related Pathways Mediated by Gut Microbiota

Inulin has been used as a prebiotic to alleviate glucose and lipid metabolism disorders in mice and humans by modulating the gut microbiota. However, the mechanism underlying the alleviation of metabolic disorders by inulin through interactions between the gut microbiota and host cells is unclear. We use ob/ob mice as a model to study the effect of inulin on the cecal microbiota by 16S rRNA gene amplicon sequencing and its interaction with host cells by transcriptomics. The inulin-supplemented diet improved glucose and lipid metabolism disorder parameters in ob/ob mice, alleviating fat accumulation and glucose intolerance. The α diversity of gut microbial community of ob/ob mice was reduced after inulin treatment, while the β diversity tended to return to the level of wild type mice. Interestingly, Prevotellaceae UCG 001 (family Prevotellaceae) was obviously enriched after inulin treatment. A comparative analysis of the gene expression profile showed that the cecal transcriptome was changed in leptin gene deficiency mice, whereas the inulin-supplemented diet partially reversed the changes in leptin gene-related signaling pathways, especially AMPK signaling pathway, where the levels of gene expression became comparable to those in wild type mice. Further analysis indicated that Prevotellaceae UCG 001 was positively correlated with the AMPK signaling pathway, which was negatively correlated with markers of glycolipid metabolism disorders. Our results suggest that the inulin-supplemented diet alleviates glucose and lipid metabolism disorders by partially restoring leptin related pathways mediated by gut microbiota.

Infant Cereals: Current Status, Challenges, and Future Opportunities for Whole Grains

Infant cereals play an important role in the complementary feeding period. The aim of this study was to review existing research about the quantity, type, and degree of infant cereal processing, with a special focus on whole grain infant cereals. Accumulating evidence shows many benefits of whole grain consumption for human health. Likewise, consumers are frequently linking the term whole grains to healthiness and naturality, and sustainable food production becomes a more important aspect when choosing an infant cereal brand. Whole grain cereals should be consumed as early as possible, i.e., during infancy. However, there are several challenges that food manufacturers are facing that need to be addressed. Recommendations are needed for the intake of whole grain cereals for infants and young children, including product-labeling guidelines for whole grain foods targeting these age stages. Another challenge is minimizing the higher contaminant content in whole grains, as well as those formed during processing. Yet, the greatest challenge may be to drive consumers' acceptance, including taste. The complementary feeding period is absolutely key in shaping the infant's food preferences and habits; therefore, it is the appropriate stage in life at which to introduce whole grain cereals for the acceptance of whole grains across the entire lifespan.

Evaluating the profound effect of gut microbiome on host appetite in pigs

Background

There are growing evidences showing that gut microbiota should play an important role in host appetite and feeding behavior. However, what kind of microbe(s) and how they affect porcine appetite remain unknown.

Results

In this study, 280 commercial Duroc pigs were raised in a testing station with the circadian feeding behavior records for a continuous period of 30–100 kg. We first analyzed the influences of host gender and genetics in porcine average daily feed intake (ADFI), but no significant effect was observed. We found that the Prevotella-predominant enterotype had a higher ADFI than the Treponema enterotype-like group. Furthermore, 12 out of the 18 OTUs positively associated with the ADFI were annotated to Prevotella, and Prevotella was the hub bacteria in the co-abundance network. These results suggested that Prevotella might be a keystone bacterial taxon for increasing host feed intake. However, some bacteria producing short-chain fatty acids (SCFAs) and lactic acid (e.g. Ruminococcaceae and Lactobacillus) showed negative associations with the ADFI. Predicted function capacity analysis showed that the genes for amino acid biosynthesis had significantly different enrichment between pigs with high and low ADFI.

Conclusions

The present study provided important information on the profound effect of gut microbiota on porcine appetite and feeding behavior. This will profit us to regulate porcine appetite through modulating the gut microbiome in the pig industry.

Electronic supplementary material

The online version of this article (10.1186/s12866-018-1364-8) contains supplementary material, which is available to authorized users.

Development of the Gut Microbiome in Children, and Lifetime Implications for Obesity and Cardiometabolic Disease

Emerging evidence suggests that microbiome composition and function is associated with development of obesity and metabolic disease. Microbial colonization expands rapidly following birth, and microbiome composition is particularly variable during infancy. Factors that influence the formation of the gut microbiome during infancy and childhood may have a significant impact on development of obesity and metabolic dysfunction, with life-long consequences. In this review, we examine the determinants of gut microbiome composition during infancy and childhood, and evaluate the potential impact on obesity and cardiometabolic risk.

Dynamic linear models guide design and analysis of microbiota studies within artificial human guts

BACKGROUND

Artificial gut models provide unique opportunities to study human-associated microbiota. Outstanding questions for these models' fundamental biology include the timescales on which microbiota vary and the factors that drive such change. Answering these questions though requires overcoming analytical obstacles like estimating the effects of technical variation on observed microbiota dynamics, as well as the lack of appropriate benchmark datasets.

RESULTS

To address these obstacles, we created a modeling framework based on multinomial logistic-normal dynamic linear models (MALLARDs) and performed dense longitudinal sampling of four replicate artificial human guts over the course of 1 month. The resulting analyses revealed how the ratio of biological variation to technical variation from sample processing depends on sampling frequency. In particular, we find that at hourly sampling frequencies, 76% of observed variation could be ascribed to technical sources, which could also skew the observed covariation between taxa. We also found that the artificial guts demonstrated replicable trajectories even after a recovery from a transient feed disruption. Additionally, we observed irregular sub-daily oscillatory dynamics associated with the bacterial family Enterobacteriaceae within all four replicate vessels.

CONCLUSIONS

Our analyses suggest that, beyond variation due to sequence counting, technical variation from sample processing can obscure temporal variation from biological sources in artificial gut studies. Our analyses also supported hypotheses that human gut microbiota fluctuates on sub-daily timescales in the absence of a host and that microbiota can follow replicable trajectories in the presence of environmental driving forces. Finally, multiple aspects of our approach are generalizable and could ultimately be used to facilitate the design and analysis of longitudinal microbiota studies in vivo.

Fiber Supplements Derived From Sugarcane Stem, Wheat Dextrin and Psyllium Husk Have Different In Vitro Effects on the Human Gut Microbiota

There is growing public interest in the use of fiber supplements as a way of increasing dietary fiber intake and potentially improving the gut microbiota composition and digestive health. However, currently there is limited research into the effects of commercially available fiber supplements on the gut microbiota. Here we used an in vitro human digestive and gut microbiota model system to investigate the effect of three commercial fiber products; NutriKane™, Benefiber® and Psyllium husk (Macro) on the adult gut microbiota. The 16S rRNA gene amplicon sequencing results showed dramatic fiber-dependent changes in the gut microbiota structure and composition. Specific bacterial OTUs within the families Bacteroidaceae, Porphyromonadaceae, Ruminococcaceae, Lachnospiraceae, and Bifidobacteriaceae showed an increase in the relative abundances in the presence of one or more fiber product(s), while Enterobacteriaceae and Pseudomonadaceae showed a reduction in the relative abundances upon addition of all fiber treatments compared to the no added fiber control. Fiber-specific increases in SCFA concentrations showed correlation with the relative abundance of potential SCFA-producing gut bacteria. The chemical composition, antioxidant potential and polyphenolic content profiles of each fiber product were determined and found to be highly variable. Observed product-specific variations could be linked to differences in the chemical composition of the fiber products. The general nature of the fiber-dependent impact was relatively consistent across the individuals, which may demonstrate the potential of the products to alter the gut microbiota in a similar, and predictable direction, despite variability in the starting composition of the individual gut microbiota.

Dilution of rice with other gluten free grains to lower inorganic arsenic in foods for young children in response to European Union regulations provides impetus to setting stricter standards

There has been an increasing realisation that young infants are exposed to elevated concentrations of the carcinogen inorganic arsenic, relative to adults. This is because many infant food products are rice based, and rice is ~10-fold elevated in inorganic arsenic compared to most other foods. The European Commission (EC) has acted on this concern setting stricter standards for infants, 100 μg of inorganic arsenic per kg of food (100 μg/kg), as compared to adults (200 μg/kg), for rice based foods, a law that was brought into place in 1^st January 2016. Here we investigate how this law has impacted on inorganic arsenic in baby food products in the UK market, and compare the findings to previous baby food surveys taken before and just after the law came into place. We find that for a wide range of UK infant products that the new regulations are being adhered to, with all samples surveyed, being under 100 μg/kg inorganic arsenic. The prevalence of pure rice products had decreased in the UK, and there appears to be careful sourcing of the rice used in these products to ensure conformity with regulations. There has been an increased presence of mixed cereal products, with rice and maize as the main ingredient, appearing on the UK market, with varying rice contents for infant porridges, cakes and mueslis, with the latter being a relatively innovative product for infant foods. There was a highly significant correlation (P<0.0001) between rice content and inorganic arsenic concentration across all infant foods. When UK infant rice cakes, breakfast cereals and porridges were compare to their general, i.e. not labelled specifically for being for infant consumption, equivalent it was found that the adult foods generally exceeded the 100 μg/kg inorganic arsenic standard for infant foods. Thus, infants should not be given rice products not specifically labelled as being for them if a lower inorganic arsenic diet is to be maintained.