Increased number of CCR4-positive cells in the duodenum of ovalbumin-induced food allergy model Nc/jic mice and antiallergic activity of fructooligosaccharides

Gut microbiota: A target for prebiotics and probiotics in the intervention and therapy of food allergy

Food allergy has become a major public health problem all over the world. Evidence showed that allergic reactions induced by food proteins often lead to disturbances in the gut microbiota (symbiotic bacteria). Gut microbiota plays an important role in maintaining the balance between intestinal immune tolerance and allergic reactions. Dietary intervention has gradually become an important method for the prevention and treatment of allergic diseases, and changing the composition of gut microbiota through oral intake of prebiotics and probiotics may serve as a new effective adjuvant treatment measure for allergic diseases. In this paper, the main mechanism of food allergy based on intestinal immunity was described firstly. Then, the clinical and experimental evidence showed that different prebiotics and probiotics affect food allergy by changing the structure and composition of gut microbiota was summarized. Moreover, the molecular mechanism in which the gut microbiota and their metabolites may directly or indirectly regulate the immune system or intestinal epithelial barrier function to affect food immune tolerance of host were also reviewed to help in the development of food allergy prevention and treatment strategies based on prebiotics and probiotics.

Bioactive Compounds in Food as a Current Therapeutic Approach to Maintain a Healthy Intestinal Epithelium

The intestinal epithelium serves as an effective barrier against the external environment, hampering the passage of potentially harmful substances (such as pathogenic microbes) that could trigger an exacerbated host immune response. The integrity of this barrier is thus essential for the maintenance of proper intestinal homeostasis and efficient protective reactions against chemical and microbial challenges. The principal consequence of intestinal barrier defects is an increase in intestinal permeability, which leads to an increased influx of luminal stressors, such as pathogens, toxins, and allergens, which in turn trigger inflammation and immune response. The fine and fragile balance of intestinal homeostasis can be altered by multiple factors that regulate barrier function, many of which are poorly understood. This review will address the role of gut microbiota as well as food supplements (such as probiotics, prebiotics, and synbiotics) in modulating gut health and regulating intestinal barrier function. In particular, we will focus on three human pathologies: inflammatory bowel disease, irritable bowel syndrome, and food allergy.

Oligosaccharides from Polygonatum Cyrtonema Hua: Structural characterization and treatment of LPS-induced peritonitis in mice

Fructooligosaccharide was isolated from Polygonatum Cyrtonema Hua (PFOS) for the first time. Structure characterized using FT-IR, MALDI-TOF-MS, NMR, AFM, and TEM, indicated that PFOS was graminan-type fructan with a degree of polymerization ranging from 5 to 10. A murine model of lipopolysaccharide (LPS)-induced peritonitis was used to evaluate the in vivo anti-inflammatory and lung protective efficacy of PFOS. The result shown that pretreatment with PFOS (1.0 mg/mL) in peritonitis-induced mice could significantly inhibit the level of pro-inflammatory cytokines (TNF-α, IL-1β) in serum (P < 0.001), increase mice survival rate from 12.5 % to 54 % (P < 0.05), and alleviated lung injury through ameliorating the damage of the pulmonary cellular architecture and reducing inflammatory monocyte accumulation in lung tissue. This effect of oligosaccharides could explain the traditional usage of P. cyrtonema as a tonic medicine for respiratory problems and it could be used as a potential natural ingredient with anti-inflammatory activity.

A Comprehensive Review on Natural Bioactive Compounds and Probiotics as Potential Therapeutics in Food Allergy Treatment

Food allergy is rising at an alarming rate and is a major public health concern. Globally, food allergy affects over 500 million people, often starting in early childhood and increasingly reported in adults. Commercially, only one approved oral immunotherapy-based treatment is currently available and other allergen-based immunotherapeutic are being investigated in clinical studies. As an alternative approach, a substantial amount of research has been conducted on natural compounds and probiotics, focusing on the immune modes of action, and therapeutic uses of such sources to tackle various immune-related diseases. Food allergy is primarily mediated by IgE antibodies and the suppression of allergic symptoms seems to be mostly modulated through a reduction of allergen-specific IgE antibodies, upregulation of blocking IgG, and downregulation of effector cell activation (e.g., mast cells) or expression of T-helper 2 (Th-2) cytokines. A wide variety of investigations conducted in small animal models or cell-based systems have reported on the efficacy of natural bioactive compounds and probiotics as potential anti-allergic therapeutics. However, very few lead compounds, unlike anti-cancer and anti-microbial applications, have been selected for clinical trials in the treatment of food allergies. Natural products or probiotic-based approaches appear to reduce the symptoms and/or target specific pathways independent of the implicated food allergen. This broad range therapeutic approach essentially provides a major advantage as several different types of food allergens can be targeted with one approach and potentially associated with a lower cost of development. This review provides a brief overview of the immune mechanisms underlying food allergy and allergen-specific immunotherapy, followed by a comprehensive collection of current studies conducted to investigate the therapeutic applications of natural compounds and probiotics, including discussions of their mode of action and immunological aspects of their disease-modifying capabilities.

Prebiotics: Mechanisms and Preventive Effects in Allergy

Allergic diseases now affect over 30% of individuals in many communities, particularly young children, underscoring the need for effective prevention strategies in early life. These allergic conditions have been linked to environmental and lifestyle changes driving the dysfunction of three interdependent biological systems: microbiota, epithelial barrier and immune system. While this is multifactorial, dietary changes are of particular interest in the altered establishment and maturation of the microbiome, including the associated profile of metabolites that modulate immune development and barrier function. Prebiotics are non-digestible food ingredients that beneficially influence the health of the host by 1) acting as a fermentable substrate for some specific commensal host bacteria leading to the release of short-chain fatty acids in the gut intestinal tract influencing many molecular and cellular processes; 2) acting directly on several compartments and specifically on different patterns of cells (epithelial and immune cells). Nutrients with prebiotic properties are therefore of central interest in allergy prevention for their potential to promote a more tolerogenic environment through these multiple pathways. Both observational studies and experimental models lend further credence to this hypothesis. In this review, we describe both the mechanisms and the therapeutic evidence from preclinical and clinical studies exploring the role of prebiotics in allergy prevention.

Multiple omics uncovers host-gut microbial mutualism during prebiotic fructooligosaccharide supplementation

Fructooligosaccharide (FOS), a prebiotic well known for its health-promoting properties, can improve the human gut ecosystem most likely through changes in its microbial composition. However, the detailed mechanism(s) of action of FOS in the modulation of the gut ecosystem remain(s) obscure. Traditional methods of profiling microbes and metabolites could barely show any significant features due to the existence of large interindividual differences, but our novel microbe–metabolite correlation approach, combined with faecal immunoglobulin A (IgA) measurements, has revealed that the induction of mucosal IgA by FOS supplementation correlated with the presence of specific bacteria. Furthermore, the metabolic dynamics of butyrate, l-phenylalanine, l-lysine and tyramine were positively correlated with that of these bacteria and IgA production, whereas p-cresol was negatively correlated. Taken together, our focused intraindividual analysis with omics approaches is a powerful strategy for uncovering the gut molecular network and could provide a new vista for understanding the human gut ecosystem.

Plant cell wall polysaccharides as potential resources for the development of novel prebiotics

Prebiotic oligosaccharides, with a degree of polymerization (DP) of mostly less than 10, exhibit diverse biological activities that contribute to human health. Currently available prebiotics are mostly derived from disaccharides and simple polysaccharides found in plants. Subtle differences in the structures of oligosaccharides can cause significant differences in their prebiotic proper-ties. Therefore, alternative substances supplying polysaccharides that have more diverse and complex structures are necessary for the development of novel oligosaccharides that have actions not present in existing prebiotics. In this review, we show that structural polysaccharides found in plant cell walls, such as xylans and pectins, are particularly potential resources supplying broadly diverse polysaccharides to produce new prebiotics.

Perinatal and postweaning exposure to galactooligosaccharides/inulin prebiotics induced biomarkers linked to tolerance mechanism in a mouse model of strong allergic sensitization

Food allergies are increasing, and no treatment exists, thus enhancing interest in prebiotic strategies. This study aimed to analyze the preventive effects of prebiotic feeding during perinatal and postweaning periods in a mouse model of allergy by studying biomarkers related to tolerance (IgG2a, IgA, IFN-γ, TGF-β, and IL-10), to allergy (IgE, IgG1, IL-4, IL-17, symptoms), and to microbiota (propionate and MyD88). Balb/c mice, both dams and their pups, were fed a diet supplemented with (+Prb) or without (-Prb) GOS/inulin prebiotics. Mice were then sensitized with allergens. Regardless of diet, sensitized mice exhibited similar levels of IgE, IgG1, CD-23, IL-4, IL-17, and symptoms. However, in comparison to -Prb-sensitized mice, +Prb-sensitized mice displayed higher concentrations of total IgG2a (6669 ± 1788 vs 3696 ± 1326 fluorescence units, p < 0.005), specific IgA (285 ± 26 vs 156 ± 9 fluorescence units, p < 0.01), IFN-γ (3194 ± 424 vs 1853 ± 434 pg/mL, p < 0.01), IL-10 (777 ± 87 vs 95 ± 136 pg/mL, p < 0.005), TGF-β (4853 ± 1959 vs 243 ± 444 pg/mL, p < 0.01), MyD88 (0.033 ± 0.019 vs 0.009 ± 0.004 relative expression, p < 0.01), and propionate (4.15 ± 0.8 vs 2.9 ± 1.15 μmol, p < 0.05). In a mouse model of allergy, prebiotic exposure during perinatal and postweaning periods induced the highest expression of biomarkers related to tolerance without affecting biomarkers related to allergy.

Yacon (Smallanthus sonchifolius)-derived fructooligosaccharides improves the immune parameters in the mouse

Owing to its high contents of fructooligosaccharides (FOSs), the yacon (Smallanthus sonchifolius) root is used in traditional Andean medicine as a substitute for cane sugar in diabetes and for obesity prevention. This study was designed to test the hypothesis that regular consumption of yacon works to improve the immune system. BALB/c mice were fed with the AIN-93 diet supplemented with 5% commercial FOS or either 3% or 5% yacon FOS for 30 consecutive days. Animals in the control group were fed with nonsupplemented ration. Food intake; weight gain; serum levels of IgA, IgM, and IgG; levels of fecal IgA, production of nitric oxide by peritoneal macrophages, frequencies of T and B lymphocytes in the spleen and peripheral blood, T-cell proliferation, and cytokine production were evaluated in all groups. No significant differences were observed in food intake and weight gain when the experimental and control groups were compared. Also, serum levels of IgA, IgM, and IgG; nitric oxide production in peritoneal macrophages; frequencies of T and B lymphocytes in the spleen and peripheral blood; T-cell proliferation; and production of interleukin (IL)-4, interferon-γ, IL-10, and tumor necrosis factor α did not differ in the different groups. The intake of FOS, however, led to a significant reduction of the proinflammatory cytokine IL-1β in macrophage cultures and elevation of the levels of fecal IgA. Together, these results indicate that the daily consumption of yacon does not exert negative effects on the immune system, helps to preserve an anti-inflammatory state in phagocytic cells, and improves mucosal immunity, possibly preventing the risks associated with autoimmune and metabolic diseases.

Dietary supplementation with fructooligosaccharides attenuates allergic peritonitis in mice

Fructooligosaccharides (FOS) are a prebiotic supplement, which can enhance immunological responses in the host to activate mucosal immunity probably through regulation of gastrointestinal microflora. Nonetheless, the therapeutic potential of prebiotics on allergic pathologies has not been fully elucidated. Therefore, the purpose of this study was to evaluate the preventive and therapeutic effects of dietary supplementation with FOS on a murine model of allergic peritonitis induced by ovalbumin (OVA). Male C3H/HeN mice were intraperitoneally administrated with OVA (1 μg) bi-weekly (Day 0-42, total four times) and were fed a diet containing 0 or 2.5% FOS ad libitum (Day 7-43). At Day 43, mice were killed and several parameters were evaluated. As results, supplementation with FOS alleviated OVA-related peritoneal inflammation characterized by trafficking of polymorphonuclear leukocytes such as eosinophils and neutrophils in the peritoneal cavity. Also, FOS significantly suppressed the protein level of interleukin (IL)-5 and eotaxin in the peritoneal lavage fluid elicited by OVA. In addition, a FOS-supplemented diet significantly reduced the serum allergen specific-IgG(1) level, whereas it significantly increased total IgA levels in the cecal contents as compared with a control diet in the presence of OVA. These results suggest that dietary supplementation with FOS can prevent/ameliorate allergic peritoneal inflammation induced by OVA. The efficacy can at least partially be associated with the regulation of Ig class switching and inhibition of the local expression of IL-5 and eotaxin.

Prebiotic effect of diosgenin, an immunoactive steroidal sapogenin of the Chinese yam

This study investigated the effect of diosgenin, a yam-derived phytochemical, on the growth of enteric lactic acid bacteria (LAB). The in vivo effect of diosgenin on the density of intestinal flora was examined in a murine model of food allergy. Oral administration with diosgenin markedly restored the diminished density of faecal LAB associated with allergic reactions. The direct effect of diosgenin and several structure-related steroidal compounds on the growth of faecal anaerobes isolated from diosgenin-administered mice was also investigated. The presence of diosgenin significantly enhanced the growth of Lactobacillus murinus and Lactobacillus reuteri, but not enterococci. Structure-activity relationship analysis showed that the prebiotic activity of steroidal sapogenins might require structural elements of the C5-C6 double bond and intact E- and F-rings. Collectively, these results indicate that steroidal sapogenins may be a novel class of prebiotics to LAB.

The effects of probiotics supplementation timing on an ovalbumin-sensitized rat model

The aim of the present study was to investigate the effect of oral probiotic bacteria administration at different times on ovalbumin-sensitized rats. Brown-Norway (BN) rats were orally sensitized with ovalbumin for 6 weeks. Probiotics were administered before the initial sensitization (prevention group) or at the end of sensitization period (treatment group). In whole-course intervention group, probiotics were administered 2 weeks before the initial sensitization until 1 week after the end of sensitization period. Ovalbumin-immunoglobulin E (IgE) level, intestinal barrier function and immune responses were analyzed. The positive control group had a significantly increased ovalbumin-IgE level (P<0.05), impaired intestinal barrier function and skewed T-helper 1 (Th1)/Th2 cytokine balance compared with the negative control group. In probiotics prevention and whole-course intervention groups, the infiltration of inflammatory cells (eosinophil and mast cells) in small intestinal mucosa was significantly lower (P<0.05), and the ratio of cytokine interferon-γ/interleukin-4 produced by spleen and mesenteric lymph nodes significantly higher (P<0.05) than in the positive control group, which suggested a cytokine profile inclined to Th1. Both probiotics prevention and prebiotics treatment could attenuate food allergic response. Probiotics prevention tends to modulate the immune response, whereas probiotics treatment has a more obvious effect in enhancing intestinal integrity.

Dietary Supplementation with Fructooligosaccharides Attenuates Airway Inflammation Related to House Dust Mite Allergen in Mice

Fructooligosaccharides (FOS) are prebiotic supplements that can enhance immunological responses in the host to activate mucosal immunity, probably through regulation of gastrointestinal microflora. An area that has not been investigated, however, is the therapeutic potential of prebiotics on allergic airway diseases. The purpose of this study is to evaluate the effects of dietary supplementation with FOS on a murine model of airway inflammation induced by the house dust mite allergen Dermatophagoides farinae (Der f). Male C3H/HeN mice were intratracheally administered with Der f and were fed a diet containing 0% or 2.5% FOS ad libitum. Supplementation with FOS alleviated mite allergen-related airway inflammation characterized by eosinophilic inflammation and goblet cell hyperplasia, which was evidenced by cytological and histological examinations. In addition, the FOS-supplemented diet reduced the serum allergen-specific IgG1 level as compared with a control diet in the presence of the mite allergen. Moreover, FOS tended to suppress the expression of IL-5 and eotaxin in the lungs, which is enhanced by mite allergen. These results suggest that dietary supplementation with FOS can prevent/improve airway inflammation induced by the mite allergen. This effect can be at least partially associated with the inhibition of allergen-specific Ig production and probably with that of IL-5 and eotaxin expression.

Role of intestinal Bifidobacterium pseudolongum in dietary fructo-oligosaccharide inhibition of 2,4-dinitrofluorobenzene-induced contact hypersensitivity in mice

Strategies to manipulate the gut microbiota have been explored for preventing allergy development. We previously showed that dietary supplementation with fructo-oligosaccharide (FOS) reduced 2, 4-dinitrofluorobenzene (DNFB)-induced contact hypersensitivity (CHS) in BALB/c mice. Because the CHS response was negatively correlated with the number of faecal bifidobacteria, particularly Bifidobacterium pseudolongum, the present study aimed to examine whether oral administration of B. pseudolongum affects CHS response. Viable B. pseudolongum was successfully isolated from mouse faeces. Female BALB/c mice were fed a synthetic diet with or without FOS supplementation, and B. pseudolongum (2 x 10(7) cells) was administered daily throughout the experimental period. Two weeks after starting the test diets, mice received DNFB on the ear auricle twice at 7-d intervals. Conventional cultivation and molecular biological analyses based on 16S rRNA gene sequences showed that administration of FOS and B. pseudolongum resulted in higher excretion of viable bifidobacteria, mainly B. pseudolongum. Although dietary FOS reduced the CHS response as demonstrated by ear swelling, B. pseudolongum administration resulted in a reduction in the initial phase only of the CHS response. B. pseudolongum administration increased hapten-specific IgG1, while dietary FOS decreased IgG2a in sera. Administration of FOS and B. pseudolongum decreased interferon-gamma production and increased IL-10 production in cervical lymph node cells restimulated with hapten in vitro. We conclude that B. pseudolongum proliferation in the intestinal tract is partially responsible for the reduction in DNFB-induced CHS response by dietary supplementation with FOS in mice, which may be mediated by the modulation of antigen-induced cytokine production.

Maternal consumption of fructo-oligosaccharide diminishes the severity of skin inflammation in offspring of NC/Nga mice

Strategies to manipulate the gut microbiota in infancy have been considered to prevent the development of allergic diseases later in life. We aimed to elucidate the effects of maternal dietary supplementation with a prebiotic oligosaccharide on gut microbiota and spontaneously developing atopic dermatitis-like skin lesions in the offspring of NC/Nga mice. Female NC/Nga mice were fed diets either with or without fructo-oligosaccharide supplementation during pregnancy and lactation. After weaning, offspring were fed the diets supplemented with or without fructo-oligosaccharide for 11 weeks in an air-uncontrolled conventional room. Changes in gut microbiota were assessed by denaturing gradient gel electrophoresis of the PCR-amplified 16S rRNA gene. Skin lesions were evaluated by a clinical score and scratching behaviour. Serum antibody levels were measured by ELISA, and expression levels of cytokines and chemokines in lesional tissue were evaluated by quantitative RT-PCR. Maternal supplementation with fructo-oligosaccharide modulated the gut microbiota in sucklings. Although maternal supplementation with fructo-oligosaccharide suppressed the increase in clinical skin severity score and scratching behaviour in offspring, dietary fructo-oligosaccharide after weaning was less effective. The diminution of skin lesions was accompanied by lower serum concentrations of total IgG1 and lower expression levels of TNF-alpha in the lesional tissue. These data suggest that maternal consumption of fructo-oligosaccharide diminishes the severity of atopic dermatitis-like skin lesions in the offspring of NC/Nga mice.

Comparison of gut microbiota and allergic reactions in BALB/c mice fed different cultivars of rice

Our preliminary clinical trial showed that consumption of cooked rice of a Japanese common cultivar Yukihikari improved atopic dermatitis associated with a suspected rice allergy, although the underlying mechanisms remain unclear. We hypothesised that the ameliorating effect of Yukihikari on atopic dermatitis is associated with the gut microbiota. BALB/c mice were fed a synthetic diet supplemented with uncooked and polished white rice powder prepared from one of four different cultivars: Yukihikari, rice A (common rice), rice B (brewery rice) and rice C (waxy rice). Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments showed that the composition of faecal microbiota was different between mice fed Yukihikari and those fed rice A. Analysis of the 16S rRNA clone library and species-specific real-time PCR showed that the abundance ofAkkermansia muciniphila, a mucin degrader, tended to be lower in mice fed Yukihikari. The incidence of allergic diarrhoea induced by oral administration of ovalbumin in systemically immunised mice was lower in mice fed Yukihikari, albeit with no difference in serum antibodies specific to ovalbumin. In a separate experiment, serum antibody levels specific to orally administered ovalbumin were lower in mice fed Yukihikari. Additionally, the translocation of horseradish peroxidase in isolated segments of ileum and colon tended to be lower in mice fed Yukihikari, suggesting a reduction in gut permeability in mice fed Yukihikari. These data indicate that changes in the gut microbiota of mice fed Yukihikari could be advantageous in the prevention of food allergy.

Probiotics, prebiotics, and synbiotics

According to the German definition, probiotics are defined viable microorganisms, sufficient amounts of which reach the intestine in an active state and thus exert positive health effects. Numerous probiotic microorganisms (e.g. Lactobacillus rhamnosus GG, L. reuteri, bifidobacteria and certain strains of L. casei or the L. acidophilus-group) are used in probiotic food, particularly fermented milk products, or have been investigated--as well as Escherichia coli strain Nissle 1917, certain enterococci (Enterococcus faecium SF68) and the probiotic yeast Saccharomyces boulardii--with regard to their medicinal use. Among the numerous purported health benefits attributed to probiotic bacteria, the (transient) modulation of the intestinal microflora of the host and the capacity to interact with the immune system directly or mediated by the autochthonous microflora, are basic mechanisms. They are supported by an increasing number of in vitro and in vivo experiments using conventional and molecular biologic methods. In addition to these, a limited number of randomized, well-controlled human intervention trials have been reported. Well-established probiotic effects are: 1. Prevention and/or reduction of duration and complaints of rotavirus-induced or antibiotic-associated diarrhea as well as alleviation of complaints due to lactose intolerance. 2. Reduction of the concentration of cancer-promoting enzymes and/or putrefactive (bacterial) metabolites in the gut. 3. Prevention and alleviation of unspecific and irregular complaints of the gastrointestinal tracts in healthy people. 4. Beneficial effects on microbial aberrancies, inflammation and other complaints in connection with: inflammatory diseases of the gastrointestinal tract, Helicobacter pylori infection or bacterial overgrowth. 5. Normalization of passing stool and stool consistency in subjects suffering from obstipation or an irritable colon. 6. Prevention or alleviation of allergies and atopic diseases in infants. 7. Prevention of respiratory tract infections (common cold, influenza) and other infectious diseases as well as treatment of urogenital infections. Insufficient or at most preliminary evidence exists with respect to cancer prevention, a so-called hypocholesterolemic effect, improvement of the mouth flora and caries prevention or prevention or therapy of ischemic heart diseases or amelioration of autoimmune diseases (e.g. arthritis). A prebiotic is "a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well being and health", whereas synergistic combinations of pro- and prebiotics are called synbiotics. Today, only bifidogenic, non-digestible oligosaccharides (particularly inulin, its hydrolysis product oligofructose, and (trans)galactooligosaccharides), fulfill all the criteria for prebiotic classification. They are dietary fibers with a well-established positive impact on the intestinal microflora. Other health effects of prebiotics (prevention of diarrhoea or obstipation, modulation of the metabolism of the intestinal flora, cancer prevention, positive effects on lipid metabolism, stimulation of mineral adsorption and immunomodulatory properties) are indirect, i.e. mediated by the intestinal microflora, and therefore less-well proven. In the last years, successful attempts have been reported to make infant formula more breast milk-like by the addition of fructo- and (primarily) galactooligosaccharides.

Prebiotics, immune function, infection and inflammation: a review of the evidence

Beta2-1 fructans are carbohydrate molecules with prebiotic properties. Through resistance to digestion in the upper gastrointestinal tract, they reach the colon intact, where they selectively stimulate the growth and/or activity of beneficial members of the gut microbiota. Through this modification of the intestinal microbiota, and by additional mechanisms, beta2-1 fructans may have beneficial effects upon immune function, ability to combat infection, and inflammatory processes and conditions. In this paper, we have collated, summarised and evaluated studies investigating these areas. Twenty-one studies in laboratory animals suggest that some aspects of innate and adaptive immunity of the gut and the systemic immune systems are modified by beta2-1 fructans. In man, two studies in children and nine studies in adults indicate that the adaptive immune system may be modified by beta2-1 fructans. Thirteen studies in animal models of intestinal infections conclude a beneficial effect of beta2-1 fructans. Ten trials involving infants and children have mostly reported benefits on infectious outcomes; in fifteen adult trials, little effect was generally seen, although in specific situations, certain beta2-1 fructans may be beneficial. Ten studies in animal models show benefit of beta2-1 fructans with regard to intestinal inflammation. Human studies report some benefits regarding inflammatory bowel disease (four positive studies) and atopic dermatitis (one positive study), but findings in irritable bowel syndrome are inconsistent. Therefore, overall the results indicate that beta2-1 fructans are able to modulate some aspects of immune function, to improve the host's ability to respond successfully to certain intestinal infections, and to modify some inflammatory conditions.

Recent advances in the understanding of egg allergens: basic, industrial, and clinical perspectives

The emergence of egg allergy has had both industrial and clinical implications. In industrialized countries, egg allergy accounts for one of the most prevalent food hypersensitivities, especially in children. Atopic dermatitis represents the most common clinical manifestation in infancy; however, the range of clinical signs is broad and encompasses life-threatening anaphylaxis. The dominant egg allergens are proteins and are mainly present in the egg white, for example, ovalbumin, ovomucoid, ovotransferrin, and lysozyme. However, egg yolk also displays low-level allergenicity, for example, alpha-livetin. Strict avoidance of the offending food remains the most common recommendation for egg-allergic individuals. Nevertheless, the omnipresence of egg-derived components in prepackaged or prepared foods makes it difficult. Therefore, more efficient preventive approaches are investigated to protect consumers from inadvertent exposure and ensuing adverse reactions. On the one hand, commercial kits have become readily available that allow for the detection of egg contaminants at trace levels. On the other hand, attempts to produce hypoallergenic egg-containing products through food-processing techniques have met with promising results, but the approach is limited due to its potentially undesirable effects on the unique functional and sensory attributes of egg proteins. Therefore, the development of preventive or curative strategies for egg allergy remains strongly warranted. Pilot studies have suggested that oral immunotherapy (IT) with raw or cooked preparations of egg may represent a safe alternative, immediately available to allergic subjects, but remains applicable to only nonanaphylactic patients. Due to the limitations of conventional IT, novel forms of immunotherapy are sought based on information obtained from the molecular characterization of major egg allergens. In the past decade, promising approaches to the treatment and prevention of egg allergy have been explored and include, among others, the production of hypoallergenic recombinant egg proteins, the development of customized peptides, and bacterial-mediated immunotherapy. Nonspecific approaches have also been evaluated, and preliminary trials with the use of probiotic bacteria have yielded encouraging results. The current understanding of egg allergens offers novel approaches toward the making of food products safe for human consumption and the development of efficient immunotherapeutic strategies.

Dietary supplementation with specific oligosaccharide mixtures decreases parameters of allergic asthma in mice

Specific mixtures of prebiotic oligosaccharides showed immune modulatory effects in previous murine vaccination experiments, suggesting a shift towards T-helper 1 (Th1) immunity. These mixtures consisted of short-chain galacto-oligosaccharides (scGOS) and long-chain fructo-oligosaccharides (lcFOS) in a 9:1 ratio (Immunofortis), with or without pectin-derived acidic oligosaccharides (pAOS). To investigate whether these mixtures could suppress Th2-related responses, they were tested in an ovalbumin (OVA)-induced model for experimental allergic asthma in BALB/c mice. Supplementation with two mixtures of scGOS/lcFOS and scGOS/lcFOS/pAOS at approximately 1% (w/w% net oligosaccharides) in the diet, starting two weeks before OVA sensitization and lasting until the end of the experiment, decreased of several parameters of allergic asthma. The OVA-induced airway inflammation and hyperresponsiveness was significantly suppressed by both mixtures. Moreover, OVA-specific IgE titers were decreased by more than 25%, although this effect was not significant. The effects of the oligosaccharide mixture with pAOS appeared to be more pronounced than the effects of the scGOS/lcFOS mixture without pAOS, but a direct comparison between the mixtures was not made. Overall, the results further support the hypothesis that specific mixtures of oligosaccharides modulate the Th1/Th2 balance by enhancing Th1-related and suppressing Th2-related parameters.