Sensorial Evaluation and Physical Chemical Characterization of a Beverage Based on Whey and β-Glucans as a Potential Prevention of Nonalcoholic Steatohepatitis

Whey and B-glucans are functional food ingredients that contribute to the prevention of non-communicable diseases. The objective of the study was to develop a functional beverage based on whey, B-glucans, and blackberry concentrate for the prevention of nonalcoholic steatohepatitis, determining its sensory, physicochemical, and nutritional qualities. The following phases were developed: 1) formulation with 75%, 85%, and 90% whey and 25%, 15%, and 10% blackberry concentrate, with a fixed amount of 0.243 g β-glucans in 100 ml;2) microbiological analysis to ensure the safety of the beverage;3) sensory analysis with untrained panelists to assess the degree of preference (appearance, color, odor, flavor, viscosity, acidity, sweetness), and general acceptance, with a seven-point hedonic scale to rate the level of acceptability;4) physicochemical and nutritional characterization of the beverage with the highest acceptance. An experimental design using complete random blocks was employed. Data analysis was performed with variance (ANDEVA) and mean DUNCAN separation at a 95% confidence level, using SAS®. A correlation study was conducted on acceptance analysis. A nutritional label was developed for the control beverage and the treatment with the highest acceptance. The formulation with 75% whey, 25% blackberry concentrate, and 0.243 g of β-glucan obtained the highest acceptance, with flavor and sweetness being the attributes that contributed to its acceptance. Nutritionally, the beverage with 80 cal, would be considered fortified with fiber (2 g), free of cholesterol, sodium, and saturated fat, according to the Central American Technical Regulation on Nutritional Labeling (Version 67.01.60:10). It is recommended that the effect of this beverage be measured to determine the benefits.

Effect of β-Glucan (Angel Yeast) Compared to a Placebo on Cold and Flu Incidence and Symptoms in an Adult Population—A Double Blind, Randomised Controlled Trial

Background: 1-3, 1-6 β-glucan derived from Baker’s yeast (Saccharomyces cerevisiae) has been widely studied for its immune stimulatory capabilities and safety. Previous studies found β-glucan to have efficacy at reducing incidence of URTIs as well as being a low risk for negative side effects. The current study aimed to examine the effects of yeast β-glucan (Angel Yeast) on cold and flu incidences and symptoms in healthy adults. Methods: Two hundred and thirty-one males and females aged 18 to 65 years old supplemented with either β-glucan or a placebo for 3-months. Participants completed a general health questionnaire every 4 weeks and in addition, if participants experienced any cold or flu symptoms, these were recorded daily (along with severity) until resolved or up to 2 weeks. Results: Supplementation with β-glucan reduced the self-reported severity of sore throats and improved sleep quality compared to the placebo group. Conclusions: Yeast β-glucan supplementation appears to be able to help reduce certain symptoms experienced during a cold or flu episode and is safe and well tolerated.

Giving Food a Fiber Boost: Adding High Beta-Glucan Ingredient from Barley to Everyday Foods

Lack of dietary fiber contributes to many health issues, particularly chronic vascular diseases. Mixed linkage β-1.3 - 1.4 beta-glucan (beta-glucan, in this paper) is a confirmed beneficial ingredient for the human diet through reduction of cholesterol and the glycemic index. Barley contains the highest beta-glucan content of all the grains, and in this study, a percentage of flour from two high beta glucan lines was, each, added to an array of wheat-based food products to measure how it impacted total dietary fiber. Results showed that beta-glucan content was higher in all the products containing the added high beta-glucan flour, along with increased total dietary fiber content. Protein content in the food products is also increased with the higher protein in the barley flours added. Beta-glucan content in the barley-added products increased to 1.2% - 4.0% versus 0.2% - 0.5% in the pure wheat products, while the dietary fibers increased to 3.5% - 24.4% versus 2.1% - 9.1% in pure wheat product controls. This research provided experimental evidence that using a high beta-glucan barley ingredient in food can increase dietary fiber to benefit health.

Effects of β-Glucan Supplementation on Repairing of Phenol-Induced Vaginal Mucosal Epithelium Damage in Rats

Objective: To investigate the effects of different concentrations of β-glucan on the repair of damaged vaginal mucosa, the expression of vascular endothelial growth factor (VEGF), and the inflammatory factor-6 (IL-6) in vaginal tissues. Methods: Thirty-six adult female specific pathogen free (SPF)-grade Wistar rats were randomly divided into 3 phase groups with 12 rats each. Vaginal inflammation rat models were established by injecting phenol gel into the vagina of each rat at a dose of 0.1 ml/100g body weight. After modeling, rats were divided into 4 groups based on different concentrations of the test agent. The control group was injected with 0.5 ml of saline, experimental group A was injected with 0.375 ml saline 0.125 ml β-glucan, experimental group B was injected with 0.25 ml saline 0.25 ml β-glucan, and experimental group C was injected with 0.50 ml β-glucan. The injection sites were selected at the 3 o’clock and 9 o’clock positions of the vagina. Rats were sacrificed at 7-, 14-, and 28-days post-injection, and tissue samples were collected from the injection sites and prepared for histological analysis. New blood vessels and fibroblast numbers in the tissues were observed after Hematoxylin-eosin (HE) staining. The expression levels of VEGF and IL-6 in the tissues were measured using quantificational reverse transcription polymerase chain reaction (qRT-PCR). Results: Histological examination of vaginal tissue specimens at 7-, 14-, and 28-days post-injection showed that on day 7, there were no significant changes in the experimental groups compared to the control group. However, on days 14 and 28, the experimental groups showed more new blood vessels, macrophages, and fibroblasts with increased activity compared to the control group. The expression levels of VEGF in vaginal tissues were elevated on days 14 and 28 in the experimental groups. The comparison of IL-6 levels in vaginal tissues on day 28 showed that serum IL-6 levels returned to normal, and there was no statistically significant difference between the experimental and control groups. Conclusion: In the 3 experimental phases, the increase in VEGF levels in vaginal tissues on day 14 post-injection was more pronounced with higher concentrations of β-glucan, and IL-6 levels returned to normal on day 28. β-Glucan can enhance VEGF levels in damaged vaginal tissues, promote the repair of damaged vaginal tissues, and higher concentrations of β-glucan have a better effect.

β-Glucans: Characterization, Extraction Methods, and Valorization

β-glucans are bioactive compounds with a wide range of biological properties, including anticancer, anti-inflammatory, antioxidant, and immune-modulating properties. Due to their specific physical properties, such as (in)solubility, viscosity, and gelation, β-glucans are increasingly being used in the food, pharmaceutical, and cosmetic industries. The purpose of this review is to provide an overview of the different types of β-glucans, their sources, especially Saccharomyces cerevisiae yeasts, and the methods of extraction, isolation, and purification of β-glucans, with the aim of optimizing these methods for the efficient production process. Moreover, the physico-chemical properties, modifications, current applications and future prospects of the use of β-glucans in food, medicines, cosmetics and other potential value-added products are summarized. The data presented indicate that β-glucans will play an increasingly important role in the sector of special-purpose food products as well as in other current and future areas.

Glucan对氰化钾致肝细胞损伤的保护作用

目的观察氰化钾对肝细胞的损伤作用和Glucan的干预效果及作用机制。方法体外培养的SD乳鼠肝细胞 ,用氰化钾诱导损伤 ,用Glucan预先处理损伤组 ,观察正常对照组、损伤组、Glucan保护组肝细胞的活性 ,并检测培养上清液中的乳酸脱氢酶、超氧化物歧化酶活性和一氧化氮含量的变化。结果氰化钾可使肝细胞中的乳酸脱氢酶漏出增多 ,同时培养液中超氧化物歧化酶活性降低 ,一氧化氮含量减少 ,预先应用Glucan后 ,可部分逆转这些改变。

Glucan在Con A所致免疫性肝损伤中的作用

目的观察Glucan对刀豆蛋白A(ConA)所致小鼠免疫性肝损伤的干预效果及其作用机制。方法ConA尾静脉注射制备小鼠免疫性肝损伤模型,在ConA注射前1h腹腔注射Glucan,观察正常对照组、ConA损伤组、Glucan/ConA组肝损伤的情况,检测血清谷丙转氨酶(ALT)、α肿瘤坏死因子(TNF-α)及组织中一氧化氮(NO)含量的变化,并用DNAladder检测肝细胞凋亡的变化。结果ConA尾静脉注射后,出现明显的肝损伤,血清ALT、TNF-α及组织中NO水平明显升高,DNAladder检测可见明显的梯状条带;预先应用Glucan后,可减轻这些改变。结论Glu-can对ConA所致小鼠免疫性肝损伤有保护作用。

Cultivar and Environmental Effects on p-glucanase Activity in Both Barley Grain and Malt and Its Function in β-glucan Degradation

Eight two-rowed barley cultivars were grown at seven locations in the southern winter-barley zone of China. Mean grainβ-glucanase activity ranged from 39.89 U kg-1 for Suyin2 to 49.75 U kg-1 for Xi-umai3 in 8 cultivars grown at 7 locations, and from 38. 74 U kg-1 in Zhengzhou to 57. 96 U kg-1 in Putian among 7 locations on an average of all cultivars. Correspondingly, mean malt β-glucanase activity of 8 cultivars ranged from 313.33 U kg-1 for ZAU3 to 489. 89 U kg-1 for Daner Barley, and of 7 locations from 330.40 U kg-1 in Yancheng to 418. 24 U kg-1 in Putian. There were significant differences among cultivars and locations in maltβ-glucanase activities. The locations showed much larger variation in maltβ-glucanase activities than cultivars. The reduction of total β-glucan content after malting varied in both cultivars and locations, with a mean of 78.31%. The analysis of correlations showed that maltβ-glucan content was significantly positively and negatively correlated with grain β-glucan content and malt β-glucanase activity, respectively, and malt β-glucanase activity was significantly positively correlated with grain β-glucanase activity.

Isolation and Structural Determination of a Glucan from the Spores of Ganoderma lucidum

A water soluble, (1 -->6)-branched, (1 -->4) linked D-glucan (LB-B1), [alpha](D)(21) = +174.2 degrees (c 0.87, H2O), was obtained from a hot-water extract of the sporoderm-broken spores of Ganoderma lucidun (Fr.) Karst by HPSEC, with 0.001 mol/L sodium hydroxide as the eluant, the molecular weight (Mw) of LB-B1 was estimated to be 9.3 x 10(3). From the results of total hydrolysis, methylation analysis, acetolysis and 1D, 2D-NMR experimentation, it was concluded that LB-B1 was composed of repeating units with the following structure: alpha -D-Glc(p)-(1 -->6)-alpha -D-Glc(p)-(1 -->6)-alpha -D-Glc(p) 1 down arrow 6 (-->4)-alpha -D-Glc(p)-(1 -->4)-alpha -D-Glc(p)-(1 -->4)-alpha -D-Glc(p)-(1 -->4)-alpha -D-Glc(p)-(1 -->4-)-alpha -D-Glc(p)-(1 -->)(n)

A Novel Exo-Glucanase Explored from a <i>Meyerozyma</i>sp. Fungal Strain

Isolating cellulase-secreting microbes followed-by screening their cellulolytic activities has been an essential approach to discover novel and potential cellulases for cellulolytic industrial applications. This study was aimed to explore competitive exoglucanases by screening avicelase activities for 92 fungal strains isolated from environmental airborne-fungal-spore samples. Results showed that an isolated fungal strain numbered 58 exhibited the best avicelase activity of 0.209 U/mL when cultured for six days at pH 5.0 - 5.3 and 25℃ - 27℃, and was lately identified as a yeast strain of Meyerozyma sp. (96% ITS fragment similar with Meyerozyma caribbica, HG970748). Based on amino acid sequences revealed from LC/MS/MS, the target exoglucanase was identical to 1,4-beta-D-glucan cellobiohydrolases and was named Mc-CBHI which had optimal avicelase reaction conditions of pH 5 and 70℃ and could remain fairly stable after 4hr incubation at acid conditions (pH 3 - 5) or wide temperature ranges (30℃ - 80℃). Additionally, the Mc-CBHI (~70 kDa and ~3.6% of crude enzyme) had specific FPase and avicelase activities of 0.179 U/mg and 0.126 U/mg, respectively (which were about 40% - 50% activities of a commercial cellulase Accellerase-1000). These results demonstrated that the newly-found Mc-CBHI could become one of potential exoglucanase resources for related cellulolytic industrial applications.

PREPARATION AND STRUCTURE OF FIVE DERIVATIVES OF β-(1→3)-D-GLUCAN ISOLATED FROM PORIA COCOS SCLEROTIUM

A new solvent of cellulose (1.5 mol/L NaOH/0.5 mol/L urea aqueous solution) was used as one of the homogeneous reaction media of polysaccharides for methylation, hydroxyethylation and hydroxypropylation. A water insoluble β -(1—>3)-D-glucan, sample PCS3- isolated from fresh sclerotium of Poria cocos was sulfated in dimethyl sulfoxide (Me 2 SO), carboxymethylated in NaOH, isopropanol solution, as well as methylated, hydroxyethylated and hydroxypropylated in the new solvent system, respectively, to obtain five water-soluble derivatives coded as S-PCS3- C- PCS3- M-PCS3- HE-PCS3- and HP-PCS3- Their chemical structure and distribution of substitution were characterized by infrared spectroscopy (IR), elementary analysis (EA), 1 H-NMR, 13 C-NMR, 2D-COSY, 2D-TOCSY and 2D- 1 H-detected 1H 13C HMQC spectra. The results reveal that the relative reactivity of hydroxyl groups of the β -(1-?3)-D-glucan is in the order C-6 > C-4 > C-2 on the whole. The substitution of the samples S-PCS3- C-PCS3- and M-PCS3- occurred mainly at C-6 position and secondly at C-4 and C-2 positions, and that of HE-PCS3- occurred at C-6 and C-4 positions and of HP-PCS3- almost completely occurred at C-6 position. The degrees of substitution (DS) obtained from 13 C-NMR range from 0.23 to 1.27. The water solubility of the derivatives is in the order S-PCS3- >C-PCS3- >M-PCS3- >HE-PCS3- >HP-PCS3- This work provides a novel and nonpolluting process for the methylation, hydroxyethylation and hydroxypropylation of β -(1—>3)-D-glucan.

Glucan-immunostimulant,adjuvant,potential drug

β-glucans belong to a group of biologically active natural compounds called biological response modifiers.These substances represent highly conserved structural components of cell walls in fungi,yeast,grain and seaweed.Despite almost 160 years of intensive research,the exact mechanisms of their action remain unsolved.The significant role of glucans in cancer treatment,infection immunity,stress reduction and restoration of damaged bone marrow has already been established.The present review focuses on the various less known but potentially significant roles glucans might play in medicine.In summary,glucan might represent the most important natural immunomodulator.

Effects of dietary yeast β-glucan on nutrient digestibility and serum profiles in pre-ruminant Holstein calves

This study aimed to investigate the effects of dietary supplementation of yeast 13-glucan on the nutrient digestibility and serum profiles in pre-ruminant Holstein calves. Forty-two neonatal Holstein calves （（39.6＋4.2） kg） were randomly allotted to six groups, and each was offered one of the following diets： a basal diet （control） or the basal diet supplemented with 25, 50, 75, 100 or 200 mg of yeast 13-glucan kg-~ feed （dry matter basis）. The basal diet consisted of a milk replacer and a starter feed. The trial lasted for 56 d. Two digestibility trials were conducted from d 14 to 20 and from d 42 to 48. Blood samples were collected on d 0, 14, 28 and 42 for serum profile analyses. On d 56, three calves from each group were slaughtered, and intestinal samples were collected to assess the villous height, crypt depth and mucosal thickness. Although feed intake was not affected by dietary treatment （P〉0.05）, the average daily gain （ADG） and gain-to-feed ratios were higher （P〈0.05） for the calves fed 75 mg of yeast β-glucan kg^-1 feed than those in the other groups. The supplementation of yeast β-glucan at 75 mg kg^-1 feed increased the apparent digestibility of dry matter （DM）, crude protein （CP）, ether extract （EE）, and phosphorus （P） （P〈0.05） and the ratio of intestinal villous height to crypt depth （V/C） （P〈0.05） when compared with the control group. No effects of yeast β-glucan on the serum concentrations of total protein （TP）, albumin （ALB）, serum urea nitrogen （SUN） and glucose （GLU） were observed （P〉0.05）. Compared with the control group, supplementation of yeast β-glucan decreased （P〈0.05） the serum concentrations of triglycerides （TG） and total cholesterol （TC）. The serum concentration of immunoglobulin G （IgG） and immunoglobulin M （IgM） increased quadratically （P〈0.05）, whereas the serum concentration of immunoglobulin A （IgA） was unaffected by dietary treatments （P〉0.05）. The supplementation of yeast β-glucan stimu- lated the enzymatic activity of alkaline phosphatase （ALP） （P〈0.05） compared with the control group. The lysozyme （LYZ） concentration increased quadratically （P〈0.05） with increasing yeast β-glucan levels. The results suggested that dietary supplementation of yeast 13-glucan at 75 mg kg^-1 feed improved nutrient digestibility, enhanced immunity by increasing the immunoglobulin concentration and stimulating ALP, and exerted no adverse effects on metabolism in pre-ruminant calves.

Structural Characterization of Glucan Produced by Lactobacillus sake L-7 from Sausage

A linear glucan was produced by Lactobacillus sake L-7 isolated from homemade sausage. Cultivation of the strain in Man–Rogosa–Sharpe(MRS) medium containing 50 g/L sucrose yielded 5.3 g/L of purified exopolysaccharide(EPS). The EPS was characterized by gas chromatography(GC), Fourier-transform infrared(FT-IR) spectroscopy, high-performance sizeexclusion chromatography(HPSEC), nuclear magnetic resonance(NMR) spectroscopy, and scanning electron microscopy(SEM). The monosaccharide composition of the EPS was glucose, and its molecular weight was 1 × 10~7 Da. The FT-IR and NMR spectra revealed that the L-7 EPS was a linear glucan with α-(1 → 6) glucosidic bonds. SEM images of the dried EPS revealed a hollow tubular structure. The water solubility index and water holding capacity of L-7 EPS were 96 and 272%, respectively. The results of hydrolysis indicated that L-7 EPS was not susceptible to hydrolysis by physiological barriers and can be used as a soluble dietary fiber with health benefits. All these characteristics suggest that L-7 EPS might have potential applications in the food, cosmetic, and pharmaceutical industries.

白色念珠菌细胞壁不溶性β-葡聚糖(β-glucan)升高白细胞机制的病理学研究

目的:观察白色念珠菌细胞壁不溶性β-葡聚糖(CAIBG)升高小鼠末梢血白细胞与其组织病理学改变之间的关系。方法:140只昆明种小鼠分为空白对照组、阴性对照组、阳性对照组及实验组;除空白对照组外均用CTX造模,再用提取的CAIBG注射于实验组小鼠;所有动物均于实验前、造模后的第1、3天及处死前静脉取血计数外周血白细胞总数;动物处死后称重、计算脾脏、胸腺指数并进行组织病理学检查。结果:实验组白细胞总数明显升高,胸腺指数升高不明显,脾脏指数明显增加;实验组脾脏有髓外造血现象,骨髓增生明显活跃。结论:CAIBG可以通过改善小鼠骨髓的造血功能、刺激小鼠髓外造血而升高其外周血白细胞。

SOLUTION PROPERTIES OF ANTITUMOR CARBOXYMETHYLATED DERIVATIVES OF α-(1→3)-D-GLUCAN FROM GANODERMA LUCIDUM

Fractions of a water insoluble α-(1→3)-D-glucan (GL) extracted from Ganoderma lucidum were carboxy-methylated (CM) to obtain water-soluble carboxymethylated derivatives (CM-GL) having a degree of substitution (DS) of0.38～0.51. Weight-average molecular weight M_w and intrinsic viscosity [η] of the samples CM-GL were measured by gelpermeation chromatography combined with laser light scattering (GPC-LLS) and viscometry. The CM-GL exhibits a stifferchain in aqueous solution at 25℃ than the original glucan, The antitumor activities against Ehrlich ascites carcinoma (EAC,5×10~6) of the carboxymethylated derivatives from the α-glucan and curdlan, a β-glucan, are significantly higher than thoseof the original glucans. The effects of the relatively low molecular weight, expanded chains and better water-solubility of theCM-GL on the enhancement of antitumor activity could not be neglected. The chain stiffness decreased speedily withincrease of temperature from 40 to 60℃ or NaOH concentration from 0.1 to 0.4 in the solution, respectively, and the changeof the chain stiffness is reversible.

Administration of Yeast Glucan on Immunity of Offspring in Turbot Scophthalmus maximus: A Trans-Generational Immune-Enhancing Effect

β-glucan has been shown to increase immunity and survival in various juvenile and adult fish both in freshwater and marine aquaculture species as well as in marine fish larvae. However, information about the trans-generational immune-enhancing effects of β-glucan remains rather limited. Here we clearly show that dietary intake of β-glucan enhanced the levels of C3, Bf and lysozyme in the serum of turbot as well as in their eggs released. We also show that yeast glucan induced a significant increase in lysozyme activity in both the serum and eggs. Moreover, the embryos derived from yeast glucan-treated turbot were more resistant to bacterial challenge than control embryos. By contrast, the administration of yeast glucan on female turbots had little influence on the egg development and embryonic development. Collectively, these data indicate that yeast glucan can be safely used to promote the non-specific trans-generational immunity in offspring of turbot.

STRUCTURE,MOLECULAR WEIGHT AND BIOACTIVITIES OF(1→3)-β-D-GLUCANS AND ITS SULFATED DERIVATIVES FROM FOUR KINDS OF LENTINUS EDODES

Lentinan samples,(1→3)-β-D-glucans containing 4.6-15.2 wt% proteins,coded as L-I_1 L-I_2 L-I_3 and L-I_4(L-I)were isolated from four kinds of Lentinus edodes.These glucans were treated with acetone to remove the protein in orderto obtain free protein glucans coded as LNP-I_1,LNP-I_2.LNP-I_3 and LNP-I_4(LNP-I).The free-protein polysaccharideswere sulfated to give derivatives(S-LNP-I)with degree of substitution(DS)from 0.4-0.8.The structural features andweight-average molecular weight(M_w)of the samples were investigated by using infrared spectroscopy,elemental analysis,^(13)C-NMR,size exclusion chromatography combined with laser light scattering(SEC-LLS)and viscometry.The effects ofstructure and conformation of the polysaccharides on antitumor activities were assayed in vivo(Sarcoma 180 solid tumors)and in vitro(Sarcoma 180,HL-60,MCF-7 and Vero tumors).The results indicated that the predominant species of thesamples L-I and LNP-I in 0.2 mol/L NaCl aqueous solution existed as triple-helical chains with high rigidity and in dimethylsulfoxide(DMSO)as single-flexible chains.Interestingly,the antitumor activities of LNP-I are lower than those of the nativeglucans(L-I),whereas their sulfated derivatives have higher inhibition ratio against Sarcoma 180 than LNP-I.The resultsreveal that the binding of protein,sulfated modification and the triple helix conformation are important factors in theenhancement of the antitumor activities of polysaccharides on the whole.

Structural Characterization and Chemical Modification of a Glucan from Spores of Ganoderma lucidum

A linear alpha -D-(1-->3)-glucan, named PSG, was obtained from the spores of Ganoderma lucidum. The synthesis of positively and negatively charged polyelectrolytes from PSG was developed. Amine groups and carboxymethyl groups were introduced through nucleophilic substitution with 3-chloropropylamine or chloroacetic acid, respectively, Reaction conditions were varied to obtain insight into the influence of variables on the degree of substitution.

A Double-Blind, Randomized, Placebo-Controlled Nutritional Study Using an Insoluble Yeast Beta-Glucan to Improve the Immune Defense System

Purpose: In a placebo-controlled, double-blind, randomized clinical trial, the effect of an insoluble yeast beta-glucan preparation on the incidences of common colds and its effect on common cold symptoms were compared to placebo. Methods: 100 healthy participants with recurring infections were randomly assigned to receive either placebo or yeast beta-glucan (Yestimun?;n = 50 each group) over a period of 26 weeks. The subjects had to document each common cold episode in a diary, and rate 6 predefined infections symptoms on a 3-point rating scale during an infection period, resulting in an infection score. The common cold episodes were confirmed by the investigators. Results: A total of 171 common cold episodes were documented. Of these, 76 were experienced by 38 subjects in the beta-glucan group and 96 were experienced by 48 subjects in the placebo group (p = 0.406). The beta-glucan group had significantly more subjects without incidences of common cold than the placebo group (15.6% vs 2.0%;p = 0.019). During the most intense infection season (first 13 weeks of the study), the beta-glucan group had significantly less infections compared to placebo (p = 0.02). Beta-glucan significantly reduced the typical cold symptoms (“sore throat and/or difficulty swallowing”, “hoarseness and/or cough” and “runny nose”) as opposed to placebo. Conclusion: The present study demonstrates a prophylactic effect of yeast beta-glucan on the occurrence of common colds as opposed to placebo. In addition, when these episodes occurred, they were from the beginning less pronounced and subsided faster.