Food allergies are reportedly on the rise, but treatments are progressing while the Holy Grail of a cure might just be in sight.
Half a century ago, a sudden jump in the reporting of allergic diseases, such as asthma and hay fever, made people take note. Now allergies, particular to certain foods, are commonplace.
Here we delve into the evolving research on the topic, investigate why food allergies appear to be on the rise, discuss the best available treatments and ask: will we ever find a cure?
Food allergies trigger your immune system to mistakenly identify common proteins found in food as a threat. Cow’s milk, eggs, peanuts, tree nuts (such as walnuts, almonds and cashews), shellfish and wheat are some of the most common culprits, but you can be allergic to any type of food, including celery, mustard and sesame seeds.
It’s important to note at this point that food allergies differ entirely from food intolerance. “The terminology is really important here,” says Professor Adam Fox of Allergy London, one of the UK’s most pre-eminent authorities on allergies. “They are often conflated but they are completely distinct from each other.”
Food allergies affect the immune system, whereby even small traces of the offending food can trigger severe or life-threatening symptoms. By contrast, food intolerances usually only affect the digestive system and cause less serious symptoms, such as bloating, diarrhea, constipation, IBS, skin problems such as eczema, and joint pain.
Essentially, a food allergy is an “immune system-mediated response” to something your body should just ignore and consider harmless, like milk or peanuts, but instead causes an allergic reaction. At a cellular level, that person’s immune system has produced antibodies specific to whatever food they have become allergic to.
“Those little antibodies are whizzing around your circulatory system in your blood, they are in your saliva, in the lining of your nose, in your gut. If they see the thing they are primed to recognize – in this case milk or peanuts – that will trigger a type 1 hypersensitivity reaction, which results in the release of a range of chemicals including histamine.”
A spike in these chemicals caused by an allergic reaction to food include dizziness, itchy skin, swelling of the lips, eyes and face, coughing, sneezing, nausea, stomach pain and diarrhea. “If you’re unlucky, histamines can also trigger a more severe reaction called anaphylaxis, which is potentially life-threatening,” adds Professor Fox.
Symptoms might occur straight away or days later. In extreme cases, an adrenaline auto-injector (such as an EpiPen) might be required to save someone’s life.
It’s still not known exactly why people develop allergies to food. You’re not born with them, but your risk is heightened if you or a close family member suffers from other allergies, asthma or eczema.
More mild symptoms, such as an itchy mouth, lips or throat, is typical for someone with a hypersensitivity to raw fruits, vegetables and nuts, known as pollen food syndrome – or, more commonly, oral allergy syndrome. Though not usually serious, consuming fruit or veg that’s been well cooked helps.
Food allergies are reportedly rising in both developed and developing countries. In the United States, it’s estimated that 32 million Americans have food allergies, including roughly two children under the age of 18 in every classroom. Each year, 200,000 people in the US require emergency medical care for allergic reactions to food (FARE).
Allergies, generally, are surging in Europe too. By 2025, the European Academy of Allergy and Clinical Immunology (EAACI) predicts that half of the entire continent will be affected with allergic disease. Closer to home, hospital A&E emergency departments have seen a huge increase in anaphylaxis admissions in the past decade.
The latest NHS figures show nearly 26,000 admissions for allergies and anaphylaxis in 2022-23, more than double that of 2002-03 (12,361 admissions). The spike is even greater for food-related anaphylaxis and other adverse reactions, rising from just under 2,000 admissions twenty years ago to over 5,000 in 2022 (up 154%).
The statistics make for grim reading, painting a picture of a crisis that’s rapidly careering out of control. Professor Fox, however, is rather more optimistic. “In the 1990s and 2000s there did seem to have been a marked increase in things like nut allergies, but there’s no suggestion the rates are continuing to rise.”
Pointing to the MHRA’s data on anaphylaxis admissions, he believes people are now more acutely aware of food allergy risks and therefore more likely to show up in A&E. “Consequently, we can say that our case fatality rate has improved. In other words, there are more people presenting with the condition, but less of them are dying.”
An increased awareness of the risks of and remedies for food allergies in the UK, Professor Fox says, can be traced back to high profile cases, such as that of 15-year-old Natasha Ednan-Laperouse, and the campaign led by her parents to pass stricter food safety laws.
In 2016, Natasha ate a sandwich from Pret a Manger which contained sesame, an ingredient to which she was allergic. As the food was made on the premises, Pret was not required by law to include any allergy information on the packaging. She soon fell ill, suffering a cardiac arrest. Despite her father administering two EpiPen injections, she died later the same day.
Five years later, Natasha’s Law was passed in October 2021, requiring full ingredient and allergen labeling on all food made on premises and pre-packed for direct sale.
So why were allergies on the rise? And why, for example, does hay fever (an allergic reaction to pollen) now affect 26% of UK adults when it was pretty much unheard of 200 years ago? Professor Fox says one reason that has been dispelled is that of the “clean child theory” – the idea that because we’re a more hygienic society today our immune systems are less robust.
Prevailing theories are more focused on the gut microbiome and the bacteria that colonize our gut. These, he says, have shifted due to “societal factors”, such as thanks to more people being born in hospitals rather than at home, the greater use of antibiotics and changes in weaning and feeding practices in early life.
“We know our gut flora has a really pivotal role to play in the way that our immune systems develop and relate to the outside world,” Professor Fox explains. “If you disturb and change that, you risk getting aberrant responses – like allergies.” Exactly how and why that’s happened will require a far better understanding of the gut microbiome.
“We’re still in the infancy of even starting to develop that knowledge.”
Diagnosis tests for food allergies include a skin-prick test, blood tests and following an elimination diet to identify the root cause of the condition. Until recently, treatment was limited to careful avoidance, the use of antihistamines for mild allergic reactions, or the use of emergency medicines in the form of an EpiPen for severe allergic reactions.
The tide on treatment, however, is starting to turn thanks to a 15-year period of intensive medical research into desensitization – also known as oral immunotherapy (OTI or OIT). Desensitization involves giving patients (typically children) a tiny daily dose of the food the child is allergic to.
Over time, the dose is gradually increased until the patient can tolerate normal quantities of the food, or at the very least, accidental exposures to small amounts will not cause adverse reactions.
Similar outcomes, but with fewer risks, can also be achieved by using desensitization patches and biologics, which is when you pair immunotherapy with monoclonal antibody medicines that dampen down any allergic responses.
The Sean N. Parker Center for Allergy and Asthma Research at Stanford University, California, led by Dr Kari Nadeau, achieved one such breakthrough in 2017, combining oral immunotherapy with omalizumab, an antibody medication used to treat asthma.
After nine months, 83% of children who had received omalizumab could tolerate at least 2g of two different food allergens, whereas only 33% receiving a placebo reached the same level of tolerance. They also had fewer gastrointestinal side effects during therapy, such as nausea and abdominal pain, and fewer respiratory side effects, such as shortness of breath.
To date the Parker Center has led the way on new treatments and diagnostic tests for food allergies, including a blood test that can provide 95% accuracy in simultaneously diagnosing allergies to multiple allergens in patients of all ages, including infants.
Dr Nadeau’s team has also patented an infant and toddler formula that can help prevent food allergies from developing, and developed the first rapid multi-allergen immunotherapy protocol, making Stanford the first to treat patients with multiple food allergies simultaneously.
Its stated mission is to make transformative changes in the field of allergy by uncovering its root causes and developing a long-lasting cure. Yet, for Professor Fox, this “Holy Grail” will only be achievable if the scientific community collectively focuses on early life prevention, rather than simply later life treatment.
“Food desensitization, patches and antibody medicines all show great promise,” he says. “But the current modalities don’t look to cure, they only look to manage. If you stop the treatment, the tolerance disappears. If we’re truly going to achieve the Holy Grail of a cure, the area that shows the most promise is that of early life allergy prevention.”
Avoidance is not the answer. “The longer you avoid certain foods, like peanuts, the more you increase the risk of developing an allergy in the first place,” he adds.
Instead, look to introduce infants to foods associated with allergies early, get a proper assessment on the first sign of any food allergy – “as we know that if you have one, you’re at a greater risk of developing another” – and if an egg or cow’s milk allergy is detected, think about using baked egg or baked milk to help your child outgrow their allergy quicker.
Words: Sam Rider
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