World Allergy Organization (WAO) Diagnosis and Rationale for Action against Cow's Milk Allergy (DRACMA) guideline update - XII - Recommendations on milk formula supplements with and without probiotics for infants and toddlers with CMA.

Background: Cow's milk allergy (CMA) is the most common food allergy in infants. The replacement with specialized formulas is an established clinical approach to ensure adequate growth and minimize the risk of severe allergic reactions when breastfeeding is not possible. Still, given the availability of multiple options, such as extensively hydrolyzed cow's milk protein formula (eHF-CM), amino acid formula (AAF), hydrolyzed rice formula (HRF) and soy formulas (SF), there is some uncertainty as to the most suitable choice with respect to health outcomes. Furthermore, the addition of probiotics to a formula has been proposed as a potential approach to maximize benefit. Objective: These evidence-based guidelines from the World Allergy Organization (WAO) intend to support patients, clinicians, and others in decisions about the use of milk specialized formulas, with and without probiotics, for individuals with CMA. Methods: WAO formed a multidisciplinary guideline panel balanced to include the views of all stakeholders and to minimize potential biases from competing interests. The McMaster University GRADE Centre supported the guideline-development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used, including GRADE Evidence-to-Decision frameworks, which were subject to review by stakeholders. Results: After reviewing the summarized evidence and thoroughly discussing the different management options, the WAO guideline panel suggests: a) using an extensively hydrolyzed (cow's milk) formula or a hydrolyzed rice formula as the first option for managing infants with immunoglobulin E (IgE) and non-IgE-mediated CMA who are not being breastfed. An amino-acid formula or a soy formula could be regarded as second and third options respectively; b) using either a formula without a probiotic or a casein-based extensively hydrolyzed formula containing Lacticaseibacillus rhamnosus GG (LGG) for infants with either IgE or non-IgE-mediated CMA.The issued recommendations are labeled as "conditional" following the GRADE approach due to the very low certainty about the health effects based on the available evidence. Conclusions: If breastfeeding is not available, clinicians, patients, and their family members might want to discuss all the potential desirable and undesirable consequences of each formula in infants with CMA, integrating them with the patients' and caregivers' values and preferences, local availability, and cost, before deciding on a treatment option. We also suggest what research is needed to determine with greater certainty which formulas are likely to be the most beneficial, cost-effective, and equitable.

Epidemiology of Paediatric Italian Food Allergy: Results of the EPIFA study.

Background: Updated epidemiologic data are important for defining effective public health strategies for pediatric food allergy (FA). Objective: The Epidemiology of Paediatric Italian Food Allergy (EPIFA) study was designed to investigate the epidemiology of pediatric FA in one of the most heavily populated Italian regions. Methods: A retrospective cohort study was performed in collaboration with family pediatricians aimed at investigating the epidemiology of Italian pediatric FA during 2009 to 2021. Family pediatricians in the Campania region were invited to use the Google Forms platform for online compilation of data forms. Data forms were reviewed by experienced pediatric allergists at the coordinating center. Results: A total population of 105,151 subjects (aged 0-14 years) was screened during the study period. Data from 752 FA patients were evaluated. A progressive increase in FA incidence and prevalence was observed from 2009 to 2021, with a relative increase up to 34% and 113.6%, respectively, at the end of study period. The relative increase in FA prevalence was higher in the 0-3-year-old age group in the same study period (+120.8%). The most frequent allergens were cow's milk, hen's egg, and nuts. Conclusion: The results of the EPIFA study showed an increase in pediatric FA incidence and prevalence from 2009 to 2021 in Italy. These results underline the necessity of new effective strategies for preventing and managing these conditions.

Skin, gut, and lung barrier: Physiological interface and target of intervention for preventing and treating allergic diseases.

The epithelial barriers of the skin, gut, and respiratory tract are critical interfaces between the environment and the host, and they orchestrate both homeostatic and pathogenic immune responses. The mechanisms underlying epithelial barrier dysfunction in allergic and inflammatory conditions, such as atopic dermatitis, food allergy, eosinophilic oesophagitis, allergic rhinitis, chronic rhinosinusitis, and asthma, are complex and influenced by the exposome, microbiome, individual genetics, and epigenetics. Here, we review the role of the epithelial barriers of the skin, digestive tract, and airways in maintaining homeostasis, how they influence the occurrence and progression of allergic and inflammatory conditions, how current treatments target the epithelium to improve symptoms of these disorders, and what the unmet needs are in the identification and treatment of epithelial disorders.

Growth pattern of paediatric patients affected by cow milk protein allergy fed with rice hydrolyzed formula.

OBJECTIVES: Formulas made from hydrolyzed rice proteins (HRPF) are well-tolerated plant-based alternatives to cow's milk protein (CMP)-based formulas for the dietary management of paediatric patients with CMP allergy (CMPA). Growth in patients with CMPA fed with HRPF has been evaluated in several studies with conflicting results. The aim was to evaluate the growth pattern of children with CMPA over a 12-month follow-up period. METHODS: Prospective cohort study evaluating growth patterns in challenge proven CMPA paediatric patients receiving HRPF for 12 months. Outcomes were anthropometry (body weight, body length, head circumference), adherence to the study formula and occurrence of adverse events (AEs). RESULTS: Sixty-six children were included and completed the 12-month study. At baseline, all CMPA patients were weaned. For the entire CMPA pediatric patients' cohort, from baseline to the end of the study period, the growth pattern resulted within the normal range of World Health Organization (WHO) growth references. The formula was well tolerated. Adherence was optimal and no AEs related to HRPF use were reported. CONCLUSIONS: HRPF is well tolerated and can help support healthy growth and development in infants and young children with CMPA. These type of formula can be given with complementary foods in the dietary management of CMPA.

A Lipopolysaccharide-Enriched Cow's Milk Allergy Microbiome Promotes a TLR4-Dependent Proinflammatory Intestinal Immune Response.

We have previously reported that the gut microbiota of healthy infants harbors allergy-protective bacteria taxa that are depleted in infants with cow's milk allergy (CMA). Few reports have investigated the role of the gut microbiota in promoting allergic responses. In this study we selected a CMA-associated microbiota with increased abundance of Gram-negative bacteria for analysis of its proinflammatory potential. LPS is the major component of the outer membrane of Gram-negative bacteria. Colonization of mice with a global or conditional mutation of the LPS receptor TLR4 with this CMA microbiota induced expression of serum amyloid A1 (Saa1) and other Th17-, B cell-, and Th2-associated genes in the ileal epithelium in a TLR4-dependent manner. In agreement with the gene expression data, mice colonized with the CMA microbiota have expanded populations of Th17 and regulatory T cells and elevated concentrations of fecal IgA. Importantly, we used both antibiotic-treated specific pathogen-free and germ-free rederived mice with a conditional mutation of TLR4 in the CD11c+ compartment to demonstrate that the induction of proinflammatory genes, fecal IgA, and Th17 cells is dependent on TLR4 signaling. Furthermore, metagenomic sequencing revealed that the CMA microbiota has an increased abundance of LPS biosynthesis genes. Taken together, our results show that a microbiota displaying a higher abundance of LPS genes is associated with TLR4-dependent proinflammatory gene expression and a mixed type 2/type 3 response in mice, which may be characteristic of a subset of infants with CMA.

Prebiotics in the management of pediatric gastrointestinal disorders: Position paper of the ESPGHAN special interest group on gut microbiota and modifications.

Prebiotics are substrates that are selectively utilized by host microorganisms conferring a health benefit. Compared to probiotics there are few studies with prebiotics in children. Most studies have been performed using infant formula supplemented with prebiotics, while add-on prebiotic supplementation as prevention or treatment of childhood gastrointestinal disorders has rarely been reported. The aim of this position paper was to summarize evidence and make recommendations for prebiotic supplementation in children with gastrointestinal diseases. Recommendations made are based on publications up to January 1, 2023. Within the scope of the European Society for Paediatric Gastroenterology Hepatology and Nutrition Special Interest Group on Gut Microbiota and Modifications, as in our previous biotic recommendations, at least two randomized controlled clinical trials were required for recommendation. There are some studies showing benefits of prebiotics on selected outcomes; however, we cannot give any positive recommendations for supplementing prebiotics in children with gastrointestinal disorders.

Nutrition in chronic inflammatory conditions: Bypassing the mucosal block for micronutrients.

Nutritional Immunity is one of the most ancient innate immune responses, during which the body can restrict nutrients availability to pathogens and restricts their uptake by the gut mucosa (mucosal block). Though this can be a beneficial strategy during infection, it also is associated with non-communicable diseases-where the pathogen is missing; leading to increased morbidity and mortality as micronutritional uptake and distribution in the body is hindered. Here, we discuss the acute immune response in respect to nutrients, the opposing nutritional demands of regulatory and inflammatory cells and particularly focus on some nutrients linked with inflammation such as iron, vitamins A, Bs, C, and other antioxidants. We propose that while the absorption of certain micronutrients is hindered during inflammation, the dietary lymph path remains available. As such, several clinical trials investigated the role of the lymphatic system during protein absorption, following a ketogenic diet and an increased intake of antioxidants, vitamins, and minerals, in reducing inflammation and ameliorating disease.

How dietary advanced glycation end products could facilitate the occurrence of food allergy.

BACKGROUND: Food allergy (FA) is one of the most common chronic conditions in children with an increasing prevalence facilitated by the exposure to environmental factors in predisposed individuals. It has been hypothesized that the increased consumption of ultra-processed foods, containing high levels of dietary advanced glycation end products (AGEs), could facilitate the occurrence of FA. OBJECTIVE: We sought to provide preclinical and clinical evidence on the potential role of AGEs in facilitating the occurrence of FA. METHODS: Human enterocytes, human small intestine organ culture, and PBMCs from children at risk for allergy were used to investigate the direct effect of AGEs on gut barrier, inflammation, TH2 cytokine response, and mitochondrial function. Intake of the 3 most common glycation products in Western diet foods, Nε-(carboxymethyl) lysine, Nε-(1-carboxyethyl) lysin, and Nδ-(5-hydro-5- methyl-4-imidazolone-2-yl)-ornithine (MG-H1), and the accumulation of AGEs in the skin were comparatively investigated in children with FA and in age-matched healthy controls. RESULTS: Human enterocytes exposed to AGEs showed alteration in gut barrier, AGE receptor expression, reactive oxygen species production, and autophagy, with increased transepithelial passage of food antigens. Small intestine organ cultures exposed to AGEs showed an increase of CD25+ cells and proliferating crypt enterocytes. PBMCs exposed to AGEs showed alteration in proliferation rate, AGE receptor activation, release of inflammatory and TH2 cytokines, and mitochondrial metabolism. Significant higher dietary AGE intake and skin accumulation were observed children with FA (n = 42) compared with age-matched healthy controls (n = 66). CONCLUSIONS: These data, supporting a potential role for dietary AGEs in facilitating the occurrence of FA, suggest the importance of limiting exposure to AGEs children as a potential preventive strategy against this common condition.

Host fecal DNA specific methylation signatures mark gut dysbiosis and inflammation in children affected by autism spectrum disorder.

The gut-brain axis involves several bidirectional pathway communications including microbiome, bacterial metabolites, neurotransmitters as well as immune system and is perturbed both in brain and in gastrointestinal disorders. Consistently, microbiota-gut-brain axis has been found altered in autism spectrum disorder (ASD). We reasoned that such alterations occurring in ASD may impact both on methylation signatures of human host fecal DNA (HFD) and possibly on the types of human cells shed in the stools from intestinal tract giving origin to HFD. To test this hypothesis, we have performed whole genome methylation analysis of HFD from an age-restricted cohort of young children with ASD (N = 8) and healthy controls (N = 7). In the same cohort we have previously investigated the fecal microbiota composition and here we refined such analysis and searched for eventual associations with data derived from HFD methylome analysis. Our results showed that specific epigenetic signatures in human fecal DNA, especially at genes related to inflammation, associated with the disease. By applying methylation-based deconvolution algorithm, we found that the HFD derived mainly from immune cells and the relative abundance of those differed between patients and controls. Consistently, most of differentially methylated regions fitted with genes involved in inflammatory response. Interestingly, using Horvath epigenetic clock, we found that ASD affected children showed both epigenetic and microbiota age accelerated. We believe that the present unprecedented approach may be useful for the identification of the ASD associated HFD epigenetic signatures and may be potentially extended to other brain disorders and intestinal inflammatory diseases.

The chemistry of gut microbiome-derived lipopolysaccharides impacts on the occurrence of food allergy in the pediatric age.

Introduction: Food allergy (FA) in children is a major health concern. A better definition of the pathogenesis of the disease could facilitate effective preventive and therapeutic measures. Gut microbiome alterations could modulate the occurrence of FA, although the mechanisms involved in this phenomenon are poorly characterized. Gut bacteria release signaling byproducts from their cell wall, such as lipopolysaccharides (LPSs), which can act locally and systemically, modulating the immune system function. Methods: In the current study gut microbiome-derived LPS isolated from fecal samples of FA and healthy children was chemically characterized providing insights into the carbohydrate and lipid composition as well as into the LPS macromolecular nature. In addition, by means of a chemical/MALDI-TOF MS and MS/MS approach we elucidated the gut microbiome-derived lipid A mass spectral profile directly on fecal samples. Finally, we evaluated the pro-allergic and pro-tolerogenic potential of these fecal LPS and lipid A by harnessing peripheral blood mononuclear cells from healthy donors. Results: By analyzing fecal samples, we have identified different gut microbiome-derived LPS chemical features comparing FA children and healthy controls. We also have provided evidence on a different immunoregulatory action elicited by LPS on peripheral blood mononuclear cells collected from healthy donors suggesting that LPS from healthy individuals could be able to protect against the occurrence of FA, while LPS from children affected by FA could promote the allergic response. Discussion: Altogether these data highlight the relevance of gut microbiome-derived LPSs as potential biomarkers for FA and as a target of intervention to limit the disease burden.

Increased dietary intake of ultraprocessed foods and mitochondrial metabolism alterations in pediatric obesity.

The increased intake of ultraprocessed foods (UPFs) in the pediatric age paralleled with the risen prevalence of childhood obesity. The Ultraprocessed Foods in Obesity (UFO) Project aimed at investigating the potential mechanisms for the effects of UPFs in facilitating pediatric obesity, focusing on the direct role of advanced glycation end-products (AGEs) on mitochondrial function, the key regulator of obesity pathophysiology. We comparatively investigated the daily dietary intake of UPFs, energy, nutrients, dietary AGEs [Nε -(carboxymethyl)lysine (CML), Nε -(1-carboxyethyl)lysine (CEL), and Nδ -(5-hydro-5- methyl-4-imidazolon-2-yl)-ornithine (MG-H1)] in 53 obese patients and in 100 healthy controls visiting the Tertiary Center for Pediatric Nutrition of the Department of Translational Medical Science at the University of Naples "Federico II". AGEs skin accumulation and mitochondrial function in peripheral blood mononuclear cells (PBMCs) were also assessed. A higher intake of UPFs and AGEs, energy, protein, fat, and saturated fatty acids was observed in obese patients. Obese children presented significantly higher skin AGEs accumulation and alterations in mitochondrial metabolism. PBMCs from healthy controls exposed to AGEs showed the same mitochondrial alterations observed in patients. These findings support the UPFs role in pediatric obesity, and the need for dietary strategies limiting UPFs exposure for obesity prevention and treatment.

Nutritional Strategies for the Prevention and Management of Cow's Milk Allergy in the Pediatric Age.

Cow's milk allergy (CMA) is one of the most common pediatric food allergies. The prevalence and severity of CMA have increased dramatically in the last decades, under the pressure of environmental factors in genetically predisposed individuals. Among the environmental influences, nutritional factors play a crucial role. Diet is the most modifiable factor, representing a potential target for the prevention and treatment of CMA. In this review, we report the most scientific-based nutritional strategies for preventing and managing pediatric CMA. In addition, we propose the most complete supplement of compounds able to prevent nutrient deficiencies in CMA pediatric patients and to positively influence the disease course.

Food allergy: cause or consequence of pediatric eosinophilic esophagitis? Potential implications of ultraprocessed foods in prevention and management.

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated disease characterized by eosinophilic infiltration, leading to esophageal dysfunction, inflammation, and fibrotic remodeling. In the last few decades, there has been an increased prevalence of EoE at an alarming rate in the pediatric age. The pathogenesis of EoE is still largely undefined, and this limits the definition of effective strategies for the prevention and management of this condition. EoE is considered a multifactorial disease arising from a negative interaction between environmental factors and genetic background, causing an impaired esophageal epithelial barrier with subsequent abnormal allergen exposure activating type 2 (Th2) inflammation. Food antigens have been suggested as key players in Th2 inflammation in pediatric patients with EoE, but emerging evidence suggests a potential role of other dietary factors, including ultraprocessed foods, as possible triggers for the occurrence of EoE. In this paper, we discuss the potential role of these dietary factors in the development of the disease, and we propose a new approach for the management of pediatric patients with EoE.

The step-down approach in children with cow's milk allergy: Results of a randomized controlled trial.

BACKGROUND: The Step-Down Approach for Cow's Milk Allergy (SDACMA) trial evaluated the tolerability and the rate of immune tolerance acquisition in CMA children starting dietary treatment with amino acid-based formula (AAF) and then switching to EHCF containing the probiotic Lacticaseibacillus rhamnosus GG (EHCF + LGG). METHODS: Randomized controlled trial involving IgE-mediated CMA children receiving AAF from at least 4 weeks. EHCF + LGG tolerance was evaluated by the results of double-blind placebo-controlled food challenge (DBPCFC). Subjects tolerating EHCF + LGG were randomly allocated to remain on AAF, or to switch to EHCF + LGG. Immune tolerance acquisition to cow's milk proteins was evaluated with DBPCFC after 12 months of treatment. Allergy screening tests and body growth were also monitored. RESULTS: Sixty IgE-mediated CMA children were enrolled. The proportion of children treated with AAF who resulted tolerant to the first exposure of EHCF + LGG was 0.98 (exact 95% CI 0.91-0.99). The rate of the immune tolerance acquisition to cow milk proteins after 12 months treatment was higher in the EHCF + LGG (0.48, 95% exact CI 0.29-0.67, n/N = 14/29) than in the AAF group (0.03, 95% exact CI 0.001-0.17, n/N = 1/30). There was an absolute benefit increase (ABI) of tolerance rate equal to 0.45 (95% CI 0.23-0.63, Newcombe method 10) for EHCF + LGG versus AAF, corresponding to a NNT of 2 (2-4, Bender's method). A normal body growth pattern was observed in the two study groups. CONCLUSION: In IgE-mediated CMA children the step-down from AAF to EHCF + LGG is well tolerated and could facilitate the immune tolerance acquisition.

Understanding the role of the gut microbiome in gastrointestinal cancer: A review.

Gastrointestinal cancer represents one of the most diagnosed types of cancer. Cancer is a genetic and multifactorial disease, influenced by the host and environmental factors. It has been stated that 20% of cancer is caused by microorganisms such as Helicobacter pylori, hepatitis B and C virus, and human papillomavirus. In addition to these well-known microorganisms associated with cancer, it has been shown differences in the composition of the microbiota between healthy individuals and cancer patients. Some studies have suggested the existence of the selected microorganisms and their metabolites that can promote or inhibit tumorigenesis via some mechanisms. Recent findings have shown that gut microbiome and their metabolites can act as cancer promotors or inhibitors. It has been shown that gastrointestinal cancer can be caused by a dysregulation of the expression of non-coding RNA (ncRNA) through the gut microbiome. This review will summarize the latest reports regarding the relationship among gut microbiome, ncRNAs, and gastrointestinal cancer. The potential applications of diagnosing and cancer treatments will be discussed.

Probiotics for the Management of Pediatric Gastrointestinal Disorders: Position Paper of the ESPGHAN Special Interest Group on Gut Microbiota and Modifications.

BACKGROUND: Probiotics, defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, are widely used despite uncertainty regarding their efficacy and discordant recommendations about their use. The European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Special Interest Group on Gut Microbiota and Modifications provides updated recommendations for the use of probiotics for the management of selected pediatric gastrointestinal disorders. METHODS: All systematic reviews and/or meta-analyses, as well as subsequently published randomized controlled trials (RCTs) (until December 2021), that compared the use of probiotics in all delivery vehicles and formulations, at any dose, with no probiotic (ie, placebo or no treatment), were eligible for inclusion. The recommendations were formulated only if at least 2 RCTs on a similar well-defined probiotic strain were available. The modified Delphi process was used to establish consensus on the recommendations. RESULTS: Recommendations for the use of specific probiotic strains were made for the management of acute gastroenteritis, prevention of antibiotic-associated diarrhea, nosocomial diarrhea and necrotizing enterocolitis, management of Helicobacter pylori infection, and management of functional abdominal pain disorders and infant colic. CONCLUSIONS: Despite evidence to support the use of specific probiotics in some clinical situations, further studies confirming the effect(s) and defining the type, dose, and timing of probiotics are still often required. The use of probiotics with no documented health benefits should be discouraged.

Therapeutic Effects of Butyrate on Pediatric Obesity: A Randomized Clinical Trial.

Importance: The pediatric obesity disease burden imposes the necessity of new effective strategies. Objective: To determine whether oral butyrate supplementation as an adjunct to standard care is effective in the treatment of pediatric obesity. Design, Setting, and Participants: A randomized, quadruple-blind, placebo-controlled trial was performed from November 1, 2020, to December 31, 2021, at the Tertiary Center for Pediatric Nutrition, Department of Translational Medical Science, University of Naples Federico II, Naples, Italy. Participants included children aged 5 to 17 years with body mass index (BMI) greater than the 95th percentile. Interventions: Standard care for pediatric obesity supplemented with oral sodium butyrate, 20 mg/kg body weight per day, or placebo for 6 months was administered. Main Outcomes and Measures: The main outcome was the decrease of at least 0.25 BMI SD scores at 6 months. The secondary outcomes were changes in waist circumference; fasting glucose, insulin, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, ghrelin, microRNA-221, and interleukin-6 levels; homeostatic model assessment of insulin resistance (HOMA-IR); dietary and lifestyle habits; and gut microbiome structure. Intention-to-treat analysis was conducted. Results: Fifty-four children with obesity (31 girls [57%], mean [SD] age, 11 [2.91] years) were randomized into the butyrate and placebo groups; 4 were lost to follow-up after receiving the intervention in the butyrate group and 2 in the placebo group. At intention-to-treat analysis (n = 54), children treated with butyrate had a higher rate of BMI decrease greater than or equal to 0.25 SD scores at 6 months (96% vs 56%, absolute benefit increase, 40%; 95% CI, 21% to 61%; P < .01). At per-protocol analysis (n = 48), the butyrate group showed the following changes as compared with the placebo group: waist circumference, -5.07 cm (95% CI, -7.68 to -2.46 cm; P < .001); insulin level, -5.41 µU/mL (95% CI, -10.49 to -0.34 µU/mL; P = .03); HOMA-IR, -1.14 (95% CI, -2.13 to -0.15; P = .02); ghrelin level, -47.89 µg/mL (95% CI, -91.80 to -3.98 µg/mL; P < .001); microRNA221 relative expression, -2.17 (95% CI, -3.35 to -0.99; P < .001); and IL-6 level, -4.81 pg/mL (95% CI, -7.74 to -1.88 pg/mL; P < .001). Similar patterns of adherence to standard care were observed in the 2 groups. Baseline gut microbiome signatures predictable of the therapeutic response were identified. Adverse effects included transient mild nausea and headache reported by 2 patients during the first month of butyrate intervention. Conclusions and Relevance: Oral butyrate supplementation may be effective in the treatment of pediatric obesity. Trial Registration: ClinicalTrials.gov Identifier: NCT04620057.

The potential role of preventive and therapeutic immunonutrition strategies for pediatric food allergy: A mini-review.

Food allergy (FA) represents one of the main chronic conditions of the pediatric population. The gut microbiome (GM)-immune system axis is a milestone in affecting FA susceptibility. The dynamic and bidirectional crosstalk between the GM and immune system starts early in life, and it is deeply modulated during the first 1,000 days of life. Nutritional factors during this crucial period mainly influence the proper GM-immune system development and function across the lifespan, with potential beneficial or detrimental effects on health status. Immunonutrition strategies, applied from conception, could represent an innovative target for prevention and treatment of pediatric FA. Here we described the potential role of preventive and therapeutic immunonutrition strategies for pediatric FA, highlighting putative future perspectives in this field.

Effects of the Mediterranean Diet during pregnancy on the onset of allergy in at risk children: A study protocol of a multi-center, randomized- controlled, parallel groups, prospective trial (the PREMEDI study).

Introduction: Maternal diet during pregnancy has been linked to offspring allergy risk and it could represent a potential target for allergy prevention. The Mediterranean Diet (MD) is considered one of the healthiest dietary models. Randomized-controlled trials on the effect of MD in preventing pediatric allergic diseases are still needed. Methods and analysis: The Mediterranean Diet during Pregnancy study (PREMEDI) will be a 9-month multi-center, randomized-controlled, parallel groups, prospective trial. Healthy women (20-35 years) at their first trimester of pregnancy at risk for atopy baby, will be randomly allocated to Group 1 (standard obstetrical and gynecological follow-up and nutritional counseling to promote MD) or Group 2 (standard obstetrical and gynecological follow-up alone). 138 mother-child pair per group will be needed to detect a reduction in cumulative incidence of ≥1 allergic disease at 24 months of age. The primary study aim will be the evaluation of the occurrence of allergic disorders in the first 24 months of life. The secondary aims will be the evaluation of maternal weight gain, pregnancy/perinatal complications, growth indices and occurrence of other chronic disorders, mother-child pair adherence to MD and gut microbiome features, breastfeeding duration and breast milk composition, epigenetic modulation of genes involved in immune system, and metabolic pathways in the offspring. Ethics and dissemination: The study protocol has been approved by the Ethics Committee of the University of Naples Federico II (number 283/21) and it will be conducted in accordance with the Helsinki Declaration (Fortaleza revision, 2013), the Good Clinical Practice Standards (CPMP/ICH/135/95), the Italian Decree-Law 196/2003 regarding personal data and the European regulations on this subject. The study has been registered in the Clinical Trials Protocol Registration System. Clinical trial registration: [http://clinicaltrials.gov], identifier [NCT05119868].