Consumption of omega3-fatty acids during perinatal life: role in immuno-modulation and allergy prevention

Cost-utility analysis of prenatal supplementation with long-chain n-3 fatty acids to reduce the incidence of wheezing and asthma in neonates

INTRODUCTION

Recent evidence indicates that Maternal Supplementation with Long-Chain n-3 Fatty Acids During Pregnancy Substantially Mitigates Offspring's Asthma. Adding information regarding its cost-utility will undoubtedly allow its adoption, or not, in clinical practice guidelines. This research aimed to determine the cost-utility of LCPUFA supplementation in the third trimester of pregnancy to reduce the risk of wheezing and asthma in infants in Colombia.

METHODS

A Markov model was formulated to estimate the cost and quality-adjusted life-years (QALYs) attributed to individuals with severe asthma in Colombia, with a time horizon of five years and a cycle length of two weeks. Probabilistic sensitivity analysis and a value of information (VOI) analysis were conducted to evaluate the uncertainties in the case base. Cost-utility was assessed at a willingness-to-pay (WTP) value of US$5180. All costs were adjusted to 2021 with a 5% annual discounting rate for cost and QALYs.

RESULTS

The mean incremental cost of LCPUFA supplementation versus no supplementation was US-43.65. The mean incremental benefit of LCPUFA supplementation versus no supplementation was 0.074 QALY. The incremental cost-utility ratio was estimated at US$590.68 per QALY. The outcomes derived from our primary analysis remained robust when subjected to variations in all underlying assumptions and parameter values.

CONCLUSION

Supplementation strategy supplementation with long-chain n-3 fatty acids during pregnancy is cost-effective in reducing the risk of developing asthma during childhood in Colombia.

Dietary long-chain omega 3 fatty acids modify sphingolipid metabolism to facilitate airway hyperreactivity

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are essential nutrients that can affect inflammatory responses. While n-3 PUFAs are generally considered beneficial for cardiovascular disease and obesity, the effects on asthma, the most common inflammatory lung disease are unclear. While prenatal dietary n-3 PUFAs decrease the risk for childhood wheezing, postnatal dietary n-3 PUFAs can worsen allergic airway inflammation. Sphingolipid metabolism is also affected by dietary n-3 PUFAs. Decreased sphingolipid synthesis leads to airway hyperreactivity, besides inflammation, a cardinal feature of asthma, and common genetic asthma risk alleles lead to lower sphingolipid synthesis. We investigated the effect of dietary n-3 PUFAs on sphingolipid metabolism and airway reactivity. Comparing a fish-oil diet with a high n-3 PUFA content (FO) to an isocaloric coconut oil-enriched diet (CO), we found an n-3 PUFA-dependent effect on increased airway reactivity, that was not accompanied by inflammation. Lung and whole blood content of dihydroceramides, ceramides, sphingomyelins, and glucosylceramides were lower in mice fed the n-3 PUFA enriched diet consistent with lower sphingolipid synthesis. In contrast, phosphorylated long chain bases such as sphingosine 1-phosphate were increased. These findings suggest that dietary n-3 PUFAs affect pulmonary sphingolipid composition to favor innate airway hyperreactivity, independent of inflammation, and point to an important role of n-3 PUFAs in sphingolipid metabolism.

Pediatric Obesity-Related Asthma: The Role of Nutrition and Nutrients in Prevention and Treatment

Childhood obesity rates have dramatically risen in numerous countries worldwide. Obesity is likely a factor in increased asthma risk, which is already one of the most widespread chronic respiratory pathologies. The pathogenic mechanism of asthma risk has still not yet been fully elucidated. Moreover, the role of obesity-related inflammation and pulmonary overreaction to environmental triggers, which ultimately result in asthma-like symptoms, and the importance of dietary characteristics is well recognized. Diet is an important adjustable element in the asthma development. Food-specific composition of the diet, in particular fat, sugar, and low-quality nutrients, is likely to promote the chronic inflammatory state seen in asthmatic patients with obesity. An unbalanced diet or supplementation as a way to control asthma more efficiently has been described. A personalized dietary intervention may improve respiratory symptoms and signs and therapeutic response. In this narrative review, we presented and discussed more recent literature on asthma associated with obesity among children, focusing on the risk of asthma among children with obesity, asthma as a result of obesity focusing on the role of adipose tissue as a mediator of systemic and local airway inflammation implicated in asthma regulation, and the impact of nutrition and nutrients in the development and treatment of asthma. Appropriate early nutritional intervention could possibly be critical in preventing and managing asthma associated with obesity among children.

Nutritional Interventions to Prevent the Development of Atopic Diseases: A Focus on Cow's Milk Allergy

In the western world the prevalence of atopic diseases such as food allergies is increasing highly significantly. One of the earliest and most prevalent food allergies occurring in the first year of life is cow's milk allergy. No treatment is available and only avoidance of the cow's milk allergens prevents the occurrence of an allergic reaction. Since cow's milk allergic children have an increased risk of developing other allergies later in life, investigating nutritional strategies to prevent the development of cow's milk allergy by developing oral tolerance is of high interest. Nutritional components such as prebiotics, probiotics, synbiotics and long-chain polyunsaturated fatty acids possess potential to support the maturation of the immune system early in life that might prevent the development of cow's milk allergy. The available research, so far, shows promising results particularly on the development of eczema. However, the preventive effects of the nutritional interventions on the development of food allergy are inconclusive. Future research may benefit from the combination of various dietary components. To clarify the preventive effects of the nutritional components in food allergy more randomized clinical trials are needed.

Childhood Origins of Adult Lung Disease as Opportunities for Prevention

Prenatal and childhood exposures have been shown to impact lung development, lung function trajectory, and incidence and prevalence of respiratory disease. Early life may serve as a window of susceptibility to such exposures, with the potential to influence lifelong respiratory health. Risk factors encountered in early life with potentially durable impact on lung health include prematurity, respiratory viral illness, allergen sensitization and exposure, tobacco use and exposure, indoor and outdoor pollution, diet, and obesity. These exposures vary in the extent to which they are modifiable, and interventions aimed at reducing harmful exposures range from individual-level behavior modification to policy initiatives implemented to promote population health. For many exposures, including tobacco-related exposures, multilevel interventions are needed. Future research is needed to provide insight as to early-life interventions to promote optimal lung growth and prevent development of chronic respiratory disease. Clinicians should play an active role, assisting individual patients in avoiding known detrimental exposures including maternal smoking during pregnancy and initiation of active smoking. Clinicians can be empowered by evidence to support policies promoting reduction of population-level risk factors, such as restriction on electronic cigarette sales and legislation to uphold air quality standards, to encourage attainment of maximal lung function and reduce risk of chronic lung disease.

Diet Modifications in Primary Prevention of Asthma. Where Do We Stand?

The steep increase in asthma prevalence, observed worldwide in recent decades, has created an urgent need to search for effective methods of its prevention. Among other environmental factors, changes in diet habits and the potential influence of individual food components on immunological processes have been extensively studied as a potential method of intervention in primary prevention of asthma. The preventive role of some nutrients has been confirmed: unpasteurized milk reduced the risk of asthma in epidemiological studies, vitamin D supplementation was effective in preventing the transient forms of wheezing in small children and high maternal intake of fish oil reduced the risk of persistent wheeze and asthma in children. However, not all studies provided consistent results, and many food ingredients are still pending for defining their role in asthma development. Moreover, a novel approach looking not only at single food ingredients, but the whole dietary patterns and diversity has recently been proposed. In this paper, we discuss the current role of nutrients in asthma primary prevention and the reasons for inconsistencies in the study results. We look at single diet components, but also the whole dietary patterns. We describe the proposed mechanisms of action at different stages of life, identify the role of modifiers and delineate future perspectives on the application of nutrients in targeting strategies for asthma primary prevention.

Feeding a Bioactive Oil Enriched in Stearidonic Acid during Early Life Influences Immune System Maturation in Neonatal Sprague-Dawley Rats

BACKGROUND

Long-chain n-3 PUFAs (LCPUFAs) improve immune development and reduce atopic disease risk in infants. Stearidonic acid (SDA) can be a substrate for biosynthesis of n-3 LCPUFAs.

OBJECTIVE

We aimed to determine the effect of feeding an SDA-enriched diet during suckling and weaning on offspring immunity and ability to develop oral tolerance (OT).

METHODS

Pregnant Sprague-Dawley rats were randomly assigned to consume either SDA (3 g SDA/100 g fat) or a control (no SDA) diet, 5 d before parturition and through lactation (21 d). For the OT treatment, 10-d-old pups were fed ovalbumin (Ova; 200 μL of 8 mg/mL) or placebo daily for 5 d. At 21 d, pups (both sexes) were weaned to their respective maternal diet until 6 wk of age or killed. Systemic immunization was induced using Ova (in 3-wk-old pups) or Ova + adjuvant (in 6-wk-old pups). The effect of suckling diet (in 3-wk-old pups) or weaning diet (in 6-wk-old pups) and OT treatment on immune function (main outcome) in spleen and blood was compared using 2-factor ANOVA.

RESULTS

An SDA-enriched maternal diet, compared with the control diet, resulted in higher plasma phospholipid (PL) EPA (15 times higher), docosapentaenoic acid (DPA; 3 times higher), and DHA (1.3 times higher) content in 3-wk-old pups, accompanied by higher B-cell function [plasma ovalbumin-specific IgG1 (Ova-IgG1), 2 times higher] ( P < 0.05). Compared with pups fed a control diet, the splenocytes from these pups had more (23%) helper T (Th) cells (CD3+CD4+) and activated (12%) Th cells (CD4+CD28+) (P < 0.02) than controls. At 6 wk, the SDA group had 30% more CD4+CD25+ splenocytes, and when stimulated ex vivo with LPS, produced less inflammatory IL-6 (50%) and TNF-α (30%) and more immunoregulatory IL-10 (45%) cytokines (P < 0.05) than the control group. The Ova-exposed group had less (30%) plasma Ova-IgG1 than the placebo group. Splenocytes and plasma PLs from the 6-wk-old SDA group had more EPA (2x) and DPA (3.5x) (P < 0.05), but not DHA, than the control group.

CONCLUSIONS

Feeding SDA during lactation and weaning altered immune responses in directions believed to be beneficial.

Prenatal dietary supplements influence the infant airway microbiota in a randomized factorial clinical trial

Maternal dietary interventions during pregnancy with fish oil and high dose vitamin D have been shown to reduce the incidence of asthma and wheeze in offspring, potentially through microbial effects in pregnancy or early childhood. Here we analyze the bacterial compositions in longitudinal samples from 695 pregnant women and their children according to intervention group in a nested, factorial, double-blind, placebo-controlled, randomized trial of n-3 long-chain fatty acids and vitamin D supplementation. The dietary interventions affect the infant airways, but not the infant fecal or maternal vaginal microbiota. Changes in overall beta diversity are observed, which in turn associates with a change in immune mediator profile. In addition, airway microbial maturation and the relative abundance of specific bacterial genera are altered. Furthermore, mediation analysis reveals the changed airway microbiota to be a minor and non-significant mediator of the protective effect of the dietary interventions on risk of asthma. Our results demonstrate the potential of prenatal dietary supplements as manipulators of the early airway bacterial colonization.

Fish Consumption at One Year of Age Reduces the Risk of Eczema, Asthma and Wheeze at Six Years of Age

Background: The role of dietary fish and n-3 polyunsaturated fatty acids (n-PUFAs) in the primary prevention of allergic diseases remains uncertain. The aim of this study was to investigate associations between the consumption of fish and cod liver oil (rich in n-PUFAs) from pregnancy to the first two years of life, and parental reported allergic diseases at six years of age. Methods: We used data from the Prevention of Allergy among Children in Trondheim study and included mother-infant pairs who had submitted questionnaires detailing both maternal or infant diet and allergic disease at six years of age. Results: Eating fish at least once a week at one year of age was associated with a 28%, 40% and 34% reduction in the odds of current eczema, asthma, and wheeze at six years of age, respectively. Cod liver oil consumption at least four times per week at one year of age tended to be associated with a lower risk of allergy-related outcomes at six years. We found no consistent associations between allergy-related outcomes and fish or cod liver oil consumption by mothers. Conclusion: The preventive effect of fish consumption is best achieved by increasing dietary fish in the first year of life.

Preeclampsia Associates with Asthma, Allergy, and Eczema in Childhood

RATIONALE

Preeclampsia reflects an unusual increase in systemic inflammation during pregnancy.

OBJECTIVES

We studied associations between preeclampsia and asthma, allergy, and eczema in Copenhagen Prospective Studies on Asthma in Childhood₂₀₀₀ (COPSAC₂₀₀₀) and in national registries.

METHODS

COPSAC₂₀₀₀ is a high-risk birth cohort of 411 Danish children. Asthma, allergy, and eczema were diagnosed prospectively, and lung function measured at age 1 month and 7 years. Sensitization was evaluated at age 6 months, 18 months, 4 years, and 6 years by skin prick tests and IgE measurements. The register-based cohort included 1.7 million children from Danish national registries in the 35-year period 1977-2012. Children born to mothers with preeclampsia were analyzed regarding risk of asthma, allergy, and eczema.

MEASUREMENTS AND MAIN RESULTS

In the COPSAC₂₀₀₀ cohort, 5.6% (n = 23) were diagnosed with preeclampsia. Preeclampsia was associated with increased risk of treatment with inhaled corticosteroids at age 7 years (adjusted odds ratio, 4.01 [95% confidence interval (CI), 1.11-14.43]; P = 0.0337), increased bronchial responsiveness to methacholine (adjusted β-coefficient log-μmol, -0.80 [95% CI, -1.55 to -0.06]; P = 0.0348), and allergic rhinitis (adjusted odds ratio, 4.83 [95% CI, 1.58-14.78]; P = 0.0057) in the 7-year-old children. Furthermore, the children had an increased risk of sensitization to both aeroallergens and food allergens, and increased amount of total IgE during childhood. In the registry-based cohort, 3.7% (n = 62,728) were born to mothers with preeclampsia. Preeclampsia was associated with increased risk of asthma, eczema, and aeroallergen and food allergy, especially pronounced after a duration of preeclampsia of 14 days or more. Maternal asthma increased the risk of preeclampsia.

CONCLUSIONS

Preeclampsia is a shared prenatal risk factor for asthma, eczema, and allergy in childhood pointing toward in utero immune programming of the child.

Fish Oil-Derived Fatty Acids in Pregnancy and Wheeze and Asthma in Offspring

BACKGROUND

Reduced intake of n-3 long-chain polyunsaturated fatty acids (LCPUFAs) may be a contributing factor to the increasing prevalence of wheezing disorders. We assessed the effect of supplementation with n-3 LCPUFAs in pregnant women on the risk of persistent wheeze and asthma in their offspring.

METHODS

We randomly assigned 736 pregnant women at 24 weeks of gestation to receive 2.4 g of n-3 LCPUFA (fish oil) or placebo (olive oil) per day. Their children formed the Copenhagen Prospective Studies on Asthma in Childhood₂₀₁₀ (COPSAC₂₀₁₀) cohort and were followed prospectively with extensive clinical phenotyping. Neither the investigators nor the participants were aware of group assignments during follow-up for the first 3 years of the children's lives, after which there was a 2-year follow-up period during which only the investigators were unaware of group assignments. The primary end point was persistent wheeze or asthma, and the secondary end points included lower respiratory tract infections, asthma exacerbations, eczema, and allergic sensitization.

RESULTS

A total of 695 children were included in the trial, and 95.5% completed the 3-year, double-blind follow-up period. The risk of persistent wheeze or asthma in the treatment group was 16.9%, versus 23.7% in the control group (hazard ratio, 0.69; 95% confidence interval [CI], 0.49 to 0.97; P=0.035), corresponding to a relative reduction of 30.7%. Prespecified subgroup analyses suggested that the effect was strongest in the children of women whose blood levels of eicosapentaenoic acid and docosahexaenoic acid were in the lowest third of the trial population at randomization: 17.5% versus 34.1% (hazard ratio, 0.46; 95% CI, 0.25 to 0.83; P=0.011). Analyses of secondary end points showed that supplementation with n-3 LCPUFA was associated with a reduced risk of infections of the lower respiratory tract (31.7% vs. 39.1%; hazard ratio, 0.75; 95% CI, 0.58 to 0.98; P=0.033), but there was no statistically significant association between supplementation and asthma exacerbations, eczema, or allergic sensitization.

CONCLUSIONS

Supplementation with n-3 LCPUFA in the third trimester of pregnancy reduced the absolute risk of persistent wheeze or asthma and infections of the lower respiratory tract in offspring by approximately 7 percentage points, or one third. (Funded by the Lundbeck Foundation and others; ClinicalTrials.gov number, NCT00798226 .).

Evidence for the essentiality of arachidonic and docosahexaenoic acid in the postnatal maternal and infant diet for the development of the infant’s immune system early in life

Long-chain polyunsaturated fatty acids (LCPUFA), especially the balance between arachidonic (AA) and docosahexaenoic (DHA) acids are known to have important immunomodulatory roles during the postnatal period when the immune system is rapidly developing. AA and DHA are required in infant formula in many countries but are optional in North America. The rationale for adding these LCPUFA to full-term formula is based on their presence in breast milk and randomized controlled studies that suggest improved cognitive function in preterm infants, but results are more variable in full-term infants. Recently, the European Food Safety Authority has proposed, based on a lack of functional evidence, that AA is not required in infant formula for full-term infants during the first year of life but DHA should remain mandatory. The purpose of this review is to review the evidence from epidemiological and intervention studies regarding the essentiality of AA and DHA in the postnatal infant and maternal diet (breast-feeding) for the immune system development early in life. Although studies support the essentiality of DHA for the immune system development, more research is needed to rule out the essentiality of AA. Nevertheless, intervention studies have demonstrated improvement in many markers of immune function in infants fed formula supplemented with AA and DHA compared with unsupplemented formula, which appears to consistently result in beneficial health outcomes including reduction in the risk of developing allergic and atopic disease early in life.

Prenatal Omega-3 Supplementation and Eczema Risk among Offspring at Age 36 Months

BACKGROUND

Long-term follow-up was completed in 84 mother-infant pairs of 118 women who completed a randomized controlled trial of prenatal supplementation with EPA- or DHA-rich fish oil or soy oil placebo. The goal of this study was to determine whether prenatal omega-3 fatty acid supplementation protects offspring against development of early childhood allergies.

METHODS AND FINDINGS

Assessment of childhood allergic/atopic disease among offspring at age 36 months was performed by maternal interview using the National Health Interview Survey (NHIS) questions for childhood digestive allergies, wheezing, eczema or skin allergy, and respiratory allergy. Multiple logistic regressions examined the association between prenatal supplementation and childhood outcomes, adjusted for covariates. Eczema was reported in 26/84 (31%) of offspring at age 36 months, and was significantly more prevalent in the omega-3 supplementation groups vs. placebo: EPA 13/31 (41.9%); DHA 10/26 (38.5%); placebo 3/27 (11.1%), p=0.019. Compared to placebo, EPA and DHA were associated with ≥5 times risk of offspring eczema [odds ratios (ORs): EPA 5.8 (95% CI 1.4-23.3); DHA 5.0 (95% CI 1.2-21.0)]. After adjusting for other potential risk factors (race, birth weight, vaginal/Cesarean delivery, and maternal eczema) the magnitudes of association for omega-3 supplementation increased: EPA OR 8.1 (95% CI 1.4-45.6); DHA OR 9.6 (95% CI 1.6-58.5). Maternal eczema was also significantly associated with offspring eczema in the adjusted model: OR 10.8 (95% CI 2.1-54.3).

CONCLUSION

Contrary to our hypothesis, acids supplementation compared to soy oil was associated with a substantial increase in risk of childhood eczema. This association was not observed on childhood respiratory or digestive outcomes. It is unclear if these findings were driven by unfavorable effects of omega-3s, or whether there may have been unanticipated protective effects of the soy-based placebo with regards to eczema.

Exploring the Effects of Omega-3 and Omega-6 Fatty Acids on Allergy Using a HEK-Blue Cell Line

BACKGROUND

Allergic reactions can result in life-threatening situations resulting in high economic costs and morbidity. Therefore, more effective reagents are needed for allergy treatment. A causal relationship has been suggested to exist between the intake of omega-3/6 fatty acids, such as docosahexanoic acid (DHA), eicosapentanoic acid (EPA), docosapentanoic acid (DPA) and arachidonic acid (AA), and atopic individuals suffering from allergies. In allergic cascades, the hallmark cytokine IL-4 bind to IL-4 receptor (IL-4R) and IL-13 binds to IL-13 receptor (IL-13R), this activates the STAT6 phosphorylation pathway leading to gene activation of allergen-specific IgE antibody production by B cells. The overall aim of this study was to characterize omega-3/6 fatty acids and their effects on STAT6 signaling pathway that results in IgE production in allergic individuals.

METHODS

The fatty acids were tested in vitro with a HEK-Blue IL-4/IL-13 reporter cell line model, transfected with a reporter gene that produces an enzyme, secreted embryonic alkaline phosphatase (SEAP). SEAP acts as a substitute to IgE when cells are stimulated with bioactive cytokines IL-4 and/or IL-13.

RESULTS

We have successfully used DHA, EPA and DPA in our studies that demonstrated a decrease in SEAP secretion, as opposed to an increase in SEAP secretion with AA treatment. A statistical Student's t-test revealed the significance of the results, confirming our initial hypothesis.

CONCLUSION

We have successfully identified and characterised DHA, EPA, DPA and AA in our allergy model. While AA was a potent stimulator, DHA, EPA and DPA were potential inhibitors of IL-4R/IL-13R signalling, which regulates the STAT6 induced pathway in allergic cascades. Such findings are significant in the future design of dietary therapeutics for the treatment of allergies.

Omega-3 long-chain PUFA intake during pregnancy and allergic disease outcomes in the offspring: a systematic review and meta-analysis of observational studies and randomized controlled trials

BACKGROUND

There is some evidence that increased maternal intake of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFAs) during pregnancy may reduce the incidence of immunoglobulin E (IgE)-mediated allergic disease.

OBJECTIVE

We aimed to evaluate prenatal n-3 LC-PUFA dietary exposure in observational studies and n-3 LC-PUFA supplementation in randomized controlled trials (RCTs) on outcomes of IgE-mediated allergic disease.

DESIGN

We conducted searches of the Cochrane Central Register of Controlled Trials, PubMed, Ovid MEDLINE, EMBASE, CINAHL, SCOPUS, and Web of Science to 30 July 2015. We included prospective cohort studies that showed an association between maternal fish or n-3 LC-PUFA intake during pregnancy and RCTs with a prenatal intervention to modify maternal n-3 LC-PUFA intake and outcomes of allergic disease (eczema, rhino-conjunctivitis, asthma) or sensitization in the offspring.

RESULTS

A total of 13 publications from 10 prospective cohort studies and 7 publications representing 5 unique RCTs were included. Three RCTs were combined in a meta-analysis for selected outcomes. Nine of 13 observational study publications and 5 of 7 publications from RCTs found a protective association between increased prenatal n-3 LC-PUFA or fish intake and incidence of allergic disease symptoms in the child. Meta-analysis was limited because of the heterogeneity of the RCTs. Pooled results showed a significant reduction in the incidence of "atopic eczema," "any positive SPT [skin-prick test]," "sensitization to egg," and "sensitization to any food" in the first 12 mo of life [RRs (95% CIs): 0.53 (0.35, 0.81), P = 0.004; 0.68 (0.52-0.89), P = 0.006; 0.55 (0.39-0.76), P = 0.0004; and 0.59 (0.46, 0.76), P < 0.0001, respectively].

CONCLUSIONS

Our systematic review and meta-analysis was suggestive of benefits of increased n-3 LC-PUFAs in the maternal diet and outcomes of childhood allergic disease. However, due to the inconsistency in results, the hypothesis linking maternal n-3 LC-PUFA intake to childhood allergic disease cannot unequivocally be confirmed or rejected.

DHA-rich tuna oil effectively suppresses allergic symptoms in mice allergic to whey or peanut

BACKGROUND

Supplementation with long-chain n-3 polyunsaturated fatty acids (LCPUFAs) has been found to reduce the development of allergic disease.

OBJECTIVE

The aim of this study was to compare the effectiveness of fish oil diets rich in eicosapentaenoic acid (20:5n-3; EPA) or docosahexaenoic acid (22:6n-3; DHA) in suppressing food allergic symptoms.

METHODS

Mice were fed a control diet (10% soybean oil) or fish oil diet rich in EPA (4% soybean oil + 6% EPA oil containing 28.8% EPA and 13.7% DHA) or DHA (4% soybean oil + 6% DHA oil containing 7% EPA and 27.8% DHA), starting 14 d before and for 5 wk during oral sensitization with peanut extract (PE) or whey. Acute allergic skin responses, serum immunoglobulins (Igs), and mucosal mast cell protease-1 (mmcp-1) were assessed. Hyperimmune serum was transferred to naive recipient mice fed the different diets.

RESULTS

The DHA diet effectively reduced the acute allergic skin response compared with the control or EPA diet in PE-allergic mice (control, 159 ± 15, or EPA, 129 ± 8, vs. DHA, 78 ± 7 μm; P < 0.0001 or P < 0.05, respectively). In contrast, both the DHA and EPA diets reduced the allergic skin response in whey allergic mice (control, 169 ± 9, vs. DHA, 91 ± 13, or EPA, 106 ± 14 μm; P < 0.001 or P < 0.01, respectively); however, only the DHA diet reduced mmcp-1 and whey-specific IgE and IgG1. The DHA and EPA diets also reduced the acute skin response in passively immunized mice.

CONCLUSIONS

The DHA-rich fish oil diet reduced allergic sensitization to whey and allergic symptoms in both PE- and whey-allergic mice. These data suggest that DHA-rich fish oil is useful as an intervention to prevent or treat food allergy symptoms.

Omega-3 fatty acid supplementation during pregnancy and respiratory symptoms in children

BACKGROUND

Prenatal consumption of omega-3 fatty acids can act as an adjuvant in the development of the immune system and affect the inflammatory response of neonates.

METHODS

We conducted a double-blind, randomized, placebo-controlled trial in Cuernavaca, Mexico. We randomly assigned 1,094 pregnant women (18-35 years of age) to receive 400 mg/d of algal docosahexaenoic acid (DHA) or placebo from 18 to 22 weeks of gestation through delivery. Birth outcomes and respiratory symptoms information until 18 months were available for 869 mother-child pairs. Questionnaires were administered, and maternal blood samples were obtained at baseline. Maternal atopy was based on specific IgE levels. During follow-up, information on infants' respiratory symptoms was collected through questionnaires administered at 1, 3, 6, 9, 12, and 18 months of age. Negative binomial regression models were used to evaluate the effect of supplementation on respiratory symptoms in infants.

RESULTS

Among infants of atopic mothers, a statistically significant protective effect of DHA treatment was observed on phlegm with nasal discharge or nasal congestion (0.78; 95% CI, 0.60-1.02) and fever with phlegm and nasal discharge or nasal congestion (0.53; 95% CI, 0.29-0.99), adjusting for potential confounders.

CONCLUSIONS

Our results support the hypothesis that DHA supplementation during pregnancy may decrease the incidence of respiratory symptoms in children with a history of maternal atopy.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00646360; URL: www.clinicaltrials.gov.

Dietary long chain n-3 polyunsaturated fatty acids prevent allergic sensitization to cow's milk protein in mice

BACKGROUND

Cow's milk allergy is one of the most common food allergies in children and no treatment is available. Dietary lipid composition may affect the susceptibility to develop allergic disease.

OBJECTIVE

Assess whether dietary supplementation with long chain n-3 polyunsaturated fatty acids (n-3 LCPUFA) prevents the establishment of food allergy.

METHODS

Mice were fed a control or fish oil diet before and during oral sensitization with whey. Acute allergic skin response, serum immunoglobulins as well as dendritic cell (DC) and T cell subsets in mesenteric lymph nodes (MLN), spleen and/or small intestine were assessed.

RESULTS

The acute allergic skin response was reduced by more than 50% in sensitized mice fed the fish oil diet compared to the control diet. In addition, anti-whey-IgE and anti-whey-IgG1 levels were decreased in the fish oil group. Serum transfer confirmed that the Th2-type humoral response was suppressed since sera of fish oil fed sensitized mice had a diminished capacity to induce an allergic effector response in naïve recipient mice compared to control sera. Furthermore, the acute skin response was diminished upon passive sensitization in fish oil fed naïve recipient mice. In addition, the percentage of activated Th1 cells was reduced by fish oil in spleen and MLN of sham mice. The percentage of activated Th2 cells was reduced in both sham- and whey-sensitized mice. In contrast, whey-sensitized mice showed an increased percentage of CD11b+CD103+CD8α- DC in MLN in association with enhanced FoxP3+ regulatory T cells (Treg) in spleen and intestine of fish oil fed whey-sensitized mice compared to sham mice.

CONCLUSIONS AND CLINICAL RELEVANCE

Dietary n-3 LCPUFA largely prevented allergic sensitization in a murine model for cow's milk allergy by suppressing the humoral response, enhancing local intestinal and systemic Treg and reducing acute allergic symptoms, suggesting future applications for the primary prevention of food allergy.

Prenatal determinants of cord blood total immunoglobulin E levels in Mexican newborns

Asthma and allergic diseases have increased worldwide; however, etilogic factors for this increase are still poor. Prenatal consumptions of fatty acids are hypothesized, although few clinical trials in developing countries have been performed. This study was designed to identify predictors of immunoglobulin E (IgE) levels in cord blood of Mexican newborns. Total IgE was measured in umbilical cord blood from 613 infants whose mothers participated in a double-blind randomized controlled trial of 400 mg of docosahexaenoic acid or placebo from 18 to 22 weeks gestation through delivery. During pregnancy, information on sociodemographic characteristics, environmental exposures, and perceived maternal stress were obtained; a maternal blood sample was also collected to determine atopy via specific IgE levels. Logistic regression models were used to identify the main prenatal predictors of detectable total IgE levels in cord blood. IgE was detectable in cord blood from 344 (53.7%) infants; the main predictors in multivariate analyses were maternal atopy (odds ratio [OR] = 1.69; 95% CI, 1.19-2.42; p < 0.05) and pesticide use in the home (OR = 1.49; 95% CI, 1.04-2.14; p < 0.05). When stratified by maternal atopy, season of birth was a significant predictor in the atopic group only (OR = 2.48; 95% CI, 1.00-6.16; p < 0.05), and pesticide use was a significant predictor for infants born to nonatopic mothers (OR = 1.64; 95% CI, 1.07-2.51; p < 0.05). No differences were seen in the proportion of infants with detectable IgE by treatment group. Prenatal supplementation with omega-3 polyunsaturated fatty acid did not alter the detectable cord blood IgE levels. Maternal atopy and pesticide use during pregnancy are strong predictors of cord blood IgE levels in newborns. Clinical trial NCT00646360, www.clinicaltrials.gov.

Supplementation with long chain polyunsaturated fatty acids in treatment of atopic dermatitis in children

Some recent studies indicate that unsaturated fatty acids, components of cellular membranes and precursors of immunomodulators, play a significant role in the pathogenesis of some symptoms of atopic dermatitis. Since they cannot be synthesized by the human body, they must be provided with nutrition as the so called exogenous fatty acids: linoleic (a precursor of arachidonic acid) and α-linolenic acid (a precursor of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)). Their deficiency facilitates the development of some disorders, e.g. of the cardiovascular system or of the nervous system, or becomes the cause of intensification of ailments in their course e.g. pruritus and dryness in atopic dermatitis. Though clinical examinations to date confirm the efficacy of fatty acid supplementation in treatment of atopic dermatitis, their results are not explicit.

Role of dietary long-chain polyunsaturated fatty acids in infant allergies and respiratory diseases

Maternal nutrition has critical effects on the developing structures and functions of the fetus. Malnutrition during pregnancy can result in low birth weight and small for gestational age babies, increase risk for infection, and impact the immune system. Long-chain polyunsaturated fatty acids (PUFAs) have been reported to have immunomodulatory effects. Decreased consumption of omega-6 PUFAs, in favor of more anti-inflammatory omega-3 PUFAs in modern diets, has demonstrated the potential protective role of omega-3 PUFAs in allergic and respiratory diseases. In this paper, we examine the role of PUFAs consumption during pregnancy and early childhood and its influence on allergy and respiratory diseases. PUFAs act via several mechanisms to modulate immune function. Omega-3 PUFAs may alter the T helper (Th) cell balance by inhibiting cytokine production which in turn inhibits immunoglobulin E synthesis and Th type 2 cell differentiation. PUFAs may further modify cellular membrane, induce eicosanoid metabolism, and alter gene expression. These studies indicate the benefits of omega-3 PUFAs supplementation. Nevertheless, further investigations are warranted to assess the long-term effects of omega-3 PUFAs in preventing other immune-mediated diseases, as well as its effects on the later immunodefense and health status during early growth and development.

Perinatal gene-gene and gene-environment interactions on IgE production and asthma development

Atopic asthma is a complex disease associated with IgE-mediated immune reactions. Numerous genome-wide studies identified more than 100 genes in 22 chromosomes associated with atopic asthma, and different genetic backgrounds in different environments could modulate susceptibility to atopic asthma. Current knowledge emphasizes the effect of tobacco smoke on the development of childhood asthma. This suggests that asthma, although heritable, is significantly affected by gene-gene and gene-environment interactions. Evidence has recently shown that molecular mechanism of a complex disease may be limited to not only DNA sequence differences, but also gene-environmental interactions for epigenetic difference. This paper reviews and summarizes how gene-gene and gene-environment interactions affect IgE production and the development of atopic asthma in prenatal and childhood stages. Based on the mechanisms responsible for perinatal gene-environment interactions on IgE production and development of asthma, we formulate several potential strategies to prevent the development of asthma in the perinatal stage.

Dietary fatty acid composition during pregnancy and the risk of asthma in the offspring

BACKGROUND

Fatty acids (FA) modulate the immune system, and it has been proposed that they affect the incidence of IgE-mediated allergic diseases. We explored the association of maternal dietary FA composition during pregnancy with the risk of asthma in the offspring.

METHODS

We analyzed data from the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Nutrition Study. Maternal dietary intake during pregnancy (8th month) was assessed by a validated 181-item food frequency questionnaire. The occurrence of asthma was assessed at the age of 5 yr with a questionnaire modified from the International Study of Asthma and Allergies in Childhood (ISAAC). Cox proportional hazards regression was used for the statistical analyses.

RESULTS

Low maternal intakes of α-linolenic acid (18:3n-3) [lowest quarter vs. mid-half HR 1.67 (95% CI 1.12-2.48)] and total n-3-polyunsaturated fatty acids (PUFA) [HR 1.66 (95% CI 1.11-2.48)] during pregnancy were associated with an increased risk of asthma in the offspring, while a low intake of arachidonic acid (20:4n-6) [HR 0.52 (95% CI 0.32-0.84)] and high intake of total saturated fatty acids [highest quarter vs. mid-half HR 0.55 (95% CI 0.34-0.90)] and palmitic acid (16:0) [HR 0.51 (95% CI 0.31-0.83)] were associated with a decreased risk of asthma. The ratios of n-6 to n-3-PUFA and 18:2n-6 to 18:3n-3, and the maternal intake of oils, fish and fish products, showed no association with the risk of asthma. The associations found were independent of several perinatal and clinical confounders.

CONCLUSION

Maternal intake of FA during pregnancy was associated with childhood asthma. Maternal α-linolenic acid, total n-3 PUFA and palmitic acid intake may decrease, while arachidonic acid intake may increase the risk of asthma in the offspring.

The effect of perinatal omega-3 fatty acid supplementation on inflammatory markers and allergic diseases: a systematic review

BACKGROUND

Maternal supplementation with omega-3 polyunsaturated fatty acids (n-3 PUFA) may modulate immune responses and allergy in neonates and children.

OBJECTIVE

To determine if n-3 PUFA supplementation during pregnancy and lactation reduces risk for childhood allergic disease.

SEARCH STRATEGY

We searched Medline and all evidence-based medicine reviews for randomised controlled trials comparing the effects of n-3 PUFA and placebo supplementation during pregnancy and/or lactation on childhood allergic diseases and inflammatory cytokines.

SELECTION CRITERIA

We included studies reporting on food allergy, response to the egg skin prick test (SPT), atopy and asthma in infancy and childhood as well as production of interleukin-13 and interferon-gamma, two cytokines involved in the pathogenesis of asthma. For assessment of inclusion, two authors reviewed all abstracts for suitability and independently extracted data.

DATA COLLECTION AND ANALYSIS

Two-by-two tables were constructed and odds ratios (OR) were calculated for the outcomes: response to the SPT, food allergy, atopy and asthma in childhood. The assays differed so data on inflammatory markers were reported in narrative form.

MAIN RESULTS

Five randomised controlled trials (n = 949) were included. n-3 PUFA supplementation during pregnancy reduced 12-month prevalence of positive egg SPT (two trials, 12/87 versus 32/100, OR 0.33, 95% CI 0.16, 0.70) and childhood asthma (two trials, 10/303 versus 17/179, OR 0.349, 95% CI 0.154, 0.788) and significantly reduced cord blood interleukin-13 levels. Supplementation during lactation did not prevent asthma, food allergy or atopy.

CONCLUSION

n-3 PUFA supplementation during pregnancy decreases childhood asthma and response to SPT.

A primary health-care intervention on pre- and postnatal risk factor behavior to prevent childhood allergy. The Prevention of Allergy among Children in Trondheim (PACT) study

Background

This study aimed to evaluate the impact of a primary prevention intervention program on risk behavior for allergic diseases among children up to 2 years of age. The setting was in ordinary pre- and postnatal primary health care in Trondheim, Norway.

Methods

The Prevention of Allergy among Children in Trondheim, Norway (PACT) study invited all pregnant women and parents to children up to 2 years of age in the community to participate in a non-randomized, controlled, multiple life-style intervention study. Interventional topics was increased dietary intake of cod liver oil and oily fish for women during pregnancy and for infants during the first 2 years of life, reduced parental smoking and reduced indoor dampness. A control cohort was established prior to the intervention cohort with "follow up as usual". Questionnaires were completed in pregnancy, 6 weeks after birth and at 1 and 2 years of age. Trends in exposure and behavior are described.

Results

Intake of oily fish and cod liver oil increased statistically significantly among women and infants in the intervention cohort compared to the control cohort. There was a low postnatal smoking prevalence in both cohorts, with a trend towards a decreasing smoking prevalence in the control cohort. There was no change in indoor dampness or in behavior related to non- intervened life-style factors.

Conclusions

The dietary intervention seemed to be successful. The observed reduced smoking behavior could not be attributed to the intervention program, and the latter had no effect on indoor dampness.

Trial registrations

(Current Controlled Trials registration number: ISRCTN28090297)

Fish oil supplementation in pregnancy and lactation may decrease the risk of infant allergy

Maternal intake of omega-3 (omega-3) polyunsaturated fatty acids (PUFAs) during pregnancy has decreased, possibly contributing to a current increased risk of childhood allergy.

AIM

To describe the effects of maternal omega-3 long-chain PUFA supplementation during pregnancy and lactation on the incidence of allergic disease in infancy.

METHODS

One hundred and forty-five pregnant women, affected by allergy themselves or having a husband or previous child with allergies, were included in a randomized placebo-controlled trial. Daily maternal supplementation with either 1.6 g eicosapentaenoic acid and 1.1 g docosahexaenoic acid or placebo was given from the 25(th) gestational week to average 3-4 months of breastfeeding. Skin prick tests, detection of circulating specific immunoglobulin E (IgE) antibodies and clinical examinations of the infants were performed.

RESULTS

The period prevalence of food allergy was lower in the omega-3 group (1/52, 2%) compared to the placebo group (10/65, 15%, p < 0.05) as well as the incidence of IgE-associated eczema (omega-3 group: 4/52, 8%; placebo group: 15/63, 24%, p < 0.05).

CONCLUSION

Maternal omega-3 fatty acid supplementation may decrease the risk of food allergy and IgE-associated eczema during the first year of life in infants with a family history of allergic disease.

Diet and asthma: looking back, moving forward

Asthma is an increasing global health burden, especially in the western world. Public health interventions are sought to lessen its prevalence or severity, and diet and nutrition have been identified as potential factors. With rapid changes in diet being one of the hallmarks of westernization, nutrition may play a key role in affecting the complex genetics and developmental pathophysiology of asthma. The present review investigates hypotheses about hygiene, antioxidants, lipids and other nutrients, food types and dietary patterns, breastfeeding, probiotics and intestinal microbiota, vitamin D, maternal diet, and genetics. Early hypotheses analyzed population level trends and focused on major dietary factors such as antioxidants and lipids. More recently, larger dietary patterns beyond individual nutrients have been investigated such as obesity, fast foods, and the Mediterranean diet. Despite some promising hypotheses and findings, there has been no conclusive evidence about the role of specific nutrients, food types, or dietary patterns past early childhood on asthma prevalence. However, diet has been linked to the development of the fetus and child. Breastfeeding provides immunological protection when the infant's immune system is immature and a modest protective effect against wheeze in early childhood. Moreover, maternal diet may be a significant factor in the development of the fetal airway and immune system. As asthma is a complex disease of gene-environment interactions, maternal diet may play an epigenetic role in sensitizing fetal airways to respond abnormally to environmental insults. Recent hypotheses show promise in a biological approach in which the effects of dietary factors on individual physiology and immunology are analyzed before expansion into larger population studies. Thus, collaboration is required by various groups in studying this enigma from epidemiologists to geneticists to immunologists. It is now apparent that this multidisciplinary approach is required to move forward and understand the complexity of the interaction of dietary factors and asthma.

[Effects of omega 3 supplementation in pregnant women]

Maternal nutrition is a major environmental factor, which can be modified and can affect fetal growth and development with potential long-term consequences. There is currently a strong mediatic pressure for supplementing diets with omega 3 fatty acids. Nevertheless, if beneficial effects seem to be confirmed in adults and in animal models, the evidence for favourable effects of omega 3 supplementation in pregnant women are less obvious. Indeed, there is a trend showing a positive effect on cerebral development, but long term effects have not been demonstrated and both the quantity of omega 3 and the omega 3:omega 6 ratios are not precisely determined. Numerous studies are needed, both in pregnant animal models and in patients, to unravel these effects.

Fish oil intake compared with olive oil intake in late pregnancy and asthma in the offspring: 16 y of registry-based follow-up from a randomized controlled trial

BACKGROUND

Evidence suggests that asthma is rooted in the intrauterine environment and that intake of marine n-3 polyunsaturated fatty acids (n-3 PUFAs) in pregnancy may have immunomodulatory effects on the child.

OBJECTIVE

Our aim was to examine whether increasing maternal intake of n-3 PUFAs in pregnancy may affect offspring risk of asthma.

DESIGN

In 1990, a population-based sample of 533 women with normal pregnancies were randomly assigned 2:1:1 to receive four 1-g gelatin capsules/d with fish oil providing 2.7 g n-3 PUFAs (n = 266); four 1-g, similar-looking capsules/d with olive oil (n = 136); or no oil capsules (n = 131). Women were recruited and randomly assigned around gestation week 30 and asked to take capsules until delivery. Among 531 live-born children, 528 were identified in registries and 523 were still alive by August 2006. Diagnoses from the International Coding of Diseases version 10 were extracted from a mandatory registry that recorded diagnoses reported from hospital contacts.

RESULTS

During the 16 y that passed since childbirth, 19 children from the fish oil and olive oil groups had received an asthma-related diagnosis; 10 had received the diagnosis allergic asthma. The hazard rate of asthma was reduced by 63% (95% CI: 8%, 85%; P = 0.03), whereas the hazard rate of allergic asthma was reduced by 87% (95% CI: 40%, 97%; P = 0.01) in the fish oil compared with the olive oil group.

CONCLUSION

Under the assumption that intake of olive oil in the dose provided here was inert, our results support that increasing n-3 PUFAs in late pregnancy may carry an important prophylactic potential in relation to offspring asthma.

Impact of PUFA on early immune and fetal development

It has recently been reported that the increased prevalence in childhood allergy may be linked to deviations in fetal immune development. One reason may be impaired nutrient supply. Hence, a well-differentiated placenta together with an optimal fetal nutrition via the mother are important prerequisites for the establishment of a functional immune system with normal immune responses. Fatty acids and their derivatives can influence both the early immune development and immune maturation by regulating numerous metabolic processes and the gene expression of important proteins such as enzymes and cytokines. The present review summarises the impact of nutritional fatty acids on the development of the immune system as well as the fetal development. It describes the mechanisms of action of PUFA, trans fatty acids and conjugated linoleic acids in programming the fetus with regard to its risk of acquiring atopic diseases in childhood.

A polymorphism in CD14 modifies the effect of farm milk consumption on allergic diseases and CD14 gene expression

BACKGROUND

Consumption of farm milk in early life is associated with less asthma and allergies.

OBJECTIVE

We hypothesized that genetic variation in the innate immunity receptor CD14 might modify the association between farm milk consumption and asthma and atopy.

METHODS

Questionnaire data, serum IgE levels, and genotypes for 4 single nucleotide polymorphisms in CD14 were assessed in farmers' and nonfarmers' children from 2 European populations (Allergy and Endotoxin study, n = 576; Prevention of Allergy Risk factors for Sensitization in children related to Farming and Anthroposophic Lifestyle study, n = 1539). In a subsample (n = 222) CD14 gene expression was measured in peripheral blood leukocytes. The effects of farm milk and CD14 genotypes on asthma, allergies, and CD14 expression and their interactions were investigated.

RESULTS

We found a significant interaction between genetic variation in CD14/-1721 and farm milk consumption. Adjusted odds ratios for the association between farm milk and asthma varied between the genotypes: AA, 0.18 (95% CI, 0.07-0.47); AG, 0.47 (95% CI, 0.26-0.86); and GG, 0.98 (95% CI, 0.46-2.08). Similar patterns were observed for symptoms of allergic rhinoconjunctivitis and pollen sensitization. CD14/-1721 also modified the association between farm milk and CD14 gene expression (adjusted geometric means ratios: AA, 1.61 (95% CI, 0.98-2.66); AG, 1.11 (95% CI, 0.71-1.72); and GG, 0.76 (95% CI, 0.39-1.48).

CONCLUSION

The protective effect of farm milk consumption on allergic diseases is stronger in children carrying the A allele in CD14/-1721 than in children homozygous for the G allele. This might be mediated through farm milk-induced upregulated CD14 gene expression.

CLINICAL IMPLICATIONS

Our results support the hypothesis that the inverse association between farm milk consumption and allergic diseases is mediated by CD14-activated innate immune mechanisms.