The increasing rates of food allergies has been alarming over the past 30 years in Western countries. So, is there a genuine rise in allergies, or just better awareness?
Allergy experts across the globe acknowledge that food allergies are genuinely rising, however the exact mechanism behind this change is yet to be identified. Confirmed diagnosis of food allergies has been linked to those people living in industrialised countries and is seen more in urban areas than rural environments.
Australia has the dubious crown as the allergy capital in the world, with the UK following as a close second. In Australia, food allergies are seen in 10% of infants, 4-8% of children and around 2% of adults. Most food allergies can be attributed to the following common foods: milk, eggs, peanuts, tree nuts, sesame, fish, shellfish, wheat, and soy. Many young children outgrow their food allergies, however those that develop in adults are more likely to persist. Admissions to hospital for anaphylaxis in Australia, the UK and the USA have doubled in the past decade. The increase for children aged 0-4 years is even higher, with a five-fold increase in the same time-frame.
So, what are the factors in the rising food allergies and anaphylaxis rates?
Many researchers have been investigating the causes and have explored the multi-factorial agents in food allergies. Several factors within the modern, urban lifestyle have been identified, although no single agent has been highlighted as the main reason. Exposure to adequate levels of vitamin D and the types of infections in childhood are thought to change the immune system development and trigger an allergic response. One study based in Melbourne found that children with vitamin D deficiency were 11 times more likely to develop a peanut allergy. Children with older siblings and pets are less likely to develop allergies, potentially in response to greater microbe exposure.
Another key factor is the changing modern diet.
The gut microbiome has been altered by the rapid changes in food manufacturing, food production and high sugar diets over the past 50 years. Previous advice to avoid allergens during the weaning phase to solids is now outdated, with significant research showing that exposure to known allergenic foods is a protective factor. It is now recommended that all children, regardless of their family history of allergies, are exposed to allergenic foods during the first 12 months of life. The gut’s immune system recognises these foods as normal food groups and is less likely to mount an allergic response. Conversely, those with eczema should avoid any food products in topical agents. Food proteins absorbed through broken skin are more likely to trigger ongoing allergies.
Even after successful diagnosis of food allergies, avoiding trigger foods is challenging and accidental exposures are common. Regular review of the allergy action plan and how to use an EpiPen is needed, as the time delay between diagnosis and the need to use an EpiPen can be months or years apart. Further research is continuing on the complex factors in food allergies and will be an evolving area of healthcare.