Dietary fats and asthma in teenagers: analyses of the first Nutrition and Health Survey in Taiwan (NAHSIT)

The Link Between Dysbiosis, Inflammation, Oxidative Stress, and Asthma-The Role of Probiotics, Prebiotics, and Antioxidants

Background: Asthma (a chronic inflammatory disease of the airways) is characterized by a variable course, response to treatment, and prognosis. Its incidence has increased significantly in recent decades. Unfortunately, modern lifestyle and environmental factors contribute to the further increase in the incidence of this disease. Progressive industrialization and urbanization, widespread use of antibiotic therapy, excessive sterility and inappropriate, highly processed diets are some of the many risk factors that are relevant today. Over the years, a lot of evidence has been gathered showing the influence of microorganisms of the gut or airways on human health. Studies published in recent years indicate that dysbiosis (microbial imbalance) and oxidative stress (pro-oxidant-antioxidant imbalance) are important elements of the pathogenesis of this inflammatory disease. Scientists have attempted to counteract the effects of this process by using probiotics, prebiotics, and antioxidants. The use of probiotic microorganisms positively modulates the immune system by maintaining homeostasis between individual fractions of immune system cells. Moreover, recently conducted experiments have shown that probiotics have antioxidant, anti-inflammatory, and protective properties in oxidative stress (OS). The aim of this study is to present the current state of knowledge on the role of dysbiosis and OS in the pathogenesis of asthma. Conclusions: This review highlights the importance of using probiotics, prebiotics, and antioxidants as potential strategies to support the treatment and prevention of this disease.

The association between adult asthma in the United States and dietary total energy intake: a retrospective cross-sectional analysis from NHANES

BACKGROUND

Epidemiological research links asthma progression to dietary nonallergic factors, particularly high-calorie intake. However, evidence supporting the relationship with total dietary calorie consumption remains scarce.

OBJECTIVE

This study aimed to explore the potential correlation between asthma occurrence and total dietary energy intake.

METHODS

A retrospective cross-sectional study of 21,354 US adults collected comprehensive participant data, including demographics, blood parameters, fatty acids, zinc, fiber intake, and asthma outcomes. Statistical analyses included interaction effects analysis, smooth curve fitting, and logistic regression.

RESULTS

Of 21,354 participants, 14.77% self-reported asthma diagnosis. After adjusting for confounders, odds ratios (OR) for asthma decreased with higher energy intake: Q2 (OR = 0.77, 95% CI: 0.69-0.86, p < .001), Q3 (OR = 0.66, 95% CI: 0.59-0.75, p < .001), and Q4 (OR = 0.61, 95% CI: 0.53-0.69, p < .001) compared to Q1 (< 17.73 kcal/kg/day). A non-linear (L-shaped) association between energy intake and asthma was observed (p < .001), with a critical threshold around 24 kcal/kg/day, supported by subgroup and sensitivity analyses.

CONCLUSION

This study reveals an L-shaped trend between total energy intake and asthma in US adults, with a significant threshold at approximately 24 kcal/kg/day.

Association between Butter, Margarine, and Olive Oil Intake and Asthma Symptoms among School Children: Result from a Large-Scale Cross-Sectional Study

Background

There are conflicting results about the association between dietary fat intake and asthma symptoms. Since few studies in the Middle East have been explored the relation between dietary fat consumption and risk of asthma, the present study was conducted to investigate the association between the consumption of butter, margarine, and olive oil and asthma risk in school children living in central Iran.

Method

In this cross-sectional study, out of 10,240 participants, asthma and its symptoms and dietary intake of butter, margarine, and olive oil of 7,667 children and adolescents were assessed using a validated International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. The relationship between fat subtypes and asthma was assessed using logistic regression.

Results

The prevalence of asthma confirmed by a doctor in the study population was 4.22%. An inverse association was found between butter and margarine consumption once or twice a week and odds of current asthma and wheezing in the past 12 months (OR = 0.52, 95% CI: 0.28-0.96; OR = 0.7, 95% CI: 0.55-0.88, respectively); however, those with higher consumption did not have a higher chance for developing wheezing or asthma.

Conclusion

We found that margarine and butter intake one or two times a week might have an inverse association with asthma and its symptoms among children. Prospective cohort studies are recommended to confirm these findings.

The Role of Diet and Nutrition in Allergic Diseases

Allergic diseases are a set of chronic inflammatory disorders of lung, skin, and nose epithelium characterized by aberrant IgE and Th2 cytokine-mediated immune responses to exposed allergens. The prevalence of allergic diseases, including asthma, allergic rhinitis, and atopic dermatitis, has increased dramatically worldwide in the past several decades. Evidence suggests that diet and nutrition play a key role in the development and severity of allergic diseases. Dietary components can differentially regulate allergic inflammation pathways through host and gut microbiota-derived metabolites, therefore influencing allergy outcomes in positive or negative ways. A broad range of nutrients and dietary components (vitamins A, D, and E, minerals Zn, Iron, and Se, dietary fiber, fatty acids, and phytochemicals) are found to be effective in the prevention or treatment of allergic diseases through the suppression of type 2 inflammation. This paper aims to review recent advances in the role of diet and nutrition in the etiology of allergies, nutritional regulation of allergic inflammation, and clinical findings about nutrient supplementation in treating allergic diseases. The current literature suggests the potential efficacy of plant-based diets in reducing allergic symptoms. Further clinical trials are warranted to examine the potential beneficial effects of plant-based diets and anti-allergic nutrients in the prevention and management of allergic diseases.

The Role of Vitamins in the Pathogenesis of Asthma

Vitamins play a crucial role in the proper functioning of organisms. Disturbances of their levels, seen as deficiency or excess, enhance the development of various diseases, including those of the cardiovascular, immune, or respiratory systems. The present paper aims to summarize the role of vitamins in one of the most common diseases of the respiratory system, asthma. This narrative review describes the influence of vitamins on asthma and its main symptoms such as bronchial hyperreactivity, airway inflammation, oxidative stress, and airway remodeling, as well as the correlation between vitamin intake and levels and the risk of asthma in both pre- and postnatal life.

Atopic Dermatitis and Water: Is There an Optimum Water Intake Level for Improving Atopic Skin?

Water is a vital nutrient with innumerable functions for every living cell. The functions of human skin include protection against dehydration of the body. Atopic dermatitis (AD) is a chronic pruritic inflammatory skin disease that presents with dry skin, erythematous and eczematous lesions, and lichenification. This paper discusses the question of whether extra water intake in children with AD affects skin hydration and the skin barrier function. Among the methods used to treat dry skin, topical leave-on products are the first-line treatment, intended to improve hydration and the skin barrier function. The effectiveness of adequate water intake as a measure to treat dry skin is still under debate. Normal skin hydration increases with dietary water intake, particularly in those with prior lower water consumption. Skin dryness in AD is instrumental to the itch and inflammation cycle, contributing to barrier impairment and aggravating disease severity and flares. Certain emollients provide significant hydration to AD skin, with relief of dryness and reduction in barrier impairment, disease severity, and flares. Further investigations are needed to evaluate the optimum water intake levels in children with AD, as important questions remain unanswered, namely, does oral hydration provide relief of skin dryness and reduce barrier impairment, disease severity, and flares; is there any additional benefit from using mineral or thermal spring water; or is there a need to specifically study the fluid/water intake in children with AD and food allergy (FA) restrictions?

Mediterranean-Type Diets as a Protective Factor for Asthma and Atopy

We are currently riding the second wave of the allergy epidemic, which is ongoing in affluent societies, but now also affecting developing countries. This increase in the prevalence of atopy/asthma in the Western world has coincided with a rapid improvement in living conditions and radical changes in lifestyle, suggesting that this upward trend in allergic manifestations may be associated with cultural and environmental factors. Diet is a prominent environmental exposure that has undergone major changes, with a substantial increase in the consumption of processed foods, all across the globe. On this basis, the potential effects of dietary habits on atopy and asthma have been researched rigorously, but even with a considerable body of evidence, clear associations are far from established. Many factors converge to obscure the potential relationship, including methodological, pathophysiological and cultural differences. To date, the most commonly researched, and highly promising, candidate for exerting a protective effect is the so-called Mediterranean diet (MedDi). This dietary pattern has been the subject of investigation since the mid twentieth century, and the evidence regarding its beneficial health effects is overwhelming, although data on a correlation between MedDi and the incidence and severity of asthma and atopy are inconclusive. As the prevalence of asthma appears to be lower in some Mediterranean populations, it can be speculated that the MedDi dietary pattern could indeed have a place in a preventive strategy for asthma/atopy. This is a review of the current evidence of the associations between the constituents of the MedDi and asthma/atopy, with emphasis on the pathophysiological links between MedDi and disease outcomes and the research pitfalls and methodological caveats which may hinder identification of causality. MedDi, as a dietary pattern, rather than short-term supplementation or excessive focus on single nutrient effects, may be a rational option for preventive intervention against atopy and asthma.

Risk factors of asthma in the Asian population: a systematic review and meta-analysis

Background and objective

An increasing trend of asthma prevalence was observed in Asia; however, contributions of environmental and host-related risk factors to the development of this disease remain uncertain. This study aimed to perform a systematic review and meta-analysis for asthma-associated risk factors reported in Asia.

Methods

We systematically searched three public databases (Web of Science, PubMed, and Scopus) in Feb 2021. We only included articles that reported environmental and host-related risk factors associated with asthma in the Asian population. Random-effect meta-analyses were conducted for frequently reported asthma-associated risk factors to provide an overall risk estimate of asthma development.

Results

Of 4030 records obtained from public databases, 289 articles were selected for review. The most frequently reported asthma-associated risk factor was the family history of allergy-related conditions. The random-effect asthma risk estimates (pooled odds ratio, OR) were 4.66 (95% confidence interval (CI): 3.73–5.82) for the family history of asthma, 3.50 (95% CI: 2.62–4.67) for the family history of atopy, 3.57 (95% CI: 3.03–4.22) for the family history of any allergic diseases, 1.96 (95% CI: 1.47–2.61) for the family history of allergic rhinitis, and 2.75 (95% CI: 1.12–6.76) for the family history of atopic dermatitis. For housing-related factors, including the presence of mold, mold spots, mold odor, cockroach, water damage, and incense burning, the random-effect pooled OR ranged from 1.43 to 1.73. Other risk factors with significant pooled OR for asthma development included male gender (1.30, 95% CI: 1.23–1.38), cigarette smoke exposure (1.44, 95% CI: 1.30–1.60), cigarette smoking (1.66, 95% CI: 1.44–1.90), body mass index (BMI)–related parameters (pooled OR ranged from 1.06 to 2.02), various types of air pollution (NO₂, PM10, and O₃; pooled OR ranged from 1.03 to 1.22), and pre- and perinatal factors (low birth weight, preterm birth, and cesarean section; pooled OR ranged from 1.14 to 1.32).

Conclusions

The family history of asthma was the most frequently reported risk factor for asthma development in Asia with the highest risk estimate for asthma development. This suggests a major role of the genetic component in asthma pathogenesis. Further study on asthma genetics is required to improve the current understanding of asthma etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40101-021-00273-x.

Allergic Diseases: A Comprehensive Review on Risk Factors, Immunological Mechanisms, Link with COVID-19, Potential Treatments, and Role of Allergen Bioinformatics

The prevalence of allergic diseases is regarded as one of the key challenges in health worldwide. Although the precise mechanisms underlying this rapid increase in prevalence are unknown, emerging evidence suggests that genetic and environmental factors play a significant role. The immune system, microbiota, viruses, and bacteria have all been linked to the onset of allergy disorders in recent years. Avoiding allergen exposure is the best treatment option; however, steroids, antihistamines, and other symptom-relieving drugs are also used. Allergen bioinformatics encompasses both computational tools/methods and allergen-related data resources for managing, archiving, and analyzing allergological data. This study highlights allergy-promoting mechanisms, algorithms, and concepts in allergen bioinformatics, as well as major areas for future research in the field of allergology.

Dietary patterns and asthma among Peruvian children and adolescents

BACKGROUND

Asthma is one of the conditions that contributes to the global burden of respiratory diseases and has been previously associated with diet intake. The goal of this study was to determine the relationship between diet, assessed by a developed score, and asthma in Peruvian children.

METHODS

This study was a cross sectional analysis nested within an unmatched case-control study of children in two peri-urban communities of Lima, Peru. We evaluated 767 children and adolescents (573 with asthma, 194 controls) between 9 and 19 years. Diet was assessed using a food frequency questionnaire (FFQ), with food groups classified as "healthy" or "unhealthy". Asthma control, Lung function and atopy were assessed by Asthma Control Test, Spirometry and InmunoCAP 250 test, respectively.

RESULTS

Mean age of participants was 13.8 years (SD 2.6). Mean diet score was 5 (SD 1.23; range 2-8). Healthy Diet Score was associated with asthma status [OR 0.83, 95% CI (0.72, 0.95), p = 0.009] in adjusted analysis. Thus, participants with higher HDS, had lower odds of asthma. In sensitivity analyses, when adjusting for atopy, results did not change significantly. [OR 0.85, 95% CI (0.72, 0.99); p = 0.04]. No association between the HDS and asthma control, FEV1, nor FeNO were observed. Atopy did not modify the association between diet and asthma outcomes.

CONCLUSIONS

In our study cohort, better diet quality was associated with lower odds of asthma, but was not associated with asthma control. Diet modification may be a potential intervention to impact the increasing prevalence of this disease.

Interactions between dietary habits and home environmental exposures on respiratory symptoms in Romanian school children: an analysis of data from the SINPHONIE project

In this study, we investigated the interactions between household pollutants and dietary habits on children's respiratory health. Our cross-sectional study collected self-reported information including health symptoms (allergy-like, asthma-like, and flu-like symptoms), home characteristics, dietary habits, and demographic information from questionnaires administered to parents of 280 school children in Romania. Unconditional logistic regression and stratified analyses were used to assess the interactions between dietary factors and environmental exposures on health symptoms among children, controlling for sociodemographic characteristics and co-exposures. We found that frequency of fruit consumption had significant interaction with residing near heavy traffic on allergy-like symptoms among children (p = 0.036). However, no association was observed by frequency of fruit consumption. Although no significant interaction was observed, we found that students with infrequent fruit consumption and residing near heavy traffic roads had elevated odds of asthma-like (POR 6.37; 95% CI 1.22, 33.29) and flu-like symptoms (POR 3.75; 95% CI 1.12, 11.86) than those who frequently consumed fruits. Likewise, low vegetable consumption was associated with increased asthma-like symptoms (POR 2.93; 95% CI 1.04, 8.24). Increased odds of asthma-like symptoms were observed among school children that resided near heavy traffic roads and frequently consumed milk (POR 2.80; 95% CI 1.24, 6.31) and yoghurt (POR 2.86; 95% CI 1.05, 7.75) compared to those that infrequently consumed dairy. Our findings suggest that frequent fruit and vegetable consumption may mitigate the negative effects of exposure to heavy traffic near dwelling on respiratory symptoms in Romanian children.

Asthma and Dietary Intake of Fish, Seaweeds, and Fatty Acids in Korean Adults

The dietary intake of fish and fatty acid may influence the risk of asthma, yet epidemiological research remains controversial and inconclusive. We examined the association between asthma and the dietary intake of fish, seaweeds, and fat in a Korean population, aged 19 to 64 years, using the data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2013-2016 (n = 13,038). The prevalence of doctor-diagnosed asthma and medication prescribed asthma were 2.5% and 1.0%, respectively. The subjects with medication prescribed asthma had significantly lower consumption of seaweeds (p = 0.0110) and lower n3/n6 polyunsaturated fatty acid (PUFA) (p = 0.0275) as compared to subjects without medication prescribed asthma. Multiple logistic regression analysis showed that the odds ratio (OR) (95% confidence interval, CI) of doctor-diagnosed asthma in the highest quartile were 0.63 (0.41-0.97) and 0.66 (0.44-1.00) for fish and seaweeds respectively, compared to the lowest quartile after adjusting confounding factors. Furthermore, there were significant inverse associations between medication prescribed asthma and seaweeds [OR (95% CI) = 0.37 (0.19-0.70)], n-3 PUFA [OR (95% CI) = 0.43 (0.21-0.89)] and n3/n6 [OR (95% CI) = 0.47 (0.22-0.99)] intake after adjusting for confounding factors. These results suggest, that the higher consumption of fish and seaweed and the high ratio of n-3 to n-6 PUFA may be associated with a lower prevalence of asthma.

Dietary fats, olive oil and respiratory diseases in Italian adults: A population-based study

BACKGROUND

Fat intake has been associated with respiratory diseases, with conflicting results.

OBJECTIVE

We studied the association between asthma and rhinitis with dietary fats, and their food sources in an Italian population.

METHODS

Clinical and nutritional information was collected for 871 subjects (aged 20-84) from the population-based multi-case-control study Genes Environment Interaction in Respiratory Diseases (GEIRD): 145 with current asthma (CA), 77 with past asthma (PA), 305 with rhinitis and 344 controls. Food intake was collected using the EPIC (European Investigation into Cancer and Nutrition) Food Frequency Questionnaire. The associations between fats and respiratory diseases were estimated by multinomial models. Fats and their dietary sources were analysed both as continuous variables and as quartiles.

RESULTS

Monounsaturated fatty acids and oleic acid were associated with a reduced risk of CA in both continuous (RRR = 0.68, 95%CI: 0.48; 0.96; RRR = 0.69; 95%CI: 0.49; 0.97, per 10 g, respectively) and per-quartile analyses (p for trend = 0.028 and 0.024, respectively). Olive oil was associated with a decreased risk of CA (RRR = 0.80; 95%CI: 0.65; 0.98 per 10 g). An increased risk of rhinitis was associated with moderate total fat and SFA intake.

CONCLUSIONS

High dietary intakes of oleic acid and of olive oil are associated with a lower risk of asthma but not of rhinitis.

Saturated fatty acids, obesity, and the nucleotide oligomerization domain-like receptor protein 3 (NLRP3) inflammasome in asthmatic patients

BACKGROUND

Both obesity and high dietary fat intake activate the nucleotide oligomerization domain-like receptor protein 3 (NLRP3) inflammasome.

OBJECTIVE

We aimed to examine NLRP3 inflammasome activity in the airways of obese asthmatic patients after macronutrient overload and in immune cells challenged by inflammasome triggers.

METHODS

Study 1 was a cross-sectional observational study of nonobese (n = 51) and obese (n = 76) asthmatic adults. Study 2 was a randomized, crossover, acute feeding study in 23 asthmatic adults (n = 12 nonobese and n = 11 obese subjects). Subjects consumed 3 isocaloric meals on 3 separate occasions (ie, saturated fatty acid, n-6 polyunsaturated fatty acid, and carbohydrate) and were assessed at 0 and 4 hours. For Studies 1 and 2, airway inflammation was measured based on sputum differential cell counts, IL-1β protein levels (ELISA), and sputum cell gene expression (Nanostring nCounter). In Study 3 peripheral blood neutrophils and monocytes were isolated by using Ficoll density gradient and magnetic bead separation and incubated with or without palmitic acid, LPS, or TNF-α for 24 hours, and IL-1β release was measured (ELISA).

RESULTS

In Study 1 NLRP3 and nucleotide oligomerization domain 1 (NOD1) gene expression was upregulated, and sputum IL-1β protein levels were greater in obese versus nonobese asthmatic patients. In Study 2 the saturated fatty acid meal led to increases in sputum neutrophil percentages and sputum cell gene expression of Toll-like receptor 4 (TLR4) and NLRP3 at 4 hours in nonobese asthmatic patients. In Study 3 neutrophils and monocytes released IL-1β when challenged with a combination of palmitic acid and LPS or TNF-α.

CONCLUSION

The NLRP3 inflammasome is a potential therapeutic target in asthmatic patients. Behavioral interventions that reduce fatty acid exposure, such as weight loss and dietary saturated fat restriction, warrant further exploration.

Biomarkers of oxidative stress and antioxidants in severe asthma: A Prospective Case-Control Study

BACKGROUND

Bronchial airway inflammation is the hallmark of asthma, which may be driven by an imbalance between oxidative stress and antioxidant defenses. Antioxidants deficiency may play a role, but this has remained unconfirmed.

OBJECTIVE

To evaluate the oxidative stress burden and antioxidants defenses in patients with increasing asthma severity.

METHODS

This prospective case-control study compared fractional exhaled nitric oxide (FeNO), exhaled breath condensate nitrite/nitrate (EBC-NOx), spirometry, and serum vitamins and trace elements among patients with and without asthma.

RESULTS

Sixty participants were recruited (30 with severe asthma number; 23 women [76.7%]; mean age, 41.4 years; mean forced expiratory volume in 1 second [FEV₁], 2.2 L [72.2% predicted]; mean inhaled corticosteroid dosage, 2,540 μg/d; 18/30 [60%] receiving maintenance oral corticosteroids; 15 with mild asthma; all corticosteroids naïve; 9 women [60%]; mean age, 34.6 years; mean FEV₁, 3.48 L [100.5% predicted]; 15 healthy controls; 12 women [80%]; mean age, 37.6 years; and mean FEV₁, 3.53 L [111.7% predicted]). The mean FeNO levels increased significantly with increasing asthma severity (P = .01), but the EBC-NOx levels did not change significantly (P = .90). Paradoxically, vitamin A and vitamin E increased with increased disease severity, with vitamin E levels increasing significantly (P = .07 and P < .001, respectively). There was no significant difference between groups in the levels of copper (P = .37), zinc (P = .97), or selenium (P = .90).

CONCLUSION

FeNO but not EBC-NOx is increased significantly with asthma severity with no evidence of vitamins or trace elements deficiency in severe asthma. Impaired oxidative stress defenses in severe asthma may be driven by factors other than vitamins or trace elements deficiency.

Dietary intake is associated with respiratory health outcomes and DNA methylation in children with asthma

BACKGROUND

Asthma is an increasingly common chronic disease among children, and data point toward a complex mechanism involving genetic, environmental and epigenetic factors. Epigenetic modifications such as DNA hypo- or hyper-methylation have been shown to occur in response to environmental exposures including dietary nutrients.

METHODS

Within the context of the asthma randomized trial of indoor wood smoke (ARTIS) study, we investigated relationships between diet, asthma health measures, and DNA methylation. Asthma health measures included a quality of life instrument, diurnal peak flow variability (dPFV) and forced expiratory volume in the first second (FEV₁). Dietary intake was assessed with a food frequency questionnaire. Methylation levels of LINE-1 repetitive element and two promoter CpG sites for interferon gamma (IFNγ, -186 and -54) from buccal cell DNA were measured using pyrosequencing assays.

RESULTS

Data were collected on 32 children with asthma living in western Montana who were recruited to the ARTIS study. Selenium and several methyl donor dietary nutrients were positively associated with the asthma quality of life measure. Intake of methyl donating nutrients including folate was positively associated LINE-1 methylation and negatively associated with IFNγ CpG-186. Higher levels of LINE-1 methylation were associated with greater dPFV.

CONCLUSION

We identified several nutrients that were associated with improved quality of life measures among children with asthma. The IFNγ promoter CpG site -186 but not -54 was associated with the intake of selected dietary nutrients. However, in this small population of children with asthma, the IFNγ promoter CpG sites were not associated with respiratory health measures so it remains unclear through which epigenetic mechanism these nutrients are impacting the quality of life measure. These findings add to the evidence that dietary nutrients, particularly foods containing methyl donors, may be important for epigenetic regulation as it pertains to the control of asthma. Trial registration ClincialTrials.gov NCT00807183. Registered 10 December 2008.

Soluble Fibre Meal Challenge Reduces Airway Inflammation and Expression of GPR43 and GPR41 in Asthma

Short chain fatty acids (SCFAs) are produced following the fermentation of soluble fibre by gut bacteria. In animal models, both dietary fibre and SCFAs have demonstrated anti-inflammatory effects via the activation of free fatty acid receptors, such as G protein-coupled receptor 41 and 43 (GPR41 and GPR43). This pilot study examined the acute effect of a single dose of soluble fibre on airway inflammation-including changes in gene expression of free fatty acid receptors-in asthma. Adults with stable asthma consumed a soluble fibre meal (n = 17) containing 3.5 g inulin and probiotics, or a control meal (n = 12) of simple carbohydrates. Exhaled nitric oxide (eNO) was measured and induced sputum was collected at 0 and 4 h for differential cell counts, measurement of interleukin-8 (IL-8) protein concentration, and GPR41 and GPR43 gene expression. At 4 h after meal consumption, airway inflammation biomarkers, including sputum total cell count, neutrophils, macrophages, lymphocytes, sputum IL-8, and eNO significantly decreased compared to baseline in the soluble fibre group only. This corresponded with upregulated GPR41 and GPR43 sputum gene expression and improved lung function in the soluble fibre group alone. Soluble fibre has acute anti-inflammatory effects in asthmatic airways. Long-term effects of soluble fibre as an anti-inflammatory therapy in asthma warrants further investigation.

Environmental Determinants of Bronchial Asthma among Saudi School Children in Southwestern Saudi Arabia

The aim here was to study the possible environmental and dietary determinants of asthma among school-aged children in Southwestern Saudi Arabia. In a cross-sectional study on a representative sample in Najran in Southwestern Saudi Arabia using an Arabic version of the modified ISAAC Phase III, parent-administered questionnaire data were collected. Skin prick tests (SPTs) were performed. The study included 1700 school children, out of them 468 (27.5%) were diagnosed with, cases of bronchial asthma and 20.8% (353) reported a 12-month nocturnal cough (as a proxy of severe asthma). In multivariable analysis, the study identified the following risk factors for having asthma or severe asthma: having dogs in the house, being male, being exposed to dense truck traffic on the street, using wood as a cooking fuel, conducting vigorous exercise, consuming eggs, consuming vegetables, having an allergic sensitization to dog hair, and being exposed to Cladosporium, pigweed, and Bermuda grass. On the other hand, the following food stuffs were found to be protective: seafood, fruit, and dairy products. Comprehensive school educational programs for both children and their parents should be adopted to prevent the use of wood in cooking and heating, to ensure that house pets are properly cared for, and to encourage proper dietary habits. Physicians should be informed of the patterns of allergens in order to improve asthma diagnosis and management.

Vitamin E and the risk of childhood asthma

INTRODUCTION

Asthma, a heterogeneous disease with multiple phenotypes, remains a significant health problem. Present treatments are not curative and prevention should be our ultimate goal. Vitamin E supplementation presents a potential easy and cheap preventive therapy but the results of studies are confusing and sometimes contradictory. Clarification is needed.

AREAS COVERED

Animal studies and research in pregnant women suggest enhanced lifetime resistance to asthma with appropriate fetal exposure to vitamin E. Vitamin E's preventive role is complex and includes functional variations of the different isoforms. Expert commentary: We review the most recent literature on the role of vitamin E isoforms on: lung inflammation, immune development, animal and clinical studies during pregnancy, and the potential influence of vitamin E isoforms on asthma development in offspring. We point out where data are seemingly contradictory, explain why this is so, and comment on where further clarifying research is needed and its future direction.

Pediatric Obesity-Related Asthma: The Role of Metabolic Dysregulation

The burden of obesity-related asthma among children, particularly among ethnic minorities, necessitates an improved understanding of the underlying disease mechanisms. Although obesity is an independent risk factor for asthma, not all obese children develop asthma. Several recent studies have elucidated mechanisms, including the role of diet, sedentary lifestyle, mechanical fat load, and adiposity-mediated inflammation that may underlie the obese asthma pathophysiology. Here, we review these recent studies and emerging scientific evidence that suggest metabolic dysregulation may play a role in pediatric obesity-related asthma. We also review the genetic and epigenetic factors that may underlie susceptibility to metabolic dysregulation and associated pulmonary morbidity among children. Lastly, we identify knowledge gaps that need further exploration to better define pathways that will allow development of primary preventive strategies for obesity-related asthma in children.

Modulación de la respuesta alérgica por los carotenoides de la dieta

<p>Los carotenoides son pigmentos isoprenoides que están presentes de manera natural y en altas concentraciones en la mayoría de alimentos vegetales —entre ellos, aguacate, papaya, tomate y zanahoria—, pero también encontrados como aditivos y colorantes en diversos productos cárnicos, aceites vegetales, salsas, aderezos, harinas, entre otros. En los últimos años, algunos estudios han descrito que los carotenoides de la dieta participan en varios procesos fisiopatológicos, incluyendo la respuesta inmune de tipo alérgico. Las tasas de prevalencia para este tipo de enfermedades han incrementado de manera alarmante durante las últimas cinco décadas en todo el mundo, a la vez que varios factores e hipótesis se han planteado tratando de explicar este fenómeno: uno de ellos es la hipótesis de la dieta, la cual plantea que la composición de varios micro y macronutrientes de la alimentación, así como los cambios en los patrones dietarios, influirían en tal problemática. Evidencia epidemiológica y básica experimental emergente señala que los carotenoides de la dieta participan en la regulación de la inflamación alérgica, y por ello se postulan como coadyuvantes en la terapia de tales padecimientos. En el presente artículo se revisará el estado del arte en relación a los efectos de los carotenoides de la dieta sobre la patología alérgica.</p>

Prevalence and association of asthma and allergic sensitization with dietary factors in schoolchildren: data from the french six cities study

Background

The prevalence of asthma and allergy has recently risen among children. This increase in prevalence might be related to various factors, particularly diet. The aim of this study is to assess the prevalence and association of asthma and allergic sensitization with dietary factors in the French Six Cities Study.

Methods

Cross-sectional studies were performed among 7432 schoolchildren aged 9–11 years in Bordeaux, Clermont-Ferrand, Créteil, Marseille, Reims, and Strasbourg. Parental questionnaires, based on the International Study on Asthma and Allergies in Childhood (ISAAC), were used to collect information on allergic diseases and potential exposure factors including a food frequency questionnaire to evaluate dietary habits. Skin prick testing to common allergens for allergic sensitization and bronchial hyper-responsiveness (BHR) testing to exercise were performed. Confounders control was performed with multiple logistic regressions.

Results

Asthma symptoms, asthma and allergic sensitization were more prevalent in boys than in girls and were more prevalent in the South than in the North of France. After adjustment for confounders, fruit juice intake was associated with a low prevalence of lifetime asthma (ORa [95 % CI]; 0.73 [0.56–0.97]), butter intake was positively associated with atopic wheeze (1.48 [1.07–2.05]) and having lunch at the canteen 1–2 times/week compared to never or occasionally was associated with a lower prevalence of past year wheeze (0.71 [0.52–0.96]), lifetime asthma (0.76 [0.60–0.96]) and allergic sensitization (0.80 [0.67–0.95]). Meat intake was inversely related to past year wheeze among atopic children (0.68 [0.50–0.98]) while fast food consumption and butter intake were associated with an increase prevalence of asthma (2.39 [1.47–3.93] and 1.51 [1.17–2.00] respectively). Fish intake was associated with a lower prevalence of asthma among non-atopic children (0.61 [0.43–0.87]. None of the dietary factors was associated with BHR.

Conclusions

Diet is associated with wheeze, asthma and allergic sensitization but not with BHR in children. These results provide further evidence that adherence to a healthy diet including fruits, meat and fish seems to have a protective effect on asthma and allergy in childhood. However, prospective and experimental studies are needed to provide causal evidence concerning the effect of diet on asthma and atopy.

Maternal intake of vitamins A, E and K in pregnancy and child allergic disease: a longitudinal study from the Danish National Birth Cohort

Fat-soluble vitamins A, E and K have been shown to play roles in immunity and inflammation, but studies on child allergic disease have been few and inconsistent. The aim of the present study was to examine the relationship between maternal intake of vitamins A, E and K in mid-pregnancy and child asthma and allergic rhinitis. We used data on 44 594 mother-child pairs from the Danish National Birth Cohort. Maternal intake of fat-soluble vitamins was calculated based on the information from a validated FFQ completed in mid-pregnancy. At 18 months, interviews with the mothers were conducted to evaluate doctor-diagnosed child asthma. At age 7 years, we assessed child asthma and allergic rhinitis using questions from the International Study of Asthma and Allergies in Childhood questionnaire and by national registries on hospital contacts and medication use. Current asthma was defined as asthma diagnosis and wheeze in the past 12 months by maternal report. We calculated multivariable risk ratios and 95 % CI by comparing the highest v. lowest quintile (Q) of maternal vitamin A, E and K intake in relation to child allergic disease outcomes. Maternal total vitamin K intake was directly associated with ever admitted asthma (Q5 v. Q1: 1·23, 95 % CI 1·01, 1·50) and current asthma at 7 years (Q5 v. Q1: 1·30, 95 % CI 0·99, 1·70). Weak inverse associations were present for maternal vitamin A and E intake during pregnancy with child allergic rhinitis. Maternal vitamin K intake during pregnancy may increase the risk of child asthma, and should be explored further on a mechanistic level. Conversely, maternal vitamin A and E intake may protect against child allergic rhinitis.

Effects of dietary habits and risk factors on allergic rhinitis prevalence among Turkish adolescents

BACKGROUND

Allergic rhinitis (AR) is a global health problem affecting many people from childhood to adulthood. The aim of this study was to evaluate the prevalence of AR and related symptoms, and to assess the risk factors, dietary habits and the Mediterranean diet affecting AR.

METHODS

In a cross-sectional study design, 9991 children, aged 13-14 years in 61 primary schools in 32 districts of Istanbul were evaluated. The prevalence of AR symptoms among the children was evaluated using the ISAAC protocol.

RESULTS

In our study, total of 10,984 questionnaires were distributed to 13-14yr-old schoolchildren to 61 schools in 32 district of Istanbul and 9991 questionnaires were suitable for analysis with an overall response of 91.7%. The rates of lifetime rhinitis, rhinitis in last 12 months and lifetime doctor diagnosed AR prevalence were 53.5%, 38.3% and 4.5%, respectively. The variation among districts in the prevalence of doctor diagnosed AR was very high. The highest prevalence was about 10 times higher than in the district with the lowest prevalence (range: 1.4-14.5) of Istanbul. A family history of atopy, mother with a university degree, presence of cat at home during last 12 months and adenoidectomy were significant for increased doctor diagnosed AR risk. Additionally, although fish and other sea foods, fermented drinks made from millets and various seeds, animal fats and butter were independent risk factors for doctor diagnosed AR, fish oil and hamburger were protective foods for doctor diagnosed AR. The MD was not associated with the prevalence of doctor diagnosed AR.

CONCLUSIONS

This study shows that that there are wide variations for the prevalence of AR related symptoms in 13-14yr-old schoolchildren among districts of Istanbul in Turkey. Socio-economical, environmental factors, some dietary habits, but not Mediterranean diet may affect the prevalence of AR.

Association of dietary soy genistein intake with lung function and asthma control: a post-hoc analysis of patients enrolled in a prospective multicentre clinical trial

BACKGROUND

Broad dietary patterns have been linked to asthma but the relative contribution of specific nutrients is unclear. Soy genistein has important anti-inflammatory and other biological effects that might be beneficial in asthma. A positive association was previously reported between soy genistein intake and lung function but not with asthma exacerbations.

AIMS

To conduct a post-hoc analysis of patients with inadequately controlled asthma enrolled in a prospective multicentre clinical trial to replicate this association.

METHODS

A total of 300 study participants were included in the analysis. Dietary soy genistein intake was measured using the Block Soy Foods Screener. The level of soy genistein intake (little or no intake, moderate intake, or high intake) was compared with baseline lung function (pre-bronchodilator forced expiratory volume in 1 second (FEV(1))) and asthma control (proportion of participants with an episode of poor asthma control (EPAC) and annualised rates of EPACs over a 6-month follow-up period.

RESULTS

Participants with little or no genistein intake had a lower baseline FEV(1) than those with a moderate or high intake (2.26 L vs. 2.53 L and 2.47 L, respectively; p=0.01). EPACs were more common among those with no genistein intake than in those with a moderate or high intake (54% vs. 35% vs. 40%, respectively; p<0.001). These findings remained significant after adjustment for patient demographics and body mass index.

CONCLUSIONS

In patients with asthma, consumption of a diet with moderate to high amounts of soy genistein is associated with better lung function and better asthma control.

Antioxidant intake and allergic disease in children

BACKGROUND

Antioxidant intake may reduce the risk of allergic disease by protecting against oxidative tissue damage. Major sources of antioxidants in the Western world are fruits, vegetables (vitamin C, β-carotene, α-tocopherol), meat and milk (selenium, magnesium, zinc). Children may exclude or eat less of some fruits and vegetables due to cross-reactivity between pollen and these foods, complicating assessment of causal relationships.

OBJECTIVE

To investigate the association between dietary antioxidant intake and allergic disease, taking potential reverse causation into account.

METHODS

Data on 2442 8-year-old children from the Swedish birth cohort study BAMSE were analysed. Children with completed parental questionnaires on exposures and health, including a food-frequency questionnaire and who provided a blood sample were included. Associations between antioxidant intake during the past year and current allergic disease were analysed using logistic regression.

RESULTS

An inverse association was observed between intake of β-carotene and rhinitis (OR(adj), highest vs. lowest quartile, 0.67, 95% CI 0.49-0.93). Magnesium intake was inversely related to asthma (OR(adj), 0.65, 95% CI 0.42-1.00) and atopic sensitisation (OR(adj), 0.78, 95% CI 0.61-1.00). Following exclusion of children who avoided certain fruits, vegetables or milk due to allergic symptoms (n = 285), the inverse association remained between magnesium intake and asthma (OR(adj), 0.58, 95% CI 0.35-0.98), whereas all other associations became non-significant.

CONCLUSION AND CLINICAL RELEVANCE

Diet modifications due to allergy may affect the antioxidant intake and needs to be considered when investigating the relationship between diet and allergic disease. Magnesium intake seems to have a protective effect on childhood asthma.

Dietary Patterns and Wheezing in the Midst of Nutritional Transition: A Study in Brazil

To assess the influence of dietary patterns on the prevalence of wheezing in the child and adolescent population in Northeastern Brazil. This is a cross-sectional study of male and female students, 6-12 years old, from the public elementary schools of São Francisco do Conde, Bahia, Northeastern Brazil. The report of wheezing in the past 12 months was collected using a questionnaire from the International Study of Asthma and Allergies in Childhood Program phase III, adapted to Portuguese. Consumption patterns were derived from principal component analysis based on the frequency of consumption of 97 food items by the food frequency questionnaire. We also obtained the anthropometric status, level of physical activity, pubertal development, and socioeconomic information, for each participant. Multivariate logistic regression analyses were used to assess the associations of interest. Of the children surveyed, 10.6% reported having wheezing. We identified 2 dietary patterns named Western and Prudent. We found a positive statistically significant association of the Western pattern with wheeze (odds ratio=1.77, 95% confidence interval: 1.10-2.84) after adjustment for total energy intake and controlling for potential confounders. The results showed that the Western dietary pattern was associated with wheezing. Our result is according with previous findings reported in several other studies.

Intakes of long-chain omega-3 (n-3) PUFAs and fish in relation to incidence of asthma among American young adults: the CARDIA study

BACKGROUND

Although long-chain ω-3 (n-3) PUFAs (LCω3PUFAs) have been linked to the prevention of some inflammatory disorders, little is known about the association between these fatty acids and incidence of asthma.

OBJECTIVE

The objective was to prospectively investigate the association between LCω3PUFAs and fish intake and incidence of asthma among American young adults.

DESIGN

A 20-y follow-up longitudinal analysis was conducted in a biracial cohort of 4162 Americans, aged 18-30 y, with a history of asthma at baseline in 1985. Diet was assessed by a validated interviewer-administered quantitative food-frequency questionnaire at the examinations in 1985, 1992, and 2005. Incident self-reported asthma was defined as having a physician diagnosis of asthma and/or the use of asthma medications between 1985 and 2005.

RESULTS

During the 20-y follow-up, 446 incident cases of asthma were identified. LCω3PUFA intake was significantly inversely associated with incidence of asthma after adjustment for sociodemographic, major lifestyle, and dietary confounders. The multivariable-adjusted HR for the highest quintile of LCω3PUFA intake as compared with the lowest quintile was 0.46 (95% CI: 0.33, 0.64; P-trend < 0.01). However, a higher frequency of nonfried fish consumption was not significantly associated with the risk of asthma. DHA showed a greater inverse association than did EPA. The association between LCω3PUFAs and incident asthma was not appreciably modified by sex, race, BMI, smoking status, or atopic status.

CONCLUSION

This study showed that intakes of LCω3PUFAs are inversely longitudinally associated with the incidence of asthma in American young adults.

Associations of intake of antioxidant vitamins and fatty acids with asthma in pre-school children

OBJECTIVE

Increasing childhood asthma rates may be due to changing dietary lifestyle. We investigated the association of dietary intake of antioxidant vitamins and fatty acids with asthma in Japanese pre-school children.

DESIGN

Cross-sectional study.

SETTING

School-based survey on lifestyle/diet and health status in children in Japan.

SUBJECTS

Parents of 452 children aged 3-6 years completed a questionnaire on the children's and parents’ lifestyle and demographics. Children were classified into asthma cases and non-asthma cases in accordance with the ATS-DLD(American Thoracic Society and Division of Lung Diseases of the National Heart, Lung, and Blood Institute) questionnaire. Children's diet was assessed using a 3 d dietary record completed by parents. Children's age, sex, BMI, history of food allergy, maternal age, parental history of allergy, maternal education,family size and second-hand smoking were included as covariates. Logistic regression models were used to examine the association between children's diet and asthma.

RESULTS

Compared with children with the lowest intake tertile for vitamin C and vitamin E, those in the highest were significantly inversely associated with asthma; adjusted OR (95% CI) were 0?35 (0?14, 0?88) and 0?32 (0?12, 0?85),respectively. A statistically significant trend was also observed. Fruit intake showed an inverse but insignificant association with asthma. There were no associations of any type of fatty acids with asthma.

CONCLUSIONS

These data suggest that children with high intakes of vitamins C and E may be associated with a reduced prevalence of asthma.

Confounding and effect modification in studies of diet and childhood asthma and allergies

OBJECTIVE

To propose a comprehensive set of confounders and effect modifiers that should be considered in epidemiologic investigations.

METHODS

Two reviewers independently critiqued studies included in a recent systematic review and extracted data on the confounders and effect modifiers that were considered and the approaches used to justify inclusion.

RESULTS

Of the 62 studies reviewed, 20 were cohort, 16 case-control, 25 cross-sectional studies, and one ecologic study. All cohort, cross-sectional, and ecologic studies had some adjustment for confounding or consideration of effect modification, but this was only the case for 7/16 (44%) case-control studies. Of the 53 studies that considered confounding or effect modification, 39/53 (74%) gave no justification for the inclusion of the variables considered. Studies that justified the inclusion of the variables did so based on empirical evidence (n = 10), conceptual justification (n = 7), or a combination of the two (n = 3). Confounding was handled mainly by using regression modeling, but some case-control studies utilized matching and anova. Ten studies handled effect modification by stratification, eight tested for interaction, and five used both strategies.

CONCLUSIONS

We have found substantial shortcomings in the handling of confounding and effect modification in studies of diet and development of childhood asthma/allergies. Selection of variables should be based on conceptual considerations and empirical evidence. Using this approach, we have proposed a comprehensive set of confounders and effect modifiers that need to be considered in future studies.

L-carnitine improves the asthma control in children with moderate persistent asthma

The objective. was to investigate L-Carnitine level and the effects of its supplementation in children with moderate persistent Asthma. Methods. Free and total serum carnitine levels were measured in 50 children having moderate persistent asthma and 50 healthy control children. The patients group was randomly divided into two subgroups. Subgroup A was supplemented with L-carnitine for 6 months while subgroup B was used as a placebo controls. Both subgroups were assessed by pulmonary function tests (PFT) and childhood-asthma control test (C-ACT) before and 6 months after carnitine supplementation. Results. Total and free carnitine levels were significantly lower in patient group than in control group. PFT and C-ACT showed significant improvements in asthmatic children supplemented with L-carnitine than in those who were not supplemented. Conclusion. L-carnitine levels were initially lower in moderate persistent asthmatic children as compared to healthy control children. Asthmatic children who received L-carnitine supplementation showed statistically significant improvement of C-ACT and PFT.

L-carnitine improves the asthma control in children with moderate persistent asthma

The objective. was to investigate L-Carnitine level and the effects of its supplementation in children with moderate persistent Asthma. Methods. Free and total serum carnitine levels were measured in 50 children having moderate persistent asthma and 50 healthy control children. The patients group was randomly divided into two subgroups. Subgroup A was supplemented with L-carnitine for 6 months while subgroup B was used as a placebo controls. Both subgroups were assessed by pulmonary function tests (PFT) and childhood-asthma control test (C-ACT) before and 6 months after carnitine supplementation. Results. Total and free carnitine levels were significantly lower in patient group than in control group. PFT and C-ACT showed significant improvements in asthmatic children supplemented with L-carnitine than in those who were not supplemented. Conclusion. L-carnitine levels were initially lower in moderate persistent asthmatic children as compared to healthy control children. Asthmatic children who received L-carnitine supplementation showed statistically significant improvement of C-ACT and PFT.

Psychosocial problems in children with allergic diseases: a population study in Taiwan

BACKGROUND

A few studies had pointed out the relationship between a single allergic disease and children's psychosocial problems; however, all of these researchers considered the allergic diseases separately. Therefore, this study aimed to investigate the relationship between collective allergic diseases and psychosocial problems among 4- to 12-year-old children in Taiwan.

METHODS

The data were generated from the 2005 Taiwan National Health Interview Survey. A total of 2955 parents or guardians completed the answers for their 4- to 12-year-old children. We used logistic regressions to investigate the association of allergic diseases and the psychosocial problems.

RESULTS

About 40.62% children had at least one allergic disease in the past year, and 17.75% children had a score of psychosocial problems higher than or equal to the 75th percentile. After controlling for demographic factors, the risk of having high-level psychosocial problem for children with any allergic disease was 1.84 times of those without allergy. For those who had one, two or more than two allergic diseases, the risks of having psychosocial problems were 1.56, 2.20 and 3.39 times of those had no allergy disease respectively. Children with asthma, dermatitis and rhinitis simultaneously had the highest psychosocial impact (odds ratio = 5.10).

CONCLUSIONS

Collective allergic diseases were associated with psychosocial problems in children, and the effect was gradient. Parents and paediatricians should pay attention to psychosocial problems in children with allergic diseases and vice versa.

Salty-snack eating, television or video-game viewing, and asthma symptoms among 10- to 12-year-old children: the PANACEA study

BACKGROUND

Salty-snack consumption, as well as the amount of time children spend watching television or playing video games, have been implicated in the development of asthma; however, results are still conflicting.

OBJECTIVE

The aim of this work was to evaluate the association of salty-snack eating and television/video-game viewing with childhood asthma symptoms.

DESIGN

Cross-sectional study.

SETTINGS

Seven hundred children (323 male), 10 to 12 years old, from 18 schools located in the greater area of Athens were enrolled. Children and their parents completed questionnaires, which evaluated, among other things, dietary habits. Adherence to the Mediterranean diet was evaluated using the KIDMED (Mediterranean Diet Quality Index for Children and Adolescents) score.

STATISTICAL ANALYSIS

The association of children's characteristics with asthma symptoms was performed by calculating the odds ratios and corresponding 95% confidence intervals.

RESULTS

Overall lifetime prevalence of asthma symptoms was 23.7% (27.6% boys, 20.4% girls; P=0.03). Forty-eight percent of children reported salty-snack consumption (≥ 1 times/week). Salty-snack consumption was positively associated with the hours of television/video-game viewing (P=0.04) and inversely with the KIDMED score (P=0.02). Consumption of salty snacks (>3 times/week vs never/rare) was associated with a 4.8-times higher likelihood of having asthma symptoms (95% confidence interval: 1.50 to 15.8), irrespective of potential confounders. The associations of salty-snack eating and asthma symptoms were more prominent in children who watched television or played video games >2 hours/day. In addition, adherence to the Mediterranean diet was inversely associated with the likelihood of asthma symptoms.

CONCLUSIONS

Unhealthy lifestyle behaviors, such as salty-snack eating and television/video-game viewing were strongly associated with the presence of asthma symptoms. Future interventions and public health messages should be focused on changing these behaviors from the early stages of life.

Diet and asthma: nutrition implications from prevention to treatment

Asthma is characterized by lung airway inflammation initiated and perpetuated by an inappropriate immune response, increased airway responsiveness, and variable airflow obstruction. In Western countries there has been a marked increase in asthma prevalence such that it has become a public health concern. It has been hypothesized that the increase may be due to changing antioxidant intake, increasing dietary ratio of n-6:n-3 polyunsaturated fatty acids (PUFA), and vitamin D deficiency (and supplementation). Observational studies have reported associations between asthma and dietary antioxidants (vitamin E, vitamin C, carotenoids, selenium, polyphenols, and fruit), PUFA, and vitamin D. However, supplementing the diets of adults with asthma with antioxidants and n-3 PUFA has minimal, if any, clinical benefit. Currently there is insufficient evidence to support the use of nutrient supplements to complement conventional treatment; however, results of ongoing studies are awaited, and additional research is required, particularly in children. Interest in the potential of dietary intervention during pregnancy to reduce the likelihood of childhood asthma has increased. A small number of cohort studies have highlighted associations between childhood asthma and reduced maternal intake of some nutrients (vitamin E, vitamin D, selenium, zinc, and PUFA) during pregnancy. Although vitamin D intervention studies during pregnancy are ongoing and two intervention studies suggest that dietary PUFA manipulation during pregnancy may be advantageous, further trials are needed to establish if modification of maternal nutrient intake during pregnancy can be used as a healthy, low cost, public health measure to reduce the prevalence of childhood asthma.

Nutrients and foods for the primary prevention of asthma and allergy: systematic review and meta-analysis

BACKGROUND

Epidemiologic studies suggest that deficiencies of the nutrients selenium; zinc; vitamins A, C, D, and E; and low fruit and vegetable intake may be associated with the development of asthma and allergic disorders.

OBJECTIVES

To investigate the evidence that nutrient and food intake modifies the risk of children developing allergy.

METHODS

We systematically searched 11 databases. Studies were critically appraised, and meta-analyses were undertaken.

RESULTS

We identified 62 eligible reports. There were no randomized controlled trials. Studies used cohort (n = 21), case-control (n = 15), or cross-sectional (n = 26) designs. All studies were judged to be at moderate to substantial risk of bias. Meta-analysis revealed that serum vitamin A was lower in children with asthma compared with controls (odds ratio [OR], 0.25; 95% CI, 0.10-0.40). Meta-analyses also showed that high maternal dietary vitamin D and E intakes during pregnancy were protective for the development of wheezing outcomes (OR, 0.56, 95% CI, 0.42-0.73; and OR, 0.68, 95% CI, 0.52-0.88, respectively). Adherence to a Mediterranean diet was protective for persistent wheeze (OR, 0.22; 95% CI, 0.08-0.58) and atopy (OR, 0.55; 95% CI, 0.31-0.97). Seventeen of 22 fruit and vegetable studies reported beneficial associations with asthma and allergic outcomes. Results were not supportive for other allergic outcomes for these vitamins or nutrients, or for any outcomes in relation to vitamin C and selenium.

CONCLUSION

The available epidemiologic evidence is weak but nonetheless supportive with respect to vitamins A, D, and E; zinc; fruits and vegetables; and a Mediterranean diet for the prevention of asthma. Experimental studies of these exposures are now warranted.

The effect of prenatal and postnatal dietary exposures on childhood development of atopic disease

PURPOSE OF REVIEW

Prenatal and early life dietary factors may influence asthma and allergic disease development. We review recent studies and consensus statements regarding the effects of prenatal/early life dietary exposures on atopic disease.

RECENT FINDINGS

The American Academy of Pediatrics consensus statement highlighted the inadequacy of evidence for pregnancy antigen avoidance diets or delay of infant complementary foods beyond 4-6 months. Recent studies raise the question of whether early food introduction may promote tolerance, though controlled trials are pending. A recent meta-analysis suggested that antioxidants may protect against the development of atopy. Furthermore, some of the conflicting results on the effects of vitamin E may be related to variability in the isoforms prevalent in local diet. Recent studies of vitamin D similarly suggest that it may be protective, though this remains controversial. Finally, prenatal methyl donor exposure promoted the development of allergy in an animal model.

SUMMARY

There are conflicting data on the effects of most prenatal and early childhood dietary exposures on childhood atopic disease. Longitudinal prenatal/birth cohort studies with prospective measurements and clinical supplementation trials of promising dietary factors will be needed to make reliable recommendations in this vulnerable population of pregnant women and their infants.

Fat intake and asthma in Spanish schoolchildren

OBJECTIVES

To study the relationship between lipid, fatty acid and lipid-rich food intake and current asthma in a group of Spanish schoolchildren.

SUBJECTS/METHODS

The subjects of this cross-sectional study were 638 Spanish schoolchildren (8-13 years of age). The weight and height of all the subjects were recorded. A questionnaire, completed by the subjects' parents, was used to obtain personal and health information. Current asthma was established when the children had ever had asthma, if they had been diagnosed with asthma by a doctor and if they had been treated with medications at some time in the previous 12 months. Food intake was monitored using a 3-day food record. All foods consumed were converted into energy and nutrients.

RESULTS

The energy derived from lipids, saturated fatty acids (SFAs) and myristic and palmitic acids was independently associated with current asthma (Odds Ratio (OR) third tertile 2.85 (1.01-8.07) P=0.049, 10.00 (0.89-111.97) P=0.002, 11.21 (1.36-92.24) P=0.002, 7.58 (1.40-41.03) P=0.022, respectively), as was the intake of butter (OR third tertile 2.97 (1.01-8.68) P=0.001). No relationship was seen between this condition and the intake of any other fatty acid, the n-6/n-3 ratio, nor the consumption of margarine, milk products, fish, meat, eggs or vegetable oils.

CONCLUSIONS

Increased intakes of SFAs, myristic and palmitic acids and butter seem to be related to the risk of current asthma in children.

Association of nutrient intake and wheeze or asthma in a Greek pre-school population

The rise of asthma prevalence in children observed the last years might be related to several dietary factors/components as suggested by several researchers. We aimed to evaluate the potential relationship between certain nutrients intake and asthma occurrence in a population of pre-school children. In the framework of the cross-sectional study 'Growth, Exercise and Nutrition Epidemiological Study In pre-schoolers', data were collected from 1964 children, aged 24-72 months, living in five different counties in Greece. The International Study of Asthma and Allergies in Childhood questionnaire was used to assess asthma related outcomes. Dietary intake was assessed with 3 days diet records. The prevalence of ever wheeze, current wheeze and diagnosed asthma was 37.7%, 27.5% and 10.5% respectively. Dietary intake of magnesium had a 0.5% and 0.6% increase in the reported risk of current wheeze and diagnosed asthma respectively. On the contrary a decrease in the prevalence of ever (OR: 0.997, 95% CI: 0.995-1.000) and current wheeze (OR: 0.996, 95% CI: 0.993-0.999) was associated with vitamin C intake. Calcium intake slightly decreased the risk of current wheeze (OR: 0.999, 95% CI: 0.998-0.999). An increase of 2% of the risk of reporting ever or current wheeze was associated with mono-unsaturated fatty acid intake. Magnesium intake was the only independent predictor for doctor's diagnosed asthma. We conclude that dietary intake of vitamin C and calcium seem to have a protective effect on the incidence of wheeze in pre-school children, whereas magnesium and mono-unsaturated fatty acid may have a harmful role.

Session 1: Allergic disease: Nutrition as a potential determinant of asthma

Asthma is characterised by chronic lung airway inflammation, increased airway responsiveness and variable airflow obstruction. In Westernised countries asthma is a public health concern because of its prevalence, associated ill health and high societal and healthcare costs. In recent decades there has been a marked increase in asthma prevalence, particularly in Westernised countries. It has been proposed that changing diet has contributed to the increase in asthma. Several dietary hypotheses exist; the first relates the increase in asthma to declining dietary antioxidant intake, the second to decreased intake of long-chain n-3 PUFA and increasing intake of n-6 PUFA. Vitamin D supplementation and deficiency have also been hypothesised to have contributed to the increase in asthma. Observational studies have reported associations between asthma and dietary antioxidants (vitamin E, vitamin C, carotenoids, Se, flavonoids, fruit), lipids (PUFA, butter, margarine, fish) and vitamin D. However, supplementing the diets of adults with asthma with antioxidants and lipids has minimal, if any, clinical benefit. There is growing interest in the possibility that childhood asthma is influenced by maternal diet during pregnancy, with studies highlighting associations between childhood asthma and maternal intake of some nutrients (vitamin E, vitamin D, Se, PUFA) during pregnancy. It has been suggested that maternal diet during pregnancy influences fetal airway and/or immune development. Further intervention studies are needed to establish whether modification of maternal nutrient intake during pregnancy can be used as a healthy low-cost public health measure to reduce the prevalence of childhood asthma.

Serum vitamin A and beta-carotene levels in children with asthma

BACKGROUND

Low serum levels of dietary antioxidants are associated with allergic diseases including asthma. Vitamin A and carotenoids are dietary antioxidants that are likely to play an important role against airway inflammation.

METHODS

This study included 433 asthmatic schoolchildren and 537 healthy control subjects, between 6 and 18 years of age. Serum beta-carotene, vitamin A, cholesterol, and triglycerides levels were studied in all subjects.

RESULTS

Serum vitamin A concentration was significantly lower in asthmatic subjects than in healthy control subjects (19.4 +/- 1.1 mg/dL vs. 28.9 +/- 0.86 mg/dL) (p < 0.001). There were no significant differences in the levels of beta-carotene, cholesterol, and triglycerides between the two groups.

CONCLUSION

Reduction of vitamin A in asthmatic children may have etiological implications for the disease.

Serum total and free carnitine levels in children with asthma

BACKGROUND

Serum carnitine is decreased in recurrent pulmonary infections. We aimed to evaluate serum carnitine levels in asthmatic children.

METHODS

Study group consisted of children with stable asthma and those with acute asthma attacks, while control group included healthy children. Attack severity was determined by the pulmonary score system. Total and free carnitine levels were studied in one blood sample from the control group and stable asthmatics and in two samples from children with acute asthma exacerbation during and after the attack.

RESULTS

All the 40 patients in the study group had moderate asthma including 30 with acute attack (13 mild and 17 moderate) and 10 with stable asthma. Carnitine levels were significantly lower in acute attack asthmatics than in the stable asthmatics and controls, while there was no significant difference between the latter two groups. Carnitine levels were not different between asthmatics with mild and moderate attack, and were similar during and after an acute attack.

CONCLUSIONS

Serum carnitine levels decrease in children with moderate asthma during exacerbation of asthma and shortly thereafter. Further studies are needed to evaluate the effect of carnitine treatment on serum carnitine level.

Mediterranean diet is associated with reduced asthma and rhinitis in Mexican children

BACKGROUND

Diet during pregnancy and childhood has been suggested to play an important role in children's asthma risk. We assessed whether the adherence to a Mediterranean dietary pattern, for children in the last 12 months and their mothers during pregnancy, was associated with both childhood asthma and allergic rhinitis.

METHODS

A cross-sectional study was conducted in 2004 using a random sample of 1476 children (6- to 7-year old) from the Mexicali region, Mexico. Dietary data of children's intake in the last 12 months and their mothers' intake during pregnancy was collected, through a parental food frequency questionnaire. A Mediterranean diet score was computed [Trichopoulou et al., N Engl J Med 348 (2003), 2599]. Data on seven asthma and rhinitis-related outcomes were obtained from the International Study of Asthma and Allergies in Childhood questionnaire.

RESULTS

Adherence to a Mediterranean dietary pattern was inversely associated with asthma ever (OR = 0.60, 95% CI = 0.40-0.91), wheezing ever (0.64, 0.47-0.87), rhinitis ever (0.41, 0.22-0.77), sneezing ever (0.79, 0.59-1.07), current sneezing (0.71, 0.52-0.96) and current itchy-watery eyes (0.63, 0.42-0.95). No associations were found using the mothers' pregnancy diet score, except for current sneezing (0.71, 0.53-0.97).

CONCLUSIONS

Our findings suggest a protective effect of following a healthy dietary pattern on asthma and allergic rhinitis in Mexican children.

The association of diet with respiratory symptoms and asthma in schoolchildren in Taipei, Taiwan

This study aimed to evaluate the association of diet with respiratory symptoms and asthma in schoolchildren in Taipei, Taiwan. An in-class interview survey elicited experiences of asthma and respiratory symptoms and consumption frequencies of the major food categories in 2290 fifth graders. Respiratory symptoms surveyed included persistent cough, chest tightness, wheezing with cold, wheezing without cold, dyspnea-associated wheezing, and exercise-induced cough or wheezing. Results showed that the consumption of sweetened beverages had the strongest association with respiratory symptoms and was positively associated with six of the seven respiratory symptoms (all p < 0.05). The adjusted odds ratios (aOR) ranged from 1.05 (95% confidence interval (CI = 1.01-1.09) for exercise-induced cough to 1.09 (95% CI = 1.03-1.16) for wheezing without cold. Egg consumption was associated with 5 of the 7 respiratory symptoms. Consumptions of seafood, soy products, and fruits were each negatively associated with one of the seven respiratory symptoms (all p < 0.05). Consumption of seafood was negatively associated with physician-diagnosed asthma and consumptions of sweetened beverages and eggs were positively associated with suspected asthma (p < 0.05). In conclusion, the study suggests that diet is associated with the respiratory symptoms in schoolchildren in Taipei. Consumptions of sweetened beverages and eggs are associated with increased risk of respiratory symptoms and asthma whereas consumptions of soy products and fruits are associated with reduced risk of respiratory symptoms.