Patients' perceptions of food-induced asthma

The influence of diet in asthma control remains unclear. However, there is likely to be a wide gap between patient perceptions and the probable actual role. Some 20-60% of people with asthma report food as a trigger factor while approximately 2.5% react to double-blind placebo-controlled challenges. The aim of this study was to determine: the frequency, type and sources of dietary advice being offered to patients, the prevalence of dietary modification, whether dietary changes were perceived to be of benefit and the type and sources of food/beverage reactions that people perceive they have experienced.

A self-administered 'food and asthma' questionnaire was developed and mailed to 156 consecutive Alfred Hospital Asthma and Allergy Clinic patients registered on a computer database.

The completed questionnaire response rate was 86.5%. Dietary advice had been offered to 47% of respondents while 61% had tried to modify their diet. Dietary restriction was the most common dietary modification. Where dietary restriction had occurred 79% of respondents perceived that this had improved their asthma control. A doctor was the most common source of dietary advice. Seventy-three per cent reported that food induced asthma.

We confirmed that patients with asthma perceived diet to be important in their asthma control and that dietary modification is common despite its lack of objective basis. The influence of diet and asthma requires more research, evaluation and clinical attention.