Food allergy and probiotics in childhood

Probiotics supplementation during pregnancy or infancy on multiple food allergies and gut microbiota: a systematic review and meta-analysis

CONTEXT

Probiotics show promise in preventing and managing food allergies, but the impact of supplementation during pregnancy or infancy on children's allergies and gut microbiota remains unclear.

OBJECTIVE

This study aimed to assess the effects of maternal or infant probiotic supplementation on food allergy risk and explore the role of gut microbiota.

DATA SOURCES

A systematic search of databases (PubMed, Cochrane Library, Embase, and Medline) identified 37 relevant studies until May 20, 2023.

DATA EXTRACTION

Two independent reviewers extracted data, including probiotics intervention details, gut microbiota analysis, and food allergy information.

DATA ANALYSIS

Probiotics supplementation during pregnancy and infancy reduced the risk of total food allergy (relative risk [RR], 0.79; 95% CI, 0.63-0.99), cow-milk allergy (RR, 0.51; 95% CI, 0.29-0.88), and egg allergy (RR, 0.57; 95% CI, 0.39-0.84). Infancy-only supplementation lowered cow-milk allergy risk (RR, 0.69; 95% CI, 0.49-0.96), while pregnancy-only had no discernible effect. Benefits were observed with over 2 probiotic species, and a daily increase of 1.8 × 109 colony-forming units during pregnancy and infancy correlated with a 4% reduction in food allergy risk. Children with food allergies had distinct gut microbiota profiles, evolving with age.

CONCLUSIONS

Probiotics supplementation during pregnancy and infancy reduces food allergy risk and correlates with age-related changes in gut microbial composition in children.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023425988.

The Role of the Microbiome in Allergy, Asthma, and Occupational Lung Disease

PURPOSE OF REVIEW

The human commensal microbiota is now widely accepted as a key regulator of human health and disease. The composition of the mucosal associated microbiota has been shown to play a critical role in the lung health. The role of the mucosal microbiota in the development and severity of allergy, asthma, and occupational lung disease is only beginning to take shape. However, advances in our understanding of these links have tremendous potential to led to new clinical interventions to reduce allergy, asthma, and occupational lung disease morbidity.

RECENT FINDINGS

We review recent work describing the relationship and role of the commensal microbiota in the development of allergy, asthma, and occupational lung disease. Our review primarily focuses on occupational exposures and the effects of the microbiome, both in composition and function. Data generated from these studies may lead to the development of interventions targeted at establishing and maintaining a healthy microbiota. We also highlight the role of environmental exposures and the effects on the commensal microbial community and their potential association with occupational lung disease. This review explores the current research describing the role of the human microbiome in the regulation of pulmonary health and disease, with a specific focus on the role of the mucosal microbiota in the development of allergy, asthma, and occupational lung disease.

Influence of Diet on the Effect of the Probiotic Lactobacillus paracasei in Rats Suffering From Allergic Asthma

Mounting evidence suggests that probiotics can be used to treat allergic asthma by modulating the gut microbiota, and that the effects of probiotics may be influenced by environmental factors such as diet. We conducted a rat model with allergic asthma (AA) modulated by Lactobacillus paracasei, feeding up with high-fat or high-fiber diets based on collecting data from 85 questionnaires. The systemic proinflammatory cytokines were detected by ELISA and the overall structure of fecal microbiota was analyzed via 16S rRNA gene sequencing. The results showed consumption of a high-fiber diet alleviated the allergic symptoms and airway inflammation, and led to improving the imbalance of T-helper type 1 (Th1)/Th2 cells with increased expression of interferon-γ and decreased expression of interleukin-4. Whereas, the high-fat diet had deteriorating implications and skewed the inflammatory perturbation. Furthermore, abundances of phylum Bacteroidetes, families Muribaculaceae, Tannerellaceae, Prevotellaceae, Enterococcaceae, genera Allobaculum, Parabacteroides, and Enterococcus were enriched in L. paracasei-modulating rats fed with high-fiber diet. Firmicutes and Proteobacteria, families Lachnospiraceae, Ruminococcaceae and Desulfovibrionaceae, genera Blautia, unidentified_Ruminococcaceae, unidentified_Clostridiales and Oscillibacter were in relatively high abundance in the rats administered high-fat diet. Association between changed microbiota and inflammatory cytokines was also conferred. These data indicated that the efficacy of L. paracasei in allergic asthma was influenced by different dietary patterns. Hence, diet is important for probiotic therapy when managing allergic asthma.

Probiotics as a Possible Strategy for the Prevention and Treatment of Allergies. A Narrative Review

Allergies are an increasing global public health concern, especially for children and people living in urban environments. Allergies impair the quality of life of those who suffer from them, and for this reason, alternatives for the treatment of allergic diseases or reduction in their symptoms are being sought. The main objective of this study was to compile the studies carried out on probiotics as a possible therapy for allergies. The most studied allergies on which probiotics have been shown to have a beneficial effect are rhinitis, asthma, and atopic dermatitis. Most studies have studied the administration of Lactobacillus and Bifidobacterium spp. in children and have shown beneficial effects, such as a reduction in hyperreactivity and inflammation caused by allergens and a decrease in cytokine release, among other beneficial effects. In the case of children, no clear beneficial effects were found in several studies, and the potential risk from the use of some opportunistic bacteria, such as probiotics, seems controversial. In the studies that reported beneficial results, these effects were found to make allergy symptoms less aggressive, thus reducing morbidity in allergy sufferers. The different effects of the same probiotic bacteria on different patients seem to reinforce the idea that the efficacy of probiotics is dependent on the microbial species or strain, its derived metabolites and byproducts, and the gut microbiota eubiosis of the patient. This study is relevant in the context of allergic diseases, as it provides a broader understanding of new alternatives for the treatment of allergies, both in children, who are the main sufferers, and adults, showing that probiotics, in some cases, reduce the symptoms and severity of such diseases.

In vitro assessment of Enterococcus faecalis MTC 1032 as the potential probiotic in food supplements

Probiotics become important bacteria in our daily life due to their benefit on human health. In this study, a subset of bacterial strains from children was isolated and evaluated for beneficial probiotic traits such as antimicrobial activity, bile and acid tolerance, and pathogenic cell adherence inhibition. The strain with the best antimicrobial activity was selected for further characterization on the basis of morphological, biochemical characteristics and gene sequence. This strain was Gram-positive, oxidase and catalase-negative, and it produced acids by fermenting sugar and starch as carbon sources. Additionally, it could only hydrolyze bile-esculin, but not red blood cells. The 16S rDNA gene sequence revealed that this strain was Enterococcus faecalis. Interestingly, this strain effectively inhibited a variety of pathogens by acid and bacteriocin production and was bile-tolerant, able to survive under acidic condition. In the safety assessments, E. faecalis MTC 1032 could adhere to host epithelial cells and evidently inhibited pathogenic cell adhesion as demonstrated by cell reduction over time of E. coli ATCC 25922 and S. typhimurium ATCC 13311 on Caco-2 cell line. In summary, it was clearly represented that E. faecalis MTC 1032 provided suitable properties and could be a candidate as a probiotic strain in food supplements.

Effects of Bifidobacterium supplementation on intestinal microbiota composition and the immune response in healthy infants

BACKGROUND

Intestinal microbiotas are thought to be the most important source of maturational stimuli to the development of the immune system. However, few studies have focused on the development of T helper (Th) 1 immune response and antibody response to vaccinations in healthy infants, especially in a large cohort. Through this randomized, double-blind control trial, we investigated the effects of Bifidobacterium longum BB536 (BB536) supplementation on intestinal microbiota composition and the immune response in term infants.

METHODS

In total, 300 healthy newborns were recruited, randomized and fed formula either supplemented with BB536 or with no supplementation. Stool samples were analyzed at months 2, 4 and 11. The representative cytokine for Th1 [interferon-γ (IFN-γ)] and Th2 [interleukin-4 (IL-4)] secretion cells were measured using enzyme-linked immunospot assay at 4 and 7 months of age. The antibody response to vaccines was measured at months 7 and 11.

RESULTS

A total of 264 infants completed the study. The amount of bifidobacteria and the bifidobacteria/ Enterobacteriaceae ratio (B/E) were significantly higher in the BB536 supplementation group at months 2 and 4. The number of IFN-γ secretion cells and the ratio of IFN-γ/IL-4 secretion cells were increased in the BB536 supplementation group at 7 months. Moreover, the higher value of B/E in the early stages seems to be related to the increased Th1 response. No difference was observed between groups in the antibody response after vaccination.

CONCLUSION

BB536 has positive effects on establishing a healthy intestinal microbiota early in life, and it also plays an important role in improving the Th1 immune response.

Legumes steam allergy in childhood: Update of the reported cases

In the past few decades, the prevalence of allergic diseases has deeply increased, with a key role played by food allergies. Legumes seem to play a major role towards the overall increase in the scenario of food allergy, since they are an appreciated source, consumed worldwide, due to their high protein content, variable amounts of lipids and for the presence of vitamins. In literature there are numerous descriptions of adverse reactions after ingestion of uncooked and cooked legumes. Nevertheless, cases of allergic reactions induced by inhaling vapours from cooking legumes have rarely been described. Herein the authors report an update of the literature data on allergic reactions caused by legume steam inhalation, underlying the possible pathogenic mechanism of these atopic events and the knowledge of literature data in paediatric age. The importance of this review is the focus on the clinical aspects concerning legume vapour allergy, referring to literature data in childhood.

Recent advances on diagnosis and management of childhood asthma and food allergies

The epidemic of childhood allergic disorders has been associated to the decline of infectious disease. However, exposure to many triggers (airborne viruses, tobacco smoke, pollution, indoor allergens, etc.) contribute to the disease. Breast feeding practices, nutrition, dietary and obesity also play a multifaceted role in shaping the observed worldwide trends of childhood allergies. Guidelines for treatment are available, but their implementation is suboptimal. Then developed countries are slowing learning integrating the development of suitable guidelines with implementation plans. Awareness, psychosocial and family factors strongly influence asthma and food allergy control. Moreover, monitoring tools are necessary to facilitate self-management. By taking into consideration these and many other pragmatic aspects, national public health programs to control the allergic epidemic have been successful in reducing its impact and trace the need for future research in the area.

Probiotics and food allergy

The exact prevalence of food allergy in the general population is unknown, but almost 12% of pediatric population refers a suspicion of food allergy. IgE mediated reactions to food are actually the best-characterized types of allergy, and they might be particularly harmful especially in children. According to the "hygiene hypothesis" low or no exposure to exogenous antigens in early life may increase the risk of allergic diseases by both delaying the development of the immune tolerance and limiting the Th2/Th1 switch. The critical role of intestinal microbiota in the development of immune tolerance improved recently the interest on probiotics, prebiotics, antioxidants, polyunsaturated fatty acid, folate and vitamins, which seem to have positive effects on the immune functions.Probiotics consist in bacteria or yeast, able to re-colonize and restore microflora symbiosis in intestinal tract. One of the most important characteristics of probiotics is their safety for human health. Thanks to their ability to adhere to intestinal epithelial cells and to modulate and stabilize the composition of gut microflora, probiotics bacteria may play an important role in the regulation of intestinal and systemic immunity. They actually seem capable of restoring the intestinal microbic equilibrium and modulating the activation of immune cells.Several studies have been recently conducted on the role of probiotics in preventing and/or treating allergic disorders, but the results are often quite contradictory, probably because of the heterogeneity of strains, the duration of therapy and the doses administered to patients. Therefore, new studies are needed in order to clarify the functions and the utility of probiotics in food allergies and ion other types of allergic disorders.

Urticaria and anaphylaxis in a child after inhalation of lentil vapours: a case report and literature review

BACKGROUND

Among legumes, lentils seem to be the most common legume implicated in pediatric allergic reactions in the Mediterranean area and India, and usually they start early in life, below 4 years of age.

CASE REPORT

A 22 -month-old child was admitted to our Pediatric Department for anaphylaxis and urticaria. At the age of 9 months she presented a first episode of angioedema and laryngeal obstruction, due to a second assumption of lentils in her diet. At admission we performed routine analyses that were all in the normal range, except for the dosage of specific IgE, that revealed a positive result for lentils. Prick tests too were positive for lentils, while they were all negative for other main food allergens. The child also performed a prick by prick that gave the same positive result (with a wheal of 8 mm of diameter). The child had not previously eaten lentils and other legumes, but her pathological anamnesis highlighted that the allergic reaction appeared soon after the inhalation of cooking lentil vapours when the child entered the kitchen Therefore a diagnosis of lentils vapours allergy was made.

CONCLUSIONS

Our case shows the peculiarity of a very early onset. In literature there are no data on episodes of anaphylaxis in so young children, considering that our child was already on lentils exclusion diet. Therefore a diet of exclusion does not absolutely preserve patients from allergic reactions, that can develop also after their cooking steams inhalation.

Evaluation of Helicobacter Pylori eradication in pediatric patients by triple therapy plus lactoferrin and probiotics compared to triple therapy alone

Background

To evaluate whether the addition of a probiotic could improve Helicobacter pylori (H.P.) eradication rates and reduce the side effects of treatment in children.

Methods

Between July 2008 and July 2011 all patients with a clinical, laboratory and endoscopic diagnosis of H.P. positive gastritis referred to our Unit were included in the study. Patients suffering from allergy to any of drugs used in the study, with previous attempts to eradicate H.P. and those who received antibiotics, PPIs or probiotics within 4 weeks were excluded from the present study. Patients were randomized into two therapy regimens (group A and B): both groups received standard triple treatment (omeprazole, amoxicillin and clarithromycin) while only group B patients were also given a probiotic (Probinul - Cadigroup). Patients compliance was evaluated at the end of the treatment. Successful eradication was defined as a negative 13 C-urea breath test (C13-ubt) result four weeks after therapy discontinuation.

Results

A total of 68 histopathologically proven H.P.-infection children (32 male and 36 females) were included in the study. All of the patients in both groups used more than 90% of the therapies and no patients were lost at follow up. All side effects were selflimiting and disappeared once the therapy was terminated. Epigastric pain was observed in 6 (17.6%) group A vs 2 (5.8%) group B patients (P<0.05), nausea in 3 (8.8%) group A vs 1 (2.9%) group B patients (P<0.05); vomiting and diarrhea were observed in 2(5.8%) and 8 (23.5%) group A patients, respectively and never in group B (P<0.05). There was no significant difference between the two groups in terms of constipation (5.8% in group A and B). Four weeks after the completion of therapy, 56/68 patients (82.3%) tested negative for H.P. on C13-ubt. H.P. was eradicated in 26 patients (76.4%) in group A and in 30 patients (88.2%) in group B. There was no significantly difference in the rate of H.P. eradication between group A and group B (p=0.1), although the success rate for H.P. eradication was higher in group B than in group A.

Conclusion

The addition of a probiotic formula to triple therapy significantly decreased the frequency of epigastric pain, nausea, vomiting and diarrhea.

A retrospective chart review to identify perinatal factors associated with food allergies

Background

Gut flora are important immunomodulators that may be disrupted in individuals with atopic conditions. Probiotic bacteria have been suggested as therapeutic modalities to mitigate or prevent food allergic manifestations. We wished to investigate whether perinatal factors known to disrupt gut flora increase the risk of IgE-mediated food allergies.

Methods

Birth records obtained from 192 healthy children and 99 children diagnosed with food allergies were reviewed retrospectively. Data pertaining to delivery method, perinatal antibiotic exposure, neonatal nursery environment, and maternal variables were recorded. Logistic regression analysis was used to assess the association between variables of interest and subsequent food allergy diagnosis.

Results

Retrospective investigation did not find perinatal antibiotics, NICU admission, or cesarean section to be associated with increased risk of food allergy diagnosis. However, associations between food allergy diagnosis and male gender (66 vs. 33; p=0.02) were apparent in this cohort. Additionally, increasing maternal age at delivery was significantly associated with food allergy diagnosis during childhood (OR, 1.05; 95% CI, 1.017 to 1.105; p=0.005).

Conclusions

Gut flora are potent immunomodulators, but their overall contribution to immune maturation remains to be elucidated. Additional understanding of the interplay between immunologic, genetic, and environmental factors underlying food allergy development need to be clarified before probiotic therapeutic interventions can routinely be recommended for prevention or mitigation of food allergies. Such interventions may be well-suited in male infants and in infants born to older mothers.

Probiotics in childhood: allergic illness and respiratory infections

Over the last decade, there has been a growing interest in the use of probiotics for allergic diseases. In the last years, some studies showed a significant improvement for atopic eczema by the administration of probiotics during pregnancy and postnatally. About food allergy, probiotics administration seems to be effective in the management of food allergy symptoms but has no effect on the prevention of sensitization. In the international literature, there are few studies that evaluated the probiotic effect on allergic rhinitis, and authors reported that probiotics might have a beneficial effect in AR by reducing symptom severity and medication use. Another major potential benefit of probiotics has been suggested in patients with asthma. On this topic, several studies have been carried out using different probiotics and the results have not been univocal. Indeed, probiotics seems to be able to offer protection about common cold and respiratory infections in healthy and hospitalized children.

Probiotics reduce gut microbial translocation and improve adult atopic dermatitis

BACKGROUND

It has been suggested that probiotics modulate atopic dermatitis (AD) progression, but no data are actually available on their mechanisms of action and on their ability to act as immunomodulators in this pathology.

OBJECTIVE

The aim of this randomized double-blinded active treatment versus placebo study was to evaluate clinical efficacy of an intake of a combination of 2 probiotics (Lactobacillus salivarius LS01 and Bifidobacterium breve BR03) for the treatment of adult AD patients.

METHODS

Forty-eight patients were enrolled in the study (randomization ratio 2:1) and treated with a combination (LS01 and BR03) or placebo (maltodextrin) for 12 weeks. Clinical efficacy was assessed from baseline by changes in the SCORAD index and DLQ index improvement. Analysis on the gut permeability barrier, immunologic parameters, and changes in fecal microbiota and recovery of probiotics were performed at baseline, at the end of therapy, and 2 months later.

RESULTS

Patients receiving probiotics showed a significant improvement in clinical parameters (SCORAD, P<0.0001 and DLQ index, P=0.021) from baseline. The probiotics reduced microbial translocation (P=0.050), immune activation (P<0.001), improved T-helper cell (Th)17/regulatory T cell (Treg) (P=0.029) and Th1/Th2 (P=0.028) ratios. None of these changes were observed in the placebo group.

CONCLUSIONS

Our results suggest that this specific mixture of probiotics (LS01 and BR03 strains) may induce beneficial effects for clinical and immunologic alterations in adult AD. This combination could be considered as adjuvant therapy for the treatment of AD in adult patients.

Diet-induced dysbiosis of the intestinal microbiota and the effects on immunity and disease

The gastrointestinal (GI) microbiota is the collection of microbes which reside in the GI tract and represents the largest source of non-self antigens in the human body. The GI tract functions as a major immunological organ as it must maintain tolerance to commensal and dietary antigens while remaining responsive to pathogenic stimuli. If this balance is disrupted, inappropriate inflammatory processes can result, leading to host cell damage and/or autoimmunity. Evidence suggests that the composition of the intestinal microbiota can influence susceptibility to chronic disease of the intestinal tract including ulcerative colitis, Crohn’s disease, celiac disease and irritable bowel syndrome, as well as more systemic diseases such as obesity, type 1 diabetes and type 2 diabetes. Interestingly, a considerable shift in diet has coincided with increased incidence of many of these inflammatory diseases. It was originally believed that the composition of the intestinal microbiota was relatively stable from early childhood; however, recent evidence suggests that diet can cause dysbiosis, an alteration in the composition of the microbiota, which could lead to aberrant immune responses. The role of the microbiota and the potential for diet-induced dysbiosis in inflammatory conditions of the GI tract and systemic diseases will be discussed.

The immunopathogenesis of cow's milk protein allergy (CMPA)

The most frequent symptoms among the manifestations of cow milk protein allergy (CMPA) are gastrointestinal. CMPA pathogenesis involves immunological mechanisms with participation of immunocompetent cells and production of immunoglobulin E (IgE). Nevertheless, recent studies have been focused on the description of other forms of CMPA, not-mediated by IgE reactions, mostly involving the T lymphocite immune system. Thus, in this field it is important to note how different kind of cells are involved in the immunopathogenesis of CMPA, such as antigen-specific T cells, T regulatory cells, cytokines secreted by the different T lymphocite subsets, B lymphocytes, antingen-presenting cells, mast cells, that together orchestrate the complex mechanism leading to the phenotipic expression of CMPA.The progress in the diagnosis of immunologic disorders allowed the recent literature to develop new models for immuno-mediate disorders, involving new cells (such as Treg cells) and thus allowing the acquisition of a new vision of the pathogenesis of atopic diseases.The aim of this review is to describe the immunopathogenetic aspects of CMPA in view of these new discoveries in the immunologic field, considering the immunologic pathway at the basis of both IgE- and not-IgE mediated CMPA.

Progress in understanding the relationship between food allergy and intestinal microflora

A food allergy is defined as a harmful immunological reaction to ingested food protein. According to 2007 CDC statistics, more than 3 million (3.9%) of children under 18 years old suffered from food allergy, and the morbidity is especially higher among children under 5 years old. Healthy intestinal microflora is very important for the development of mature human immune system. The composition of intestinal microflora differs significantly between children with and without food allergy. Food allergy in children may be closely associated with the immature development and damage of the intestinal mucosal barrier, intestinal dysbacteriosis and microflora disorder. Probiotics, as the balancer of intestinal microflora and regulator of intestinal mucosal immunity, can be used to prevent and treat allergic diseases; however, more larger randomized, controlled clinical studies are needed to verify its efficacy.

Anti-alpha-Gal antibody titres remain unaffected by the consumption of fermented milk containing Lactobacillus casei in healthy adults

Alpha-Gal is a glycoconjugate present on cell membranes of non-primate mammals and bacteria, but not in humans, who display anti-Gal antibodies (ABs) in high titres. Probiotics contain bacterial strains which colonize the intestinal tract. In the present study, we investigated whether intake of fermented milk containing Lactobacillus casei (FML) affects anti-Gal AB titres. Serum was drawn from healthy probands (n = 19) for 6 weeks. After the second week, the probands consumed 125 ml of FML per day. Anti-Gal ABs of all isotypes and cytokines were measured. Bacterial cultures were bred from FML and bacteria were stained for alpha-Gal. Concentration of bacteria in FML was manifold higher than in conventional yoghurt (2 × 10(5)/g yoghurt vs. 1.1 × 10(7)/g FML). Both stained highly positive for Alpha-Gal. Alpha-Gal-specific ABs and cytokines remained unaffected by FML intake. Our results indicated that the consumption of FML does not elicit a humoral immune response in healthy adults.