Avoidance Diets Linked to Adult-Onset Asthma, Study Finds

A positive association was identified between avoidance diets and adult-onset asthma, as well as with allergic disease and aspirin-exacerbated respiratory disease (AERD), according to one study.

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This cross-sectional study is published in the European Clinical Respiratory Journal.¹

“We sought to study the prevalence of self-reported dietary restrictions in adult-onset asthmatics and in a subgroup of patients with allergic disease or AERD since we found that information on avoidance diets in adult-onset disease is limited,” wrote the researchers of the study. “Here, we show that avoidance of certain dietary aliments was more common among asthmatics compared to non-asthmatic controls, and even more so in allergic asthmatics compared to non-allergic asthmatics, and in asthmatics with AERD compared to NSAID [non-steroidal anti-inflammatory drugs]/aspirin-tolerant asthmatics.”

The study was based on a study population of patients with asthma who participated in the matched cohort study Adult Asthma in Finland Survey conducted in 1997. All patients were matched for gender and area of residence by postal code. After excluding nonresponders and patients with self-reported onset of asthma symptoms and/or diagnosis before the age of 16 years, a total of 3217 patients were included in the study. Of these patients, 1247 were asthmatic and 1970 were matched as nonasthmatic.

The questionnaire consisted of demographic information, asthma-specific questions, and questions on allergic diseases. Additionally, patients with asthma were asked about aspirin and NSAID hypersensitivity.

All patients were asked if they had to follow a special diet because of an illness or because their body does not tolerate a substance in their diet. If the answer was yes, a nutritionist further classified the answers into 9 specific avoidance diets, including milk protein, egg, fish, meat, gluten, some grains, some fruits or vegetables, some spices, and low sugar. Additionally, 5 groups of typical diets for medical conditions or preferences included diets for cardiovascular disease, reflux, gallbladder disease, gout, and vegetarian diet.

Patients were also asked if they had any comorbidities, such as hypertension, cardiovascular disease, diabetes, rheumatoid diseases, psychiatric diseases, glaucoma, back pain, or arthrosis.

Furthermore, the researchers selected covariates based on their potential impact on asthma and/or diets reported in literature, including sex, age, body mass index, education level, smoking, and chronic comorbidities.

Asthma was positively associated with adoption of any avoidance diet (adjusted OR, 1.24; 95% CI, 1.02-1.51; P = .029), as well as allergic disease (adjusted OR, 1.79; 95% CI, 1.29-2.48; P = .001) and self-reported AERD (adjusted OR, 1.69; 95% CI, 1.15-2.49; P = .007) among patients with asthma.

Additionally, patients with asthma and allergic asthma were more likely to avoid fish, fruits and vegetables, and spices (P ≤ .03) compared with patients without asthma and nonallergic asthma.

Furthermore, AERD was associated with multiple diets (adjusted OR, 2.57; 95% CI, 1.34-4.95; P = .005). In the validation cohorts, 26.2% of patients with allergic asthma and 10.8% of patients with AERD reported having avoidance diets.

However, the researchers acknowledged some limitations to the study, such as that the validation data set lacked information on the patient’s own avoidance diets and that patients without asthma might less frequently have been asked for food allergies or avoidance diets. These limitations may have partly explained the lower proportion of avoidance diets in the validation data.

Despite these limitations, the researchers believe the study suggests that there should be greater patient education regarding differences between food intolerances, allergies, and healthy diets, finding a positive association between specialized diets and adult-onset asthma.

These findings are similar to those of a previous study published in Maedica, suggesting, “More research in nutrition recommendations for asthma patients must be performed and practical guidelines in asthma nutritional interventions are future steps.”²

“The most common food restrictions included aliments that are essential for maintaining a healthy, anti-inflammatory diet,” wrote the researchers of the new study.¹ “Our findings suggest the importance of asking patients with asthma or other inflammatory airway disease, about their dietary choices and other methods of self-managing their disease.”

References

1. Lundberg M, Voutilainen H, Lyly A, et al. Adult-onset asthma, allergy, and aspirin hypersensitivity associate with self-reported food avoidance. Eur Clin Respir J. 2024;11(1):2347073. doi:10.1080/20018525.2024.2347073

2. Hancu A, Mihaltan F, Radulian G. Asthma and ultra-processed food. Maedica (Bucur). 2019;14(4):402-407. doi:10.26574/maedica.2019.14.4.402