Biomedical issues of dietary fiber beta-glucan

Factors Influencing Elderly Consumers' Preferences for Edible Gels: Insights from Slovakia

As dietary needs shift with the growing and aging population, there is a demand for food products that meet nutritional, safety, and tribological requirements while being cost-effective. Seniors must be given significant consideration in new product development. This study examines consumer preferences for arabinogalactan (AG) and beta-glucan (BG) hydrogels with vanilla and coffee-biscuit flavors, using consumer tests (N = 80) and an online survey (N = 852). It focuses on the gels' physical properties, such as texture and viscosity, and their impact on sensory perception. The use of two different gel-forming polysaccharides, each with a unique sensory profile, was observed to affect the sensory properties of the resulting gels and subsequently influence product acceptance. This study analyzed preferences across three age groups: young (18-39 years), middle-aged (40-59 years), and older adults (60+ years). The results showed that seniors preferred AG-based gels. Significant attributes such as the intensity of flavor and bitter taste influenced the overall liking of the gels. Texture also notably impacted preferences. The survey findings revealed statistically significant (p < 0.05) differences in preferences between older adults and younger age groups. Tailoring product development and marketing strategies based on age and sensory preferences could enhance consumer acceptance of edible gels.

Structural and rheological characterization of water-soluble and alkaline-soluble fibers from hulless barley

BACKGROUND

Highland hulless barley has garnered attention as a promising economic product and a potential healthy food ingredient. The present study aimed to comprehensively investigate the molecular structure of extractable fibers obtained from a specific highland hulless barley. Water-soluble fiber (WSF) and alkaline-soluble fiber (ASF) were extracted using enzymatic digestion and an alkaline method, respectively. The purified fibers underwent a thorough investigation for their structural characterization.

RESULTS

The monosaccharide composition revealed that WSF primarily consisted of glucose (91.7%), whereas ASF was composed of arabinose (54.5%) and xylose (45.5%), indicating the presence of an arabinoxylan molecule with an A/X ratio of 1.2. The refined structural information was further confirmed through methylation, 1 H NMR and Fourier-transform infrared spectroscopy analyses. WSF fiber exclusively exhibited α-anomeric patterns, suggesting it was an α-glucan. It has a low molecular weight of 5 kDa, as determined by gel permeation chromatography. Conversely, ASF was identified as a heavily branched arabinoxylan with 41.55% of '→2,3,4)-Xylp-(1→' linkages. ASF and WSF exhibited notable differences in their morphology, water absorption capabilities and rheological properties.

CONCLUSION

Based on these findings, molecular models of WSF and ASF were proposed. The deep characterization of these fiber structures provides valuable insights into their physicochemical and functional properties, thereby unlocking their potential applications in the food industry. © 2023 Society of Chemical Industry.

Exploring β-glucan as a micro-nano system for oral delivery targeted the colon

The critical role of oral colon-specific delivery systems (OCDDS) is important for delivering active agents to the colon and rectum specifically via the oral route. The use of micro/nanostructured OCDDS further improves drug stability, bioavailability, and retention time, leading to enhanced therapeutic effects. However, designing micro/nanoscale OCDDSs is challenging due to pH changes, enzymatic degradation, and systemic absorption and metabolism. Biodegradable natural polysaccharides are a promising solution to these problems, and β-glucan is one of the most promising natural polysaccharides due to its unique structural features, conformational flexibility, and specific processing properties. This review covers the diverse chemical structures of β-glucan, its benefits (biocompatibility, easy modification, and colon-specific degradation), and various β-glucan-based micro/nanosized OCDDSs, as well as their drawbacks. The potential of β-glucan offers exciting new opportunities for colon-specific drug delivery.

Prebiotics: Ignored player in the fight against cancer

BACKGROUND

Prebiotics is a relatively neglected area in cancer research, despite evidence suggesting that it plays a key role in suppressing tumour growth and improving immune function.

RECENT FINDINGS

Including prebiotics in the diet has been shown to strengthen the immune system and can better slow down or prevent the growth of tumours. It has also been strongly indicated in various scientific studies that prebiotics can contribute to the sustenance of a healthy microbiome, which in turn plays an important role in increasing the effectiveness and reducing the side effects of cancer treatments.

CONCLUSION

In the present review article we highlight the mechanisms by which prebiotics like inulin, fructooligosaccharide (FOS), β-glucan, pectin, and xylooligosaccharide (XOS) function. Furthermore, the beneficial effect of incorporating prebiotics during cancer therapy to improvise gut health and prevent/reverse the damage caused to patients due to chemotherapy has also been elaborated.

Effects of Sparassis latifolia neutral polysaccharide on immune activity via TLR4-mediated MyD88-dependent and independent signaling pathways in RAW264.7 macrophages

Background

Sparassis latifolia (S. latifolia) is a precious edible fungus with multiple biological activities. To date, no study has been investigated the underlying molecular mechanism of immunoregulation caused by the neutral polysaccharide of S. latifolia.

Materials and methods

To investigate immunomodulatory mechanism of S. latifolia neutral polysaccharide (SLNP), SLNP was obtained from S. latifolia and its structure, immune receptors and regulation mechanism were studied.

Results

S. latifolia neutral polysaccharide consisted of arabinose, galactose, glucose, xylose, and mannose with a molar ratio of 6:12:63:10:5. SLNP was a pyran polysaccharide with a relative molecular weight of 3.2 × 105 Da. SLNP promoted the proliferation of RAW264.7, which further induced the secretions of nitric oxide, TNF-α, IL-6, and IFN-β, and upregulated the immune receptor TLR4 expression. Moreover, SLNP increased remarkably the levels of TRAF6, IRF3, JNK, ERK, p38, and p38 mRNA and protein mediated by TLR4.

Conclusion

S. latifolia neutral polysaccharide regulated the immune function of RAW264.7 through MyD88-dependent and -independent signaling pathways mediated by TLR4 receptor, which suggests that SLNP is a new immunomodulator.

Ameliorating Effects of β-Glucan on Epigastric Artery Island Flap Ischemia-Reperfusion Injury

BACKGROUND

Ischemia-reperfusion injury has been one of the culprits of tissue injury and flap loss after island flap transpositions. Thus, significant research has been undertaken to study how to prevent or decrease the spread of ischemia-reperfusion injury. Preventive effects of β-glucan on ischemia-reperfusion injury in the kidney, lung, and small intestine have previously been reported. In this study, we present the ameliorating effects of β-glucan on ischemia-reperfusion injury using the epigastric artery island-flap in rats.

MATERIALS AND METHODS

Thirty Wistar-Albino rats were equally divided into three groups: sham, experimental model, and treatment groups. In the sham group, an island flap was elevated and sutured back to the original position without any ischemia. In the experimental model group, the same-sized flap was elevated and sutured back with 8 h of ischemia and consequent 12 h of reperfusion. In the treatment group, 50 mg per kilogram β-glucan was administered to the rats using an orogastric tube for 10 d before the experiment. The same-sized flap is elevated and sutured back to its original position with 8 h of ischemia and 12 h of consequent reperfusion in the treatment group. Tissue biopsies were taken on the first day of the experimental surgery. Tissue neutrophil aggregation and vascular responses were evaluated by histological examinations. Tissue oxidant and antioxidant enzyme levels are evaluated biochemically after tissue homogenization. Topographic follow-up and evaluation of the flaps were maintained, and photographs were taken on the first and seventh day of the experimental surgery.

RESULTS

Topographic flap survival was significantly better in the β-glucan administered group. The neutrophil number, malondialdehyde, and myeloperoxidase levels were significantly lower while glutathione peroxidase and superoxide dismutase levels were significantly higher in the β-glucan administered group respective to the experimental model group.

CONCLUSIONS

Based on the results of our study, we can conclude that β-glucan is protective against ischemia-reperfusion injury. Our study presents the first experimental evidence of such an effect on skin island flaps.

Immunomodulating Effects of Fungal Beta-Glucans: From Traditional Use to Medicine

The importance of a well-functioning and balanced immune system has become more apparent in recent decades. Various elements have however not yet been uncovered as shown, for example, in the uncertainty on immune system responses to COVID-19. Fungal beta-glucans are bioactive molecules with immunomodulating properties. Insights into the effects and function of beta-glucans, which have been used in traditional Chinese medicine for centuries, advances with the help of modern immunological and biotechnological methods. However, it is still unclear into which area beta-glucans fit best: supplements or medicine? This review has highlighted the potential application of fungal beta-glucans in nutrition and medicine, reviewing their formulation, efficacy, safety profile, and immunomodulating effects. The current status of dietary fungal glucans with respect to the European scientific requirements for health claims related to the immune system and defense against pathogens has been reviewed. Comparing the evidence base of the putative health effects of fungal beta-glucan supplements with the published guidance documents by EFSA on substantiating immune stimulation and pathogen defense by food products shows that fungal beta-glucans could play a role in supporting and maintaining health and, thus, can be seen as a good health-promoting substance from food, which could mean that this effect may also be claimed if approved. In addition to these developments related to food uses of beta-glucan-containing supplements, beta-glucans could also hold a novel position in Western medicine as the concept of trained immunity is relatively new and has not been investigated to a large extent. These innovative concepts, together with the emerging success of modern immunological and biotechnological methods, suggest that fungal glucans may play a promising role in both perspectives, and that there are possibilities for traditional medicine to provide an immunological application in both medicine and nutrition.

Dietary Fiber: An Opportunity for a Global Control of Hyperlipidemia

Dietary fiber has a long history in the intervention study of hyperlipidemia. In this review, current understandings of structures, sources, and natures of various kinds of dietary fibers (DFs) were analyzed first. Available evidences for the use of different varieties of DFs in the lipid-lowering action both in vitro and in vivo were subsequently classified, including both soluble ones, such as glucans, pectins, and gums, and insoluble ones, including arabinooxylans and chitosans, in order to draw a primary conclusion of their dose and molecular weight relationship with lipid-lowering effect. Their potential mechanisms, especially the related molecular mechanism of protective action in the treatment and prevention of hyperlipidemia, were summarized at last. Five major mechanisms are believed to be responsible for the antihyperlipidemic benefits of DFs, including low levels of energy, bulking effect, viscosity, binding capacity, and fermentation thus ameliorating the symptoms of hyperlipidemia. From the molecular level, DFs could possibly affect the activities of HMG-CoA reductase, LDL receptors, CYP7A1, and MAPK signaling pathway as well as other lipid metabolism-related target genes. In summary, dietary fibers could be used as alternative supplements to exert certain lipid-lowering effects on humans. However, more clinical evidence is needed to strengthen this proposal and its fully underlying mechanism still requires more investigation.

β-Glucans as a panacea for a healthy heart? Their roles in preventing and treating cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Factors increasing the risks for CVD development are related to obesity, diabetes, high blood cholesterol, high blood pressure and lifestyle. CVD risk factors may be treated with appropriate drugs, but prolonged can use cause undesirable side-effects. Among the natural products used in complementary and alternative medicines, are the β-ᴅ-glucans; biopolymers found in foods (cereals, mushrooms), and can easily be produced by microbial fermentation. Independent of source, β-glucans of the mixed-linked types [(1 → 3)(1 → 6)-β-ᴅ-glucans - fungal, and (1 → 3)(1 → 4)-β-ᴅ-glucans - cereal] have widely been studied because of their biological activities, and have demonstrated cardiovascular protective effects. In this review, we discuss the roles of β-ᴅ-glucans in various pathophysiological conditions that lead to CVDs including obesity, dyslipidemia, hyperglycemia, oxidative stress, hypertension, atherosclerosis and stroke. The β-glucans from all of the sources cited demonstrated potential hypoglycemic, hypocholesterolemic and anti-obesogenicity activities, reduced hypertension and ameliorated the atherosclerosis condition. More recently, β-glucans are recognized as possessing prebiotic properties that modulate the gut microbiome and impact on the health benefits including cardiovascular. Overall, all the studies investigated unequivocally demonstrated the dietary benefits of consuming β-glucans regardless of source, thus constituting a promising panaceutical approach to reduce CVD risk factors.

INVESTIGATION OF THE STRUCTURE OF WATER-SOLUBLE GLUCAN YEAST SACCHAROMYCES CEREVISIAE

It is known that a well-functioning immune system is important for human health. There are many natural and synthetic preparation that are widely used as immunomodulators. One such natural preparat is β-glucan. Beta-glucans are a group of natural polysaccharides. They are recognized as an effective immunocorrector. Their use is advisable both for the prevention of immunodeficiency pathologies and for the complex treatment of many diseases from cardiovascular to oncological. The physiological activity of β-glucan depends on the type and configuration between monosaccharide residues, branching and conformation of macromolecules, solubility in water. One major source of β-glucan is the baker’s yeast Saccharomyces cerevisiae. Much research has been carried out over the years examining cell wall glucans from Saccharomyces cerevisiae. This work is the development devoted to the characterization of water-soluble beta-glucan obtained as a result of controlled degradation with the enzyme Rovabio Excel AP of glucan cell walls of yeast Saccharomyces cerevisiae. In this study conditions were selected which allow to accumulate the maximum water-soluble fractions with a molecular mass of 1–30 kDa presumably as fractions with a high immunomodulatory effect. The results of the paper show that glucan can be isolated from Saccharomyces cerevisiae in very pure form by the method used in this study. Thus structural analysis gives reliable results. The structural characterization of pure product was performed using the common analytical procedures: enzymes hudrolyses and spectral analyses FTIR, NMR spectroscopy. On the basis of the obtained results it was concluded that  investigated glucan is a (1→3)-β-linked glucose polymer with (1→6)-β-linked side chains with sparsely branched. Further work will concern the physiological effect of water-soluble glucan in comparision to the native glucan. The structural requirements for example for an immunomodulation in humans or animals are still under discussion.

β-Glucan Improves Conditions of Chronic Fatigue in Mice by Stimulation of Immunity

Background:

Various natural molecules have been studied for the enhancement of physical endurance. Glucan has been found to improve various stress-related conditions and to improve fatigue and endurance.

Objective:

In our study, we focused on evaluation of glucan effects on some reactions involved in chronic fatigue.

Methods:

We measured phagocytosis of neutrophils, the production of IL-2, IL-4, and IL-10 by spleen cells, and levels of antioxidant glutathione and oxidative stress marker superoxide dismutase in brain. In addition, we measured the effects of glucan on water immersion and on rotarod.

Results:

The glucan supplementation strongly improved the suppressed phagocytosis and changes in cytokine and levels of oxidative stress markers caused by fatigue. In addition, glucan supplementation also increased the motor functioning of tested animals.

Conclusion:

Our data suggested that anti-fatigue properties of glucan are related with its well-established effects as stimulator of immune reactions.

Therapeutic effects of different doses of prebiotic (isolated from Saccharomyces cerevisiae) in comparison to n-3 supplement on glycemic control, lipid profiles and immunological response in diabetic rats

BACKGROUND

The regular intake of fiber generates numerous health benefits. However, the efficacy depends on the duration of consumption and the ingested dose. Studies investigating the optimal dose are of interest to enable the inclusion of fiber in the routine treatment of diabetic patients.

OBJECTIVE

We aimed to evaluate the effects of different doses of β-glucan (BG-isolated from Saccharomyces cerevisiae), in comparison to n-3 supplement, on the inflammatory and metabolic parameters of Wistar rats induced to diabetes by streptozotocin.

METHODS

Forty animals were randomly divided into six groups receiving 0 mg/kg, 10 mg/kg, 20 mg/kg, or 40 mg/kg BG daily for 4 weeks or fish oil derivative [1000 mg/kg of omega-3 fatty acids (n-3)] for the same period. One additional group was composed of healthy controls. Serum metabolic and immunological parameters were evaluated by colorimetric and ELISA assays respectively. Histopathological analysis of the liver, small intestine and pancreas were also conducted. Significant changes due to BG intake were set into regression models with second-degree fit in order to estimate the optimal BG dose to achieve health benefits.

RESULTS

The animals that ingested BG had lower food and water intake (p < 0.05) than the negative control group (0 mg/kg). However, consumption was still elevated in comparison to healthy controls. Blood glucose and serum levels of total cholesterol, LDL-c, and TG (p < 0.05) reduced in comparison to diabetic animals without treatment (better or similar to n-3 group depending on dose), but did not reach normal levels (in comparison to healthy controls). HDL-c was not different (p > 0.05) among all groups. These reductions were already seen with the lowest dose of 10 mg/kg. On average, the serum levels of the hepatic enzymes ALT and AST were 40% and 60% lower in the BG groups in comparison to diabetic animals without treatment (better results than n-3 group). The group receiving 40 mg/kg reached similar values of healthy controls for ALT; whereas the same result occurred from the dose of 10 mg/kg for AST. The ideal dose, estimated from the mean of all metabolic parameters was approximately 30 mg/kg/day. Regarding the immunological profile, TNF-α significantly decreased in the BG groups compared to controls (p < 0.05), reaching better values than n-3 group and similar to healthy controls. No significant differences were found between the groups in IL-1β or IL-10 (p > 0.05). No histological changes were found in the pancreas, liver, or intestine due to treatment among diabetic animals.

CONCLUSIONS

BG significantly reduced blood glucose as well as serum total cholesterol, LDL-c and TG. There was a hepatoprotective effect due to the reduction in ALT and AST and a reduction in TNF-α, indicating a modulation of the immune response. In general, BG effects were better than n-3 supplement (or at least comparable) depending on the dose.

Nutritionally Attenuating the Human Gut Microbiome To Prevent and Manage Metabolic Syndrome

Metabolic syndrome (MSyn) constitutes a litany of pathophysiological conditions, such as central adiposity, hypertension, dyslipidemia, and hyperglycemia. As a result of the epidemic levels of MSyn, several efforts have been made to identify the etiologies of the condition and develop methods by which to reduce its prevalence. The attenuation of the gut microflora ratio of Firmicutes/Bacteroidetes through bioactive compounds found in the Mediterranean diet, dietary polysaccharides, and pre- and probiotics can be used as functional foods to improve derangements in cardiometabolic markers correlated with the development of MSyn. Although more studies are needed to understand the role of manipulating the gut microbiota in health and disease in human models, this review based on current data from epidemiologic studies and clinical trials will serve as a review to elucidate the role nutrition plays in attenuating the gut microbiota in preventing and managing MSyn.

Distinct β-glucan molecules modulates differently the circulating cortisol levels and innate immune responses in matrinxã (Brycon amazonicus)

This study investigated the effects of two β-glucan molecules with different purities and isolated by different biotechnological processes on the immune response of matrinxã (Brycon amazonicus) prior and after challenge with Aeromonas hydrophila. In this sense, we evaluated serum cortisol and plasma glucose levels, the number of leukocytes (lymphocytes, neutrophils and monocytes), as well as the respiratory activity of leukocytes prior to, 6 and 24 h post infection (hpi). During 15 days, fish were fed with diets containing 0.1% of two β-glucans (β-G 1 and β-G 2, with 71 and 62% of purity, respectively) and then submitted to challenge. Results were compared with a positive control group fed with a β-glucan-free diet. A negative control group, also fed with β-glucan-free diet but inoculated with PBS, was established to evaluate the effect of handling during injection. Our results showed that different β-glucans affected differently the biological responses of matrinxã. The βG 2 modulated the cortisol profile prior to and after the acute infection with A. hydrophila, and increased the mobilization and activity of leukocytes. The infection promoted lymphopenia at 6 hpi and both β-glucans increased the circulating lymphocyte population 24 hpi. Moreover, the β-G 2 prevented the infection-induced neutrophilia at 6 and 24 hpi. Finally, the β-G 2 caused a marked increase in the circulating monocytes prior to infection, and a reduction at 6 hpi that was reversed at 24 hpi. In summary, our study demonstrates that β-G 2 was more efficient on the induction of the cell-mediate immunity in matrinxã.

Processing of oat: the impact on oat's cholesterol lowering effect

Epidemiological and interventional studies have clearly demonstrated the beneficial impact of consuming oat and oat-based products on serum cholesterol and other markers of cardiovascular disease. The cholesterol-lowering effect of oat is thought to be associated with the β-glucan it contains. However, not all food products containing β-glucan seem to lead to the same health outcome. Overall, highly processed β-glucan sources (where the oat tissue is highly disrupted) appear to be less effective at reducing serum cholesterol, but the reasons are not well understood. Therefore, the mechanisms involved still need further clarification. The purpose of this paper is to review current evidence of the cholesterol-lowering effect of oat in the context of the structure and complexity of the oat matrix. The possibility of a synergistic action and interaction between the oat constituents promoting hypocholesterolaemia is also discussed. A review of the literature suggested that for a similar dose of β-glucan, (1) liquid oat-based foods seem to give more consistent, but moderate reductions in cholesterol than semi-solid or solid foods where the results are more variable; (2) the quantity of β-glucan and the molecular weight at expected consumption levels (∼3 g day-1) play a role in cholesterol reduction; and (3) unrefined β-glucan-rich oat-based foods (where some of the plant tissue remains intact) often appear more efficient at lowering cholesterol than purified β-glucan added as an ingredient.

Clinical and Physiological Perspectives of β-Glucans: The Past, Present, and Future

β-Glucans are a group of biologically-active fibers or polysaccharides from natural sources with proven medical significance. β-Glucans are known to have antitumor, anti-inflammatory, anti-obesity, anti-allergic, anti-osteoporotic, and immunomodulating activities. β-Glucans are natural bioactive compounds and can be taken orally, as a food supplement, or as part of a daily diet, and are considered safe to use. The medical significance and efficiency of β-glucans are confirmed in vitro, as well as using animal- and human-based clinical studies. However, systematic study on the clinical and physiological significance of β-glucans is scarce. In this review, we not only discuss the clinical and physiological importance of β-glucans, we also compare their biological activities through the existing in vitro and animal-based in vivo studies. This review provides extensive data on the clinical study of β-glucans.

The anti-obesity effect of fermented barley extracts with Lactobacillus plantarum dy-1 and Saccharomyces cerevisiae in diet-induced obese rats

Fermented cereals have significant potential for improving the nutritional quality and health effects of foods and ingredients.

Zymosan and PMA activate the immune responses of Mutz3-derived dendritic cells synergistically

Beta-glucan (β-glucan) including zymosan has been known as a super food because of its multifunctional activities, such as the enhancement of immune responses. To study the functional mechanism of β-glucan in immune stimulation, the effect of zymosan on dendritic cell (DC) was investigated by monitoring the production of TNF-α, a pro-inflammatory cytokine. DC was differentiated from Mutz-3, a human acute myeloid leukemia cell line, by cytokine treatment and characterized. DC-specific cell surface markers were increased during the differentiation. Especially, Dectin-1, a β-glucan receptor, was upregulated during DC differentiation, and mediated zymosan-induced TNF-α production, which was inhibited by silencing of dectin-1. Zymosan exhibited synergistic effect with other immune stimuli such as lipopolysaccharide (LPS) and phorbol 12-myristate 13-acetate (PMA), a well-known PKC activator. Simultaneous treatment of zymosan and PMA enhanced the nuclear translocation of NF-κB subunits, p50 and p65, mediating the increase of TNF-α production. Bay 11-7082, an NF-κB inhibitor, blocked morphological changes and TNF-α production induced by zymosan and/or PMA treatment. Western blot analysis has showed zymosan-Dectin-1 pathway mediated destructive phosphorylation of inhibitor of NF-κB (IκB) kinase α subunit (IKKα) in IKK complexes, while PMA-PKC pathway regulated selective phosphorylation and degradation of IKKβ. Simultaneous phosphorylation of separate IKK subunits by co-treatment of zymosan and PMA resulted in cooperative activation of NF-κB and TNF-α production.

Bacterial β-(1,3)-glucan prevents DSS-induced IBD by restoring the reduced population of regulatory T cells

Bacterial β-(1,3)-glucan has more advantages in terms of cost, yield and efficiency than that derived from mushrooms, plants, yeasts and fungi. We have previously developed a novel and high-yield β-(1,3)-glucan produced by Agrobacterium sp. R259. This study aimed to elucidate the functional mechanism and therapeutic efficacy of bacterial β-(1,3)-glucan in dextran sulfate sodium (DSS)-induced inflammatory bowel disease (IBD).Mice were orally pretreated with bacterial β-(1,3)-glucan at daily doses of 2.5 or 5mg/kg for 2 weeks. After 6 days of DSS treatment, clinical assessment of IBD severity and expression of pro-inflammatory cytokines were evaluated. In vivo cell proliferation was examined by immunohistochemistry using Ki-67 and ER-TR7 antibodies. The frequency of regulatory T cells (Tregs) was analyzed by flow cytometry. Natural killer (NK) activity and IgA level were evaluated using NK cytotoxicity assay and ELISA.The deterioration of body weight gain, colonic architecture, disease score and histological score was recovered in DSS-induced IBD mice when pretreated with bacterial β-(1,3)-glucan. The recruitment of macrophages and the gene expression of proinflammatory cytokines, such as IL-1β, IL-6 and IL-17A/F, were markedly decreased in the colon of β-(1,3)-glucan-pretreated mice. β-(1,3)-Glucan induced the recovery of Tregs in terms of their frequency in DSS-induced IBD mice. Intriguingly, β-(1,3)-glucan reversed the functional defects of NK cells and excessive IgA production in DSS-induced IBD mice.We conclude that bacterial β-(1,3)-glucan prevented the progression of DSS-induced IBD by recovering the reduction of Tregs, functional defect of NK cells and excessive IgA production.

Effects of cationic hydroxyethyl cellulose on dyslipidemia in hamsters

Cationic hydroxyethyl cellulose (cHEC) was supplemented in a high-fat diet to determine if this new soluble fiber had an effect on hypercholesterolemia and dyslipidemia associated with cardiovascular disease using Golden Syrian hamster as an animal model. Supplementation of 3-5% cHEC in a high-fat diet for 4 weeks led to significant weight gain reduction in hamsters. In addition, significant decreases in adipose and liver weights, concentrations of plasma total, VLDL, and LDL cholesterol, and hepatic lipids were shown. No significant improvements in glucose and insulin levels were observed with cHEC; however, a significant increase in plasma adiponectin and a decrease in leptin were observed. As compared with controls, 8% cHEC-fed hamsters had greater levels of mRNA for CYP7A1 (cytochrome P450 7A1; 2-fold of control; P < 0.05), CYP51 (lanosterol 14α-demethylase; 6-fold of control; P < 0.05), and LDLR (LDL receptor; 1.5-fold of control) in the liver. These findings suggest the possibility of the use of cHEC for cholesterol reduction and beneficial effects on the cardiovascular risk factors.

Effects of cationic hydroxyethyl cellulose on glucose metabolism and obesity in a diet-induced obesity mouse model

BACKGROUND

To investigate the effect of a new soluble fiber, namely cationic hydroxyethyl cellulose (cHEC), on weight loss and metabolic disorders associated with obesity using a high-fat diet-induced obese mouse model.

METHODS

Obese male C57BL/6J (B6) mice were fed high-fat (60% kcal) diets supplemented with cHEC for 5 weeks. Body weight, energy intake, mesenteric adipose and liver weights, plasma cholesterol, plasma insulin, glucose, adiponectin, and leptin were assessed to determine the effects of cHEC. Hepatic and fecal lipids were also analyzed to investigate the effect of cHEC on lipid absorption and metabolism.

RESULTS

Supplementation of the high-fat diet with cHEC resulted in significant weight loss in obese mice. In addition, significant decreases were seen in mesenteric adipose and liver weights, as well as concentrations of plasma cholesterol and hepatic lipids. A significant improvement in glucose homeostasis, insulin sensitivity, and leptin concentrations were observed at 4% cHEC. Moreover, increases in fecal excretion of total bile acids, sterols, and fats indicated altered fat absorption when cHEC was supplemented in the diet.

CONCLUSIONS

We have shown in the present study that cHEC reduces body weight, improves insulin sensitivity, and prevents the development of metabolic syndrome. Furthermore, the effects of cHEC on glucose and lipid homeostasis in B6 mice are mediated by improvements in leptin sensitivity resulting from reduced fat absorption.

Cholesterol-lowering effects of oat β-glucan

Elevated total and low-density lipoprotein (LDL) cholesterol levels are considered major risk factors for cardiovascular disease. Oat β-glucan, a soluble dietary fiber that is found in the endosperm cell walls of oats, has generated considerable interest due to its cholesterol-lowering properties. The United States Food and Drug Administration (FDA) approved a health claim for β-glucan soluble fiber from oats for reducing plasma cholesterol levels and risk of heart disease in 1997. Similarly, in 2004 the United Kingdom Joint Health Claims Initiative (JHCI) allowed a cholesterol-lowering health claim for oat β-glucan. The present review aims to investigate if results from more recent studies are consistent with the original conclusions reached by the FDA and JHCI. Results of this analysis show that studies conducted during the past 13 years support the suggestion that intake of oat β-glucan at daily doses of at least 3 g may reduce plasma total and low-density lipoprotein (LDL) cholesterol levels by 5-10% in normocholesterolemic or hypercholesterolemic subjects. Studies described herein have shown that, on average, oat consumption is associated with 5% and 7% reductions in total and LDL cholesterol levels, respectively. Significant scientific agreement continues to support a relationship between oat β-glucan and blood cholesterol levels, with newer data being consistent with earlier conclusions made by the FDA and JHCI.

Dietary fiber improves lipid homeostasis and modulates adipocytokines in hamsters

BACKGROUND

The hypocholesterolemic and hypoglycemic effects of various natural and semisynthetic dietary fibers have been studied for their potential use in the prevention and improvement of metabolic syndrome. Of these dietary fibers, hydroxypropyl methylcellulose (HPMC) has been shown to lower plasma cholesterol and reduce weight gain. However, the underlying mechanisms are not known. In the present study, we examined associations between plasma adipocytokine levels and both lipid metabolism and insulin sensitivity after HPMC intake in golden Syrian hamsters. In addition, endogenous adiponectin from hamster plasma was purified and characterized.

METHODS

Hamsters were treated with HPMC (2% and 4% in a high-fat diet) or 2% or 4% microcrystalline cellulose (MCC; control diet) for 8 weeks. Plasma glucose, insulin, lipids, adiponectin, leptin, and hepatic lipid levels were assessed using standard techniques.

RESULTS

After 8 weeks of feeding, plasma total cholesterol and triglyceride levels in hamsters fed the 4% HPMC-supplemented diet were significantly lower than in hamsters fed the control diet. Moreover, a significant increase in adiponectin levels and a decrease in leptin levels were observed in hamsters fed the 4% HPMC-supplemented diet. Hamster adiponectin was found to be comprised of 244 amino acid residues with an apparent molecular weight of 30 kDa, consistent with the adiponectin reported in other species.

CONCLUSIONS

Reductions in plasma cholesterol and triglyceride levels were correlated with a decrease in plasma leptin and an increase in adiponectin. These results suggest that adipocytokines are regulated by HPMC and may play a pivotal role in the hypocholesterolemic effect.

The effects of barley-derived soluble fiber on serum lipids

PURPOSE

We wanted to determine the association between consumption of barley and changes in plasma lipids in healthy and hypercholesterolemic men and women.

METHODS

A systematic literature search was conducted from the earliest possible date through January 2008. Trials were included in the analysis if they were randomized controlled trials of barley that reported efficacy data on at least 1 lipid endpoint. A DerSimonian and Laird random-effects model was used in calculating the weighted mean difference (WMD) and its 95% confidence interval (CI). Statistical heterogeneity was addressed using the I(2) statistic. Visual inspection of funnel plots, Egger's weighted regression statistics, and the trim and fill method were used to assess for publication bias.

RESULTS

We found 8 trials (n = 391 patients) of 4 to 12 weeks' duration evaluating the lipid-reducing effects of barley. The use of barley significantly lowered total cholesterol (weighted mean difference [WMD], -13.38 mg/dL; 95% CI, -18.46 to -8.31 mg/dL), low-density lipoprotein (LDL) cholesterol (WMD, -10.02 mg/dL; 95% CI, -14.03 to -6.00 mg/dL) and triglycerides (WMD, -11.83 mg/dL; 95% CI, -20.12 to -3.55 mg/dL) but did not appear to significantly alter high-density lipoprotein (HDL) cholesterol (P=.07).

CONCLUSION

Barley-derived beta-glucan appears to beneficially affect total cholesterol, LDL-cholesterol, and triglycerides, but not HDL-cholesterol.

Beta-glucan, immune function, and upper respiratory tract infections in athletes

PURPOSE

This study investigated the effects of oat beta-glucan (BG) supplementation on chronic resting immunity, exercise-induced changes in immune function, and self-reported upper respiratory tract infection (URTI) incidence in human endurance athletes.

METHODS

Trained male cyclists were randomized to BG (N = 19) or placebo (P; N = 17) groups and under double-blind procedures received BG (5.6 g x d(-1)) or P beverage supplements for 2 wk before, during, and 1 d after a 3-d period in which subjects cycled for 3 h x d(-1) at approximately 57% maximal watts. URTI symptoms were monitored during BG supplementation and for 2 wk afterward. Blood samples were collected before and after 2 wk of supplementation (both samples, 8:00 a.m.), immediately after the 3-h exercise bout on day 3 (6:00 p.m.), and 14 h after exercise (8:00 a.m.) and were assayed for natural killer cell activity (NKCA), polymorphonuclear respiratory burst activity (PMN-RBA), phytohemagglutinin-stimulated lymphocyte proliferation (PHA-LP), plasma interleukin 6 (IL-6), IL-10, IL-1 receptor agonist (IL-1ra), and IL-8, and blood leukocyte IL-10, IL-8, and IL-1ra mRNA expression.

RESULTS

Chronic resting levels and exercise-induced changes in NKCA, PMN-RBA, PHA-LP, plasma cytokines, and blood leukocyte cytokine mRNA did not differ significantly between BG and P groups. URTI incidence during the 2-wk postexercise period did not differ significantly between groups.

CONCLUSIONS

An 18-d period of BG versus P ingestion did not alter chronic resting or exercise-induced changes in immune function or URTI incidence in cyclists during the 2-wk period after an intensified exercise.

Pharmacologic management of isolated low high-density lipoprotein syndrome

High-density lipoprotein (HDL) cholesterol is a heterogeneous group of lipoproteins exhibiting a variety of properties like prostacyclin production stimulation, decrease in platelet aggregation, endothelial cell apoptosis inhibition, and low-density lipoprotein oxidation blockade. Epidemiologic studies have shown an inverse relation between HDL cholesterol levels and cardiovascular risk. Low HDL cholesterol is associated with increased risk for myocardial infarction, stroke, sudden death, peripheral artery disease, and postangioplasty restenosis. In contrast, high HDL levels are associated with longevity and protection against atherosclerotic disease development. Given the evolving epidemic of obesity, diabetes mellitus, and metabolic syndrome, the prevalence of low HDL will continue to rise. In the United States, low HDL is present in 35% of men, 15% of women, and approximately 63% of patients with coronary artery disease. Data extracted from the Framingham study highlight that 1-mg increase in HDL levels decreases by 2% to 3% the risk of cardiovascular disease. There is no doubt regarding clinical importance about isolated low HDL, but relatively few clinicians consider a direct therapeutic intervention of this dyslipidemia. In this sense, lifestyle measures should be the first-line strategy to manage low HDL levels. On the other hand, pharmacologic options include niacin, fibrates, and statins. Fibrates appear to reduce risk preferentially in patients with low HDL with metabolic syndrome, whereas statins reduce risk across all levels of HDL. Torcetrapib, a cholesteryl esters transfer protein inhibitor, represented a hope to raise this lipoprotein; however, all clinical trials on this drug had ceased after ILLUMINATE, RADIANCE and ERASE trials had recorded an increase in mortality, rates of myocardial infarction, angina, and heart failure. In the near future, drugs as beta-glucans, Apo-A1 mimetic peptides, and ACAT inhibitors, are the new promises to treat this condition.

Issues surrounding health claims for barley

Government-approved health claims support dietary intervention as a safe and practical approach to improving consumer health and provide industry with regulatory guidelines for food product labels. Claims already allowed in the United States, United Kingdom, Sweden, and The Netherlands for reducing cholesterol through consumption of oat or barley soluble fiber provide a basis for review, but each country may have different criteria for assessing clinical evidence for a physiological effect. For example, the FDA-approved barley health claim was based on a petition that included 39 animal model studies and 11 human clinical trials. Since then, more studies have been published, but with few exceptions, clinical data continue to demonstrate that the consumption of barley products is effective for lowering total and LDL cholesterol. More research is needed to fully understand the mechanism of cholesterol reduction and the role of beta-glucan molecular weight, viscosity, and solubility. In an assessment of the physiological efficacy of a dietary intervention, consideration should also be given to the potential impact of physical and thermal food-processing treatments and genotypic variation in the barley source. New barley cultivars have been generated specifically for food use, possessing increased beta-glucan, desirable starch composition profiles, and improved milling/processing traits. These advances in barley production, coupled with the establishment of a government-regulated health claim for barley beta-glucan, will stimulate new processing opportunities for barley foods and provide consumers with reliable, healthy food choices.

Simultaneous characterization of bile acid, sterols, and determination of acylglycerides in feces from soluble cellulose-fed hamsters using HPLC with evaporative light-scattering detection and APCI-MS

The rapid rise in obesity-related diseases has increased interest in oral and dietary agents that disrupt fat metabolism, resulting in the excretion of dietary lipids in the feces. In this study, a rapid and convenient liquid chromatography method to comprehensively analyze fecal lipids in a single injection was developed. An evaporative light-scattering detector (ELSD) for routine analysis or atmosphere pressure chemical ionization tandem mass spectrometry [(+)APCI-MS/MS] for structural confirmation and peak purity was used. The method was applied to characterize lipid components of feces from hamsters fed high-fat diets with either 5% microcrystalline cellulose or 5% hydroxypropyl methylcellulose (HPMC) fibers, to test the effect of HPMC on lipid metabolism. HPMC is a nonfermentable, soluble cellulose fiber. The fecal lipid components identified using this method includes two secondary bile acids, deoxycholic acid, lithocholic acid, and neutral sterols including cholesterol, coprostanol, stigmastanol, and sitosterol. The profile of fecal lipid components was compared between two groups. It was found that the bile acid excretion was increased 2-fold in HPMC-fed hamsters. More interestingly, diacylglycerides and triacylglycerides were detected in feces from hamsters on HPMC-included high-fat diets. We believe that this is the first report of excretion of acylglycerides following neutral soluble fiber feeding.