A new study shows that the number of people with food allergies in England more than doubled between 2008 and 2018. Researchers at Imperial College London found that the rate is highest among preschool children, 4% of whom have a “probable” food allergy.
They also found that a third of people at risk of anaphylaxis (a life-threatening allergic reaction) did not own adrenaline autoinjector “pens” such as EpiPens. People living in deprived areas were found to be less likely to have access to these life-saving injectors.
The actual number of people with food allergies has been difficult to establish, with estimates ranging from 1% to 9% in children. This is because a number of methods are used to estimate the frequency of food allergies, including the number of adrenaline pen prescriptions, self-reporting or blood tests to identify telltale antibodies.
Self-reporting is the least reliable method, as many people mistake food intolerances for allergies, as evidenced by a recent report from the UK Food Standards Agency.
Over 30% of adults reported adverse reactions to foods, but only 6% were later confirmed to have an actual food allergy. To fill this gap in understanding how common food allergies are, the new Imperial College study took a much broader approach to better estimate the incidence of food allergy.
These health records used a combination of population health data and clinical criteria from more than 7.5 million people in England to identify people with food allergies.
People were considered allergic if doctors indicated they had either a possible or probable allergy or were prescribed adrenaline pens or both. Using this combination, the number of people with food allergies doubled in a decade. Interestingly, since 2018, the rate has stabilized somewhat at around 4% in preschool children, 2.4% in school-age children and less than 1% in adults.
The study, published in The Lancet Public Health, used a variety of criteria to identify people with food allergies. Not all cases were confirmed by medical professionals using additional tests such as the presence of antibodies in the blood or food-challenge tests, in which people are given increasing amounts of certain foods to see if an allergic reaction occurs.
Some types of food allergies can be overlooked, such as pollen food allergy syndrome. This occurs when people with specific pollen allergies eat certain raw foods, including some stone fruits, which cause mild irritation symptoms such as itching in the mouth. Still, there are important questions about why food allergies are on the rise, and why they may now be stagnant.
tangled
The trend of rising allergy rates in developed countries has puzzled scientists for years. The “old friend hypothesis” is one theory that may account for the rising incidence of chronic diseases such as allergies.
This hypothesis considers the role of the microbiome (the collection of helpful bacteria, fungi, and viruses that live in and on us), infection, and the environment in shaping and thwarting our immune response.
Evidence supporting this theory is accumulating. For example, studies show that greater use of antibiotics during childhood when the immune system and microbiome are developing is associated with a greater likelihood of allergies in later life.
Exposure to pollution can increase the risk of allergies and worsen the severity of symptoms.
The food we were introduced to in childhood can be important in determining whether or not we develop allergies. The UK government’s previous advice about avoiding exposure to peanuts and eggs may have inadvertently been linked to a rise in food allergies to peanuts and eggs.
In contrast, studies show that exposure to peanuts and eggs before the age of five decreases the risk of developing allergies.
The advice in the UK to avoid peanuts and eggs during pregnancy and childhood was changed in 2009, but trials showing positive effects of early exposure to eggs and peanuts were only published in 2015 and 2016. However, it is possible that the stability in food allergy cases is linked to the change in advice and the published infant food exposure trials.
The diagnosis is only part of the story. People also need to be able to manage their condition effectively. This requires patients to get the right advice and support from specialists such as dietitians, as well as the necessary medications to prevent an anaphylactic attack.
For infants with food allergies, there is good evidence that gradually reintroducing the allergen-causing food can retrain the immune system and help the child overcome their allergy. However, this should only be done under the guidance of a medical team.
The new study has shown that allergy care in England is mainly managed in GP clinics. However, GP clinics may lack the specialist resources needed to provide appropriate allergy support, such as reintroducing foods safely.
It’s clear that allergy sufferers in the UK need better support.
Sheena Cruickshank, Professor of Immunology at the University of Manchester
This article is republished from The Conversation under a Creative Commons license. Read the original article.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
