Dietary primary prevention of allergic diseases in children: the Philippine guidelines.

Allergic diseases, such as asthma, allergic rhinitis, eczema, and food allergy, are preventable diseases. Primary prevention strategies of allergic diseases have been in scrutiny. Effective prevention strategies maybe started prenatally, postnatally, during infancy, and even during childhood. These guidelines have been prepared by the Philippine Society of Allergy, Asthma and Immunology and the Philippine Society for Pediatric Gastroenterology, Hepatology and Nutrition. They aim to provide evidence-based recommendations for the dietary primary prevention of allergic diseases in children. The primary audience of these guidelines is all healthcare practitioners who manage patients with potential allergic conditions. These guidelines are based on an exhaustive review of evidences, mostly systematic reviews, randomized controlled trials, and cohort studies. However, there are still many gaps in the evidence of dietary primary prevention of allergic diseases.

INTRODUCTION

The incidence of allergic diseases among children has been increasing worldwide. Maternal and child dietary interventions and lifestyle strategies to decrease the risk of sensitization and allergic diseases in children have been an ongoing subject for decades that is met with conflicting views. Primary prevention strategies directed against potential sensitizing factors have been proposed at different stages of early life such as in antenatal period, early postnatal period (infancy), and early childhood (2 years and above). However, many of the studies show conflicting results [1]. These guidelines summarize the evidence on dietary primary prevention of allergic diseases in the general and high-risk population. These present guidelines have been prepared by the Philippine Society of Allergy, Asthma and Immunology (PSAAI) and the Philippine Society for Pediatric Gastroenterology, Hepatology and Nutrition (PSPGHAN). The objectives of this document are to give evidence-based guidelines for the primary prevention of allergic conditions in children through nutritional means available in the Philippine setting. These guidelines are the first of its kind in the Philippines and contributory to other foreign guidelines on this topic.

METHODS

Formation of Technical Working Group

The Technical Working Group was composed of members from the PSAAI and the PSPGHAN. The E-mail discussions and face-to-face meetings were held to discuss group composition, formulation of clinical questions and rating of outcomes, preparation of evidence summaries and rating the evidence, panel meetings weighing the desirable and undesirable values and preferences of available dietary interventions pertinent to the Philippine setting, formulation of statements, and consultation (stakeholders meeting) of clinicians and lay person involved in the care of the patient. A nominal group consensus model approach was adopted for making operational definitions for essential terms and framing the questions.

Search strategy for selection of studies

The Cochrane Library, PubMed, Ovid, ClinicalTrials.gov, Google Scholar, and Herdin were searched for publications related to allergic diseases prevention and dietary interventions. Experts in the field were contacted for unpublished studies. Citations and reference lists in reviews and guidelines were searched for additional studies. No language restriction was applied.

Systematic reviews, randomized controlled trials (RCTs), quasi-RCTs, and cohort studies on primary prevention of allergic diseases (asthma, allergic rhinitis, atopic dermatitis, and food allergy) through dietary interventions in the general and high-risk population were included. Qualitative studies, case series/reports, animal studies, letters, and editorials were excluded.

Assessing quality of included studies and formulating recommendations

The Technical Working Group which includes a third-party evaluator reviewed and critically appraised the evidence. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach was used to assess the quality of evidence and the strength of recommendation.

The validity, clinical relevance, and applicability of the evidence for the infant and childhood allergy were discussed. After considering the evidence, the Technical Working Group achieved a consensus on a number of recommendations (Table 1).

Table 1

Summary of recommendations

Rationale behind panel selection

The panel for stakeholders meeting comprised of an allergist, a pediatric gastroenterologist, 2 general pediatricians, an adult patient with allergic disease, a breastfeeding advocate, mother who breastfed, a mother who did not breastfeed, a mother with a child with allergic disease, a lay person, a neonatologist, and an obstetrician. The panel is multisectoral to ensure adequate representation and to make the consensus statement relevant and acceptable to intended end-users.

Recommendation 1: Increased maternal intake of certain foods during pregnancy to prevent allergy in the child is not recommended (Strong recommendation / Low quality evidence).

RECOMMENDATIONS

Diet during pregnancy

The type and quantity of food of a pregnant mother may influence the development of allergic diseases in her child. Famine in pregnancy was associated with obstructive lung disease in the offspring [2]. Intake of protein, carbohydrates, and milk correlated negatively with emergence of allergic disease in the high-risk infant. In contrast, high intake of fats, vegetable oil, celery, citrus, raw sweet pepper, and nuts were associated with increased sensitization [345].

Dietary polyphenols from certain plants (cocoa, coffee, tea) and fruits (apples and grapes) have been studied and proposed to possess antiallergic activity through binding allergenic protein in the diet [6]. A systemamic review and meta-analysis showed that a maternal diet high in fruits and vegetables (as well as Mediterranean type of diet) could prevent sensitization and the development of asthma [7]. However, due to the poor quality of the studies evaluated, no concrete recommendations can be made. A subsequent study noted increased risk of wheezing in children by 5 years with previous maternal intake of leafy vegetables, certain fruits (apple, pear, peach, apricot, prune, and plum), and chocolate increased the risk of wheezing in children at 5 years of age; fruit juice intake, however, increased the risk of allergic rhinitis [8]. Moreover, increased intake of isoflavones, which are found primarily in soybeans (a highly allergenic food), was associated with decreased asthma risk [6].

Recommendation 2: Maternal avoidance of allergenic foods during pregnancy to prevent allergy in the child is not recommended (Strong recommendation / Moderate quality evidence).

A maternal avoidance diet of foods considered to be highly allergenic, such as milk, eggs, peanuts, nuts, wheat, soy, and seafood during pregnancy has been proposed as a primary prevention strategy against food allergy and other allergic diseases in the high-risk offspring. One study suggested that diet devoid of peanut, nuts, fish, eggs, and sesame during the last trimester of pregnancy in women with high-risk families has a protective effect for the child, but this was contradicted by later studies [9]. Three recent systematic reviews on elimination of highly allergenic foods in maternal diet, particularly milk, egg, and peanut during pregnancy, noted conflicting results in the included studies. Thus, restricting common highly allergenic foods during pregnancy cannot be recommended at present, even for high-risk infants [101112].

However, this proposed dietary avoidance primary prevention strategy is currently being challenged. Recent literature suggests that oral exposure to food allergens by the mother during pregnancy could promote tolerance to food antigens in her offspring [13]. A Cochrane review on maternal allergen avoidance during pregnancy revealed the absence of a protective effect on atopic dermatitis or asthma in the first 18 months of infancy [12]. Also, its effects on risk of allergic rhinitis, conjunctivitis and urticaria were inconclusive. More importantly, however, this review noted that dietary restrictions during pregnancy had detrimental effects on maternal nutrition and eventually on fetal health.

No special maternal diet is proven to be effective as a form of primary allergy prevention in the child. The pregnant woman's diet should be healthy and well-balanced as it would impact the infant's health. Avoidance of food allergens is only justified if the mother is truly allergic to specific foods.

Recommendation 3: Supplements (vitamins, minerals, antioxidants, and long chain polyunsaturated fatty acids [LCPUFA]) to prevent allergic disease in the child are not recommended in pregnant women (Strong recommendation / Low quality evidence).

Supplements during pregnancy

Supplementation with vitamin A and vitamin C during pregnancy had no preventive effect on the development of wheezing in the child [7]. However, the studies were observational and of low methodologic quality.

Three large birth cohort studies showed consistent positive associations between maternal intake of vitamin E in pregnancy and prevention of childhood asthma or wheeze at 2 years of age [5]. But in a recent systematic review looking into the association of maternal Vitamin E intake in pregnancy on atopic eczema, sensitization, allergic rhinoconjunctivitis, lung function and asthma, a meta-analysis could not be done due to variations in study design. The quality of evidence of included studies was weak [7].

Vitamin D is thought to inhibit the maturation of dendritic cells and may modulate Th1 response. However, studies about its role in allergy prevention are conflicting. Some reported that high maternal vitamin D intake during pregnancy was associated with reduced risk of wheezing in the child, while some showed no effect. In more recent observation studies, high-dose maternal intake of vitamin D was associated with increased atopic diseases such as atopic dermatitis and/or allergic rhinitis [14]. The conflicting results may reflect genetic variability in the general population in the metabolism and allergy preventive effects of vitamin D supplementation in the child [67].

Maternal selenium supplementation, in a systematic review, did not prevent allergy development in the child. Zinc supplementation, however, could be protective against asthma. However, because of the low quality of evidence, strong conclusions could not be made [7].

Intake of antioxidants during pregnancy may be positively associated with prevention of childhood asthma, and to a lesser degree, atopic dermatitis and allergic rhinitis [1516].

Increased maternal consumption of LCPUFA may be a promising strategy in allergy prevention. Omega-6 PUFAs were noted not to have high levels of anti-inflammatory effects compared to omega-3 PUFA contained in oily fish. The anti-inflammatory effect of omega-3 PUFA has been attributed to the cytokine regulatory effects of TGF-beta [17]. The higher ratio of omega-3 to omega-6 PUFA may be more clinically relevant for allergy prevention. However, omega-6 PUFA also exhibit anti-inflammatory actions and may be needed in synergism with omega-3 PUFA for allergy prevention [18].

The allergy preventive effect of high maternal LCPUFA intake becomes evident if these are taken the last 4 weeks of pregnancy [18]. In a RCT, there was no decrease in atopic dermatitis incidence though, in children born from women supplemented with LCPUFA [19]. Also, a meta-analysis of six RCTs on the use of omega-3 and omega-6 PUFA for allergy prevention in various populations, including pregnant women, concluded that these PUFAs may not have a role in prevention of sensitization or allergic disease in the population [20].

The effects of fish oil supplementation in pregnant mothers on high-risk children were evaluated in 5 RCTs. One study showed a decrease in the risk of egg sensitizations; however, it did not evaluate whether clinical egg or food allergy could be prevented in the infants or if there is any benefit in the general population [21]. Despite the lack of effect of fish oil supplementation in decreasing prevalence of allergic symptoms in children, 2 studies showed a decrease in the cumulative incidence of allergic disease during the first two years of life [2223]. However, two other studies did not detect any preventive effect on allergic disease [24, 25]. These studies had heterogenous outcomes indicating the tenuous role of maternal fish oil supplementation for allergy prevention in their offspring.

Recommendation 4: For ATOPIC pregnant women, Lactobacillus rhamnosus GG from 36 weeks age of gestation (AOG) and continued while breastfeeding or given directly to the infant until 6 months old to prevent ATOPIC DERMATITIS in children is recommended (Weak recommendation / Moderate quality evidence).

Recommendation 5: For NON-ATOPIC pregnant women, maternal probiotic supplementation to prevent allergic disease in children is not recommended (Strong recommendation / Very low quality evidence).

The hygiene hypothesis postulates that an absence of early life microbial immunomodulation predisposes to development of allergic conditions. The human microbiota, especially in the gut, has been documented to be important in normal immune programming of the host and in the maintenance of a normal gut mucosal barrier. Probiotic supplementation has been proposed as a means of providing optimal microbial stimulation necessary for immune regulation [2627]. A meta-analysis of 6 prevention clinical trials showed that probiotics is more efficacious than placebo in preventing pediatric atopic dermatitis [27]; however, its role in preventing other types of allergic disease was not seen in another meta-analysis [28].

Perinatal probiotic supplementation has been proposed as a means of introducing microbial immunostimulation in very early life. Studies have documented that neonatal gut microbiota originate from maternal gut microbiota either transplacentally, through fecal-oral exposure via vaginal delivery or through bacterial translocation from the maternal gastrointestinal tract to the breast milk [293031]. A landmark RCT on the effect of probiotic L. rhamnosus GG given to pregnant women at least 2 weeks prior to delivery and continued after birth for 6 months either through breastfeeding or supplemented to formula-fed infants noted a 40%–50% decrease in pediatric eczema at 2, 4, and 7 years of follow-up [313233]. Some studies have indicated that earlier probiotic supplementation in late pregnancy rather than postnatal exposure may be more effective in primary prevention of allergic disease [3435]. Prenatal probiotic supplementation provides for a microflora predominantly comprised of lactobacilli and bifidobacteria, similar to that of a healthy breastfed baby [3637].

One RCT evaluated the efficacy of probiotics in the prevention of eczema when given to women during their pregnancy only. L. rhamnosus GG was given from 36 weeks AOG until delivery to pregnant women carrying high-risk infants. Apparently, prenatal probiotic supplementation was not effective in reducing the risk of eczema [38].

There are, however, no studies done to explore the preventive role of prenatal probiotic supplementation in nonatopic pregnant women for prevention of allergic disease in children. Because of the lack of evidence and cost, it is strongly not recommended.

Recommendation 6: Any specific type of maternal diet during lactation to prevent allergy in the child is not recommended (Strong recommendation / Low quality evidence).

Maternal diet during lactation

There are no RCTs evaluating any specific type of maternal diet during lactation to prevent allergic diseases in the child.

Maternal avoidance diets in the prevention of food allergies are under debate. In a cross-over trial, elimination of cow milk, egg, and soy milk from diet of lactating mothers of infants with established atopic dermatitis was associated with a nonsignificant reduction in the severity of atopic dermatitis [39].

A prospective birth cohort involving 145 dyads showed significant reduction in casein- and beta-lactoglobulin-specific IgA in breast milk of mothers who eliminated cow milk from their diet. The decreased levels of IgA were associated with the development of cow milk allergy in the child [40].

Despite the low quality evidence, the recommendation is strong because of possible consequences on maternal and infant nutrition.

Recommendation 7. Exclusive breastfeeding for at least 3 to 6 months is recommended to prevent asthma (Strong recommendation / Moderate quality evidence).

Postnatal diets

The impact of breastfeeding on the risk of allergy is difficult to establish because no RCTs have been performed for ethical reasons. As the gold standard for infant nutrition, human milk per se is not a “dietary intervention” for primary allergy prevention; although compared to standard cow milk formula, breast milk is less allergenic [41].

Systematic reviews and meta-analyses on breastfeeding to prevent allergic diseases showed conflicting results [4243444546]. One systematic review involving 21 prospective cohort studies showed no strong evidence for protective effect of exclusive breastfeeding in the first 3 months of life in atopic dermatitis [42]. Three systematic reviews showed preventive effects of breastfeeding in asthma [434445]. The most recent of the systematic reviews included 117 studies (57 cohort studies, 47 cross-sectional, 13 case-controls) on breastfeeding among children in the general population [45]. The meta-analysis showed a positive association of breastfeeding with reduced asthma or wheezing. In addition, exclusive breastfeeding for at least 3 months is associated with decrease in asthma incidence at 0 to 2 years old as compared to exclusive breastfeeding for less than 3 months [45]. Another meta-analysis showed that exclusive breastfeeding during the first 3 months of life showed no evidence that it protects against allergic rhinitis in children [46].

Recommendation 8: In high-risk infants who cannot be breastfed or when breast milk is not available, partially hydrolyzed-whey milk formula (pHF-W) or extensively hydrolyzed-casein milk formula (eHF-C) for at least 6 months is recommended to prevent allergic diseases (Weak recommendation / Moderate quality evidence).

Soy protein-based, pHF-W, eHF-C, eHF-W and amino acid formulas are the most commonly used breast milk substitutes to prevent atopic diseases. The appropriate choice should meet certain essential criteria: (1) it should fulfill the nutritional needs of the infant providing adequate growth and development; (2) it should have no or little cross-reactivity with protein from nonhuman sources; and (3) it should have good palatability [47].

There are systematic reviews and a recent 15-year analysis of an RCT evaluating the efficacy of HF in allergic disease prevention [4849,50,5152,53,5455]. Systematic reviews on HF to prevent allergic diseases showed variable preventive effects [505152535455]. The meta-analysis of Osborn and Sinn [50] showed that HF compared to cow milk reduced infant allergy but did not show reduction in childhood allergy, eczema, asthma, rhinitis, and food allergy.

These preventive effects of HF have been confirmed by the recent follow-up of the German Infant Nutritional Intervention study which looked at the long-term effects of hydrolyzed formulas on allergies [4849]. On its fifteenth year, this RCT involving children at high risk for allergy had significantly decreased asthma with eHF-C as compared to cow's milk formula. It also showed that early intervention using eHF-C and pHF-W resulted in lower allergic rhinitis prevalence. There was reduction in the cumulative incidence of atopic dermatitis with pHF-W and eHF-C but not for asthma and allergic rhinitis. eHF-W showed no preventive effects for any allergic disease.

Recommendation 9: In high-risk infants who cannot be breastfed or when breast milk is not available, soy milk formula to prevent allergic disease is not recommended (Strong recommendation / High quality evidence).

One systematic review with a meta-analysis compared soy formula with cow's milk formula among high risk infants [56]. There was no significant difference between the two comparators in the incidence of childhood allergic diseases including asthma, atopic dermatitis, rhinitis, infant cow milk allergy, childhood soy protein allergy, and urticaria [56].

Recommendation 10: In high-risk infants who cannot be breastfed or when breast milk is not available, amino acid-based milk formulas, organic cow's milk formulas, and non-bovine formulas to prevent allergic disease are not recommended (Strong recommendation / Very low quality evidence).

There are no RCTs or cohort studies on amino-acid-based, organic cow milk, and non-bovine milk formulas for the primary prevention of allergy. Due to the lack of studies, we do not recommend these formulas. The Australasian Society of Clinical Immunology and Allergy also does not recommend other formulas such as goat milk to reduce the risk of food allergy [57].

Recommendation 11: Delaying complementary feeding beyond the age of 6 months for all infants is not recommended (Strong recommendation / Moderate quality evidence).

Complementary feeding is the process of starting solid food and other liquids on an infant when breastmilk alone is already insufficient. The initiation of complementary feeding entails tolerance to the food antigens consumed. Immune tolerance occurs when there is antigen-specific suppression of host cellular or humoral immune responses. In oral tolerance development, age of exposure has been found to be a factor along with antigen properties, route of exposure, and genetics and age of host [58].

A prospective cohort study of 642 children with late introduction of solids did not show a protective effect in the development of preschool wheezing, transient wheezing, atopy, or eczema [59]. In contrast, late introduction of egg and milk significantly increased the risk of eczema. This association of delayed introduction of solids and the increase in the frequency of atopic diseases have been shown in other cohort studies [6061].

A systematic review with nine cohort studies showed conflicting results [62]. Five studies showed positive association of early solid feeding and eczema. Four studies showed no association. Many of the studies included in this review have methodologic problems.

Recommendation 12: Timing of introduction of highly allergenic foods in infant diet to prevent allergic diseases is recommended as follows: cooked egg at 4–6 months (Weak recommendation / Low quality evidence), wheat at less than 6 months (Weak recommendation / Moderate quality evidence), fish at 6–9 months (Weak recommendation / Moderate quality evidence), and peanut at 4–11 months (Strong recommendation / High quality evidence).

There are a few studies on timing of introduction of highly allergenic foods to prevent allergic diseases. Most studies are cohort or cross-sectional. There is only 1 RCT done to evaluate introduction of intake of peanuts among infants.

Inversely, a prospective cohort study enrolling 3,781 children suggested that early introduction of highly allergenic foods such as wheat, egg and fish, seemingly decreases the risk of asthma, allergic rhinitis, and allergic sensitization. Giving wheat at 5 to 5.5 months was inversely associated with asthma and allergic rhinitis. This inverse association is also true with introduction of fish at 9 months or less for allergic rhinitis and atopic sensitization and egg at 11 months for asthma, allergic rhinitis, and atopic sensitization [63].

A population-based cross-sectional study participated by 2,589 infants showed that early introduction of egg at 4–6 months old was associated with lower risks of egg allergy as than if it was introduced at 10–12 months and more than 12 months [64]. Moreover, it is the cooked (hardboiled, fried, scrambled, poached) eggs given at age 4–6 months reduced the risk of egg allergy as compared to egg in baked goods.

A prospective, birth cohort study on 994 including children with HLA-conferred susceptibility to type 1 diabetes mellitus revealed that delayed introduction wheat (>6 months), eggs (>10.5 months), fish (>8.2 months), and other solid foods was significantly directly associated with sensitization to food allergens. Moreover, late introduction of fish (>8.2 months) was significantly associated with sensitization to any inhalant allergen [65].

A prospective cohort study on 516 children did not show significant association between the timing of introduction of solid foods and protection against asthma or other allergic diseases at age 5 years. However, introduction of solid foods after 3 months was associated with an increased risk of atopy at age 5 years [66].

A RCT involving 530 infants with severe eczema, egg allergy, or both that were given peanuts at 4–11 months had significantly decreased risk for peanut allergy among children at high risk for this allergy [67]. Also, infants with siblings diagnosed with peanut allergy should be assessed prior to giving peanuts because there is a 7% risk of peanut allergy among siblings [68].

If there is no risk or no sibling with nut allergy, peanut butter, as well as tree nut butter, may be introduced between 6 to 12 months. Caution should be exercised in giving nut kernels at an early age due to the risk of aspiration [11].

Recommendation 13: Organic food to prevent allergic diseases is not recommended (Strong recommendation / Moderate quality evidence).

Organic products are known to contain on average more antioxidants such as vitamin and higher amount of n-3 fatty acids. Antioxidants are suggested to prevent wheezing complaints possibly through protect of bronchial epithelium against oxidative stress. Likewise, n-3 fatty acids are hypothesized to be anti-inflammatory and contributory to skin barrier hence reducing atopic reactions. The KOALA Birth Cohort Study found no association between consumption of organic products (meat, fruit, vegetable, and eggs) and development of eczema, wheeze, or atopic sensitization [69]. However, consumption of strictly organic dairy products is associated with reduced risk of eczema. Despite this mere association, organic food is not recommended to prevent allergic diseases. There are no RCTs found to affect this recommendation.

Recommendation 14: Increased intake of fish rich in LCPUFA in infants and children to prevent asthma is recommended (Weak recommendation / Low quality evidence).

High intake of LCPUFA has been hypothesized to prevent asthma, which is an inflammatory process. A meta-analysis of 3 prospective cohort studies showed that infants who consumed fish have lower risk of childhood asthma [70]. There are no RCTs found to confirm this finding. Despite this, fish rich in LCPUFA in is recommended to prevent asthma.

Recommendation 15: Fish oil supplementation in infants and children to prevent allergic diseases is not recommended (Strong recommendation / High quality evidence).

A systematic review including 5 RCTs on the effects of fish oil intake during infancy and childhood on atopic outcomes showed inconclusive evidence [71].

A more recent RCT, which is not included in the aforementioned systematic review, included 420 high-risk infants and evaluated n-3 PUFA supplementation from birth up to age 6 months did not prevent childhood allergic disease [72]. With this latest RCT and the inconclusive systematic review, fish oil supplementation in infants and children is strongly not recommended.

Recommendation 16: Postnatal probiotics to prevent allergic diseases are not recommended (Strong recommendation / Moderate quality evidence).

There are 2 meta-analyses on probiotic supplementation during the prenatal and postnatal periods. One meta-analysis involving 14 RCTs on prenatal and postnatal (early-life) probiotic supplementation did not show significant reduction in the risk of atopic sensitization nor risk of asthma. On subgroup analysis, prenatal supplementation showed significant reduction in atopic sensitization as compared to postnatal supplementation [28]. Another meta-analysis involving 13 RCTs on prenatal or postnatal probiotic supplementation showed reduction in atopic dermatitis among children in the probiotic arm [73].

Recommendation 17: Prebiotics, vitamin D, and virgin coconut oil (VCO) to prevent allergic diseases are not recommended (Strong recommendation / Low quality evidence).

Prebiotics are nutritional supplements that stimulate the growth and function of the gastrointestinal microbiome. Giving prebiotics during infancy could lead to modification of the immune development. A meta-analysis of 4 RCTs involving 1,218 infants showed a reduction in eczema among infants given prebiotics [74]. There was no significant difference in asthma. However, included studies were noted to have attrition bias (incomplete outcome data) and were all commercially sponsored (possible publication bias). Moderate heterogeneity was likewise found in the included studies.

There are no RCTs done on vitamin D supplementation in allergy prevention. Also, the 2 cohort studies on vitamin D supplementation have conflicting results. In 1 large birth cohort study, regular vitamin D supplementation was associated with the risk of developing atopy (odds ratio [OR], 1.66) and allergic rhinitis (OR, 1.46) than those who received it irregularly or none at all [75]. In another cohort study of infants given peanut oil-based Vitamin D supplement, no significant associations were observed for allergic rhinitis or eczema [76].

VCO, a monounsaturated fatty acid, contains a high amount of lauric acid. When the lauric acid is converted to monolaurin in the small intestine, it has the potential to inactivate the microbes. One RCT involving 13 high-risk neonates evaluated the VCO immunomodulation in the prevention of atopic diseases. There was a decrease in the IgE level among high-risk infants given VCO. However, the study had a small sample size [77].

Recommendation 18: Bovine colostrum, beta-glucan, spirulina, mangosteen, and other dietary supplements to prevent allergic disease are not recommended (Strong recommendation / Very low quality evidence).

No clinical studies are found on bovine colostrum, beta-glucan, spirulina, and mangosteen to prevent allergic diseases. With lacking data, these dietary supplements for allergy prevention are not recommended.

Recommendation 19: Lifestyle modification, including exercise and diet modification, to prevent allergic diseases in children with obesity is recommended (Strong recommendation / Moderate quality evidence).

During childhood

There are no RCTs found on lifestyle modification to prevent allergic disease in children with obesity.

A cohort study showed more patients with asthma among patients with overweight or obesity. Obesity increases the odds of incident asthma in children [78].

A cross-sectional study of 13,153 children aged 6–7 years old showed an association between obesity and atopic dermatitis [79].

A retrospective case-control study involving 414 children with atopic dermatitis showed higher odds of developing atopic dermatitis among those with onset of obesity before less than 2 years of age and 2 through 5 years of age. The development of atopic dermatitis was also seen when obesity was prolonged for 2.5 to 5 years and greater than 5 years [80].