Misinformation around food allergies and is rife — as ubiquitous as Trump gaffes or fidget spinners landing in your lap on the bus – and experts willingly admit there’s still so much they don’t know. Frustrated patients, or their parents, are tapping away at Google, and companies are cashing in. From looking at one’s iris to gauging electric currents in the body, there's a host of tests out there – some of them very questionable - promising to diagnose your every stomach pain, headache and skin irritation – some you can even do from your lounge room.
Food allergies are, unfortunately, on the rise. , and two per cent of adults, have been diagnosed with a food allergy. Hospital admissions for anaphylaxis from food have doubled over the last decade in Australia, and the US and UK.
Food allergy and intolerance is not the same thing. A involves the immune system reacting to a substance that would normally be harmless – causing symptoms such as swelling of the face, lips or eyes, hives or welts, abdominal pain and vomiting, and wheezing and coughing. In extreme cases, anaphylaxis can lead to death. , on the other hand, doesn’t involve the immune system but can trigger symptoms similar to a moderate food allergy. While the symptoms of an allergy develop soon after exposure, symptoms of food intolerance can take hours or days to surface.
Understandably, parents are on high alert when it comes to food sensitivity, but if they’re self-diagnosing their kids or test results are misinterpreted by health practitioners, the consequences can be devastating. In , 34 per cent of parents reported food allergies in their kids – but just five per cent were found to actually have an allergy – which experts say can lead to malnutrition, as worried parents cut out foods unnecessarily.
The price isn’t right
There’s no shortage of mail-order tests available online to seemingly allay our concerns around food allergy and intolerance. Many are unproven, based on pseudoscience, and expensive. One company spruiks a hair-sample test costing up to $290, claiming it’s more accurate and less invasive than a blood or urine test. Using “bio resonance technology” (which a live-chat consultant told the writer to ‘Google’ when asked, ‘What is bio resonance?’) it says it tests five strands of the customer’s hair against more than 600 food and non-food items, such as metals, sending back a detailed list of items to avoid.
One brand of blood screen, which the manufacturer claims can indicate intolerances to up to 270 foods, can be ordered on the internet for a whopping $795.
Sites peddling dodgy food intolerance tests (to be fair, most companies admit they are unable to test food allergies, the symptoms of which can be fast-acting and life-threatening) incorporate science-y words and rely on the number of tests sold globally, anecdotes or customer “satisfaction scores” as evidence of success. Any mentions of legit scientific evidence proving these tests’ efficacy is thin on the ground, which is legally OK. There is in Australia; they can be promoted by unregistered medical practitioners without having to provide evidence they actually work.
According to , the cost of using unproven diagnostic techniques and treatments for allergies – whether online or in the real world – amounts to more than $600 million per year in consultations, and more than $1.5 billion per year in complementary medicines in Australia. That’s more than we’re spending on smashed avocado, surely.
Weird science
Experts such as Perth-based immunologist and allergist, Dr Richard Loh, are worried about the prevalence of unproven and unorthodox tests. Dr Loh equates them to “snake oil”.
“It’s potentially dangerous for patients, and expensive, depending on what test you order,” he warns. “If a report comes back [wrongly] saying, ‘avoid these foods’, such as cow’s milk, wheat or soy, the patient could end up on an extremely restrictive diet and become nutrient deficient.”
“The problem is we don’t have a cure for a lot of allergies, so people start looking on the internet. They go on often very well-written websites. People are quite desperate, especially parents of children with eczema or reflux... they look, hope and unfortunately pay a lot of money for these tests, which lack scientific evidence.”
One of the biggest misconceptions is that the presence of IgG (Immunoglobulin G) antibodies can signal food intolerance – as per the $795 blood test mentioned above. But any normal, healthy person will test positive for IgG antibodies, says Dr Loh. (IgE antibodies, on the other hand, are those associated with allergic reactions.)
IgG is a ‘memory antibody’, and signals exposure to a food, rather than an adverse reaction to it. Because a healthy immune system should produce IgG antibodies in the presence of foreign proteins, a positive IgG test to a food is a good sign that the patient’s immune system is working, often .
According to ASCIA, “There is no credible evidence that measuring IgG antibodies is useful for diagnosing food allergy or intolerance, nor that IgG antibodies cause symptoms. Despite studies showing the uselessness of this technique, it continues to be promoted in the community.”
Meanwhile, that, “tests have found that in even in people with known, genuine intolerances, proven by elimination diets and oral challenge, don’t show raised IgG antibodies.” The science just doesn’t stack up.
As for hair-strand testing? Think of it as a very expensive hair cut. “Hair analysis has no basis,” says Dr Loh. “There have been cases where people have sent two hair samples [from the same head] to the same lab, a few weeks’ apart, and been given completely different results.”
An alternative view
Testing for IgG antibodies is worthwhile, maintains Dr Kylie Dodsworth, Vice President of the (AIMA). “IgG tests can be useful guides to identifying possible food intolerances when ordered by a practitioner who is trained in interpretation and dietary management,” she explains.
Dr Dodsworth also advocates the Alcat (antigen leucocyte cellular antibody) test for food intolerance, in which the appearance of white blood cells is assessed after being mixed with food extracts under a microscope. (According to ASCIA, Alcat tests are not useful, and “give different results when duplicate samples of the same blood are analysed repeatedly, and ‘diagnose’ food allergy in people with symptoms that do not actually suggest food allergy.”)
Dr Dodsworth does not recommend doctors use any other alternative tests, such as hair-strand analysis, iridology, kinesiology, or ‘Vega’: changes in electrical currents in the body are measured while the patient holds an electrode and a sealed container of the allergen is connected to the circuit.
The bottom line
Most experts – whether they specialise in the traditional medical or complementary field (or both) – agree on a couple of things when it comes to food allergy and intolerance tests.
One: because they are life-threatening and can cause anaphylaxis, food allergies should be diagnosed by an immunologist or allergist through skin-prick testing or a blood test, after a thorough patient history is taken. There is no one legitimate diagnostic test for an allergy that can be done in isolation, insists Dr Loh. In rare cases, immunologists may even throw a into the mix, where the patient is given small amounts of the allergen in a safe hospital environment.
“The (CMA) does not endorse or encourage any of its members to diagnose food allergies, which have the potential to be life threatening or cause serious conditions,” says Paul Kern, president of the CMA. In regard to intolerance tests, “[unorthodox] tests should be regarded as indicative tests only, that further investigation is warranted.”
“You’re playing with fire if you’re trying to manage a food allergy in the alternative therapy space,” says Maria Said, co-chair of the Steering Committee (Dr Loh is also co-chair) and CEO of . “Sometimes it’s very much to the detriment of the person, as it can delay treatment that is proven and is tested. It can be a danger because if they’re told to stop eating a food they’re currently tolerating, the risk of becoming allergic to it increases.”
Two: Do not buy unproven food allergy or intolerance tests on the internet. It’s commonsense, say our sources. “The management of any health condition needs to be undertaken in consultation with a qualified practitioner and with ongoing monitoring,” advises Dr Dodsworth.
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