Anorexia

2'-Fucosyllactose (2'-FL) is the most abundant human milk oligosaccharide and has been studied in infant formulas for allergy prevention. A 2025 open-label prospective clinical trial (338 infants) found formula supplemented with 2'-FL was associated with reduced incidence of atopic dermatitis compared to standard formula. Preclinical and clinical evidence links 2'-FL to gut microbiota modulation, SCFA production, and reduced allergic sensitization in infancy.

Bifidobacterium animalis subsp. lactis HN019 was used in a foundational perinatal probiotic RCT alongside L. rhamnosus HN001 in pregnant women and high-risk infants, demonstrating reduced prevalence of early atopic dermatitis. Specific Toll-like receptor genetic variations were found to be associated with this strain's protective effect against eczema in children.

Bifidobacterium bifidum has been evaluated as part of probiotic combinations for infant and childhood allergy prevention. It was included in perinatal probiotic supplementation trials that demonstrated reduced prevalence of early atopic dermatitis. Mechanistic research shows B. bifidum FN120 utilizes 2'-fucosyllactose via cross-feeding to reshape gut microbiota and prevent atopic dermatitis in experimental models.

Bifidobacterium breve has been used in RCTs of children with allergic rhinitis and asthma. A Bifidobacterium mixture including B. breve M-16V significantly improved quality of life in children with seasonal allergic rhinitis and intermittent asthma in a published clinical trial. The PROPAM study used B. breve B632 in a randomized, double-blind trial in pediatric asthma management. Early-life supplementation with B. breve has also been associated with reduced allergic sensitization.

Bifidobacterium infantis M-63 was part of a tested Bifidobacterium mixture (BB536, M-63, M-16V) in children with seasonal allergic rhinitis and intermittent asthma, showing improved quality of life. It is one of the dominant bifidobacteria in the infant gut, supporting early immune development, and is linked in clinical and mechanistic literature to allergy risk reduction when present in sufficient abundance in early life.

Bifidobacterium lactis (also known as B. animalis subsp. lactis) has been studied in infants and children for allergy prevention and treatment. RCTs have found that supplementation with Lactobacillus rhamnosus HN001 and B. lactis HN019 perinatally reduced prevalence of early atopic dermatitis, with specific Toll-like receptor genetic variations associated with protection. It is also an ingredient in specialized infant formulas studied for atopic dermatitis reduction.

Bifidobacterium longum has been studied in children with allergic rhinitis and atopic dermatitis. A 2024 randomized, double-blind, placebo-controlled trial in children aged 6–19 found that a mixture of B. longum and Lactobacillus plantarum significantly improved nasal symptom scores and quality of life in perennial allergic rhinitis. Meta-analyses support its role in reducing eczema and wheezing in children, and mechanistic work shows it lowers Th2 cytokines and serum IgE.

Butterbur (Petasites hybridus) extract has been studied in multiple RCTs for allergic rhinitis. A 2002 BMJ RCT found butterbur extract Ze 339 was as effective as cetirizine in reducing hay fever symptoms without causing drowsiness. A systematic review identified six RCTs showing P. hybridus superior to placebo or similarly effective to non-sedating antihistamines for intermittent allergic rhinitis. NCCIH (NIH) confirms studies suggest butterbur leaf extract may help symptoms of allergic rhinitis orally.

Lactobacillus acidophilus has been studied in pediatric allergy contexts, with some RCTs showing reductions in atopic dermatitis severity and IgE levels in children. A 2025 network meta-analysis identified Lactobacillus acidophilus LB as an effective candidate for IgE reduction in children with food allergy. It was also included in multi-strain probiotic combinations used in pediatric allergy prevention trials.

Lactobacillus casei has been studied in combination with L. rhamnosus strains in children with atopic dermatitis and cow's milk protein allergy, showing superiority over placebo in improving SCORAD severity in a 2021 multicenter RCT. It also appears in probiotic pediatric asthma management trials. Its mechanism involves immune modulation through cytokine shifts and gut microbiota restoration. Evidence is strain-specific and generally positive in allergic-sensitized children.

Lactobacillus plantarum in combination with Bifidobacterium longum (NVP-1703, 10^10 CFU/day) was tested in a randomized, double-blind, placebo-controlled RCT in children aged 6–19 with perennial allergic rhinitis. After 4 weeks, TNSS and quality-of-life scores improved significantly versus placebo, accompanied by Th2 cytokine reduction. L. plantarum also appears in systematic reviews linking early-life probiotic use to reduced eczema and wheezing in children.

Lactobacillus reuteri DSM 12246 was combined with L. rhamnosus 19070-2 in a double-blind, placebo-controlled, crossover RCT in children aged 1–13 with atopic dermatitis. The combination significantly reduced SCORAD and showed greater effects in allergic patients. L. reuteri also appears in pediatric allergy trials cited in recent meta-analyses supporting probiotic use in childhood eczema and allergic disease.

Multiple randomized controlled trials (RCTs) have evaluated Lactobacillus rhamnosus strains in children with atopic dermatitis (eczema) and cow's milk protein allergy. A 2021 multicenter RCT of 151 children under age 2 found a probiotic preparation including L. rhamnosus ŁOCK strains superior to placebo in improving SCORAD severity scores, especially in allergen-sensitized patients. The strain modulates Th1 cytokines and regulatory IL-10 while suppressing pro-allergic IL-5. A 2025 network meta-analysis identified Lactobacillus rhamnosus GG (LGG) as standout for pediatric food allergy management.

Omega-3 fatty acids (from fish oil) have been evaluated in pediatric RCTs for atopic dermatitis. A 2024 longitudinal, prospective, randomized, triple-blind, placebo-controlled RCT in children aged 1–8 with moderate-to-severe AD found omega-3 combined with GLA significantly reduced SCORAD (median from 42 to 25, p<0.001), decreased topical corticosteroid use, and improved itch, sleep, and QoL. Some meta-analyses note mixed results; maternal omega-3 intake during pregnancy reduces eczema and egg allergy risk in newborns.

Purple butterbur root (Petasites hybridus root) contains petasin and isopetasin, compounds with established anti-leukotriene and antihistamine-like properties studied in RCTs for allergic rhinitis. NIH/NCCIH notes that butterbur root extract may reduce frequency of migraines in adults and children, and studies of butterbur leaf extract suggest it may help symptoms of allergic rhinitis. PA-free preparations are required for safe use.

Quercetin is a flavonoid with well-documented mast cell-stabilizing and anti-histamine properties. It inhibits IgE-mediated mast cell degranulation, reduces histamine, IL-4, IL-5, TNF-α, and eosinophil infiltration in preclinical models. A 2025 systematic review and meta-analysis of preclinical studies found it significantly reduces IgE, OVA-specific IgE, histamine, and inflammatory cytokines. A pediatric RCT (PMC, 2025) used quercetin as part of a nutraceutical add-on in seasonal allergic rhinitis in children, showing symptom reduction. Human clinical data remain limited but direction-consistent.

Vitamin C (ascorbic acid) is a potent antioxidant that has been hypothesized to attenuate allergic disease mechanisms involving oxidative stress and type 2 immune reactions. A 2025 narrative review (PMC12191256, journal Children) examined vitamin C's role in preventing and managing asthma, allergic rhinitis, and atopic dermatitis in pediatric populations. Studies have found zinc and vitamin C deficiency correlated with more severe asthma. Evidence is mixed for direct supplementation effects but some benefit is observed for asthma symptom reduction.

Vitamin D3 deficiency is consistently associated with increased risk of atopic dermatitis, asthma, and allergic sensitization in children. A Spanish birth cohort (n=2525) found higher child 25(OH)D3 at age 4 was associated with significantly lower odds of atopic eczema from ages 4–9 (aOR=0.90 per 5 ng/ml). Small RCTs show vitamin D3 supplementation reduces eczema severity and decreases asthma exacerbation risk in children. A 2022 systematic review and meta-analysis of pediatric RCTs evaluated vitamin D supplementation specifically in children with allergic diseases.

Zinc supports the immune system and has anti-inflammatory effects. Studies in asthmatic children found zinc deficiency correlated with more severe airway obstruction (reduced FEV1 and FEV1/FVC). Zinc deficiency has been associated with increased allergic disease severity in children. A 2025 review in Children (MDPI) published as part of vitamin C and allergy research notes that all enrolled asthmatic pediatric patients had zinc deficiency, with plasma zinc positively correlated with lung function parameters.