Half of people who think they have a food allergy do not – study

Authored by theguardian.com and submitted by mvea
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US study finds some people needlessly avoid foods while others do not have life-saving medication

Half of people who think they have a food allergy do not – study

The number of adults who think they have a food allergy is almost double the figure who actually have one, research has revealed.

While the study was conducted in the US, experts say a similar situation is also seen in other countries, including the UK. The researchers found that many people with an allergy do not have a prescription for potentially life-saving medication, while others might be avoiding foods unnecessarily.

The study suggests almost 11% of adults in the US have a food allergy, equating to more than 26 million people. About 12 million of these are estimated to have developed the allergy as an adult, highlighting that allergies do not only begin in childhood.

“This is really concerning because chances are they could eat the food and then all of a sudden they have a reaction to a food that they could previously tolerate – so what changed in their environment or in them that caused them to now develop this food allergy?” said Ruchi Gupta, a professor of paediatrics at Northwestern University and a co-author of the research.

“Some of these foods you know that they probably were able to eat [previously] because they are such common foods in the diet, but shellfish was interesting – it could be one that they are trying for the first time as an adult.”

Gideon Lack, a professor of paediatric allergy at King’s College London, who was not involved in the research, said the growing problem of food allergies in adults might be linked to the dramatic rise seen in children over the past 20 years.

“We have been focusing efforts and concerns about food allergy in children, and this study is telling us there is a very significant burden of food-allergic disease in adults and we ought to be directing more attention and resources towards diagnosing and treating those adults,” he said.

Writing in the journal Jama Network Open, researchers in the US describe how they conducted a survey in two groups of participants between October 2015 and September 2016. In total more than 40,000 adults in the US took part.

Participants were asked if they had a food allergy and were questioned about their reactions and diagnoses. The team then assessed whether the reported allergy, whether diagnosed or not, was “convincing” – for example if the participant had experienced symptoms such as throat tightening or vomiting.

“If they only had, say, bloating or stomach pain or diarrhoea then we took them out because that could be a lactose intolerance or a food intolerance,” said Gupta.

The results reveal that the most common “convincing” allergy was to shellfish, affecting 2.9% of adults, with milk and peanuts in second and third place, affecting 1.9% and 1.8% of adults respectively.

But while 10.8% of participants were deemed to have at least one convincing food allergy, almost twice as many – 19% – reported they had such a problem.

“There are so many adults out there who have a negative reaction to a food. It is really important to get a proper diagnosis so that they can really know is this something treatable like lactose intolerance, or is this a life-threatening food allergy that they need to be very careful with,” said Gupta.

Why are food allergies in children on the rise – and is there anything parents can do to protect them? Read more

Of those with a “convincing” allergy, almost half said they had developed at least one of their food allergies as an adult, while about 38% said they had undertaken an emergency hospital visit as a result of a food allergy. However, only 48% said they had received a diagnosis from a doctor and just a quarter said they had a prescription for adrenaline, a common allergy treatment.

Prof Clare Mills, an expert in food allergies at the University of Manchester, welcomed the study but said it had limitations, including relying on self-reported data, including for symptoms. What’s more, she said, the healthcare system in the US is very different to the UK, meaning access to healthcare, and even the way adrenaline is prescribed, is very different.

Stephen Till, a professor of allergy at King’s College London, said the prevalence of “true” allergies seen in the study seemed surprisingly high, but the widespread misapprehension of having an allergy chimed with his clinical experience in the UK.

“I often see patients who think that they have a severe allergy who either aren’t allergic or who have mild allergy. They may have been unnecessarily prescribed adrenaline auto-injectors and be on a restricted diet avoiding even trace exposure to the suspected culprit,” he said, noting that this could cause significant anxiety and difficulties.

“Unfortunately … we have a shortage of physicians who are trained in adult allergy and so this amplifies these kinds of problems.”

SisterHelena on January 6th, 2019 at 02:20 UTC »

The problem with articles as this, is that if a person doesn’t actually read the article the take away is, ‘oh, people with food allergies -really- don’t have them.’ Which creates things even worse for the people who have to deal with life threatening food allergies already.

drmyk on January 6th, 2019 at 00:45 UTC »

Edit.

its 1am, I hadn't planned on AMA'ing allergies when I wrote this but its been fun and I hope everyone enjoyed the discussion. I know I didn't answer every question, I hope I was able to cover the big topics.

If you think you have allergies please talk to your doctor. they can be life threatening and there are excellent treatments to treat severe reactions.

If you want to read some more, Food allergy research and education (FARE) has some great patient-oriented resources.

https://www.foodallergy.org/

If I have time tomorrow I'll try to go through and see if there's anything else to add. Feel free to ask, if I'm able I'll try to answer.

Thanks.

I work with food allergy patients.

People have a lot of issues with foods, but food allergy is a very narrow, specific term. Allergist define food allergy as being an IgE mediated reaction to a food. These types of reaction lead to mast cell activation, histamine release, and anaphylaxis. They can kill you very dead and very fast. That's why we care about them, that's why there's good testing for them, and that's why we change people's lives that have them by making them paranoid about avoiding the food and always, always carrying an epi injector. Food allergies don't make your stomach ache or legs hurt or your vision blur or your headache or you lose concentration and get brain fog or cause your autism to flare. Its anaphylaxis (or other mast cell associated symptoms that are less severe than anaphylaxis like eczema flares, hives...you get the idea)

There are a thousand reasons that a food can make you feel bad. These are food intolerances. Malabsorbing sugars, fats, difficult to digest proteins, bacterial overgrowth-any one of these deserves a full reddit post on its own. But none of these will kill you. None of them activate mast cells and lead to anaphylaxis. Importantly, for many there aren't great tests so it becomes an issue of not eating food that makes you feel bad because it makes you feel bad, not because the food making you feel bad has been validated by a test.

There are a lot of bogus tests that people will offer you to find the foods that are making you feel bad. They all have fancy names and very precise numbers, but their numbers are meaningless because in general they don't correlate with any specific food reaction. They'll bill you for it (directly, since insurance won't pay because it isn't validated). Often they'll come with some odd rotation diet, or instructions to avoid foods that come from dicot plants or seeds only grown in sandy soil or foods that don't contain the letter 'e' or ones that match your blood type. These are bogus tests. Don't fall for them.

There are a couple of exceptions here. Celiac disease isn't an allergy but an intolerance, but it can kill you and there's a couple of great tests to find it. FPIES can be very severe, but no test to identify it except for looking like you're trying to die when you eat a specific food.

There are exceptions to everything, if you think you're allergic to a food see a doctor and ask if you should be evaluated.

I'm going to hit the comment button now before I think of 4 more exceptions to anything I've already written.

blackcoffeeredwine on January 6th, 2019 at 00:20 UTC »

People with eosinophilic esophagus often react in allergy-like ways to foods where allergy testing shows no reaction. The reaction is such that it can still be alarming, uncomfortable, and attributed to allergy or sensitivity. Avoiding the triggering foods in these instances is both needful and desirable.

https://www.aaaai.org/conditions-and-treatments/related-conditions/eosinophilic-esophagitis