Controlling asthma with fruit and vegetables

Set of products and wooden cubes with space for text on grunge background. Asthma concept

Image: Yastremska/

Asthma is a chronic inflammatory disorder of the airways. According to Asthma Australia, one in nine people have the condition and it can affect any age group. It’s the most common chronic disease affecting children worldwide!

But did you know that what you eat can affect the severity of the problem?

How is your diet making you breathless?

The Westernised diet, with its frequent consumption of red meat, fast foods, and processed snacks, increases your risk of developing asthma. The latest research shows that even if you already have asthma, this dietary pattern can make it worse.

The same foods also promote obesity—a major risk factor for asthma. Studies show that as the number of fat cells increases, inflammation in the body also rises. Furthermore, corticosteroid drugs (the kind found in inhalers) prescribed to reduce inflammation are less effective in obese people.

The power of fruit and veg

An international study of asthma and allergies, studying over one million children aged 13-14 in nearly 100 countries, has demonstrated a clear relationship between diet and asthma symptoms. Researchers proposed that eating fewer fruits and vegetables has led to lower antioxidant defences in the lungs, and therefore there’s an increased likelihood of exposure to harmful, inhaled substances.

There are two ways to test the effect of fruit and vegetables on asthma. Either add more fruit and veg to your diet and see if symptoms improve, or remove fruit and veg from the diet to see if symptoms get worse. One study published in the American Journal of Clinical Nutrition in 2012 did just that!

Researchers placed study participants on a low antioxidant diet (one or two fruit/veg servings per day) and found in just 10 days lung function and asthma control significantly worsened.

Okay, but how do we know adding fruits and vegetables actually helps with asthma? This was the second part of the study.

Participants on the low antioxidant diet were found to have a 40 per cent chance of relapsing with asthma exacerbation within three months. But when fruit and vegetables were increased to seven servings per day, exacerbation rates were cut in half!

The plant-based effect

Fruit and vegetables work by targeting inflammatory pathways in the body. All fruit and veg are loaded with antioxidants, which can suppress the viral and allergen triggers for asthma. In fact, the level of oxidative stress (which increases inflammation) can be measured by the level of oxidative products exhaled in our breath. Inflammation starts to drop as fruit and vegetable intake increases and it drops even further when combined with more plant foods and less animal foods.

Another protective effect of plant-based foods, including fruit and veg, may also be related to the effects on gut microflora. Eighty percent of immune cells can be found in the gut, so priming the immune system with a high fibre diet (especially in early childhood) can decrease inflammation and improve asthma control. Children with allergies have been found to harbour less lactobacilli (an important healthy bacteria) which is naturally found in fruits and vegetables!

Final advice

If you want to improve your asthma control and reduce the severity of your symptoms, eating more fruits and vegetables is an easy change with fast results. Aim for seven serves per day—two pieces of fruit and five serves of vegetables.

Sue Radd is an Advanced Accredited Practising Dietitian and one of Australia’s leading nutritionists and health communicators. Her most recent book Food as Medicine: Eating for Your Best Health received the Gourmand World Cookbook Award for Best Health and Nutrition Book in the world for 2016.

Category: Physical Health

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