A decade after a landmark study proved that feeding peanut products to young babies could prevent them from developing life-threatening allergies, a new US study has shown it's making a big difference in the real world.
The study found about 60,000 children in the United States have avoided developing peanut allergies after new guidance was issued in 2015 about when to introduce the allergen to youngsters.
Before the new guidelines, parents were warned to avoid exposing their children to potentially risky foods until they were three years old, in the hope of avoiding a full-blown allergy.
Peanut allergy is one of the most common of these conditions, caused when the body's immune system mistakenly identifies proteins in peanuts as harmful and releases chemicals that trigger symptoms like hives, respiratory issues, and sometimes, life-threatening anaphylaxis.
But groundbreaking research, known as Learning Early About Peanut Allergy, or LEAP, published by professor Gideon Lack of King's College London, suggested earlier exposure might actually help children.
"The LEAP study ... showed that if we actually introduce that allergen to children by mouth, having them eat it, before they're introduced to it via their skin, we can reduce the risk that that child's going to go on to develop the food allergy itself," Dr David Hill, from the Children's Hospital of Philadelphia, told SBS News.
Hill has published a new study after analysing electronic health records from dozens of paediatric practices to track diagnoses of food allergies in young children before, during and after the new guidelines were issued.
It's found thousands of other children in the US have also avoided developing peanut allergies after their parents followed the dietary advice.
"What our data shows is that because of, or at least associated with those early introduction guidelines, there's about 60,000 less kids with food allergy today than there would have been. And that's a remarkable thing, right? That's the size of some cities," he said.
Australian research shows 'modest reduction'
Associate Professor Rachel Peters has been part of food allergy research at the Murdoch Children's Research Institute's National Allergy Centre of Excellence.
She said at least two major studies have been completed in Australia in the last decade to explore what might prevent such allergies in the first place — one before Australia adopted new infant feeding guidelines in 2016, and one after.
"We had two population-based studies recruited in the same region, which was Melbourne, Australia," she said.
"So we had two cohorts recruited with exactly the same methods, but 10 years apart."
She said the research measured what parents were doing in early feeding practices, which showed that nearly 90 per cent of babies were being fed peanut-containing products in the first year of life, as recommended by the guidelines.
The research showed a "modest reduction" in food allergy but not as much as researchers expected.
"Even though we are certainly starting to see a reduction in the rates of peanut allergy in Australia, they are still quite high, and higher than in some other countries around the world, and higher than what was shown in this American study as well," she said.
Peters says the Australian findings suggest much more study needs to be done to establish the various causes of food allergies.
She said some research — including exploration of whether less sunlight and vitamin D exposure increases the likelihood of developing allergies — has offered promising evidence.
"We even see that within Australia. We have higher rates of food allergy in Melbourne compared to what we see in Queensland," she said.
According to the charity group Allergy and Anaphylaxis Australia, peanut allergy is one of the most common food allergies in childhood in Australia, affecting three per cent of infants up to the age of 12 months.
