Australia is often called the “allergy capital of the world”.
an estimated one out of 10 Australian children develop a food allergy in their first 12 months of life. Research has previously suggested that food allergies are more common in infants Australia than babies living in Europe, the United States or Asia.
So why are food allergies so common in Australia? We don’t know exactly – but local researchers are constantly making progress in understanding childhood allergies.
What causes food allergies?
There are many different types of reactions to food. When we refer to food allergies in this article, we are talking about something called IgE-mediated food allergy. This type of allergy is caused by an immune response to a specific food.
Reactions can occur within minutes of eating the food and can include swelling of the face, lips or eyes, “hives” or patches on the skin, and vomiting. Signs of a serious allergic reaction (anaphylaxis) include difficulty breathing, swelling of the tongue, swelling of the throat, wheezing or persistent coughing, difficulty speaking or a hoarse voice, and persistent dizziness or collapse.
Recent results from Australia’s large, long-term food allergy study, HealthNutsshows one in 10 one-year-olds has a food allergy, while around six in 100 children have a food allergy at the age of 10.
In Australia, the most common food that causes allergies include eggs, peanuts, cow’s milk, shellfish (for example, shrimp and lobster), fish, tree nuts (for example, walnuts and cashews), soybeans, and wheat.
Allergies to foods such as eggs, peanuts and cow’s milk often first appear in infancy, while allergies to fish and shellfish may be more common later in life. While most children will outgrow their egg and milk allergies, peanut allergy is more likely to be lifelong.
Findings of HealthNuts showed that about three out of 10 children outgrew their peanut allergy by age six, compared to nine out of 10 children with an allergy to egg.
Are food allergies becoming more common?
Food allergies seem to have become more common in many countries around the world recent decades. The exact timing of this increase is not clear because in most countries food allergies were not well measured 40 or 50 years ago.
We don’t know exactly why food allergies are so common in Australia, or why we’re seeing a rise around the world, despite extensive research.
But possible reasons for rising allergies around the world include changes in the diet of mothers and infants and increase disinfection, leading to fewer infections as well as less exposure to “good” bacteria. In Australia, factors such as increasing vitamin D deficiency in infants and high levels of migration to the country may play a role.
In several Australian studies, children born in Australia to parents born in Asia have higher rates of food allergies compared to non-Asian children. On the other hand, children born in Asia who later migrated to Australia appear to have a lower risk nut allergies.
Meanwhile, studies have shown that pet dogs and brothers and sisters as a young child can reduce the risk of food allergies. This may be because pets and siblings increase contact with a variety of bacteria and other organisms.
This evidence suggests that both genetics and environment play a role in the development of food allergies.
We also know that babies with eczema are more likely to develop a food allergy, and trials is in progress to see if this link can be broken.
Can I do anything to prevent food allergies in my children?
One of the questions we get asked most by parents is, “Can we do anything to prevent food allergies?”
We now know the introduction of peanuts and eggs from about six months of age making it less likely that a baby will develop an allergy to these foods. In 2016the Australasian Society of Clinical Immunology and Allergy has introduced guidelines recommending giving common allergy-causing foods including peanuts and eggs in the first year of life.
Our research has shown this advice excellent recording and may have slowed the rise in food allergies in Australia. There was no increase in peanut allergies between 2007–11 to 2018–19.
Introducing other common allergy-causing foods in the first year of life can also be helpful, although the proof because it is not as strong compared to peanuts and eggs.
What next?
Unfortunately, some babies will develop food allergies even when the foods in question are introduced in the first year of life. Managing food allergies can be a significant burden for children and families.
Several Australian trials are currently underway to test new strategies to prevent food allergies. A major trial, soon to be completed, tests whether vitamin D supplements in babies the risk of food allergies is reduced.
Another trial is to test whether the amount of eggs and peanuts a mother eats during pregnancy and breastfeeding has an influence on whether or not her baby will develop food allergies.
For most people with food allergies, avoidance of their known allergens remains the standard of care. Oral immunotherapy, which involves gradually increasing amounts of food allergen given under medical supervision, is starting to be offered in some facilities across Australia. However, current oral immunotherapy methods have potential side effects (including allergic reactions), can involve high time commitment and cost, and do not cure food allergies.
There is hope on the horizon for new food allergy treatments. Multiple clinical trials is underway in Australia with the aim of developing safer and more effective treatments for people with food allergies.
This article was original published in the Conversation.
Jennifer Koplin is group leader of childhood allergy and epidemiology at the University of Queensland. Desalegn Markos Shifti is a postdoctoral research fellow at the Child Health Research Center at the University of Queensland.
