How does food trigger asthma symptoms?
The good news is that very few people with asthma need to watch the foods they eat apart from following the usual healthy eating advice.
But a small number of people with asthma do have a problem with certain foods triggering their asthma symptoms.
This is usually because:
- they’re allergic to certain foods and the allergic reaction sets off their asthma symptoms
- they’re sensitive to certain foods which trigger their asthma symptoms.
Food allergies and sensitivities
Although a lot of food allergies start in childhood, you can develop them as an adult too.
Some of the most common food allergens are gluten (from wheat and cereal products), shellfish, eggs, milk, tree nuts, peanuts, sesame seeds, and soya.
Some food allergies, such as allergies to milk and eggs, are more common in children.
People with food allergies need to be strict about avoiding certain foods. Allergic reactions to food can happen very quickly. A severe allergic reaction (anaphylaxis) can be life-threatening.
Reactions to food can quickly bring on asthma symptoms too, like wheezing, coughing and breathing difficulties.
An anaphylactic reaction and an asthma attack can look similar. If you have both a food allergy and asthma, and are in any doubt about your symptoms, use your auto-injector pen and get help straight away.
You can also find out more about particular food allergies on the NHS website.
Call 999 if:
- you're having a severe allergic reaction or
- you're having an asthma attack and your blue reliever isn't helping or
- you're not sure if your symptoms are an allergic reaction, or an asthma attack.
Being sensitive to certain foods is not the same as a true allergy. There’s less clear-cut evidence to show a link to asthma symptoms. However, it could be that some of the chemicals and ingredients in food and drink products trigger asthma symptoms.
The most common food sensitivities that can trigger asthma symptoms are:
- Histamine is a naturally produced ingredient in some foods such as yogurt, mature cheese, and smoked meats. It’s also found in alcoholic drinks like wine. It’s the same substance that’s released in your body when you have an allergic reaction, for example to pollen.
- Sulphites (look out for E numbers E221 to E228) are used as preservatives in foods such as dried fruits, processed meats and pickled foods. They’re also found in drinks such as wine, beer and cider.
How do you know if food is one of your asthma triggers?
If you think certain foods trigger your asthma symptoms or your child’s symptoms, talk to your GP or asthma nurse as soon as possible. This is important because an asthma attack triggered by an allergic reaction to food can be worse, particularly for children.
Your GP or asthma nurse can help you work out if you’re allergic or sensitive to certain foods. They can:
- refer you for an allergy test to confirm or rule out any food allergies, usually a skin prick test
- help you identify foods you’re sensitive to that don’t show up in allergy tests by supporting you to keep a food and symptom diary, which you can review at your appointment
- support you in excluding certain foods or food groups for a while, and reintroducing them safely to see which foods trigger asthma symptoms
- confirm or rule out anything else which could be making your asthma worse, such as acid reflux
- update your asthma action plan with new food triggers, and any action you need to take if your asthma symptoms are triggered by food.
Cut your risk of an asthma attack triggered by food
- Avoid the foods you’re allergic or sensitive to – especially if you’re at risk of anaphylaxis.
- Always keep your asthma reliever inhaler with you, so you can deal with asthma symptoms quickly.
- Use your preventer inhaler every day so you're less likely to react badly to asthma triggers, and your asthma is well controlled. If you have a food allergy and your asthma’s not well controlled, it increases your risk of having a severe allergic reaction.
- Talk to your GP or asthma nurse and get your written asthma action plan updated with any new triggers. You can share your plan with friends and family. It’s important that you manage your asthma and food allergy, or sensitivity, together to cut the risk of one making the other worse.
- If you have an auto-injector, keep it with you and use it immediately if you’re having severe anaphylactic symptoms.
Top tips to avoid food triggers
- Supermarkets should have ‘free from’ lists online. These will show you products free from different allergens. Most supermarkets also have ‘free-from’ shelves in store.
- Plan ahead for eating out. Call ahead to make sure all restaurant staff, from the chef to the kitchen staff to the waiters know about your allergy.
- Read labels carefully. The 14 major allergens (including wheat, milk, nuts and egg) should be clearly listed in bold on pre-packed manufactured foods. If you’re allergic or sensitive to ingredients outside of this list, you’ll need to read the whole list through to check. Check and double check because it may not be immediately obvious that your trigger ingredient is in a product.
- Avoid ready meals. If you prepare your own meals, you will feel more confident about what’s gone into them.