Friend or foe? The roles of inulin-type fructans

Dietary pectin and inulin: A promising adjuvant supplement for collagen-induced arthritis through gut microbiome restoration and CD4+ T cell reconstitution

Dietary strategies rich in fiber have been demonstrated to offer benefits to individuals afflicted with rheumatoid arthritis (RA). However, the specific mechanisms through which a high-fiber diet (HFD) mitigates RA's autoimmunity remain elusive. Herein, we investigate the influence of pectin- and inulin-rich HFD on collagen-induced arthritis (CIA). We establish that HFD significantly alleviates arthritis in CIA mice by regulating the Th17/Treg balance. The rectification of aberrant T cell differentiation by the HFD is linked to the modulation of gut microbiota, augmenting the abundance of butyrate in feces. Concurrently, adding butyrate to the drinking water mirrors the HFD's impact on ameliorating CIA, encompassing arthritis mitigation, regulating intestinal barrier integrity, and restoring the Th17/Treg equilibrium. Butyrate reshapes the metabolic profile of CD4+ T cells in an AMPK-dependent manner. Our research underscores the importance of dietary interventions in rectifying gut microbiota for RA management and offers an explanation of how diet-derived microbial metabolites influence RA's immune-inflammatory-reaction.

Inulin enhanced rifaximin-inhibited colon cancer pulmonary metastasis by flora-regulated bile acid pathway

Inulin as a natural polysaccharide regulates intestinal microorganisms, and improves the immune and gastrointestinal function. In order to explore the effect of inulin on pulmonary metastasis of colon cancer, we set up a CT26 injected pulmonary metastatic model. The results showed that inulin used alone did not improve pulmonary metastasis of colon cancer, while inulin combined with rifaximin significantly prolonged the survival time of mice, and inhibited pulmonary metastasis compared with model and inulin groups. Inulin treatment increased the abundance of harmful bacteria such as Proteobacteria and Actinobacteria, while combined treatment decreased their abundance and increased the abundance of beneficial bacteria containing Firmicutes and Eubacterium which belonged to the bile acid-related bacteria. The combination treatment decreased the content of primary bile acids and secondary bile acids in the feces of mice, especial for DCA and LCA which were the agonists of TGR5. Furthermore, the combination treatment reduced the mRNA expression of the TGR5, cyclin dependent kinase 4, cyclin 1 and CDK2, increased the mRNA expression of p21 in the lung, down-regulated the level of NF-κB p65, and up-regulated the level of TNF-α compared with the model group. The above may be the reason for the better use of the combination treatment.

Quality characteristics of cereal-based foods enriched with different degree of polymerization inulin: A review

Vegetables, cereals and fruit are foods rich in fibre with beneficial and nutritional effects as their consumption reduces the onset of degenerative diseases, especially cardiovascular ones. Among fibres, inulin, oligofructose or fructooligosaccharide (FOS) are the best-studied. Inulin is a generic term to cover all linear β(2-1) fructans, with a variable degree of polymerization. In this review a better understanding of the importance of the degree of polymerization of inulin as a dietary fibre, functions, health benefits, classifications, types and its applications in the food industry was considered in different fortified foods. Inulin has been used to increase the nutritional and healthy properties of the product as a sweetener and as a substitute for fats and carbohydrates, improving the nutritional value and decreasing the glycemic index, with the advantage of not compromising taste and consistency of the product. Bifidogenic and prebiotic effects of inulin have been well established, inulin-type fructans are fermented by the colon to produce short-chain fatty acids, with important local and systemic actions. Addition of inulin with different degrees of polymerization to daily foods for the production of fortified pasta and bread was reviewed, and the impact on sensorial, technological and organoleptic characteristics even of gluten-free bread was also reported.

Arctium Lappa L

Arctium lappa L. is widely consumed for its various biological effects, and polysaccharides are its main functional components. The present study aimed to evaluate the immunoregulatory effects of the main polysaccharides from burdock (ALP-1) and reveal the underlying mechanisms. ALP-1 consisted of fructose and glucose (14.57:1) and had a molecular weight of 2757 Da, with typical characteristics of (1 → 2)-linked linear fructans. Oral intake of ALP-1 significantly increased the number of colonic goblet cells, serum immunoglobulin A and immunoglobulin G levels, and fecal secretory immunoglobulin A content as well as up-regulated antioxidant enzymes and increased short chain fatty acid production. In addition, ALP-1 administration regulated pro/anti-inflammatory cytokines (i.e., interleukin (IL)-1β, IL-6, tumor necrosis factor-α, interferon-γ, and IL-10), intestinal microbiota structure, and the spatial information on key metabolites. Some gut-microbiota-mediated metabolic processes were also significantly altered. These results indicated that ALP-1 could exert beneficial effects on immune responses and intestinal health in healthy mice.

Hepatic injury and ileitis associated with gut microbiota dysbiosis in mice upon F-53B exposure

Chlorinated polyfluorinated ether sulfonate (F-53B), a substitute of perfluorooctane sulfonic acid (PFOS), has attracted significant attention for its link to hepatotoxicity and enterotoxicity. Nevertheless, the underlying mechanisms of F-53B-induced enterohepatic toxicity remain incompletely understood. This study aimed to explore the role of F-53B exposure on enterohepatic injury based on the gut microbiota, pathological and molecular analysis in mice. Here, we exposed C57BL/6 mice to F-53B (0, 4, 40, and 400 μg/L) for 28 days. Our findings revealed a significant accumulation of F-53B in the liver, followed by small intestines, and feces. In addition, F-53B induced pathological collagen fiber deposition and lipoid degeneration, up-regulated the expression of fatty acid β-oxidation-related genes (PPARα and PPARγ, etc), while simultaneously down-regulating pro-inflammatory genes (Nlrp3, IL-1β, and Mcp1) in the liver. Meanwhile, F-53B induced ileal mucosal barrier damage, and an up-regulation of pro-inflammatory genes and mucosal barrier-related genes (Muc1, Muc2, Claudin1, Occludin, Mct1, and ZO-1) in the ileum. Importantly, F-53B distinctly altered gut microbiota compositions by increasing the abundance of Akkermansia and decreasing the abundance of Prevotellaceae_NK3B31_group in the feces. F-53B-altered microbiota compositions were significantly associated with genes related to fatty acid β-oxidation, inflammation, and mucosal barrier. In summary, our results demonstrate that F-53B is capable of inducing hepatic injury, ileitis, and gut microbiota dysbiosis in mice, and the gut microbiota dysbiosis may play an important role in the F-53B-induced enterohepatic toxicity.

Inulin alleviates perinatal 2-ethylhexyl diphenyl phosphate (EHDPHP) exposure-induced intestinal toxicity by reshaping the gut microbiota and suppressing the enteric-origin LPS/TLR4/NF-κb pathway in dams and pups

Organophosphorus flame retardants (OPFRs), such as 2-ethylhexyl diphenyl phosphate (EHDPHP), are ubiquitously used, leading to pervasive environmental contamination and human health risks. While associations between EHDPHP and health issues such as disruption of hormones, neurotoxic effects, and toxicity to reproduction have been recognized, exposure to EHDPHP during perinatal life and its implications for the intestinal health of dams and their pups have largely been unexplored. This study investigated the intestinal toxicity of EHDPHP and the potential for which inulin was effective. Dams were administered either an EHDPHP solution or a corn oil control from gestation day 7 (GD7) to postnatal day 21 (PND21), with inulin provided in their drinking water. Our results indicate that inulin supplementation mitigates damage to the intestinal epithelium caused by EHDPHP, restores mucus-secreting cells, suppresses intestinal hyperpermeability, and abates intestinal inflammation by curtailing lipopolysaccharide leakage through reshaping of the gut microbiota. A reduction in LPS levels concurrently inhibited the inflammation-associated TLR4/NF-κB pathway. In conclusion, inulin administration may ameliorate intestinal toxicity caused by EHDPHP in dams and pups by reshaping the gut microbiota and suppressing the LPS/TLR4/NF-κB pathway. These findings underscore the efficacy of inulin as a therapeutic agent for managing health risks linked to EHDPHP exposure.

The effects of inulin-type fructans on cardiovascular disease risk factors: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Inulin-type fructans (ITF) are the leading prebiotics in the market. Available evidence provides conflicting results regarding the beneficial effects of ITF on cardiovascular disease risk factors.

OBJECTIVES

This study aimed to evaluate the effects of ITF supplementation on cardiovascular disease risk factors in adults.

METHODS

We searched MEDLINE, EMBASE, Emcare, AMED, CINAHL, and the Cochrane Library databases from inception through May 15, 2022. Eligible randomized controlled trials (RCTs) administered ITF or placebo (for example, control, foods, diets) to adults for ≥2 weeks and reported one or more of the following: low, very-low, or high-density lipoprotein cholesterol (LDL-C, VLDL-C, HDL-C); total cholesterol; apolipoprotein A1 or B; triglycerides; fasting blood glucose; body mass index; body weight; waist circumference; waist-to-hip ratio; systolic or diastolic blood pressure; or hemoglobin A1c. Two reviewers independently and in duplicate screened studies, extracted data, and assessed risk of bias. We pooled data using random-effects model, and assessed the certainty of evidence (CoE) using the Grading of Recommendations, Assessment, Development and Evaluation approach.

RESULTS

We identified 1767 studies and included 55 RCTs with 2518 participants in meta-analyses. The pooled estimate showed that ITF supplementation reduced LDL-C [mean difference (MD) -0.14 mmol/L, 95% confidence interval (95% CI: -0.24, -0.05), 38 RCTs, 1879 participants, very low CoE], triglycerides (MD -0.06 mmol/L, 95% CI: -0.12, -0.01, 40 RCTs, 1732 participants, low CoE), and body weight (MD -0.97 kg, 95% CI: -1.28, -0.66, 36 RCTs, 1672 participants, low CoE) but little to no significant effect on other cardiovascular disease risk factors. The effects were larger when study duration was ≥6 weeks and in pre-obese and obese participants.

CONCLUSION

ITF may reduce low-density lipoprotein, triglycerides, and body weight. However, due to low to very low CoE, further well-designed and executed trials are needed to confirm these effects.

PROSPERO REGISTRATION NUMBER

CRD42019136745.

Simple procedure to enhance pulsed amperometric detector (PAD) response stability for inulin-type fructans analysis. Application to a case study with chicory taproot

A new electrode management, within the HPAEC-PAD systems, was proposed to measure inulin-type fructans in chicory roots, grown under two lighting periods: 12 h (T-12 h) and 24 h continuous lighting (T-24 h-CL), with the same daily light integral (DLI). The amperometric cell turn-off (PAD-Off) after elution of carbohydrate of interest, allowed the stabilization of the PAD response, avoiding excessive electrode surface oxidation. The enhanced signal stability allowed the application of fucose as internal standard (ISTD) for data normalization, improving the correctness of linear calibration curves and the quantification of fructans in the case study of chicory plants. T-24 h-CL decreased FW and DW of chicory leaves while increasing these parameters in roots. Fructans amount in chicory roots was significantly higher in the T-24-CL photoperiod. The accuracy of prebiotics quantification by PAD-Off emphasized significant differences between light treatments. CL can improve the yield and quality of chicory roots.

An inulin-type fructan isolated from Serratula chinensis alleviated the dextran sulfate sodium-induced colitis in mice through regulation of intestinal barrier and gut microbiota

Herein, we aimed to explore the polysaccharide material basis of Serratula chinensis and establish its beneficial effects against colitis. A neutral polysaccharide (SCP) was extracted from S. chinensis in high yield using hot water. The molecular weights were calculated by HPSEC as Mw = 2928 Da, Mn = 2634 Da, and Mw/Mn = 1.11. FT-IR and 1D/2D-NMR spectroscopic analyses confirmed that SCP was an inulin-type fructan with α-D-Glcp-(1 → [1)-β-D-Fruf-(2]17) linkages. Treatment with SCP (200 or 400 mg/kg) alleviated dextran sulfate sodium (DSS)-induced mouse colitis symptoms, including the loss of body weight, increase of disease activity index score, and shortening of colon length. Histopathological and immunofluorescence assessments revealed that SCP could reduce pathological damage to the colon, restore the number of goblet cells, increase the content of glycoproteins in goblet cells and mucins in crypts, and enhance the expression of tight junction proteins ZO-1 and occludin. In addition, metagenomic sequencing revealed that SCP could improve the dysbiosis of gut microbiomes and act on multiple microbial functions. Moreover, SCP treatment increased the content of colonic acetic acid and butanoic acid. Collectively, these results indicated that SCP could alleviate the DSS-induced colitis in mice through regulation of intestinal barrier and gut microbiota.

Fructose-Containing Plant Carbohydrates: Biological Activities and Medical Applications

The review considers the chemical structure specifics and distribution in plants for fructose-containing carbohydrates (fructans). Various biological activities were observed in fructans and associated with their physicochemical features. Fructans affect many physiological and biochemical processes in the human body, improving health and reducing the risk of various disorders. Prebiotic activity is the most important physiological function of fructans. Fructans improve the microflora composition in the colon and intestinal mucosa by increasing the content of useful bacteria and decreasing the content of potentially harmful microorganisms, stimulate the physiological functions of the microflora, and provide for a better state of the intestine and a better health status. By modifying the intestinal microbiota and utilizing certain additional mechanisms, fructans can favorably affect the immune function, decrease the risk of various inflammatory processes, and to reduce the likelihood of tumorigenesis due to exposure to carcinogens. Fructans improve carbohydrate and lipid metabolism by reducing the blood levels of glucose, total cholesterol, low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL) and increasing the blood content of high-density lipoprotein (HLD). Fructans are low in calories, and their use in foods reduces the risk of obesity. Fructans facilitate higher calcium absorption and increase the bone density, thus reducing the risk of osteoporosis. Fructants protect the body from oxidative stress, intestinal infections, and parasitic invasions.

Plant fructans: Recent advances in metabolism, evolution aspects and applications for human health

Fructans, fructose polymers, are one of the three major reserve carbohydrate in plants. The nutritional and therapeutic benefits of natural fructans in plants have attracted increasing interest by consumers and food industry. In the course of evolution, many plants have developed the ability of regulating plant fructans metabolism to produce fructans with different structures and chain lengths, which are strongly correlated with their survival in harsh environments. Exploring these evolution-related genes in fructans biosynthesis and de novo domestication of fructans-rich plants based on genome editing is a viable and promising approach to improve human dietary quality and reduce the risk of chronic disease. These advances will greatly facilitate breeding and production of tailor-made fructans as a healthy food ingredient from wild plants such as huangjing (Polygonatum cyrtonema). The purpose of this review is to broaden our knowledge on plant fructans biosynthesis, evolution and benefits to human health.

Inulin: properties and health benefits

Inulin, a soluble dietary fiber, is widely found in more than 36 000 plant species as a reserve polysaccharide. The primary sources of inulin, include Jerusalem artichoke, chicory, onion, garlic, barley, and dahlia, among which Jerusalem artichoke tubers and chicory roots are often used as raw materials for inulin production in the food industry. It is universally acknowledged that inulin as a prebiotic has an outstanding effect on the regulation of intestinal microbiota via stimulating the growth of beneficial bacteria. In addition, inulin also exhibits excellent health benefits in regulating lipid metabolism, weight loss, lowering blood sugar, inhibiting the expression of inflammatory factors, reducing the risk of colon cancer, enhancing mineral absorption, improving constipation, and relieving depression. In this review paper, we attempt to present an exhaustive overview of the function and health benefits of inulin.

Structural elucidation and hypoglycemic effect of an inulin-type fructan extracted from Stevia rebaudiana roots

Diabetes mellitus (DM) is a common chronic medical condition characterized by hyperglycemia resulting from abnormal insulin functionality, of which type 2 DM (T2DM) is the predominant form. An inulin-type fructan, denoted as SRRP, was obtained from Stevia rebaudiana roots via hot-water extraction and alcoholic precipitation, which was subsequently purified by column chromatography. The extracted SRRP sample had a molecular weight of 5.4 × 10³ Da. Structural analyses indicated that SRRP was composed of 2,1-linked-β-D-fructofuranosyl and α-D-glucopyranosyl residues in a ratio of approximately 29 : 1. In vivo assays revealed that SRRP significantly reduced fasting blood glucose levels, improved insulin resistance, decreased oxidative stress, and regulated lipid metabolism in T2DM mouse models. In addition, SRRP altered the diversity of the gut microbiota and its metabolites in T2DM mice; it increased probiotic bacteria and the concentration of short-chain fatty acids and decreased harmful bacteria. The findings demonstrate the potential of SRRP in the treatment of T2DM.

The Interplay of Dietary Fibers and Intestinal Microbiota Affects Type 2 Diabetes by Generating Short-Chain Fatty Acids

Foods contain dietary fibers which can be classified into soluble and insoluble forms. The nutritional composition of fast foods is considered unhealthy because it negatively affects the production of short-chain fatty acids (SCFAs). Dietary fiber is resistant to digestive enzymes in the gut, which modulates the anaerobic intestinal microbiota (AIM) and fabricates SCFAs. Acetate, butyrate, and propionate are dominant in the gut and are generated via Wood-Ljungdahl and acrylate pathways. In pancreatic dysfunction, the release of insulin/glucagon is impaired, leading to hyperglycemia. SCFAs enhance insulin sensitivity or secretion, beta-cell function, leptin release, mitochondrial function, and intestinal gluconeogenesis in human organs, which positively affects type 2 diabetes (T2D). Research models have shown that SCFAs either enhance the release of peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) from L-cells (entero-endocrine), or promotes the release of leptin hormone in adipose tissues through G-protein receptors GPR-41 and GPR-43. Dietary fiber is a component that influences the production of SCFAs by AIM, which may have beneficial effects on T2D. This review focuses on the effectiveness of dietary fiber in producing SCFAs in the colon by the AIM as well as the health-promoting effects on T2D.

Antibiotics in avian care and husbandry-status and alternative antimicrobials

Undoubtedly, the discovery of antibiotics was one of the greatest milestones in the treatment of human and animal diseases. Due to their over-use mainly as antibiotic growth promoters (AGP) in livestock farming, antimicrobial resistance has been reported with increasing intensity, especially in the last decades. In order to reduce the scale of this phenomenon, initially in the Scandinavian countries and then throughout the entire European Union, a total ban on the use of AGP was introduced, moreover, a significant limitation in the use of these feed additives is now observed almost all over the world. The withdrawal of AGP from widespread use has prompted investigators to search for alternative strategies to maintain and stabilize the composition of the gut microbiota. These strategies include substances that are used in an attempt to stimulate the growth and activity of symbiotic bacteria living in the digestive tract of animals, as well as living microorganisms capable of colonizing the host’s gastrointestinal tract, which can positively affect the composition of the intestinal microbiota by exerting a number of pro-health effects, i.e., prebiotics and probiotics, respectively. In this review we also focused on plants/herbs derived products that are collectively known as phytobiotic.

Prebiotic oligofructose protects against high-fat diet-induced obesity by changing the gut microbiota, intestinal mucus production, glycosylation and secretion

Obesity is a major risk factor for the development of type 2 diabetes and cardiovascular diseases, and gut microbiota plays a key role in influencing the host energy homeostasis. Moreover, obese mice have a different gut microbiota composition, associated with an alteration of the intestinal mucus layer, which represents the interface between the bacteria and the host. We previously demonstrated that prebiotic treatment with oligofructose (FOS) counteracted the effects of diet-induced obesity, together with changes in the gut microbiota composition, but it is not known if the intestinal mucus layer could be involved. In this study, we found that, in addition to preventing high-fat diet (HFD) induced obesity in mice, the treatment with FOS increased the expression of numerous genes involved in mucus production, glycosylation and secretion, the expression of both secreted and transmembrane mucins, and the differentiation and number of goblet cells. These results were associated with significant changes in the gut microbiota composition, with FOS significantly increasing the relative and absolute abundance of the bacterial genera Odoribacter, Akkermansia, two unknown Muribaculaceae and an unknown Ruminococcaceae. Interestingly, all these bacterial genera had a negative association with metabolic parameters and a positive association with markers of the mucus layer. Our study shows that FOS treatment is able to prevent HFD-induced metabolic disorders, at least in part, by acting on all the processes of the mucus production. These data suggest that targeting the mucus and the gut microbiota by using prebiotics could help to prevent or mitigate obesity and related disorders.

Production of fructan synthesis/hydrolysis of endophytic bacteria involved in inulin production in Jerusalem artichoke

Endophytic bacteria refer to bacteria which promote plant growth via direct and indirect mechanisms. Three endophytic bacteria isolated from Jerusalem artichoke exhibited plant growth induction and inulin production. These bacteria had functions of fructan degradation and synthesis from inulinase and levansucrase, respectively. Rossellomorea aquimaris 3.13 and Priestia megaterium 3.5 obtained inulinase/levanase enzyme with inulin and levan as substrates; enzyme production showed the optimum conditions in 1% inulin medium of 35 °C, pH 7.0. Bacillus velezensis 5.18 and Priestia megaterium 3.5 had inulosucrase/levansucrase enzyme with sucrose as a major carbon source; the enzyme had optimum temperature and pH conditions of 30 °C and pH 7.0, respectively. A combination of carbon sources had effect on decreasing enzyme activity; in addition, co-inoculation of bacteria showed a slight difference in enzyme production compared with single inoculation. The inulosucrase/levansucrase was produced earlier in co-culture containing bacteria with inulinase activity. Plant fructan synthesis was involved in 1-SST and 1-FFT, while 1-FEH encoded inulin degradation; these genes were evaluated in Jerusalem artichoke inoculated with the endophytic bacteria to quantify gene expression level using qPCR. All genes expressed in low levels at early stage of growth, responding to all endophytic bacteria. Significantly, Bacillus velezensis 5.18 induced all genes of the plant at 65 days of inoculation; Rossellomorea aquimaris 3.13 induced 1-FFT while Priestia megaterium 3.5 induced 1-SST.

Sheep Milk Symbiotic Ice Cream: Effect of Inulin and Apple Fiber on the Survival of Five Probiotic Bacterial Strains during Simulated In Vitro Digestion Conditions

We conducted a study to determine the survival of bacterial cells under in vitro digestion. For this purpose, ice cream mixes were prepared: control, with 4% inulin, 2.5% inulin and 1.5% apple fiber and 4% apple fiber. Each inoculum (pH = 4.60 ± 0.05), containing 9 log cfu g^-1 bacteria, at 5% (w/w) was added to the ice cream mixes (Lacticaseibacilluscasei 431, Lactobacillus acidophilus LA-5, Lacticaseibacillus paracasei L-26, Lacticaseibacillusrhamnosus, Bifidobacterium animalis ssp. lactis BB-12) and fermentation was carried out to pH 4.60 ± 0.05. The in vitro digestion method simulated the stages of digestion that occur in the mouth, stomach and small intestine under optimal controlled conditions (pH value, time and temperature). At each stage of digestion, the survival rate of probiotic bacteria was determined using the plate-deep method. As expected, in the oral stage, there was no significant reduction in the viability of the probiotic bacteria in any ice cream group compared to their content before digestion. In the stomach stage, Bifidobacterium animalis ssp. lactis BB-12 strain had the highest viable counts (8.48 log cfu g^-1) among the control samples. Furthermore, a 4% addition of inulin to ice cream with Bifidobacterium BB-12 increased gastric juice tolerance and limited strain reduction by only 16.7% compared to the number of bacterial cells before digestion. Regarding ice cream samples with Bifidobacterium BB-12, replacing part of the inulin with apple fiber resulted in increased survival at the stomach stage and a low reduction in the bacterial population of only 15.6% compared to samples before digestion. At the stomach stage, the positive effect of the addition of inulin and apple fiber was also demonstrated for ice cream samples with Lacticaseibacilluscasei 431 (9.47 log cfu g^-1), Lactobacillus acidophilus LA-5 (8.06 log cfu g^-1) and Lacticaseibacillus paracasei L-26 (5.79 log cfu g^-1). This study showed the highest sensitivity to simulated gastric stress for ice cream samples with Lacticaseibacillusrhamnosus (4.54 log cfu g^-1). Our study confirmed that the 4% addition of inulin to ice cream increases the survival rate of L. casei and Bifidobacterium BB-12 in simulated intestinal juice with bile by 0.87 and 2.26 log cfu g^-1, respectively. The highest viable count in the small intestine stage was observed in ice cream with L. acidophilus. The addition of inulin increased the survival of L. rhamnosus by 10.8% and Bifidobacterium BB-12 by about 22% under conditions of simulated in vitro digestion compared to their control samples. The survival rates of L. casei and L. paracasei were also highly affected by the 4% addition of apple fiber, where the increase under gastrointestinal passage conditions was determined to range from 7.86-11.26% compared to their control counterparts. In comparison, the lowest survival rate was found in the control ice cream with L. rhamnosus (47.40%). In our study at the intestinal stage, only five ice cream groups: a sample with 4% inulin and L. acidophilus, a control sample with Bifidobacterium BB12, a sample with 2.5% inulin and 1.5% apple fiber with Bifidobacterium BB12, a control sample with L. rhamnosus, a sample with 4% fiber and L. rhamnosus reported bacterial cell counts below 6 log cfu g^-1 but higher than 5 log cfu g^-1. However, in the remaining ice cream groups, viable counts of bacterial cells ranged from 6.11 to 8.88 log cfu g^-1, ensuring a therapeutic effect. Studies have clearly indicated that sheep milk ice cream could provide a suitable matrix for the delivery of probiotics and prebiotics and contribute to intestinal homeostasis. The obtained results have an applicative character and may play an essential role in developing new functional sheep milk ice cream.

Diversity of bacterial community in Jerusalem artichoke (Helianthus tuberosus L.) during storage is associated with the genotype and carbohydrates

Jerusalem artichoke (JA) is a fructan-accumulating crop that has gained popularity in recent years. The objective of the present study was to determine the dynamics of the JA-microbiome during storage. The microbial population on the surface of the JA tuber was determined by next-generation sequencing of 16S rRNA amplicons. Subsequently, the changes in carbohydrate and degree of polymerization of fructan in tubers during storage were measured. Among different genotypes of JA varieties, intergeneric differences were observed in the diversity and abundance of bacterial communities distributed on the surface of tubers. Additionally, bacterial diversity was significantly higher in storage-tolerant varieties relative to the storage-intolerant varieties. Redundancy analysis (RDA) and the correlation matrix indicated a relationship between changes in the carbohydrates and microbial community succession during tuber storage. The tuber decay rate correlated positively with the degree of polymerization of fructan. Moreover, Dysgonomonas and Acinetobacter in perishable varieties correlated significantly with the decay rate. Therefore, the bacteria associated with the decay rate may be involved in the degradation of the degree of polymerization of fructan. Furthermore, Serratia showed a significant positive correlation with inulin during storage but a negative correlation with the decay rate, suggesting its antagonistic role against pathogenic bacteria on the surface of JA tubers. However, the above correlation was not observed in the storage-tolerant varieties. Functional annotation analysis revealed that storage-tolerant JA varieties maintain tuber quality through enrichment of biocontrol bacteria, including Flavobacterium, Sphingobacterium, and Staphylococcus to resist pathogens. These results suggested that crop genotype and the structural composition of carbohydrates may result in differential selective enrichment effects of microbial communities on the surface of JA varieties. In this study, the relationship between microbial community succession and changes in tuber carbohydrates during JA storage was revealed for the first time through the combination of high-throughput sequencing, high-performance liquid chromatography (HPLC), and high-performance ion-exchange chromatography (HPIC). Overall, the findings of this study are expected to provide new insights into the dynamics of microbial-crop interactions during storage.

Dysregulation of intestinal flora: excess prepackaged soluble fibers damage the mucus layer and induce intestinal inflammation

Soluble fiber is commonly used as a dietary supplement to improve intestinal flora, and many prepackaged products are sold in the market. However, whether these prepared soluble fibers are harmless for intestinal flora has not been systematically evaluated. Here, we assessed the dose-effect of fructooligosaccharides (FOSs) on obesity and intestinal flora using a mouse model. Gavage of low- and medium-dose FOS improved the microbiota in high-fat diet fed mice, but high-dose FOS leads to intestinal flatulence, diarrhea and flora disorders, including an increase in Akkermansia muciniphila and Clostridium difficile, which disrupt the mucus barrier and cause intestinal inflammation. Besides, a high dose of xylooligosaccharide by gavage induces symptoms similar to those of FOS in mice. These adverse effects can be alleviated by regulating intestinal flora. In addition, we experimentally proved that supplementary probiotics protect against the negative effects of FOS in obese mice. Therefore, prepackaged soluble fiber supplements need to be taken with caution, and excessive consumption of soluble fibers results in intestinal dysfunction and even induces intestinal inflammation. Combining probiotics and soluble fiber can be considered if necessary.

Effects of inulin-type fructans supplementation on cardiovascular disease risk factors: a protocol for a systematic review and meta-analysis of controlled trials

INTRODUCTION

This review aims to assess the effects of dietary supplementation with inulin-type fructans (ITF) compared with no supplementation on cardiovascular disease risk factors in adults and assess the quality of trial reporting using the Consolidated Standards of Reporting Trials (CONSORT) and CONSORT for abstract (CONSORT-A) checklists.

METHODS AND ANALYSIS

We will search randomised controlled trials (RCTs) in MEDLINE, EMBASE, CINAHL, Emcare, AMED and the Cochrane Database of Systematic Reviews from inception to 31 March 2022, without any language restrictions. The RCTs need to administer ITF in adults for at least 2 weeks and assess effects on at least one cardiovascular risk factor. We will exclude RCTs that (1) assessed the postprandial effects of ITF; (2) included pregnant or lactating participants; (3) enrolled participants undergoing treatment that might affect the response to ITF. We will assess the study risk of bias (RoB) using V.2 of the Cochrane RoB tool for RCTs (RoB 2) and the certainty of the evidence using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. We will pool data using a random-effects model. We will use the χ² test to compare compliance of CONSORT and CONSORT-A checklists and Poisson regression to identify factors associated with better reporting.

ETHICS AND DISSEMINATION

Ethics approval is not required for secondary analysis of already published data. We will publish the reviews in a peer-review journal.

PROSPERO REGISTRATION NUMBER

CRD42019136745.

Long-term maternal intake of inulin exacerbated the intestinal damage and inflammation of offspring rats in a DSS-induced colitis model

This study aimed to investigate the effects of long-term maternal intake of inulin on intestinal morphology, permeability, inflammation and microbiota of offspring rats treated with dextran sulfate sodium (DSS). Sixteen female adult Sprague-Dawley rats were assigned to two groups receiving the fiber-free diet (FFD) or inulin diet (INU, 5% inulin) for three parities. The offspring weaned rats (third-parity) were fed with the same diet for four weeks until receiving 6% DSS for 7 days; the four groups were as follows: FFD, FFD + DSS, INU and INU + DSS. The results showed that maternal intake of inulin increased the histopathology score and activity of diamine oxidase (DAO) in serum, and the highest histopathology scores and activity of DAO were observed in INU + DSS rats. Maternal intake of inulin increased the activity of myeloperoxidase (MPO), mRNA expressions of inflammatory factors and protein expression of IL-1β in colonic tissues. Likewise, INU + DSS rats had the highest activity of MPO and mRNA expressions of inflammatory factors in colonic tissues. Maternal intake of inulin increased the abundances of Bacteroidetes, Bacteroides and Parasutterella, which were the highest enriched in INU + DSS rats. The level of acetate in the colonic digesta of INU + DSS rats was lower than that in FFD and INU rats. These results indicated that long-term maternal intake of inulin exacerbated the intestinal damage and inflammation of DSS-induced offspring rats, associated with the decreased level of acetate and altered intestinal microbiota.

Physicochemical, Nutritional, Microstructural, Surface and Sensory Properties of a Model High-Protein Bars Intended for Athletes Depending on the Type of Protein and Syrup Used

The main objective of this study was to investigate the possibility of using a combination of vegetable proteins from soybean (SOY), rice (RPC), and pea (PEA) with liquid syrups: tapioca fiber (TF), oligofructose (OF), and maltitol (ML) in the application of high-protein bars to determine the ability of these ingredients to modify the textural, physicochemical, nutritional, surface properties, microstructure, sensory parameters, and technological suitability. Ten variants of the samples were made, including the control sample made of whey protein concentrate (WPC) in combination with glucose syrup (GS). All combinations used had a positive effect on the hardness reduction of the bars after the storage period. Microstructure and the contact angle showed a large influence on the proteins and syrups used on the features of the manufactured products, primarily on the increased hydrophobicity of the surface of samples made of RPC + ML, SOY + OF, and RPC + TF. The combination of proteins and syrups used significantly reduced the sugar content of the product. Water activity (<0.7), dynamic viscosity (<27 mPas∙g/cm3), and sensory analysis (the highest final ratings) showed that bars made of RPC + OF, SOY + OF, and SOY + ML are characterized by a high potential for use in this type of products.

Soluble Dietary Fiber, One of the Most Important Nutrients for the Gut Microbiota

Dietary fiber is a widely recognized nutrient for human health. Previous studies proved that dietary fiber has significant implications for gastrointestinal health by regulating the gut microbiota. Moreover, mechanistic research showed that the physiological functions of different dietary fibers depend to a great extent on their physicochemical characteristics, one of which is solubility. Compared with insoluble dietary fiber, soluble dietary fiber can be easily accessed and metabolized by fiber-degrading microorganisms in the intestine and produce a series of beneficial and functional metabolites. In this review, we outlined the structures, characteristics, and physiological functions of soluble dietary fibers as important nutrients. We particularly focused on the effects of soluble dietary fiber on human health via regulating the gut microbiota and reviewed their effects on dietary and clinical interventions.

Inulin-type prebiotics reduce serum uric acid levels via gut microbiota modulation: a randomized, controlled crossover trial in peritoneal dialysis patients

PURPOSE

Increased levels of uric acid (UA), which is mainly excreted through the kidneys, are independently associated with higher mortality in end-stage renal disease (ESRD) patients. The uricolysis of gut microbiota plays an important role in extrarenal excretion of UA. This study aimed to examine the effect of inulin-type prebiotics (a type of fermentable dietary fiber) on intestinal microbiota modulation and serum UA levels in ESRD patients.

METHODS

Continuous ambulatory peritoneal dialysis (CAPD) patients were recruited to a randomized, double-blind, placebo-controlled crossover trial of 12-week inulin-type prebiotics. Participants were visited before and after treatment with prebiotics or placebo. Serum UA levels, dietary purine intake, serum xanthine oxidase (XO) activity, daily "renal excretion" of UA, and fecal UA degradation capability were measured at each visit. Fecal metagenomic analysis was conducted to assess microbial composition and function.

RESULTS

Sixteen participants (mean age = 37 y; 10 men and 6 women) completed the trial, and 64 specimens were analyzed. The average concentration of serum UA decreased by approximately 10% in the prebiotic intervention group in comparison to the placebo group (p = 0.047) without an increase in daily "renal excretion" of UA via urine and dialysate. There were no significant changes in purine intake or activity of XO. Notably, enhanced fecal UA degradation was observed after prebiotic intervention (p = 0.041), and the ratio of Firmicutes/Bacteroidetes, which was positively associated with fecal UA degradation, increased in the prebiotic period (p = 0.032). Furthermore, prebiotics enriched purine-degrading species in the gut microbiota, including unclassified_o_Clostridiales, Clostridium sp. CAG:7, Clostridium sp. FS41, Clostridium citroniae, Anaerostipes caccae, and Clostridium botulinum.

CONCLUSIONS

Inulin-type prebiotics is a promising therapeutic candidate to reduce serum UA levels in renal failure patients, and this urate-lowering effect could possibly be attributed to intestinal microbial degradation of UA.

TRIAL REGISTRY

This study was registered at the Chinese Clinical Trials Registry ( http://www.chictr.org.cn/ ), registration ID: ChiCTR-INR-17013739, registration date: 6th Dec 2017.

Hepatic Adenosine Triphosphate Reduction Through the Short-Chain Fatty Acids-Peroxisome Proliferator-Activated Receptor γ-Uncoupling Protein 2 Axis Alleviates Immune-Mediated Acute Hepatitis in Inulin-Supplemented Mice

How liver tolerance is disrupted in immune-mediated liver injury is currently unclear. There is also insufficient information available regarding susceptibility, precipitation, escalation, and perpetuation of autoimmune hepatitis. To explore how dietary fiber influences hepatic damage, we applied the concanavalin A (ConA)-induced acute immune-mediated liver injury model in mice fed a diet supplemented with 6.8% inulin, a water-soluble fermentable fiber. Twelve hours after ConA administration, inulin-supplemented diet-fed mice demonstrated significantly alleviated hepatic damage histologically and serologically, with down-regulation of hepatic interferon-γ and tumor necrosis factor and reduced myeloperoxidase (MPO)-producing neutrophil infiltration. Preconditioning with an inulin-supplemented diet for 2 weeks significantly reduced hepatic adenosine triphosphate (ATP) content; suramin, a purinergic P2 receptor antagonist, abolished the protective effect. Of note, the portal plasma derived from mice fed the inulin-supplemented diet significantly alleviated ConA-induced immune-mediated liver injury. Mechanistically, increased portal short-chain fatty acid (SCFA) levels, such as those of acetate and butyrate, by inulin supplementation leads to up-regulation of hepatic γ-type peroxisome proliferator-activated receptor (Pparg) and uncoupling protein 2 (Ucp2), which uncouples mitochondrial ATP synthesis downstream of PPARγ. Pparg down-regulating small interfering RNA cancelled the protective effect of inulin supplementation against MPO-producing neutrophil infiltration and the subsequent immune-mediated liver injury, suggesting that the SCFA-PPARγ-UCP2 axis plays a key role in the protective effect by inulin supplementation. Moreover, significant changes in the gut microbiota, including increased operational taxonomic units in genera Akkermansia and Allobaculum, also characterized the protective effect of the inulin-supplemented diet. Conclusion: There is a possible unraveled etiopathophysiological link between the maintenance of liver tolerance and dietary fiber. The SCFA-PPARγ-UCP2 axis may provide therapeutic targets for immune-mediated liver injury in the future.

The Athlete and Gut Microbiome: Short-chain Fatty Acids as Potential Ergogenic Aids for Exercise and Training

Short-chain fatty acids (SCFAs) are metabolites produced in the gut via microbial fermentation of dietary fibers referred to as microbiota-accessible carbohydrates (MACs). Acetate, propionate, and butyrate have been observed to regulate host dietary nutrient metabolism, energy balance, and local and systemic immune functions. In vitro and in vivo experiments have shown links between the presence of bacteria-derived SCFAs and host health through the blunting of inflammatory processes, as well as purported protection from the development of illness associated with respiratory infections. This bank of evidence suggests that SCFAs could be beneficial to enhance the athlete's immunity, as well as act to improve exercise recovery via anti-inflammatory activity and to provide additional energy substrates for exercise performance. However, the mechanistic basis and applied evidence for these relationships in humans have yet to be fully established. In this narrative review, we explore the existing knowledge of SCFA synthesis and the functional importance of the gut microbiome composition to induce SCFA production. Further, changes in gut microbiota associated with exercise and various dietary MACs are described. Finally, we provide suggestions for future research and practical applications, including how these metabolites could be manipulated through dietary fiber intake to optimize immunity and energy metabolism.

The β-Fructofuranosidase from Rhodotorula dairenensis: Molecular Cloning, Heterologous Expression, and Evaluation of Its Transferase Activity

The β-fructofuranosidase from the yeast Rhodotorula dairenensis (RdINV) produces a mixture of potential prebiotic fructooligosaccharides (FOS) of the levan-, inulin- and neo-FOS series by transfructosylation of sucrose. In this work, the gene responsible for this activity was characterized and its functionality proved in Pichia pastoris. The amino acid sequence of the new protein contained most of the characteristic elements of β-fructofuranosidases included in the family 32 of the glycosyl hydrolases (GH32). The heterologous yeast produced a protein of about 170 kDa, where N-linked and O-linked carbohydrates constituted about 15% and 38% of the total protein mass, respectively. Biochemical and kinetic properties of the heterologous protein were similar to the native enzyme, including its ability to produce prebiotic sugars. The maximum concentration of FOS obtained was 82.2 g/L, of which 6-kestose represented about 59% (w/w) of the total products synthesized. The potential of RdINV to fructosylate 19 hydroxylated compounds was also explored, of which eight sugars and four alditols were modified. The flexibility to recognize diverse fructosyl acceptors makes this protein valuable to produce novel glycosyl-compounds with potential applications in food and pharmaceutical industries.

Probiotic Sheep Milk Ice Cream with Inulin and Apple Fiber

The aim of the study was to assess the effect of the addition of inulin and the replacement of part of the inulin with apple fiber on the physicochemical and organoleptic properties of ice cream. Moreover, the survival of Bifidobacterium animalis ssp. Lactis Bb-12 and Lactobacillus rhamnosus was studied in sheep milk ice cream. There was no effect of the apple fiber and the type of bacteria on the number of bacteria in the probiotics after fermentation. As a result of freezing, in the mixture containing Bifidobacterium animalis ssp. Lactis Bb-12, there was a significant reduction in the bacteria from 0.39 log cfu g^-1 to 0.46 log cfu g^-1. In all of the ice cream on the 21st day of storage, it exceeded 10 log cfu g^-1, which means that the ice cream retained the status of a probiotic product. The Lactobacillus rhamnosus ice cream showed a lower yellow color compared to the Bifidobacterium Bb-12 ice cream. The overrun of the sheep's milk ice cream was within the range of 78.50% to 80.41%. The appearance of the sheep's milk ice cream is influenced significantly by the addition of fiber and the type of bacteria and the interaction between the type of bacteria and the addition of fiber, and storage time and fiber.