Diet, wheeze, and atopy in school children in Menorca, Spain

Greater fruit and vegetables consumption, and adherence to a Mediterranean type of diet reduces the risk for asthma in children; a systematic review and meta-analysis

The objective of this study was to explore the relationship between the consumption of fruits, vegetables and adherence to the Mediterranean diet with childhood asthma development and severity. A systematic literature search and synthesis of the results was performed throughout the last two decades. A total of 45 studies were analysed and 392,797 children were included. Greater adherence to a Mediterranean type of diet was inversely associated with asthmatic outcomes (OR:0.71,95% CI:0.54,0.88). Regarding fruits, vegetables consumption, a significant inverse association between increased fruits or vegetable intake and asthma was found (OR:0.82,95% CI:0.77,0.86; 0.84,95% CI:0.77,0.91, respectively). Fruits and vegetables consumption combined was also inversely related to all asthmatic outcomes (OR:0.65,95% CI:0.49,0.78). The level of heterogeneity was moderate-to-high (30%-97%). The present review and meta-analysis show a trend to an inverse association between adherence to the Mediterranean diet or a healthy diet rich in fruits and vegetables and the occurrence of childhood asthma but with a low level of certainty.

The Effects of a Healthy Diet on Asthma and Wheezing in Children and Adolescents: A Systematic Review and Meta-Analysis

Background

Asthma is a public health problem requiring focused attention. This study aimed to systematically evaluate the association between dietary structure and asthma or wheezing in children.

Methods

The study protocol of this meta-analysis has been registered in the International Prospective Register of Systematic Reviews (PROSPERO) with the registration code CRD42023390191. A total of 8397 articles were retrieved, searching PubMed, Medline, Embase, Web of Science, and Scopus databases as of November 21, 2022. Two independent authors were responsible for independently conducting the literature screening process. Effect-size estimates were expressed as odds ratio (OR) in cross-sectional studies and risk ratio (RR) in cohort studies with a 95% confidence interval (CI). Summary effect estimates were evaluated with random-effect models. Meanwhile, subgroup and sensitivity analyses were performed to assess the potential sources of heterogeneity and the robustness of the pooled estimation.

Results

A total of 65 studies, including 567,426 subjects had been analyzed. Overall analyses of cross-sectional studies revealed that a healthy diet was protective against asthma (adjusted OR=0.85, 95% CI: 0.80-0.89, P <0.001, I2=69.8%, Tau2=0.026) and wheezing (adjusted OR=0.85, 95% CI: 0.81-0.89, P <0.001, I2=66.8%, Tau2=0.015) in children and adolescents. Conversely, unhealthy diets can exacerbate asthma (adjusted OR=1.28, 95% CI: 1.20-1.36, P <0.001, I2=64.9%, Tau2=0.019) and wheeze (adjusted OR=1.09, 95% CI: 1.02-1.16, P =0.006, I2=75.2%, Tau2=0.023) in children and adolescents. The same trend was found in cohort studies (adjusted RR=0.72, 95% CI: 0.58-0.90, P =0.003, I2=83.5%, Tau2=0.105). A clear trend was observed between high-frequency healthy diets (OR=0.80; 95% CI: 0.71-0.89; P <0.001) is more protective against asthma than low-frequency healthy diets (OR=0.81; 95% CI: 0.70-0.94; P =0.007).

Conclusion

Our findings highlight the protective effects of a healthy diet on asthma and wheezing in children, including fruit, seafood, cereals, and the Mediterranean diet.

Dietary factors and risk for asthma: A Mendelian randomization analysis

Background

Previous research has found a link between dietary factors and asthma. However, few studies have analyzed the relationship between dietary factors and asthma using Mendelian randomization. Methods: The IEU Open GWAS project (https://gwas.mrcieu.ac.uk/) was the source of exposure and outcome datasets. The exposure datasets included Alcoholic drinks per week, Alcohol intake frequency, Processed meat intake, Poultry intake, Beef intake, Non-oily fish intake, Oily fish intake, Pork intake, Lamb/mutton intake, Bread intake, Cheese intake, Cooked vegetable intake, Tea intake, Fresh fruit intake, Cereal intake, Salad/raw vegetable intake, Coffee intake, and Dried fruit intake. The weighted median, MR-Egger, and Inverse Variance Weighted methods were used as the main methods of Mendelian randomization analysis. Heterogeneity and pleiotropic analysis were performed to ensure the accuracy of the results.

Results

Alcohol intake frequency (after removing outliers OR: 1.217; 95% CI: 1.048-1.413; p=0.00993) was related to an increased risk of Asthma. Fresh fruit intake (OR: 0.489; 95% CI: 0.320-0.748; p=0.000954) and Dried fruit intake (after removing outliers OR: 0.482; 95% CI: 0.325-0.717; p= 0.000312) were discovered as protective factors. Other dietary intakes found no causal relationship with asthma.

Conclusion

This study found that dried fruit intake and fresh fruit intake were associated with a reduced risk of asthma, and alcohol intake frequency was associated with an increased risk of asthma. This study also found that other factors included in this study were not associated with asthma.

Solanum melongena allergy (A comprehensive review)

The Solanaceae family, including, among other, eggplants, represents the sixth most widely cultivated crops around the globe. We review the current data regarding allergies to Solanum melongena (eggplants), generating symptoms that range from gastrointestinal to respiratory allergic reactions. Currently, there are more than 4 mechanisms and molecules presumably involved in triggering allergic reactions to Solanum melongena: The lipid transfer protein (LTP) pathway, the profilin pathway, polyphenol oxidase (PPO) mechanism and other molecules. Allergies may be triggered both by pollen respiratory reactions and fruit intake. There is also an important cross-reactivity mechanism revealed by recent studies. Our literature review revealed many case series studies, some with in-depth molecular analysis of the triggering mechanism. However, wide population studies are still scarce. Current geographical distribution of the crops and population migrations should enhance the awareness of allergy and immunology specialists, ENT specialists, emergency physicians and pediatricians to the need for proper routine laboratory testing for possible Solanum allergy.

[Diet and asthma: Better eating for better breathing?]

Inhaled therapies are the cornerstone of asthma treatment. However, according to national and international guidelines, non-pharmacological interventions should not be neglected in asthma. It has been demonstrated that a healthy diet is beneficial to general health. Recently, the effect of diet on asthma has been highlighted in many studies. Two diets have been particularly studied: the Mediterranean diet (high in fruits and vegetables and low in fat) and the Western diet (high in saturated fat and low in fruits and vegetables). A beneficial effect of the Mediterranean diet and deleterious effect of the Western diet on the development or control of asthma has been shown in some studies even after adjustment for overweight. Study findings have not been unanimous, probably related to the complexity of conducting studies on a diet that may change from day to day for any individual subject. In addition, the effect of physical exercise, which is known to be beneficial in asthma, is rarely taken into account in these studies. However, studies on diet are becoming more complex with the use of specific dietary indices, which should bring interesting data in the future.

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.

EAACI position paper on diet diversity in pregnancy, infancy and childhood: Novel concepts and implications for studies in allergy and asthma

To fully understand the role of diet diversity on allergy outcomes and to set standards for conducting research in this field, the European Academy of Allergy and Clinical Immunology Task Force on Diet and Immunomodulation has systematically explored the association between diet diversity and allergy outcomes. In addition, a detailed narrative review of information on diet quality and diet patterns as they pertain to allergic outcomes is presented. Overall, we recommend that infants of any risk category for allergic disease should have a diverse diet, given no evidence of harm and some potential association of benefit in the prevention of particular allergic outcomes. In order to harmonize methods for future data collection and reporting, the task force members propose relevant definitions and important factors for consideration, when measuring diet diversity in the context of allergy. Consensus was achieved on practice points through the Delphi method. It is hoped that the definitions and considerations described herein will also enable better comparison of future studies and improve mechanistic studies and pathway analysis to understand how diet diversity modulates allergic outcomes.

The Role of Diet Diversity and Diet Indices on Allergy Outcomes

Nutrients in foods are not eaten in isolation and food intake interacts in a complex manner, affecting health and disease outcomes. For this reason, focusing on the whole "pattern" of dietary intake instead of the single nutrients or groups of nutrients when studying diseases outcomes is increasingly appealing and growing. Diet diversity refers to the variety of foods being eaten, and the terms, diversity or variety, are often used interchangeably. When the overall diet is characterized by healthy foods, diet diversity will reflect a diversity/variety of healthy foods eaten over a period of time. The introduction of solid foods in the 1st year of life is considered a measure of increased diet diversity. Consuming a diverse range of foods and food allergens in the first year of life may increase intake of important nutrients and positively affect the gut microbiome structure and function. Intake of omega-3 fatty acids and fibers/prebiotics may be particularly important but more information is required about dose and which individuals are most likely to benefit. Increased diet diversity in the first year of life is also associated with reduced food allergy outcomes. In addition to diet diversity, diet indices are considered measures of overall diet quality and can be used as a simple assessment of dietary intake. The focus of this paper is to review and critically address the current knowledge of the association between diet diversity and diet indices and allergy outcomes. Based on the current evidence, we recommend the introduction of solid foods, including common allergenic solids, during the 1st year of life, according to the infant's neuro-developmental abilities and familial or cultural habits. For infants with severe AD and/or FA, medical assessment may be advisable before introducing common food allergens into the diet. Limited evidence exist about the role of diet indices in pregnancy and allergic disease in the offspring, and the most promising results indicate a reduction in childhood wheeze and/or asthma intake.

Associations of Prenatal Dietary Inflammatory Potential with Childhood Respiratory Outcomes in Project Viva

BACKGROUND

Inflammation during pregnancy may be a factor in the developmental programming of asthma and wheeze in childhood.

OBJECTIVE

To examine associations of inflammatory potential of prenatal diet with respiratory outcomes in early childhood and midchildhood.

METHODS

Among 1424 mother-child pairs in Project Viva, a prebirth cohort, we examined associations of Dietary Inflammatory Index (DII®) (first trimester, second trimester, and average of first and second trimesters) scores in relation to ever asthma and wheezing in the past year (early childhood and midchildhood); current asthma and lung function (midchildhood), and wheeze trajectory during 1 to 9 years. We used multivariable linear and logistic regression modeling, adjusting for relevant confounders.

RESULTS

In a fully adjusted analysis, a more proinflammatory diet was associated with an early versus never wheeze trajectory (first- and second-trimester average fourth vs first quartile: odds ratio, 1.89; 95% CI, 1.14-3.13). A more proinflammatory diet during pregnancy also was associated with lower forced expiratory flow (forced expiratory flow at 25%-75%) in midchildhood (first- and second-trimester average fourth vs first quartile: β, -132 mL; 95% CI, -249 to -14). Results were evident for first-, but not second-, trimester DII and wheeze trajectory and midchildhood forced expiratory flow at 25% to 75%. Other child respiratory outcomes, including ever asthma, were not related to any DII measure during pregnancy.

CONCLUSIONS

Proinflammatory diet during pregnancy is associated with wheeze trajectory during early childhood and decrements in small airways caliber in midchildhood, but not other respiratory outcomes in the offspring.

Diet and asthma in Lebanese schoolchildren: A cross-sectional study

OBJECTIVES

The causes of the global increase in asthma in children are unknown. It has been hypothesized that diet is an important factor that may play a role in the pathogenesis of the disease. The objective was to evaluate the association between diet and current asthma among Lebanese children.

METHODS

A cross-sectional study was conducted on 1000 children recruited from public and private schools in Lebanon. Of the total enrolled participants, 107 children were diagnosed with current asthma and were analyzed. The food frequency questionnaire was used to assess participants' dietary habits.

RESULTS

The consumption of sweets ≥3 times weekly (ORa = 5.42), white bread ≥3 times weekly (ORa = 26.38), and olive oil daily (ORa = 9.80) were associated with higher odds of current asthma. Drinking carbonated beverages occasionally (ORa = 0.25) and ≥3 times per week (ORa = 0.03) was significantly associated with lower odds of current asthma. Adhering to Mediterranean diet (occasional, >3 times weekly and daily) was significantly associated with lower odds of current asthma compared to never consuming Mediterranean diet (ORa = 0.23 and ORa = 0.22, respectively). The occasional consumption of bread was significantly associated with higher odds of current asthma (ORa = 8.2), whereas daily consumption was significantly associated with lower odds (ORa = 0.336). Moreover, the occasional, ≥3 times weekly and daily consumption of meat were significantly associated with higher odds of current asthma (ORa = 9.6; ORa = 5.1 and ORa = 4.5), respectively. An occasional consumption of junk food was significantly associated with lower odds of current asthma (ORa = 0.044), whereas a daily consumption was associated with higher odds.

CONCLUSION

Adhering to certain diets might be associated with higher odds of current asthma.

Serum perfluoroalkyl substances (PFAS) and risk of asthma and various allergies in adolescents. The Tromsø study Fit Futures in Northern Norway

BACKGROUND

Exposure to environmental pollutants may contribute to the development of asthma and other allergies. The aim of this study was to investigate possible associations between asthma and other allergies with exposure to perfluoroalkyl substances (PFASs) in adolescents from the Arctic region of Norway.

METHODS

The Tromsø study Fit Futures 1 (TFF1) and 3-year follow-up Fit Futures 2 study (TFF2) included 675 adolescents that completed a questionnaire about health conditions and underwent a clinical examination with blood tests and fractional nitric oxide (FeNO) measurement. Serum concentrations of 18 PFASs were measured by UHPLC-MS/MS method.

RESULTS

Total PFASs (ΣPFAS) serum concentration over 4th quartile was positively associated with asthma in the TFF1 (OR 3.35 (95% CI 1.54-7.29), p = 0.002). Total perfluorooctane sulfonate (ΣPFOS), linear PFOS (linPFOS), linear perfluorohexane sulfonate (linPFHxS) concentrations over 4th quartiles were associated with 2 times higher odds of asthma in the TFF1. The positive associations between ΣPFAS, ΣPFOS, linPFOS and asthma remained statistically significant in the TFF2. ΣPFAS and linPFHxS concentrations over 3rd tertiles were associated with positive marker of eosinophilic airways inflammation FeNO> 25 ppb. Concentrations of ΣPFOS and linPFOS over 3rd quartiles were positively associated with self-reported nickel allergy (OR 2.25 (95% CI 1.17-4.35) p = 0.016 and OR 2.53 (95% CI 1.30-4.90) p = 0.006, respectively). Allergic rhinitis, self-reported pollen allergy, food allergy and atopic eczema were not associated with PFASs concentrations.

CONCLUSIONS

This study of Norwegian adolescents showed a positive association between several PFASs and asthma, as well as between PFOS and nickel allergy.

Prevalence of asthma symptoms and association with obesity, sedentary lifestyle and sociodemographic factors: data from the Hellenic National Action Plan for the assessment, prevention and treatment of childhood obesity (MIS301205)

Objectives: To evaluate the prevalence of asthma symptoms in a representative sample of Greek schoolchildren and to evaluate its association with overweight/obesity as well as other socioeconomic, demographic, and lifestyle factors. Methods: This is a cross-sectional study conducted from 10/2012 to 12/2013 on a pre-selected, representative elementary school cohort. Parents completed standardized questionnaires evaluating among others socioeconomic and sedentary activity habits. Students were measured with high sensitivity methods. Socioeconomic status (SES) index (range: 0-13) was calculated on years of parental education, rented versus owned residence, size of residence evaluated as meters squared per person (m²/person), and number of vehicles. Asthma was defined according to the approved Greek version of the International Study on Allergies and Asthma in Childhood (ISAAC) criteria. Results: The prevalence of any asthma symptoms was documented in 31% of population. The odds of presenting any asthma symptoms decreased with increase in age (odds ratio: 0.96, 95% CI: 0.94-0.98) and increased with overweight (odds ratio: 1.13, 95% CI: 1.03-1.25), obesity (odds ratio: 1.27, 95% CI: 1.11-1.46) and sedentary lifestyle. Conclusion: This is the first representative survey of prevalence of asthma symptoms in children and adolescents in Greece indicating its continuous increase. A strong association between presence of asthma symptoms and obesity and sedentary activities was documented irrespectively of socioeconomic and regional factors. The findings stress the importance of public health policies toward obesity prevention and enhancement of physical activities in pediatric populations.

Efficacy of a Mediterranean diet supplemented with fatty fish in ameliorating inflammation in paediatric asthma: a randomised controlled trial

BACKGROUND

Childhood asthma is the most common respiratory disorder worldwide, being associated with increased morbidity and a decreased quality of life. Omega-3 fatty acids have anti-inflammatory and immunomodulating properties; however, their efficacy in asthma is controversial. The present study aimed to examine the efficacy of a Mediterranean diet supplemented with a high omega-3 'fatty' fish intake in Greek asthmatic children.

METHODS

A single-centred, 6-month, parallel randomised controlled trial compared the consumption of a Mediterranean diet supplemented with two meals of 150 g of cooked fatty fish weekly (intervention) with the usual diet (control) with respect to pulmonary function in children (aged 5-12 years) with mild asthma. Pulmonary function was assessed using spirometry and bronchial inflammation by fractional exhaled nitric oxide analysis.

RESULTS

Sixty-four children (52% male, 48% female) successfully completed the trial. Fatty fish intake increased in the intervention group from 17 g day^-1 at baseline to 46 g day^-1 at 6 months (P < 0.001). In the unadjusted analysis, the effect of the intervention was of borderline significance (P = 0.06, β = -11.93; 95% confidence interval = -24.32 to 0.46). However, after adjusting for age, sex, body mass index and regular physical activity, a significant effect was observed (P = 0.04, β = -14.15 ppb; 95% confidence interval = -27.39 to -0.91). No difference was observed for spirometry, asthma control and quality of life scores.

CONCLUSIONS

A Mediterranean diet supplemented with two fatty fish meals per week might be a potential strategy for reducing airway inflammation in childhood asthma. Future robust clinical trials are warranted to replicate and corroborate these findings.

The role of fish intake on asthma in children: A meta-analysis of observational studies

BACKGROUND

The evidence is mixed on the use of long chain Omega-3 fatty acids in the prevention and management of childhood asthma.

METHODS

We conducted a systematic search and meta-analysis investigating the role of fish intake, the main dietary source of long chain omega-3 fatty acids, on asthma in children.

RESULTS

A total of 1119 publications were identified. Twenty-three studies on fish intake in association with childhood asthma were included in the final review. In 15 of 23 studies, early introduction of fish (6-9 months) and regular consumption (at least once a week) improved asthma symptoms and reduced risk in children 0-14 years as compared to no fish consumption; 6 of 23 showed no effect and 2 of 23 studies suggest adverse effects. Meta-analysis revealed an overall "beneficial effect" for "all fish" intake on "current asthma" [OR: 0.75; 95%CI: 0.60-0.95] and "current wheeze" [OR: 0.62; 95%CI: 0.48-0.80] in children up to 4.5 years old. An overall protective effect of "fatty fish" intake as compared to "no fish" intake in children 8-14 years old was also observed [OR: 0.35; 95%CI: 0.18-0.67].

CONCLUSION

This meta-analysis suggests that introduction of fish early in life (6-9 months) and regular consumption of all fish (at least once a week) reduces asthma and wheeze in children up to 4.5 years old, while fatty fish intake may be beneficial in older children. Future well-designed clinical trials are recommended to confirm the promising findings documented in this literature analysis.

Maternal vegetable intake in early pregnancy and wheeze in offspring at the age of 2 years

BACKGROUND/OBJECTIVES

Vegetable intake during childhood may reduce the risk of subsequent asthma. We verified the effect of maternal intake during pregnancy on asthma risk in offspring, which has rarely been studied.

SUBJECTS/METHODS

In a hospital-based birth cohort study conducted in Tokyo, we administered a food frequency questionnaire at two periods during the respondents' pregnancy: early and mid to late periods. In addition, a questionnaire including the International Study of Asthma and Allergies in Childhood questionnaire was conducted when the offspring were 2 years old. Multivariate Poisson regression adjusting for maternal baseline demographics was used to elucidate the association between maternal vegetable intake and the incidence of wheeze in the offspring.

RESULTS

Among 310 singletons, 82 (26.5%) experienced wheeze at 2 years of age. Women with the highest intake of cruciferous, and folate-rich vegetables during early pregnancy reported a significantly lower prevalence of wheeze in their child at 2 years of age in comparison with those who reported the lowest intake (adjusted risk ratio: 0.48 and 0.47, 95% confidence interval: 0.26-0.89, and 0.25-0.87, respectively). In trend analysis, a higher maternal intake of cruciferous, folate-rich vegetables, and total vegetables during early pregnancy was less likely to be associated with wheeze in the offspring at 2 years old (p for trend: 0.038, <0.001, and 0.028, respectively). Maternal vegetable intake during mid to late pregnancy was not associated with wheeze in the offspring.

CONCLUSIONS

Maternal vegetable intake during early pregnancy may have a protective effect against asthma in offspring at 2 years of age.

Polyunsaturated fatty acids in plasma at 8 years and subsequent allergic disease

BACKGROUND

Polyunsaturated fatty acids (PUFAs) are hypothesized to modulate the risk of allergic disease. However, evidence from previous studies is inconclusive, and limited longitudinal data exist using circulating biomarkers of PUFA intake and metabolism.

OBJECTIVE

We aimed to investigate associations between n-3 and n-6 PUFAs at age 8 years and asthma, rhinitis, and aeroallergen sensitization at age 16 years.

METHODS

Proportions of n-3 PUFAs (very long-chain n-3 [VLC n-3; sum of eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid] and α-linolenic acid) and n-6 PUFAs (linoleic acid and arachidonic acid [AA]) in blood samples at age 8 years were measured for 940 children from the prospective Swedish birth cohort BAMSE (Children, Allergy, Milieu, Stockholm, Epidemiology). Allergic disease phenotypes were defined by using questionnaires and IgE measures at the ages of 8 and 16 years. Logistic regression was used to examine potential associations.

RESULTS

A higher proportion of total VLC n-3 PUFAs in plasma at age 8 years was associated with a reduced risk of prevalent asthma, rhinitis, and aeroallergen sensitization at age 16 years and with incidence of asthma between 8 and 16 years (adjusted odds ratio, 0.67; 95% CI, 0.47-0.94). AA was associated with a reduced risk of asthma, aeroallergen sensitization, and allergic rhinitis. The findings were most evident for allergic phenotypes of asthma and rhinitis. Additionally, AA was associated with an increased probability of asthma and rhinitis remission between 8 and 16 years of age.

CONCLUSION

Higher proportions of certain VLC n-3 and very long-chain n-6 PUFAs in plasma phospholipids at age 8 years were associated with a reduced risk of allergic disease at age 16 years.

Diet and Asthma: Is It Time to Adapt Our Message?

Asthma is a chronic respiratory disorder which is associated with airway inflammation. Environmental factors, in association with genetic susceptibility, play a critical role in asthma pathophysiology. Inhaled allergens, smoke exposure, indoor and outdoor air pollution are common triggers of asthma symptoms. Although the role of diet has clearly established mechanisms in diseases such as cardiovascular disease, type 2 diabetes, and cancer, it is not commonly identified as a causal factor in asthma. However, some dietary patterns, such as the Western diet, which includes a high intake of refined grains, processed and red meats, and desserts, have pro-inflammatory effects. On the contrary, the Mediterranean diet, with high intake of fruits and vegetables has anti-inflammatory properties. The influence of food on asthma outcomes is of growing interest, but dietary habits of asthma patients are not commonly investigated in clinical practice. In this review, we focus on the impact of diet on asthma risk and asthma control. We also detail the influence of diet on obese patients with asthma.

Effect of diet and maternal education on allergies among preschool children: A case-control study

INTRODUCTION

The prevalence of asthma and allergy has increased among children. This increase in prevalence might be related to dietary patterns.

AIMS

The present epidemiological study investigated the relationship between the consumption of fruit, vegetables, nuts, meat and fish, and the prevalence of wheeze, asthma, and eczema among preschool children.

METHODS

This nested case-control study included 1489 children aged 4-6 years and residing in Kaunas city, Lithuania. The subjects were recruited to the KANC newborn cohort study during 2007-2009. Parents' responses to questionnaires were used to collect information on allergic diseases, diet, and other variables. The association between dietary patterns and children's allergic diseases were tested by using logistic regressions, after adjustment for maternal education level, smoking during pregnancy, parental asthma, children's sex, parity, and antibiotic usage during the first year of life.

RESULTS

In this study, 83.3% of all children consumed fresh fruit and/or vegetables at least three times per week. A significantly lower adjusted odds ratio (aOR) of wheeze was found among children who ate fruit than among those who did not (aOR: 0.48; 95% CI: 0.22-0.96). The consumption of nuts was also associated with a lower 61% risk of eczema among 4-6 years old children.

CONCLUSION

The results indicated a beneficial effect of a frequent consumption of fresh fruit and nuts on the prevalence of allergies among children. These results might have important implications for children's health.

Folic Acid Modulates DMBA/TPA-Induced Changes in Skin of Mice: A Study Relevant to Carcinogenesis

The present study was aimed at investigating the modulatory effects of folic acid (FA) on early stages of chemically induced skin cancer. For this, a two-stage model of skin tumorigenesis was employed. 7,12-Dimethylbenz(a)anthracene (DMBA, 500 nmol/100 ul of acetone) was applied topically for two weeks (twice weekly), followed by phorbol-12-myristate-13-acetate (TPA, 1.7 nmol/100 ul) twice weekly for six weeks on the depilated skin of mice, and FA was administered orally at a dose of 40 microgram/animal for 10 weeks daily. Balb/c mice were divided into four groups depending upon the treatment they received (control, DMBA/TPA, FA, and FA+DMBA/TPA). DMBA/TPA treatment led to the formation of papillomas in DMBA/TPA and FA+DMBA/TPA groups. Ornithine decarboxylase (ODC), proliferating cell nuclear antigen (PCNA), epidermal thickness, and cell count were evaluated to assess the beneficial effects in the early stages. FA exhibited its ameliorative potential as indicated by decreased epidermal thickness and cell count in FA+DMBA/TPA group when compared to DMBA/TPA group. Concomitantly, FA decreased the expression of ODC and PCNA in skin and activity of serum lactate dehydrogenase, suggesting inhibitory effects on cell proliferation and cell damage. Differential modulation in lipid peroxidation and reduced glutathione was observed in response to DMBA/TPA treatment and its intervention with FA. Although these findings suggest the inhibitory potential of FA during initial stages of murine skin cancer, detailed studies are warranted considering the ambiguous reports available in literature regarding the association of FA and cancer.

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.

The Current Evidence of Integrative Approaches to Pediatric Asthma

Asthma is a complex, multifactorial, and inflammatory chronic condition, and many children who are diagnosed with asthma integrate complementary therapies into their overall care. Due to the chronic nature of asthma, potentially negative side effects of long-term use of allopathic medications, and desire for natural approaches, patients and their families turn toward complementary therapies. Up to 89% of parents use complementary and alternative medicine (CAM) to treat their child's asthma. This article reviews the current evidence on the most commonly used complementary therapies for pediatric asthma.

Association between dietary habits and asthma severity in children

OBJECTIVE

To investigate association between dietary habits and asthma severity in children.

DESIGN

Cross-sectional study.

SETTING

Two teaching hospitals in Brazil.

PARTICIPANTS

Cases (n=268) were children (3-12yr) with persistent asthma and age-matched controls (n=126) were those with intermittent asthma.

MAIN OUTCOME MEASURES

Dietary habits were determined based on food consumption in the past 12 months classified as frequent (≥3 times per week) or infrequent (never or <3 times per week).Nutritional status was classified into two categories according to WHO Child Growth Standards: obese: >2Z-score of BMI-for-age; non-obese: ≤2Z-score of BMI-for-age.

RESULTS

After adjusting for confounding factors, maternal smoking during pregnancy, preterm birth and obesity were significantly associated with persistent asthma, with adjusted ORs (95% CI) of 2.11 (1.08- 4.13), 2.61(1.07-6.35) and 2.89 (1.49-5.61), respectively. No significant association was observed between frequency of consumption of specific foods, food groups, or dietary pattern (pro- or contra-Mediterranean diet) and the severity of asthma.

CONCLUSIONS

This study did not find a significant association between dietary habits and asthma severity in children. Maternal smoking during pregnancy, preterm birth and obesity were independent factors associated with persistent asthma.

Mediterranean diet and childhood asthma

BACKGROUND

The incidence of bronchial hyperreactivity has increased to one-third of the population in developed countries, which requires the adoption of preventive and therapeutic measures. The objective of the present study was to assess the effects of a traditional Mediterranean diet on patients diagnosed with childhood asthma and determine if there is a beneficial effect from this dietary intervention.

METHODS

Prospective before-after comparison study of 50 girls and 54 boys aged 1-5 years, who were enrolled in the 1-year programme "Learning to Eat from the Mediterranean", designed to promote the adoption of a traditional Mediterranean diet. We studied the clinical and therapeutic variables and anthropometric measurements.

RESULTS

All studied symptomatic indicators (number and intensity of asthmatic attack, infections and hospital admissions) showed a positive and statistically significant evolution of bronchial hyperreactivity from the first weeks of the intervention onwards. Throughout the treatment, 32.2% of patients remained free of crisis, 35.3% of the patients only had one attack throughout the year and 24.9% had two episodes, compared to 4.73 episodes on average in the previous year. The use of inhaled corticosteroids markedly decreased from 3.92 ± 1.61 to 1.11 ± 1.09 times per patient per year (P<0.001) and that of inhaled bronchodilators decreased from 4.14 ± 1.61 to 1.12 ± 1.40 (P<0.001). As a result, the families involved in the programme reported a high level of satisfaction.

CONCLUSIONS

The adoption of a traditional Mediterranean diet could contribute significantly to the improvement of patients diagnosed with childhood asthma.

Fat intake and breast milk fatty acid composition in farming and nonfarming women and allergy development in the offspring

BACKGROUND

Children growing up on small family farms are at much lower risk of developing allergy than other children. We hypothesized that low intake of margarine and polyunsaturated fats among farming families could contribute to this protection.

METHODS

Twenty-eight mother-infant pairs living on small dairy farms and 37 nonfarm rural resident pairs were recruited in the FARMFLORA birth cohort. Food items expected to affect dietary fat composition were recorded by food frequency questionnaires during pregnancy and by 24-h recalls followed by 24-h food diaries during lactation. Allergy was diagnosed by doctors, using strict predefined criteria. Maternal diet and breast milk fat composition were compared between farming and nonfarming mothers and related to children's allergy at age 3 y.

RESULTS

Farming mothers consumed more butter, whole milk, saturated fat, and total fat than nonfarming mothers, who consumed more margarine, oils, and low-fat milk. Farming mothers' breast milk contained higher proportions of saturated and lower proportions of polyunsaturated fat. Allergy was eight times more common in nonfarm children. Mothers of allergic children consumed more margarine and oils than mothers of nonallergic children.

CONCLUSION

Low maternal consumption of margarine and vegetable oils might contribute to the allergy-preventive effect of growing up on small dairy farms.

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.

Omega-3 Fatty Acids Supplementation in Children to Prevent Asthma: Is It Worthy?-A Systematic Review and Meta-Analysis

Asthma is one of the most common respiratory diseases affecting all age groups. The world is now trying to identify some dietary factors which can play a preventive role. We performed this systematic review and meta-analysis of RCTs to assess the effect of intake of polyunsaturated fatty acid (PUFA) in infancy and/or childhood on incidence of asthma or wheezing episodes. We searched MEDLINE, EBSCO, Trip, and Google Scholar up to January 31, 2015. All RCTs where infants or children who were given omega-3 fatty acid supplementation and which reported incidence of asthma and/or wheezing episodes as dichotomous outcomes were included in this review. Random effects model was used for pooling the risk estimates. Total five articles were included. Most of them were from Australia. On meta-analysis, the pooled estimate of odds ratios by random effects model showed no significant change in incidence of asthma after supplementation of omega-3 FA in infancy or childhood (OR 0.974; CI 0.646, 1.469; p = 0.900). We concluded that a multicentric RCT is required to assess the effect of omega-3 FA supplementation exclusively to infants or children to predict the best time of omega-3 FA supplementation to prevent asthmatic or wheezing episodes later in life.

Role of omega-3 fatty acids and their metabolites in asthma and allergic diseases

Omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are found naturally in fish oil and are commonly thought to be anti-inflammatory nutrients, with protective effects in inflammatory diseases including asthma and allergies. The mechanisms of these effects remain mostly unknown but are of great interest for their potential therapeutic applications. Large numbers of epidemiological and observational studies investigating the effect of fish intake or omega-3 fatty acid supplementation during pregnancy, lactation, infancy, childhood, and adulthood on asthmatic and allergic outcomes have been conducted. They mostly indicate protective effects and suggest a causal relationship between decreased intake of fish oil in modernized diets and an increasing number of individuals with asthma or other allergic diseases. Specialized pro-resolving mediators (SPM: protectins, resolvins, and maresins) are generated from omega-3 fatty acids such as EPA and DHA via several enzymatic reactions. These mediators counter-regulate airway eosinophilic inflammation and promote the resolution of inflammation in vivo. Several reports have indicated that the biosynthesis of SPM is impaired, especially in severe asthma, which suggests that chronic inflammation in the lung might result from a resolution defect. This article focuses on the beneficial aspects of omega-3 fatty acids and offers recent insights into their bioactive metabolites including resolvins and protectins.

Overweight/obesity and respiratory and allergic disease in children: international study of asthma and allergies in childhood (ISAAC) phase two

Background

Childhood obesity and asthma are increasing worldwide. A possible link between the two conditions has been postulated.

Methods

Cross-sectional studies of stratified random samples of 8–12-year-old children (n = 10 652) (16 centres in affluent and 8 centres in non-affluent countries) used the standardized methodology of ISAAC Phase Two. Respiratory and allergic symptoms were ascertained by parental questionnaires. Tests for allergic disease were performed. Height and weight were measured, and overweight and obesity were defined according to international definitions. Prevalence rates and prevalence odds ratios were calculated.

Results

Overweight (odds ratio = 1.14, 95%-confidence interval: 0.98; 1.33) and obesity (odds ratio = 1.67, 95%-confidence interval: 1.25; 2.21) were related to wheeze. The relationship was stronger in affluent than in non-affluent centres. Similar results were found for cough and phlegm, rhinitis and eczema but the associations were mostly driven by children with wheeze. There was a clear association of overweight and obesity with airways obstruction (change in FEV1/FVC, −0.90, 95%-confidence interval: −1.33%; −0.47%, for overweight and −2.46%, 95%-confidence interval: −3.84%; −1.07%, for obesity) whereas the results for the other objective markers, including atopy, were null.

Conclusions

Our data from a large international child population confirm that there is a strong relation of body mass index with wheeze especially in affluent countries. Moreover, body mass index is associated with an objective marker of airways obstruction (FEV1/FVC) but no other objective markers of respiratory and allergic disorders.

Dietary pattern and nutrient intake of korean children with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is characterized by itching and eczema-like skin lesions, and its symptoms alleviate with age. Recently, the prevalence of AD has increased among adolescents and adults. The increasing prevalence of AD seems to be related to westernized lifestyles and dietary patterns.

OBJECTIVE

The aim of this study was to evaluate the dietary patterns and nutrient intake of patients with AD.

METHODS

The study population consisted of 50 children with AD who visited the Department of Dermatology at Kangnam Sacred Heart Hospital, Seoul, Korea from May 2008 to May 2009. Physical condition and calorie intake were evaluated using the Eczema Area and Severity Index score and Food Record Questionnaire completed by the subjects, and the data were analyzed using the Nutritional Assessment Program Can-pro 3.0 (The Korean Nutrition Society, 2005) program to determine the gap between the actual ingestion and average requirements of 3 major nutrients (i.e. carbohydrates, proteins, and lipids), vitamins (i.e. A, B, C, and E), niacin, folic acid, calcium, iron, phosphorus, and zinc in all subjects.

RESULTS

The intake rate of proteins was 18.02% (recommended dietary allowance [RDA], 7%~20%), of carbohydrates was 67.7% (RDA, 55%~70%), and of lipids was 14.24% (RDA, 15%~30%). Thirty-one subjects (62%) showed deficiency of folic acid, and 21 subjects (42%), of iron supplements.

CONCLUSION

Essential nutrient intake tends to be lower in AD patients than in healthy subjects, and this low intake is closely related to the severity of AD.

Fruit and vegetable intake and risk of wheezing and asthma: a systematic review and meta-analysis

Major bibliographic databases were searched for studies examining the relationship between fruit and vegetable consumption and the risk of wheezing and asthma. Random-effects models were used to pool study results. Subgroup analyses were conducted by fruit and vegetable categories, study design, and age group. Twelve cohorts, 4 population-based case-control studies, and 26 cross-sectional studies published between January 1990 and July 2013 were identified. For the meta-analysis of adults and children, the relative risk (RR) and confidence intervals (CI) when comparing the highest intake group with the lowest intake group were 0.78 (95%CI, 0.70-0.87) for fruit and 0.86 (95%CI, 0.75-0.98) for vegetables. High intake of fruit and vegetables (RR = 0.76; 95%CI, 0.68-0.86 and RR = 0.83; 95%CI, 0.72-0.96) reduced the risk of childhood wheezing. Total intake of fruit and vegetables had a negative association with risk of asthma in adults and children (RR = 0.54; 95%CI, 0.41-0.69). Consuming fruit and vegetables during pregnancy had no association with the risk of asthma in offspring. High intake of fruit and vegetables may reduce the risk of asthma and wheezing in adults and children.

Relative validity of an FFQ for pre-school children in the mother–child ‘Rhea’ birth cohort in Crete, Greece

Objective

To examine the relative validity of an FFQ based on parental report for pre-school children in the mother–child ‘Rhea’ birth cohort.

Design

The children’s mothers completed an FFQ that referred to the children’s dietary intake for the previous year by telephone interview. Mothers completed also three food records, two on weekdays and one on a weekend day. Spearman correlation coefficients were calculated for the energy-adjusted values. Weighted kappa statistics (κw) and the Bland–Altman technique were used to test the degree of agreement between the two dietary methods.

Setting

Heraklion, Crete, Greece, 2011–2012.

Subjects

A total of ninety-nine mothers (corresponding to fifty-one boys and forty-eight girls) participated in the validation study.

Results

The mean and median values of all food group and nutrient intakes did not differ significantly between the two dietary methods. Overall, fair agreement was observed between the FFQ and the food records for ranking participants based on their intake, with κw ranging from 0·21 to 0·40 for most foods and nutrients. On average, 88 % of participants were classified into the same or adjacent tertiles for nutrient and food group intakes by both dietary methods. The degree of agreement was also confirmed by the visual examination of the Bland–Altman plots.

Conclusions

The study indicates that the Rhea 4 years FFQ is a relatively accurate tool for assessing habitual food group and nutrient intakes among pre-school children in Crete, Greece.

Diet and allergic diseases among population aged 0 to 18 years: myth or reality?

Allergic diseases are an important health problem. However, epidemiological studies concerning childhood diet-related allergic diseases are scarce. This review examines published articles dealing with diet, dietary patterns and nutrition in relation with allergic diseases among population aged 0 to 18 years. Studies and trials were identified using MEDLINE/PubMed and Cochrane Database of Systematic Reviews and were limited to those published in English or French from 1992 until 2012. This manuscript also reviews the evidence for maternal diet during pregnancy and diet during early childhood and their association with childhood atopic diseases, taking into account the methodology used to evaluate dietary patterns. The evidence reviewed is derived from large epidemiological studies exploring the effects of different food categories on asthma, atopic dermatitis, and allergic rhinitis in children. Overall, maternal diet during pregnancy and a childhood diet rich in antioxidants and omega-3 fatty acids are considered as healthy diets that could be protective for allergic diseases in childhood.

Flavonoids and asthma

Asthma is a chronic disease, characterized by airway inflammation, airflow limitation, hyper-reactivity and airway remodeling. It is believed that asthma is caused by the interaction between genetic and environmental factors. The prevalence of allergic diseases, including asthma, has increased worldwide during the past two decades. Although the precise reasons that have caused this increase remain unknown, dietary change is thought to be one of the environmental factors. Flavonoids, which are polyphenolic plant secondary metabolites ubiquitously present in vegetables, fruits and beverages, possess antioxidant and anti-allergic traits, as well as immune-modulating activities. Flavonoids are powerful antioxidants and anti-allergic nutrients that inhibit the release of chemical mediators, synthesis of Th2 type cytokines, such as interleukin (IL)-4 and IL-13, and CD40 ligand expression by high-affinity immunoglobulin E (IgE) receptor-expressing cells, such as mast cells and basophils. They also inhibit IL-4-induced signal transduction and affect the differentiation of naïve CD4+ T cells into effector T-cells through their inhibitory effect on the activation of the aryl hydrocarbon receptor. Various studies of flavonoids in asthmatic animal models have demonstrated their beneficial effects. The results of several epidemiological studies suggest that an increase in flavonoid intake is beneficial for asthma. Moreover, clinical trials of flavonoids have shown their ameliorative effects on symptoms related to asthma. However, these human studies are currently limited; further validation is required to clarify whether an appropriate intake of flavonoids may constitute dietary treatment and for part of a preventive strategy for asthma.

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.

Influence of Mediterranean diet on asthma in children: a systematic review and meta-analysis

BACKGROUND

There is epidemiological evidence that Mediterranean diet exposure is associated with lower asthma prevalence in children. We aimed to summarize the available data and to know whether the Mediterranean setting modifies this association.

METHODS

The literature search, up to May 2012, was on epidemiological studies in the general population of children assessing whether adherence to Mediterranean diet (measured as a score) was associated with the prevalence of 'current wheeze'; 'current severe wheeze'; or 'asthma ever'. Odds ratios (OR) of the eight included studies compared the highest tertile of the score with the lowest. Random-effects meta-analyses for the whole group of studies and stratified by Mediterranean setting (centers <100 Km from the Mediterranean coast) were performed. Differences between strata were assessed using the Q test.

RESULTS

For 'current wheeze', there was a negative significant association with the highest tertile of Mediterranean diet score (OR 0.85, 95% CI 0.75-0.98; p = 0.02), driven by Mediterranean centers (0.79, 0.66-0.94, p = 0.009), although the difference with the non-Mediterranean centers (0.91, 0.78-1.05, p = 0.18) was not significant. The results for 'current severe wheeze' were as follows: 0.82, 0.55-1.22, p = 0.330 (all); 0.66, 0.48-0.90, p = 0.008 (Mediterranean); and 0.99, 0.79-1.25, p = 0.95 (non-Mediterranean); with the difference between regions being significant. For 'asthma ever', the associations were as follows: 0.86, 0.78-0.95, p = 0.004 (all); 0.86, 0.74-1.01, p = 0.06 (Mediterranean); 0.86, 0.75-0.98; p = 0.027 (non-Mediterranean); with the difference between regions being negligible.

CONCLUSIONS

Adherence to the Mediterranean diet tended to be associated with lower occurrence of the three respiratory outcomes. For current and current severe wheeze, the association was mainly driven by the results in Mediterranean populations.

Nutrigenetic response to omega-3 fatty acids in obese asthmatics (NOOA): rationale and methods

Uncontrolled asthma is a major cause of hospitalizations and emergency room visits. Factors including obesity, African ancestry and childhood are associated with increased asthma severity. Considering the high morbidity caused by asthma, relatively few classes of drugs exist to control this common disease. Therefore, new therapeutic strategies may be needed to reduce asthma's impact on public health. Data suggest that a high fat diet that is deficient in omega-3 fatty acids could promote both obesity and excessive inflammation, resulting in greater asthma severity. Small trials with supplemental omega-3 fatty acids have been conducted with encouraging but inconsistent results. The variability in response seen in past trials may be due to the past subjects' genetics (specifically ALOX5 rs59439148) or their particular asthma phenotypes. Therefore, the "Nutrigenetic response to Omega-3 Fatty acids in Obese Asthmatics (NOOA)" trial is currently underway and was designed as a randomized, double-blind, placebo controlled intervention study to determine if supplemental omega-3 fatty acids improves symptoms among obese adolescents and young adults with uncontrolled asthma. Here we report the design and rationale for the NOOA trial. Participants were given either 3.18 g daily of eicosapentaenoic acid and 822 mg daily docosahexaenoic acid, or matched control soy oil, for 24 weeks. Change in the asthma control questionnaire score was the primary outcome. Secondary outcomes included spirometry, impulse oscillometry, exacerbation rate, airway biomarkers, systemic inflammation, leukotriene biosynthesis and T-lymphocyte function. NOOA may lead to a new therapeutic treatment strategy and greater understanding of the mechanistic role of diet in the pathogenesis of asthma.

Low vegetable intake is associated with allergic asthma and moderate-to-severe airway hyperresponsiveness

BACKGROUND

In recent decades, children's diet quality has changed and asthma prevalence has increased, although it remains unclear if these events are associated.

OBJECTIVE

To examine children's total and component diet quality and asthma and airway hyperresponsiveness (AHR), a proxy for asthma severity.

METHODS

Food frequency questionnaires adapted from the Nurses' Health Study and supplemented with foods whose nutrients which have garnered interest of late in relation to asthma were administered. From these data, diet quality scores (total and component), based on the Youth Healthy Eating Index (YHEI adapted) were developed. Asthma assessments were performed by pediatric allergists and classified by atopic status: Allergic asthma (≥1 positive skin prick test to common allergens >3 mm compared to negative control) versus non-allergic asthma (negative skin prick test). AHR was assessed via the Cockcroft technique. Participants included 270 boys (30% with asthma) and 206 girls (33% with asthma) involved in the 1995 Manitoba Prospective Cohort Study nested case-control study. Logistic regression was used to examine associations between diet quality and asthma, and multinomial logistic regression was used to examine associations between diet quality and AHR.

RESULTS

Four hundred seventy six children (56.7% boys) were seen at 12.6 ± 0.5 years. Asthma and AHR prevalence were 26.2 and 53.8%, respectively. In fully adjusted models, high vegetable intake was protective against allergic asthma (OR 0.49; 95% CI 0.29-0.84; P < 0.009) and moderate/severe AHR (OR 0.58; 0.37-0.91; P < 0.019).

CONCLUSIONS

Vegetable intake is inversely associated with allergic asthma and moderate/severe AHR.

Fish consumption in infancy and asthma-like symptoms at preschool age

OBJECTIVE

To assess whether timing of introduction of fish and the amount of fish consumption in infancy were associated with asthmalike symptoms at preschool age.

METHODS

This study was embedded in the Generation R study (a population-based birth cohort in Rotterdam, Netherlands). At the age of 12 and 14 months, timing of introduction of fish into the infant's diet was assessed. The amount of fish consumption at 14 months was assessed by a semiquantitative food frequency questionnaire. Presence of asthmalike symptoms in the past year was assessed at the child's age of 36 and 48 months.

RESULTS

Relative to no introduction in the first year of life, introduction between age 6 and 12 months was significantly associated with a lower risk of wheezing at 48 months (odds ratio [OR]: 0.64; 95% CI: 0.43-0.94). When compared with introduction between 6 and 12 months, no introduction in the first year and introduction between 0 and 6 months were associated with an increased risk of wheezing at 48 months (OR: 1.57; 95% CI: 1.07-2.31 and OR: 1.53; 95% CI: 1.07-2.19, respectively). The amount of fish at age 14 months was not associated with asthmalike symptoms (P > .15).

CONCLUSIONS

Introduction of fish between 6 and 12 months but not fish consumption afterward is associated with a lower prevalence of wheezing. A window of exposure between the age of 6 and 12 months might exist in which fish might be associated with a reduced risk of asthma.

Influence of mediterranean diet on asthma symptoms, lung function, and systemic inflammation: a randomized controlled trial

OBJECTIVE

The rapidly increasing prevalence of asthma in developed countries suggests an environmental cause. The benefits of Mediterranean diet (MD) in cardiovascular disease have been tentatively attributed to its anti-inflammatory properties. Asthma is an inflammatory disease and MD is associated with reduced asthma risk in epidemiological studies, but there are no reported interventional studies of MD in asthma.

METHODS

In this 12-week open-label randomized trial, 38 adults with symptomatic asthma were allocated to high-intervention (HI), low-intervention (LI), and control groups. The first two groups were encouraged to adopt an MD and received multiple consultation sessions with a nutritionist, written advice, and vouchers for the purchase of appropriate foods. Food frequency questionnaires, asthma control questionnaires, asthma-related quality of life questionnaires (AQLQs), and spirometry were completed at the beginning and at the end of the study.

RESULTS

The MDt score increased in the HI group (p < .001), indicating successful alteration of dietary behavior. Statistically, nonsignificant improvements were seen in spirometry and several AQLQ subdomains in the two intervention groups. No changes were seen in the asthma control or in inflammatory markers.

CONCLUSIONS

The trial intervention has successfully altered the dietary behavior among adults with asthma. Small but consistent improvements were seen in quality of life and spirometry among the intervention group. The use of the MD to treat asthma is feasible and warrants evaluation in a larger study, powered to examine clinical endpoints.

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.

Critical review: vegetables and fruit in the prevention of chronic diseases

BACKGROUND

Vegetables and fruit provide a significant part of human nutrition, as they are important sources of nutrients, dietary fibre, and phytochemicals. However, it is uncertain whether the risk of certain chronic diseases can be reduced by increased consumption of vegetables or fruit by the general public, and what strength of evidence has to be allocated to such an association.

METHODS

Therefore, a comprehensive analysis of the studies available in the literature and the respective study results has been performed and evaluated regarding obesity, type 2 diabetes mellitus, hypertension, coronary heart disease (CHD), stroke, cancer, chronic inflammatory bowel disease (IBD), rheumatoid arthritis (RA), chronic obstructive pulmonary disease (COPD), asthma, osteoporosis, eye diseases, and dementia. For judgement, the strength of evidence for a risk association, the level of evidence, and the number of studies were considered, the quality of the studies and their estimated relevance based on study design and size.

RESULTS

For hypertension, CHD, and stroke, there is convincing evidence that increasing the consumption of vegetables and fruit reduces the risk of disease. There is probable evidence that the risk of cancer in general is inversely associated with the consumption of vegetables and fruit. In addition, there is possible evidence that an increased consumption of vegetables and fruit may prevent body weight gain. As overweight is the most important risk factor for type 2 diabetes mellitus, an increased consumption of vegetables and fruit therefore might indirectly reduces the incidence of type 2 diabetes mellitus. Independent of overweight, there is probable evidence that there is no influence of increased consumption on the risk of type 2 diabetes mellitus. There is possible evidence that increasing the consumption of vegetables and fruit lowers the risk of certain eye diseases, dementia and the risk of osteoporosis. Likewise, current data on asthma, COPD, and RA indicate that an increase in vegetable and fruit consumption may contribute to the prevention of these diseases. For IBD, glaucoma, and diabetic retinopathy, there was insufficient evidence regarding an association with the consumption of vegetables and fruit.

CONCLUSIONS

This critical review on the associations between the intake of vegetables and fruit and the risk of several chronic diseases shows that a high daily intake of these foods promotes health. Therefore, from a scientific point of view, national campaigns to increase vegetable and fruit consumption are justified. The promotion of vegetable and fruit consumption by nutrition and health policies is a preferable strategy to decrease the burden of several chronic diseases in Western societies.

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.

Diet for the prevention of asthma and allergies in early childhood: much ado about something?

In the last decades there has been an increase in allergic disease throughout the world, particularly in children. Attempts have been made to identify the causes of this "allergy epidemic" in environmental changes and changes in population hygiene, lifestyle, socioeconomic level, and eating habits that would exert epigenetic effects. Dietetic hypotheses have been mainly focussed in long-chain polyunsaturated fatty acids, vitamin D, antioxidants, Mediterranean diet, and fruits, vegetables and fish consumption. Although the data suggest a certain association between diet and the development of asthma/allergy, there is no evidence that diet has an impact upon the prevalence of such diseases after early infancy. If indeed there is such an impact, it is likely to be confined to the prenatal period and the first months of life - when it is still possible to modulate the development of the respiratory, digestive and immune systems. Thus, once the most appropriate preventive measures have been defined, these should be implemented during pregnancy and lactation. The existing scientific evidence is unable to recommend any primary preventive measure in the general population or in different population subgroups. Special or restrictive diets in pregnant or nursing women are not indicated. Exclusive breastfeeding for six months is questioned, since solid foods should begin to be introduced at around four months of age. Once the atopic process has started, no nutritional strategies have been found to be effective as secondary or tertiary preventive measures. Longitudinal studies in cohorts of pregnant women or newborn infants could help clarify these issues.

Self-reported seafood intake and atopy in Japanese school-aged children

BACKGROUND

The effects of fish consumption and n-3 poly-unsaturated fatty acid (PUFA) levels on atopic disorders are inconsistent in previous reports, but few studies have investigated the effects of both fish and n-3 PUFA. The aim of the present study was to investigate whether erythrocyte fatty acids and the consumption of fish are associated with atopic diseases in pre- and early adolescents.

METHODS

A total of 135 students with eczema, 136 students with asthma, and 137 healthy control students were selected from fifth and eighth grades in Shunan, Japan. Atopic disorders and dietary intake were evaluated with questionnaires, and total serum IgE was measured using an enzyme-linked immunosorbent assay. In addition, erythrocyte membrane levels of PUFA were assessed via gas chromatography.

RESULTS

Total IgE was significantly elevated in the atopic subjects (P < 0.001). The intake of fatty and dried fish or seafood was significantly associated with eczema (odds ratios of the highest quartiles: 0.46, 95% confidence interval (95%CI): 0.22-0.94; 0.34, 95%CI: 0.16-0.71, respectively). Additionally, only erythrocyte eicosapentaenoic acid (EPA) level had a negative association with eczema (P= 0.048). For asthma, the effect of fish consumption was not significant.

CONCLUSIONS

Fish consumption was related to a low prevalence of eczema, but not asthma in Japanese pre- and early adolescents. EPA may be involved in this mechanism.

Prenatal concentrations of polychlorinated biphenyls, DDE, and DDT and overweight in children: a prospective birth cohort study

BACKGROUND

Recent experimental evidence suggests that prenatal exposure to endocrine-disrupting chemicals (EDCs) may increase postnatal obesity risk and that these effects may be sex or diet dependent.

OBJECTIVES

We explored whether prenatal organochlorine compound (OC) concentrations [polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyltrichloroethane (DDT)] were associated with overweight at 6.5 years of age and whether child sex or fat intakes modified these associations.

METHODS

We studied 344 children from a Spanish birth cohort established in 1997-1998. Overweight at 6.5 years was defined as a body mass index (BMI) z-score ≥ 85th percentile of the World Health Organization reference. Cord blood OC concentrations were measured and treated as categorical variables (tertiles). Children's diet was assessed by food frequency questionnaire. Relative risks (RRs) were estimated using generalized linear models.

RESULTS

After multivariable adjustment, we found an increased RR of overweight in the third tertile of PCB exposure [RR = 1.70; 95% confidence interval (CI): 1.09, 2.64] and the second tertile of DDE exposure (RR = 1.67; 95% CI: 1.10, 2.55), but no association with DDT exposure in the population overall. Associations between overweight and PCB and DDE concentrations were strongest in girls (p-interaction between 0.01 and 0.28); DDT was associated with overweight only in boys. For DDT we observed stronger associations in children with fat intakes at or above compared with below the median, but this interaction was not significant (p-interaction > 0.05).

CONCLUSIONS

This study suggests that prenatal OC exposures may be associated with overweight in children and that sex and high-fat intake may influence susceptibility.

Atopy risk in infants and children in relation to early exposure to fish, oily fish, or long-chain omega-3 fatty acids: a systematic review

There are two main families of polyunsaturated fatty acids (PUFAs), the n-6 and the n-3 families. It has been suggested that there is a causal relationship between n-6 PUFA intake and allergic disease, and there are biologically plausible mechanisms, involving eicosanoid mediators of the n-6 PUFA arachidonic acid, that could explain this. Fish and fish oils are sources of long-chain n-3 PUFAs and these fatty acids act to oppose the actions of n-6 PUFAs. Thus, it is considered that n-3 PUFAs will protect against atopic sensitization and against the clinical manifestations of atopy. Evidence to examine this has been acquired from epidemiologic studies investigating associations between fish intake in pregnancy, lactation, infancy, and childhood, and atopic outcomes in infants and children and from intervention studies with fish oil supplements in pregnancy, lactation, infancy, and childhood, and atopic outcomes in infants and children. All five epidemiological studies investigating the effect of maternal fish intake during pregnancy on atopic or allergic outcomes in infants/children of those pregnancies concluded protective associations. One study investigating the effects of maternal fish intake during lactation did not observe any significant associations. The evidence from epidemiological studies investigating the effects of fish intake during infancy and childhood on atopic outcomes in those infants or children is inconsistent, although the majority of the studies (nine of 14) showed a protective effect of fish intake during infancy or childhood on atopic outcomes in those infants/children. Fish oil supplementation during pregnancy and lactation or during infancy or childhood results in a higher n-3 PUFA status in the infants or children. Fish oil provision to pregnant women is associated with immunologic changes in cord blood and such changes may persist. Studies performed to date indicate that provision of fish oil during pregnancy may reduce sensitization to common food allergens and reduce prevalence and severity of atopic dermatitis in the first year of life, with a possible persistence until adolescence with a reduction in eczema, hay fever, and asthma. Fish oil provision to infants or children may be associated with immunologic changes in the blood but it is not clear if these are of clinical significance and whether they persist. Fish oil supplementation in infancy may decrease the risk of developing some manifestations of allergic disease, but this benefit may not persist as other factors come into play. It is not clear whether fish oil can be used to treat children with asthma as the two studies conducted to date give divergent results. Further studies of increased long-chain n-3 PUFA provision in during pregnancy, lactation, and infancy are needed to more clearly identify the immunologic and clinical effects in infants and children and to identify protective and therapeutic effects and their persistence.

Dietary intake of α-linolenic acid and low ratio of n-6:n-3 PUFA are associated with decreased exhaled NO and improved asthma control

As recently described, adherence to the Mediterranean diet is associated with improved asthma control. However, evidence of how specific nutrients such as fatty acids and antioxidants may affect this relationship remains largely unknown. We aimed to examine the association between dietary intake of fatty acids and antioxidants and asthma control. A cross-sectional study was developed in 174 asthmatics, mean age of 40 (SD 15) years. Dietary intake was obtained by a FFQ, and nutritional content was calculated using Food Processor Plus™ software (ESHA Research, Inc., Salem, OR, USA). Good asthma control was defined by the combination of forced expiratory volume during the first second, exhaled NO (eNO) and Asthma Control Questionnaire (ACQ) score (control: forced expiratory volume in the first second ≥80 %; eNO ≤35 ppb; ACQ <1·0, scale 0-6 score). Multiple linear and logistic regression models were performed to analyse the associations between nutrients and asthma outcomes, adjusting for confounders. A high n-6:n-3 PUFA ratio predicted high eNO, whereas high intakes of n-3 PUFA, a-linolenic acid (ALA) and SFA were associated with low eNO. Odds for controlled asthma improved along with an increased intake of n-3 PUFA (OR 0·14, 95% CI 0·04, 0·45; P for trend=0·001), SFA (OR 0·36, 95% CI 0·13, 0·97; P for trend=0·047) and ALA (OR 0·18, 95% CI 0·06, 0·58; P for trend=0·005). A high n-6:n-3 PUFA ratio increased the odds for uncontrolled asthma (OR 3·69, 95% CI 1·37, 9·94; P for trend=0·009), after adjusting for energy intake, sex, age, education and use of inhaled corticosteroids. Higher intakes of n-3 PUFA, ALA and SFA were associated with good asthma control, while the risk for uncontrolled asthma increased with a higher n-6:n-3 PUFA ratio. The present results introduce a protective effect of ALA in asthma control, independent of marine n-3 fatty acids, and provide a rationale to dietary intervention studies in asthma.