Asthma and diet: Foods to try and foods to avoid

Asthma causes airways to narrow. This can make it harder to breathe. Although there is currently no cure, most people manage asthma through lifestyle changes and medication. 

Inflammation can make asthma symptoms worse. Eating foods that increase inflammation, such as refined sugars, red meat, and processed food, may contribute to asthma severity.

That’s why it may help to eat a diet that reduces inflammation in the body. Some research shows that eating lots of vegetables and fruits can help with asthma.

How can diet affect asthma?

Currently, research is very limited on the link between diet and asthma. Some results are contradictory, and some do not come to firm conclusions. But research is ongoing, and some researchers suggest that what you eat can affect your asthma symptoms.

There is no single diet for asthma. Yet you may be able to manage some asthma symptoms by avoiding certain foods. Adopting a healthy diet may also reduce some risk factors for asthma, such as obesity.

The authors of a 2021 research review gave some reasons why diet may affect asthma, though they noted there’s limited research evidence that conclusively supports eating any specific food.

Eating a healthy diet during pregnancy may lead to a stronger immune system and support lung development in the fetus, so the child is less likely to develop asthma. 

For someone who already has asthma, antioxidants, such as those found in fruits and vegetables, could reduce airway inflammation.

On the other hand, a pro-inflammatory diet that’s high in refined sugars and saturated fats can make inflammation worse, making it harder to breathe. 

Your diet can also affect asthma in indirect ways. A diet high in processed foods and sweetened drinks can lead to weight gain, and this may lead to obesity, which is a risk factor for asthma.

The same diet can also change the composition of gut bacteria so your body makes fewer short-chain fatty acids. But these acids are needed because they reduce inflammation and support the immune system. 

If you have a food allergy, an allergic reaction may trigger your asthma, according to 2017 research. Even though a food allergy trigger for asthma is uncommon, it’s best to avoid foods you’re allergic to.

What diet is helpful?

A 2017 review of studies found evidence that some foods and diets helped manage asthma symptoms and risk.

Fruits and vegetables were found to be beneficial in children and adults. In adults, eating more apples and oranges specifically was thought to lead to a larger decrease in asthma risk.

In addition, a Mediterranean diet rich in vegetables and olive oil is thought to be beneficial, possibly due to its anti-inflammatory properties.

Some research in a 2022 review of studies suggests that consistently eating a Mediterranean diet can help prevent the development of allergic conditions like asthma.

Foods rich in vitamin E may also be recommended, according to a 2022 research review. This vitamin, which is also called tocopherol, may help reduce coughing and wheezing. You can find vitamin E in almonds, sunflower seeds, and kale.

But it’s important to note that most studies looking into the benefits of vitamin E use larger amounts of the vitamin than are usually found naturally in foods. More research is needed to determine whether foods containing vitamin E will have similar effects.

The 2021 research review mentioned previously also notes that there’s some evidence that a diet high in vegetables and fruits may protect against pollutants, which can make asthma worse. This is because antioxidants found in these foods may fight oxidative stress caused by pollution. 

One 2023 case report also notes an improvement in asthma symptoms after a person followed a ketogenic diet. The researchers believe this may be due to the fact that the person lost weight while following the diet.

What diet is harmful?

A diet high in processed foods, sweets, and red meats with relatively low fruit and vegetable intake may contribute to asthma, 2017 research suggests. 

Research shows that there is a link between this type of diet and asthma, but it does not necessarily prove that this type of diet directly causes asthma. For this reason, more research is needed.

Certain chemicals and food types may also cause asthma symptoms. Some older 2012 research notes that 3–10% of people with asthma are sensitive to foods with sulfites.  

These include:

• dried fruit
• pickled food
• bottled lemon juice
• wine
• beer
• processed potatoes

Salicylates are sometimes thought to have an effect on asthma. According to the American Lung Association, it’s rare for salicylates — found in foods and drinks like tea, coffee, and herbs and spices — to affect asthma, but they may make symptoms worse for some people.

Again, it’s important to remember that there is an overall lack of research into the effects of diet on asthma. It’s always best to speak with a doctor or dietitian, if one is available to you, for guidance that’s personalized for you.

Treatments and prevention

Although there is no cure for asthma, every person with asthma can create an individual action plan to manage the condition.

In general, this includes learning and avoiding asthma triggers like pollen or dust. Many people also take medication for asthma.

According to the Asthma and Allergy Foundation of America, which can include:

• Quick-relief medications: These are usually taken via an inhaler you use during an attack. Examples of these include albuterol and levalbuterol.
• Controller medications: These medications are usually used to reduce swelling and mucus in the airways. They include corticosteroids, such as budesonide (Symbicort), and mast cell stabilizers like cromolyn.
• Combination medications: These may provide quick relief and long-term management. They include budesonide and formoterol.

A doctor may also recommend diet changes to help reduce symptoms and improve health overall. This may include adopting a diet high in fruits and vegetables and low in saturated fats, sweets, and processed foods. 

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Summary

Asthma is a manageable condition. Eating lots of fruits and vegetables and reducing saturated fats, processed foods, and sweets may help reduce asthma symptoms. These lifestyle changes can form part of an asthma action plan, along with taking prescribed medications and avoiding triggers.

It’s important to remember that research into the effects of diet on asthma is conflicting, and future research is needed.

It’s best to speak with a doctor or a dietitian before making any dietary changes. In general, though, maintaining a nutritious diet low in processed foods can have many benefits for your overall health.

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