Foods to Avoid in Asthma
Patients with asthma should only avoid specific foods if they have a documented IgE-mediated food allergy, as food allergies are rarely an aggravating factor in asthma itself, with the notable exception of sulfites in sensitive individuals. 1, 2
Key Principle: Food Allergy vs. Asthma Triggers
The evidence is clear that asthma alone as a manifestation of food allergy is rare and atypical 3. Less than 5% of patients experience wheezing without cutaneous or gastrointestinal symptoms during food challenges. However, the coexistence of food allergy and asthma creates significant risk—patients with both conditions are at increased risk for severe asthma exacerbations and fatal anaphylactic reactions 1, 4, 2.
Specific Foods Requiring Avoidance
1. Sulfites (Most Important Exception)
Sulfites in foods can precipitate asthma symptoms in sensitive individuals, particularly those with unstable asthma 2. Sulfites produce bronchoconstriction in up to 5% of adults with asthma 5.
Avoid these sulfite-containing foods if sensitive:
- Shrimp and shellfish
- Dried fruit
- Processed potatoes
- Beer and wine 2
2. Foods with Documented IgE-Mediated Allergy
Only avoid foods to which the patient has confirmed IgE-mediated allergy (not just sensitization). The most common allergenic foods in patients with asthma include:
Critical Diagnostic Requirement
Do not eliminate foods based on positive skin testing or IgE levels alone. A diagnosis of IgE-mediated food allergy requires both sensitization AND clinical symptoms after exposure 4. False-positive tests are common, and unnecessary dietary restrictions can harm nutritional status 4.
Who Needs Food Allergy Evaluation
Consider food allergy testing in asthmatic patients who:
- Experience anaphylaxis or immediate reactions (within minutes to hours) after eating specific foods
- Have moderate-to-severe atopic dermatitis, especially children under 5 years 4
- Report reproducible symptoms with specific food exposures
- Have severe or poorly controlled asthma despite optimal management 1, 4
Common Pitfalls to Avoid
Do not recommend broad elimination diets without documented food allergy. Studies show that avoidance of specific foods has not been shown to improve asthma, even in patients who perceive that particular foods worsen their asthma 3. However, 53% of adults with asthma report adverse reactions to foods (compared to 30% of non-asthmatics), often leading to unnecessarily restrictive diets 7, 6.
Food additives rarely cause problems. There is no convincing evidence that tartrazine (yellow dye) or monosodium glutamate induce asthma responses 3. Only sulfites have clear evidence of triggering bronchospasm in susceptible asthmatics 5, 2.
Special Considerations
Aerosolized Food Particles
Inhalation of aerosolized food particles during cooking can cause respiratory symptoms in selected food-allergic individuals, particularly with fish and shellfish. However, this has not been demonstrated with smelling or casual contact with peanut butter 3.
Risk Stratification
The factor most commonly identified with severe food reactions is the coexistence of asthma, especially with peanut or tree nut allergy 4. A high prevalence of asthma has been reported among people who died from food-induced anaphylaxis 4.
Bottom Line Algorithm
- Screen for food allergy if patient reports immediate reactions to foods or has severe atopic dermatitis
- Confirm diagnosis with skin testing or specific IgE, followed by oral food challenge when indicated
- Eliminate only confirmed food allergens, not foods with positive testing alone
- Avoid sulfite-containing foods if patient has documented sulfite sensitivity
- Do not restrict diet based on perception alone without objective evidence
- Ensure emergency action plan for all asthmatic patients with confirmed food allergies, as they are at higher risk for fatal reactions 1, 4