PURPOSE OF THE STUDY.
The investigators sought to test the relationship between food diversity in the first year of life and outcome of allergic diseases.
There were a total of 856 children included in this study with data available on allergic diseases up to 6 years of age. They were part of a prospective birth cohort called Protection Against Allergy Study in Rural Environments/EFRIAM in which pregnant women were recruited during the third trimester of pregnancy in 2002–2005 in rural Austria, Finland, France, Germany, and Switzerland.
Data were collected by using questionnaires identifying a physician’s diagnosis of asthma or food allergy, as well as history of symptoms of allergic rhinitis. Immunoglobulin (Ig)E antibodies to common allergens were measured at 4.5 and 6 years of age. Diet records were kept and food diversity scores assigned based on the number of different foods in the child’s diet and by what age the foods were introduced.
There was an inverse dose–response effect between food diversity and asthma even after adjusting for confounders (odds ratio [OR]: 0.74 [95% confidence interval (CI): 0.61–0.89]). There was a 26% reduction in asthma for every additional item of food added in the first year of life. An increased association was found between children with a low food diversity score and development of food allergies by 6 years of age (OR: 0.70 [95% CI: 0.57–0.86]) compared with children with a more diverse diet after adjusting for confounding variables. This variable, however, was no longer statistically significant after excluding children with food allergy within the first year of life. Those with low food diversity were also found to have increased sensitization to food allergens at 4.5 or 6 years of age (OR: 0.72 [95% CI: 0.57–0.90]). No significant association was found between food diversity and allergic rhinitis or sensitization to inhalant allergens. Children with a low food diversity score also had significantly increased levels of Cε germline transcript, a marker of antibody isotope switching to IgE (geometric mean ratio: 1.81 [95% CI: 1.21–2.70]) and lower levels of Foxp3, a marker for regulatory T cells that helps limit inflammation (geometric mean ratio: 0.7 [95% CI: 0.51–0.96]). Higher levels of Cε found among children with lower food diversity suggest that increasing food diversity may play a role in inhibiting isotype switching to IgE.
Introducing an increasing diversity of foods within the first year of life may have a protective effect on development of asthma, food allergy, and food sensitization in children up to 6 years of age. Higher levels of Cε found among children with lower food diversity suggest that increasing food diversity may play a role in inhibiting isotype switching to IgE.
This study is the first linking increased food diversity in the first year of life with a decrease in allergic diseases. The investigators were careful to limit reverse causality by using multiple models for statistical analysis. The findings of this study are encouraging because the role of nutrition in the development of allergic diseases is still a topic of debate.
- Copyright © 2014 by the American Academy of Pediatrics