Asthma is a chronic disease of the airways (the tubes leading to the lungs). When people with asthma are exposed to certain triggers their airways become inflamed and narrowed, restricting airflow to the lungs. This causes wheezing, coughing, difficulty breathing and a tight feeling around the chest. Although there’s no cure, there are a range of medications that help people with asthma live an active life with infrequent symptoms.
No one is sure why New Zealand has one of the highest rates of asthma in the world. In New Zealand, one in seven children and one in nine adults take medication to control asthma. If you’re Māori or Pacifika you’re more likely to be diagnosed with asthma. And genetics, living in low income areas, living in a damp house, antibiotic use in early childhood and respiratory infections in early life all increase your risk of getting asthma.
Food and asthma
Food allergy can trigger asthma, although this is fairly uncommon. Research suggests that less than five percent of asthma attacks are caused by a food allergy. However, a quarter of people with asthma may report that they seem to have breathing problems after eating certain foods.
Once you’ve been diagnosed, there’s no diet for asthma. But if you think that food is a trigger, removing any problem foods from the diet can help. Your doctor can suggest allergy tests, and a dietitian can suggest how to safely remove suspected foods from your diet, and challenge foods as needed.
Possible food triggers for asthma include: peanuts, tree nuts, sesame seeds, fish, shellfish, dairy products, food colouring or flavourings and sulphites (a type of preservative). These foods can trigger breathing problems in people with asthma either as they’re eaten, or if food particles are breathed in.
Sometimes food particles can make the airways over-sensitive, which can cause breathing difficulties.
Sulphites and asthma
Sulphites are a normal product of metabolism, and are naturally present in the body. They can also be produced by microorganisms and are present in small quantities in many foods, even where none have been added.
Sulphites are known to be safe, but a small amount of people can have an allergy-like reaction to them, and these people are mainly those with asthma.
Find out more about sulphites and where to find them here.
Weight and asthma
Being overweight can make asthma worse. Results from studies suggest there are two reasons for this. Firstly, there’s a type of asthma that is aggravated by being overweight. People who are overweight take less deep breaths, leading to hyper-responsive airways. Secondly there’s a different type of asthma that is associated with inflammation. This type of asthma mainly affects women. Obesity increases levels of certain types of inflammatory cells which may provoke asthma.
Protecting against asthma
A 2013 international study looked at the diet and health of more than 319,000 13 to 14-year-olds in 51 countries, and more than 181,000 seven-year-olds in 31 countries. Researchers found that teens who ate three or more servings of fast food a week were 39 per cent more likely to suffer severe asthma. In younger children the risk was increased by 27 per cent. The results also showed a 15 percent reduction in asthma among children who ate at least three serves of fruit a day.
One of the study authors, University of Auckland professor Innes Asher says and there is “a lot of potential for bad things in fast food, so we should be clever about it”. The conclusion of the study was that children should be encouraged to eat fresh fruit and veges regularly, as they were likely to protect against developing asthma, and reducing fast food consumption would help.
There’s no evidence that you can reduce the risk of your baby having asthma by changing your diet when pregnant or breast feeding. But if you have food allergies, continue to avoid these foods for your own health. It’s important to let your doctor or midwife know so they can check you’re getting the right nutrition for you and your baby. Early exposure to allergens may be significant in the later development of asthma, but it may also be protective. At this stage we just don’t have the answer.
Common triggers for asthma
• Colds and the flu
• Dusts mites
• Pollens and plants
• Premenstrual and hormone changes
Where can I go for help and advice?
The Asthma Foundation recommends people see their GP and use medication as prescribed. The foundation’s affiliated societies can make life easier with one-on-one education, advice and ongoing support. Services are either free or available for a small charge. Visit www.asthmafoundation.org.nz
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