Should you take your health into your hands and play detective to find out your food foes, or are allergy and intolerance tests just a fad?
Is gluten a no-go? Are you ditching the dairy? Whether it’s digestion, brain fog, or headaches, we often can have a gut feeling that certain foods can worsen our symptoms. Some of us would go as far as to say we’re actually allergic or intolerant to food. With the BBC reporting that there was a 72% rise in hospital admissions for children as a result of anaphylaxis in England between 2013 and 2019, the headlines can certainly emphasise the increased risk of having an allergy these days. But the number of people who think they have an allergy or intolerance has increased even more – in fact, a study published in Jama Network Open suggests that up to 50% of people who think they have an allergy actually don’t.
So, why the rise? Well part of this is down to the terminology and misunderstandings of this; the words ‘allergy’ and ‘intolerance’ are mixed up all the time, but they’re actually very different.
“There is often much confusion around the terms allergy and intolerance,” says Dr Helen Evans-Howells, a GP who specialises in supporting adults and children with allergies. “An allergy is an abnormal response by the immune system, producing characteristic signs and symptoms. An intolerance is a reproducible, adverse reaction that does not involve the immune system.”
The other reason many more people believe they have an issue with certain foods is the boom in at-home allergy tests, which is now a billion dollar industry with a report by MarketsandMarkets suggesting it’s currently worth $5.3 billion (£4.03 billion), and expected to rise to $9.8 billion (£7.45 billion) by 2029. With many of us battling to get a GP appointment, or to be taken seriously when we do, an at-home kit can seem like a great solution. We can do it in the comfort of our own home, without invasive tests, or the need to fit in an appointment in our schedule with our GP. But can they actually give us an accurate diagnosis?
How do allergy tests work?
Allergy tests work in several different ways, usually by either taking a small sample of your blood, or even a strand of your hair. You send this off in the post for analysis, and receive your results (such as a list of allergens or suspected food intolerances) a few weeks later. These tests vary from offering simple reports to having follow-up support from experts.
Are allergy tests worth trying?
The jury’s still out on whether many at-home allergy tests are actually proven to work. When it comes to hair strands, the experts I asked agreed these aren’t worth trying. “Hair analysis has no scientific evidence and should be avoided,” says nutritional therapist Donna Peters. The NHS uses skin-prick tests to diagnose potential allergic reactions to certain triggers, but these can’t always be replicated in a home environment without advice, and it doesn’t recommend trying at-home tests for suspected food intolerances.
Some of the at-home kits claim to work by detecting levels of certain antibodies (like IgE and IgG) in our blood. These may be usually present in small amounts in the blood, but the theory is that when they are elevated, it could suggest your body is actually overreacting to certain foods you are sensitive to or have allergies to (depending on the test you buy).
While this sounds scientific enough, these tests by themselves can’t tell us the full picture.
“Higher levels could be taken as an indication of a possible food intolerance, but it’s not a definite diagnosis, as false positives are commonly recorded,” explains Donna Peters.
According to Dr Evans-Howells, there can’t be a one-size-fits-all solution. “As all intolerances have a different mechanism, some of which are known and some not, there is no one blood test which is available which could possibly diagnose all intolerances. Equally, some forms of allergy are not picked up on the traditional IgE mediated blood test.”
If you are going to use these tests, both experts I spoke with advise you need to combine them with medical advice for them to be truly useful.
“There are some excellent home allergy tests, including one which I provide, but they are only interpretable in the light of an allergy focused history, so it is therefore vital that a careful history is taken beforehand to work out what the mechanism may be, and the appropriate management. Tests which claim they can diagnose all allergies and intolerances, are simply misleading – meaning people could end up inappropriately excluding food,” explains Dr Evans-Howells.
“While home allergy and intolerance testing kits could be helpful in a few cases, my preferred alternative is to work with a qualified nutrition practitioner to conduct an elimination diet, where you eliminate a food which you suspect is causing issues for a set period with professional help, then gradually introduce in a control setting while monitoring for any adverse reactions,” says Donna Peters.
What should I do if I suspect I have an allergy or intolerance?
It’s important to understand the difference between an allergy and intolerance when seeking help, but the first step is to always gather as much information as possible and head to a professional. “Putting together a summary of the symptoms you have seen with various foods, along with photographs of reactions (if relevant), and taking this to your GP is a useful first step,” explains GP Dr Helen Evans-Howells.
For allergic reactions, you may be referred to an allergy specialist, while if you suspect food sensitivities or intolerances, you may see a dietitian.
It’s important to not self-diagnose an allergy, or assume you have a food sensitivity when it may actually have another cause. An example is gluten, where many individuals may stop eating the food, assuming they are intolerant. Coeliac disease, a condition where your immune system attacks your own tissues when you eat gluten, is different to being sensitive to gluten or wheat, and can only be diagnosed by your GP arranging a specific blood test for the condition, which requires you to be eating gluten before the test.
“It is important to also see your GP to rule out any other serious causes for your symptoms,” adds Dr Evans-Howells.
It’s clear that while allergy tests could give insight into our health, without the experts guiding us we shouldn’t play detective, and make big life and diet changes on our own. Like any health issue, the first step you should always take is to seek advice from a qualified professional.
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