Are fast foods behind the rising prevalence of allergic diseases?

The prevalence of allergic diseases has drastically increased over recent decades, particularly in Westernised countries. The factors driving increased prevalence remain unclear, but it has previously been suggested that there may be a link with consumption of fast foods. Researchers in China and Australia have undertaken a first-ever systematic review and meta-analysis of published studies, seeking to shed light on the issue.

The study primarily looked at asthma, wheeze, rhino-conjunctivitis and eczema in relation to fast foods such as hamburgers, carbonated soft drink and takeaway foods. Dose–response relationships were also explored to assess whether the amount of fast food impacted on asthma/wheeze symptom severity.

Results indicated consumption of fast foods, especially hamburgers, more than three times per week, was more likely to be associated with severe asthma and current wheeze compared with the consumption of these foods 1-2 times per week. While high consumption of fast foods are often viewed as an indicator of lower socio-economic status, relationships between the consumption of fast foods and asthma/wheeze were found to exist in high‐ or middle‐income populations.

Given nutritious foods would be displaced from the diet when high amounts of fast foods are consumed, poor quality diet is a likely contributor to the development and progression of asthma/wheeze. Similarly, associations have previously been demonstrated between obesity and allergic disease. While the review could not find a causal relationship between eating a lot of fast foods and the development of allergic disease, diet quality and body weight are likely to be important factors.

The findings need to be further validated in longitudinal and interventional studies.

Reference: Wang et al. 2018 Respirology. DOI: org/10.1111/resp.13339

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