Polyunsaturated fatty acids (PUFAs) are involved both in immune system regulation and inflammation. In particular, within the PUFAs category, omega-3 (ω-3) may reduce inflammation, whereas omega-6 (ω-6) PUFAs are generally considered to have a proinflammatory effect. Recent evidence highlights an imbalance in the ω-3:ω-6 ratio with an increased intake of ω-6, as a consequence of the shift towards a westernized diet. In critical age groups such as infants, toddlers and young children, as well as pregnant and lactating women or fish allergic patients, ω-3 intake may be inadequate. This review aims to discuss the potential beneficial effects of PUFAs on pediatric food allergy prevention and treatment, both at prenatal and postnatal ages. Data from preclinical studies with PUFAs supplementation show encouraging effects in suppressing allergic response. Clinical studies results are still conflicting about the best timing and dosages of supplementation and which individuals are most likely to benefit; therefore, it is still not possible to draw firm conclusions. With regard to food-allergic children, it is still debated whether PUFAs could slow disease progression or not, since consistent data are lacking. In conclusion, more data on the effects of ω-3 PUFAs supplementation alone or in combination with other nutrients are warranted, both in the general and food allergic population.

Postbiotics are commonly defined as preparations of inanimate probiotics and/or their cellular components and/or their metabolites/end products that confer health benefits on the host. They have been suggested as a promising strategy to limit infectious diseases. Emerging evidence support the efficacy of the postbiotic derived from cow’s milk fermentation with the probiotic Lacticaseibacillus paracasei CBAL74 (FM-CBAL74) in preventing pediatric infectious diseases. We aimed at reviewing the evidence available.

Background: Alterations of epithelial barrier integrity and immune response play a key role in the pathogenesis of allergic diseases and represent promising targets for nutritional interventions. Selected postbiotics and plant-derived compounds have been proposed as potential modulators of epithelial barrier and immune function. Methods: We investigated the effects of a novel food supplement combining heat-inactivated Lacticaseibacillus rhamnosus GG, butyrate, Quercetin, and Perilla frutescens extracts on epithelial barrier function and innate immunity in an experimental model of the human epithelial gut barrier. Results: Exposure to the food supplement resulted in epithelial barrier integrity enhancement, consisting of increased transepithelial electrical resistance, tight-junction protein expression, mucus production, and enterocyte differentiation. Moreover, the formulation markedly stimulated the expression of the innate immunity peptides β-defensin-2 and cathelecidin LL-37. Conclusions: The novel food supplement induces a beneficial modulation of the epithelial gut barrier and immune response. These findings support its potential use as a functional food strategy to restore mucosal homeostasis and to promote immune tolerance in allergic diseases.

Intake of a postbiotic product can support immunity depending on specific conditions of the consumer. The present study evaluates the potential impact of baseline values on the change of various immune factors (α-defensin, β-defensin, cathelicidin, and secretory IgA) after three months of consumption of a postbiotic based on cow’s milk fermented with Lactobacillus paracasei CBA L74 in a young population. For the analysis, raw data of three studies were used in a multivariate analysis applying confounding factors. One study in newborns demonstrated that intake of the postbiotic yielded an increase in the concentrations of α-defensin and secretory IgA (at least p < 0.02), while for all factors, except β-defensin, the higher the baseline values the lower the increase (at least p < 0.002). Two combined studies in young children (aged 1–4 years) showed an increase in the concentration of all factors after intake of the postbiotic (at least p < 0.003), but now showing the higher the baseline values the higher the increase after three months (at least p < 0.02) in only the postbiotic group. It is concluded that consumption of the postbiotic leads to a baseline- and age-dependent increase in the concentrations of the immune factors under study in both newborns and young children. It is hypothesized that maturation of the immune system leads to different effects on optimizing host defense factors via this postbiotic intake.