Hair testing for allergies is pooh-poohed by the medical establishment but remains popular. Skye Wishart takes a closer look.
Around 20 percent of the population – mainly young people of working age and their children – are affected by allergies, says Allergy New Zealand. This puts New Zealand near the top of the chart for rates of allergic disease in the developed world.
How is this diagnosed?
There are three medically accepted ways to detect food allergies: oral challenge, blood test and skin prick test. An alternative method using hair testing is also growing in popularity – every year more than 1,000 Kiwis have their hair sent to West Auckland allergy testing clinic Allergenics alone.
Naturopathy may have its place in certain situations, but when it comes to allergies, the hair testing method is widely dismissed by the established medical profession. Nor is it cheap: tests at clinics such as Allergenics, including the consultant fee, can cost up to $150 a pop.
What are you paying for?
Using principles of “quantum physics”, practitioners claim the homeopathic technique enables the identification of allergies or intolerances by analysing a hair, preferably plucked from the nape of the neck.
Central to the method is the belief that hair carries an “energy” from the body it is from, and that this energy can be detected and corresponds directly to imbalances in the body.
In the lab, the practitioner places the hair in a ziplock bag on a metal plate, says Brett Friedman of Allergenics. This plate is connected by wires to both the practitioner’s own acupuncture points on their finger, and to their hand, and to an upside-down titanium cup.
Under the cup will be a sample of the food, an environmental compound, or a homeopathic-like tincture of the substance (or in modern labs, a pre-programmed value in the computer for that substance). Together these components form a complete circuit. A type of current-detector (or galvanometer) is calibrated to the energy of the practitioner before being used to measure the “energy feedback” from the hair.
This reading is said to determine the degree of allergy or intolerance in the client’s diagnosis, taking into consideration any information provided by the client such as skin or cardiovascular problems, foods they’re avoiding, and medications the client is taking (which would interfere with the reading because it’s an “energy-based” test). This information can then be used by a naturopathic consultant to set up a customised dietary plan.
What the science says
“The hair test is one of the most popular and effective forms of food sensitivity testing,” claims the Allergenics website. “Compared with other standard testing procedures, EAV testing appears to be effective and accurate, along with food rechallenging testing, which is widely considered the most effective of the standard methods.”
The mainstream medical profession, however, remains unconvinced. Dr Andrew Baker, of Waitemata Allergy Clinic, says the way hair testing is described to work is “completely implausible. But more importantly there is no published evidence to show that the test works when compared to a food challenge,” he says. “The statement made on hair testing websites, that it performs as well as other allergy testing, has no evidence published to support it, and is a dangerous statement to make. The travesty is that this is alternative medicine, but is presented as if it is mainstream medicine.”
A study published in 2011 in the journal Allergy, Asthma, and Clinical Immunology reviewed the websites of 53 naturopathic clinics in Alberta and British Columbia “to gain a sense of the degree to which the services advertised by naturopaths are science-based”. The authors found the services and treatments advertised, which included hair testing as well as homeopathy, colon hydrotherapy and detoxification, were “largely scientifically unsupportable”.
“Patients should have the option to access a wide range of healthcare practitioners,” wrote the authors. “But this choice should be as informed as possible ... It is misleading to imply that the core services provided by naturopaths – as disclosed on clinic websites – are based on sound scientific evidence or, at least, that there is a scientific consensus about their efficacy … If the naturopathic profession wishes to present itself as science-based, the treatments offered by naturopath clinics should reflect these claims.”
“We don’t recommend hair testing,” says Penny Jorgensen, long-time chief executive and advisor at Allergy New Zealand. “There’s no scientific validity in it and ... in the context of IgE-mediated food allergy, it could put people at risk.”
Dr Baker says potential dangers can include missing a true diagnosis (for instance, of a condition such as bowel cancer) through lack of thorough patient consultation. Even avoidance diets (where you can only eat a limited range of foods) are not to be prescribed lightly. “It is not okay to tell people to avoid foods that they don’t have to,” says Baker. “For example, I know of a 70-year-old lady, who was on a completely unnecessary avoidance diet, who developed a food aversion because of anxiety, thinking she was going to react. She lost 25kg and became dangerously malnourished.”
The diets can also be socially disruptive – this is especially problematic for children, fostering an identity of them as an ‘allergy kid’ as well as being potentially unhealthy for them in terms of nutrition.
Baker says it is concerning that hair testing and IgG blood testing is marketed directly at parents with young children. “Would the parents consent to this method if they knew there was no scientific evidence to support hair testing?” he asks.
What about intolerances?
Allergies and food intolerances are not the same. A food allergy is when the body’s immune system reacts abnormally to specific foods – anything from mild to life-threatening. Food intolerances don’t involve these allergic reactions at all, and happen when the body has trouble digesting specific substances, or the substances affect the body somehow. They are hard to diagnose, involving symptoms such as diarrhoea, bloating, stomach cramps and rashes – symptoms which may not be due to food at all.
Jorgensen says food intolerances are difficult to diagnose because they involve a vast range of factors within the body, from digestive problems and toxins to missing enzymes (for example, in the case of lactose intolerance), and it’s also confounded by the fact the reaction can be delayed.
“I do feel sorry for people with intolerances – it’s an arduous task for them to find out exactly what it is they’re reacting to. But because there are so few allergy specialists in New Zealand, and not many good diagnostic tests for intolerances (usually you have to go to a dietician for an elimination diet) the hair test option would no doubt seem easier. These people can fork out quite a lot of money and justify it works, but they’ve ended up with 30 different foods they’ve had to cut out of their diet, which is a huge undertaking … and could also bring potential nutritional consequences, particularly for children still growing and developing.”
What of website testimonials that the method really works?
The mind is a powerful thing, says Baker. Being given a long list of foods to avoid can be reassuring and give hope that symptoms will alleviate, simply because the list provides clear guidelines. “A placebo effect is very common in this situation and people often feel better,” he adds. “The placebo effect is very powerful, having up to 50 percent effect in depression studies and a similar result in pain studies. Unfortunately, it often wears off after a few months. This is when we see the [aforementioned] real harms that are occurring from this method.”
The debate continues ...
In 2012 the New Zealand Clinical Immunology and Allergy Group, as well as Allergy New Zealand, complained to the Commerce Commission that some hair-test providers were claiming to be able to diagnose and cure allergies using methods with no sound clinical and scientific evidence. The Commerce Commission agreed and issued a release that “urged alternative health providers to review their claims about diagnosing and curing allergies, particularly to food, to ensure they do not breach the Fair Trading Act”.
Drawing on 2009 rulings from the Federal Court of Australia and published studies the ruling stated that “allergies can only be diagnosed on the basis of clinical history and symptoms, confirmed if necessary by either a skin prick test, blood test or oral food challenge – all of which should only be performed by an appropriately qualified medical practitioner”.