Former Visiting Professor Patrick Holford is still Head of Science and Education at Biocare. It is possible that such impressive titles convince the unwary that Holford has an evidence-base for his supplement, health, lifestyle or self-empowerment-through-testing advice.
Holford frequently recommends IgG testing for the diagnosis of food intolerance although there is currently no clinical validation for such a recommendation and several associations of clinical allergists and immunologists have declared that the tests are without merit.[a],[b] Some leading consultants and allergists such as the redoutable and remarkably compelling Dr Glenis Scadding, Consultant Allergist at the Royal Nose, Ear and Throat Hospital, characterise IgG tests for food intolerance as “a waste of money”. Despite this, Holford maintains a remarkable and seemingly contagious chutzpah and cleaves to his recommendation.
We are still researching an update to the story of the IgG test for the diagnosis of food intolerance. However, in the interim, and because this builds into one of the most notable pieces of chutzpah that we have come across recently, we offer the Which? investigation into commonly available food intolerance tests: Food allergy tests could risk your health.
Many people confuse intolerances – which can be caused by an inability to digest a particular food and have symptoms such as nausea, vomiting and headaches – with allergies, which affect the immune system and can cause severe reactions including anaphylactic shock.
Neil Fowler, editor of Which? magazine, said: ‘A severe allergy can be life-threatening, so it’s no surprise that people want to find out if they should avoid certain foods. But some companies are playing on these fears to sell expensive intolerance tests that are not medically proven.
‘Our tests have shown them to be unreliable – and they could even endanger your health as following their recommendations could lead to nutritional deficiencies.’
Several newspapers have picked up the story. The Sun: DIY food allergy tests are cash down the loo.
Researchers vetted several readily available food testing kits.
They included blood tests for immunoglobulin G, an antibody produced when the immune system is under attack, hair analysis and kinesiology…
In all cases, experts concluded, there was no evidence to justify their use…some experts fear people risk health problems by cutting foods from their diet.
Professor Christopher Corrigan, allergy specialist at Guy’s and St Thomas’ Hospital in London, says: “The danger is that people avoid more and more foods and eventually become malnourished.
“There is not much scientific evidence to support these tests. I would like to see much more regulation of them.”
Daily Mail: How £275 food allergy tests ‘feed on fear and could be health hazard’.
The investigation by consumer watchdog Which? throws the spotlight on a multi-million-pound industry selling tests that are unregulated, or self-regulated by practitioners.
An astonishing 27million Britons claim to be intolerant to one food group or another…
But Which? says tests being used to identify food intolerance may put the health of users at risk by wrongly advising them to avoid essential food groups.
It asked researchers to go undercover and pay for four kinds of tests claimed to diagnose food intolerances.
These were blood samples tested for IgG antibodies, tests on strands of hair, changes in a person’s electromagnetic field and kinesiology, which involves resistance to pressure applied to legs or arms.
The tests found a total of 183 intolerances, even though the researchers had just one medically confirmed allergy and one already recognised food intolerance between them.
Different test results were produced from identical blood and hair samples sent to the same company under different names. There was little or no overlap of test results from different companies for the same researcher.
A panel of medical specialists and a dietician concluded that none of the tests, which cost between £45 and £275, had ‘ diagnostic value’ for genuine allergies or intolerances.
Other coverage reproduces similar points: Times: Expensive allergy tests could damage your health; Telegraph: Food allergy diagnosis firms ‘may be risking clients’ health’; Glasgow Daily Record: Food Fears Exploited By Firms for Allergy Tests Warns Which?.
Several of the stories mention that YorkTest and Cambridge Nutritional Sciences reject the findings although the grounds for their objections are not stated in a satisfactory manner. So, in the spirit of fair play, we consulted YorkTest’s own website, assuming that we would find a full explanation of their objections.
We didn’t find an explanation. We did find one of the most remarkable examples of chutzpah that we have encountered. Breaking News: Which? magazine.
The September 2008 edition of Which? Magazine featured a review of Food Intolerance testing. While there was some confusion between Allergy and Intolerance, the overall view of the article was that there are many different ways of testing for Food Intolerance and that some are less scientific than others.
It is difficult to tell because we haven’t seen the original report but from the newspaper reports, it seems unlikely that Which? actually declared that there is scientific support for the use of IgG blood tests for the diagnosis of food intolerance. On a prime facie basis, the tests may seem more scientific but it doesn’t make them relevant and when you are comparing the test to VEGA testing, hair analysis, or applied kinesiology then there really isn’t that much competition.
They stated that “some companies are not diagnosing food allergies and intolerances properly.” The good news however is that YorkTest’s IgG method was recognised by Which? as a “validated scientific test”.
HolfordWatch has also just seen a sponsored Google ad that repeats the claim: “Which? Magazine Report Says “Validated Scientific Test”" (see illustration).
Help us out here. Which? gave this account of their investigation:
- identical blood and hair samples sent under different names to the same company produced different test results
- there was little or no overlap between test results from different companies.
How many of you believe that Which? excluded YorkTest from its round-up of companies that “are not diagnosing food allergies and intolerances properly”? If so, there has been some remarkably poor reporting and Which?‘s own summary notes add nothing to confirm this. Update note: WWFI has kindly quoted the relevant part from the Which? article:
Experts’ verdict: Although IgG testing is a validated scentific test, our three expert believe that in line with our findings and other published research, its use in diagnosing food intolerance is difficult to prove scientifically. IgG antibodies are commonly found in healthy people and do not prove intolerance, only that the food itself has been eaten. The experts were also concerned that the diets recommended by these tests exclude up to 39 foods – which could lead to nutritional problems.
As for the claim about the “validated scientific test”, HolfordWatch is not aware of anyone who argues against the validity of IgG testing, the argument is against the purported use of it for diagnosing food intolerance by companies such as YorkTest and Cambridge Nutritional Sciences.[c] When YorkTest’s Technical Director, Dr Gill Hart, gave evidence to the House of Lords, she admitted that the IgG test does not have reference samples for food intolerance; it follows that the test has not been ‘scientifically validated’ for the purpose of IgG testing for the diagnosis of food intolerance or sensitivity.
Returning to the YorkTest account of the Which? investigation.
When looking at the different tests available Which? also raised concerns over the lack of support that consumers receive to aid them in changing their diet. Once again this highlights the importance of the two telephone consultations with BANT qualified nutritionists – a key part of the YorkTest FoodScan service.
Well, that may well be the spin that YorkTest is putting on the Which? report but we doubt that it is one that Which? would recognise. If you want advice on diet, consult a registered dietitian, there is no indication that BANT registration (qualification is a misnomer) is a guarantee of quality or even a decent selling point (as the sad case of Dawn Page and Barbara Nash illustrates).
FoodScan is the only food intolerance test endorsed by Allergy UK. In addition to the support of qualified nutritionists, FoodScan customers also receive a year’s free membership to Allergy UK for ongoing support and advice.
Yes, it is true: despite the House of Lords recommendation that charities such as Allergy UK should not endorse food intolerance tests such as those offered by YorkTest and Cambridge Nutritional Sciences or other direct-to-consumer tests, Allergy UK still endorses the tests and YorkTest continues to publicise this endorsement.
We are still gathering together more information about IgG tests and food intolerance and shall post some more updates in the near future. However, in the interim, it looks like Which?‘s recommendations are grounded in expert observations. If you are troubled by food intolerance they reccomend that you should save your money, keep a food journal and consult your GP – you might even request a referral to a registered dietitian.
Related Reading
Update on Which?, YorkTest and Selective Quoting in Google Sponsored Links.
You and Yours on Which? Investigation into Food Intolerance Tests.
YorkTest, Hardman & Hart: there’s a difference between the BMJ and Nutrition and Food Science.
Notes
[a] House of Lords issued a comprehensive report HL 166-I (pdf from which pg numbers are given) and summed up their advice as follows (pg 87):
We are concerned both that the results of allergy self testing kits available to the public are being interpreted without the advice of appropriately trained healthcare personnel, and that the IgG food antibody test is being used to diagnose food intolerance in the absence of stringent scientific evidence…We urge general practitioners, pharmacists and charities not to endorse the use of these products until conclusive proof of their efficacy has been established.
[b] Stapel SO, Asero R, Ballmer-Weber BK, Knol EF, Strobel S, Vieths S, Kleine-Tebbe J; EAACI Task Force. Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report Allergy. 2008 Jul;63(7):793-6.
In contrast to the disputed beliefs, IgG4 against foods indicates that the organism has been repeatedly exposed to food components, recognized as foreign proteins by the immune system. Its presence should not be considered as a factor which induces hypersensitivity, but rather as an indicator for immunological tolerance, linked to the activity of regulatory T cells. In conclusion, food-specific IgG4 does not indicate (imminent) food allergy or intolerance, but rather a physiological response of the immune system after exposition to food components. Therefore, testing of IgG4 to foods is considered as irrelevant for the laboratory work-up of food allergy or intolerance and should not be performed in case of food-related complaints.
[c] Ibid.
Testing for allergen-specific IgG, however, certainly has a role in allergy diagnosis. An example is testing for precipitating antibodies, mainly belonging to the IgG class, against Type III allergens.
In addition, in IgE-mediated allergic disease, however, there is renewed interest for determining specific IgG: IgG4, formed in the course of allergen-specific immunotherapy, not only shows blocking activity by inhibiting IgE-mediated facilitated antigen presentation (7), increasing evidence points to the conclusion that allergen-specific IgG4 responses are the result of the activities of regulatory T cells, being associated with the induction of immunological tolerance upon prolonged exposition to antigen…
Testing for IgG against foods may occasionally be indicated. An example is testing for IgG against wheat gliadin for the diagnosis of celiac disease, but the information obtained is of very poor clinical specificity and sensitivity, and this test should be applied only in case of IgA deficiency.
NB, the latter refers to coeliac disease, not the usual food tolerance that YorkTest and Cambridge Nutritional Sciences claim to diagnose with their IgG test.
43 Comments
August 22, 2008 at 6:03 pm
Apologies for not scanning and emailing the article as I promised – I’ve had a busy week. I’ll ty to get it to you soon.
The relevant quote about IgG testing is:
“Experts’ verdict: Although IgG testing is a validated scentific test, our three expert believe that in line with our findings and other published research, its use in diagnosing food intolerance is difficult to prove scientifically. IgG antibodies are commonly found in healthy people and do not prove intolerance, only that the food itself has been eaten. The experts were also concerned that the diets recommended by these tests exclude up to 39 foods – which could lead to nutritional problems”
August 22, 2008 at 6:15 pm
Wow, wewillfixit. Thank you so much for posting that snippet which is pretty much as we thought.
I’d be shocked if it were not par for the course.
August 22, 2008 at 6:30 pm
Interesting stuff. I’ve read a bit about IgG previously (here and on BreathSpaKids, mostly). Re wewillfixit’s comment – the pasted quote from the experts seems in line with something I heard once on the radio. I think it was Catherine Collins who pointed out that IgG antibodies only showed that a person had eaten a particular food, not that they were allergic to that foodstuff.
Given the amount of legitimat criticism that the tests have already had and the lack of anything resembling an adequate rebuttal, I’m a little surprised anyone still has the chutzpah to promote them.
August 22, 2008 at 8:08 pm
Catherine Collins was one of the Which? experts.
August 22, 2008 at 8:21 pm
I think that Catherine Collins is in Part 2. Listen again: Rise of the Lifestyle Nutritionists Part 2. These programmes are scheduled for a repeat but it has been postponed because Ben Goldacre currently has a series on placebo on R4 and it might otherwise look as if he is dominating the airwaves.
From the Which? account, it looks like the experts were Dr Adrian Morris, allergy specialist at the London Medical Centre and Guildford Nuffield hospital; Andrew Williams, consultant allergy nurse at Homerton University Hospital NHS Foundation Trust; and Catherine Collins, chief dietitian at St George’s Hospital, London.
August 22, 2008 at 10:00 pm
“Catherine Collins was one of the Which? experts.”
Good. I think the world needs to hear more from Catherine Collins, she really is excellent. I’m glad you buy ‘Which?’ wewillfixit – I enjoyed the Bad Science forum thread on this, but missed (or forgot about) your comment about Catherine Collins being one of the testers.
dvnutrix – yep, that was it. I haven’t listened to that bit of the show recently but it was definitely CC on RLN.
August 22, 2008 at 10:09 pm
nnnnnrggghh
*bangs head on desk*
It is also another of those “err.. consider that the experts might perhaps know more than you?” issues.
Unfortunately, the Holfies and similar can easily say: “Well, look, coeliac, which is a food intolerance, can be diagnosed to some degree of accuracy with blood antibody testing”
..which is true-ish, though it contains a lot of caveats.
And then:
“So why shouldn’t OTHER “Food Intolerances” be diagnosed with our very high-tech antibody tests? Those stick-in-the mud doctors and dieticians blah blah blah”
Of course, this leaves out all the nuances about when coeliacs have to be tested in relation to what they are eating, the fact that they run at least two different antibody tests, the “standardisation of ELISA test results in various labs” questions, the false-positive and -negative rate questions, the assay cut offs etc etc. And the reality that the coeliac “diagnosis ” would get made by a consultant allergist or gastroenterologist, with n years of training and experience, looking at the test results AND reading the case history. AND the fact that even then you would need an endoscopy / biopsy to be clinically certain.
…i.e., you sort of can, but more sort of can’t exactly, diagnose coeliac from the blood tests;
- and if that’s so-so, with all the research and trials and expertise, then there is Triple F-All chance that a half-trained nitwit blindly applying sort-of-ish the same methodology in a totally clueless way for tens of other poorly understood “intolerances” will give meaningful results.
As ever, it’s our old buddy Cargo Cult Science. It kind of looks the same, but in fact is crap.
How many times have we had to say that?
All of which, of course, lies behind the “Experts is experts ‘cos they is knowin’ and understand stuff you isn’t, like, innit” thing.
But of course if the Holfies tell people what they want to hear and are allowed to sell them a line of bullshit, and the Punters consume it enthusiastically and come back for more…
*sigh*
Admin edit: adding in a quotation that is just too good to pass by. Climate progress comments on the retraction of a mistaken interpretation of data by a climate change dissenter.
August 23, 2008 at 12:58 am
I have no wish to make people miserable, but rather akin to Unity’s speculation about the chiropractors and why they want to hear nothing but *crickets* rather than criticism from science journalists…
We shall blog this but YorkTest is trying (again) to have their tests made available on the NHS, including the IgG food intolerance test. How loud a Kerching can you hear? And how many openings would there be for nutritional therapists – whom it would have to be because RDs don’t promote this nonsense.
YorkTest made this presentation to some MPs July 3. You will not read anything about the House of Lords’ strong recommendations in Zero Tolerance. Exploring the Burden of the UK’s Food Intolerance Problem (pdf).
August 23, 2008 at 2:12 am
nnnnrrrrggg
*more head-banging*
I only hope some of the real doctor or scientist MPs went along to point out what a sack of shite the stuff is.
PS Have you ever come across this? Don’t know its age, but what struck that even someone from the US’s most prominent “naturopathic university” (a place that trains the dreaded “NDs”) was writing that the IgG tests basically were completely unreliable and didn’t tell you anything meaningful.
August 23, 2008 at 11:41 am
Apologies if you have already covered this but YorkTest do more than publicise the endorsement of Allergy UK but they seem to have some sort of inappropriate relationship with an ostensibly independent charity (and with BANT – but no surprise there).
Buying at least some tests gives you:
August 23, 2008 at 1:19 pm
There are several discussions of Allergy UK and YorkTest: the endorsement of paid friends; What does Allergy UK’s Consumer Award for Products Mean?; Allergy UK and YorkTest co-design a dtc IgE test; AUK’s evidence to House of Lords where they recommend YorkTest because nothing else is available. There are lots of commentaries about the relationship of YorkTest and Allergy UK.
Dr Mike Matthews of AUK was a medical director for YorkTest before he joined AUK. As the first link indicates, the Food Intolerance Awareness division that AUK set up after the House of Lords’ criticism has some familiar faces on the Expert Panel. and leads with recommendations about consulting nutritionists rather than RDs (hint, no RDs are members of the Expert Panel).
August 23, 2008 at 1:32 pm
AUK’s Muriel Simmons is adamant that there is no financial benefit for AUK from YorkTest in excess of the £1000 that they pay annually for their Consumer Award. Although customers are offered free membership of AUK for a year, not all take it up, and for those that do, YorkTest pays £10 per person to defray costs.
YorkTest gets enormous value for money from that endorsement which is a bargain for £1000 pa. Plus, it gets rather difficult to follow because AUK have paid for audits of YorkTest customers to publish as studies – and to some extent, this reads like a subsidy of YorkTest, rather than income from YorkTest. All of which is at odds with the claim that Simmons was going to introduce strategic financing etc. into AUK.
AUK’s endorsement of YorkTest is mentioned in the majority of adverts and almost all newspaper coverage. AUK adds to YorkTest’s brand equity in a substantial way.
August 23, 2008 at 1:37 pm
Thanks dvnutrix, it is understandable that medical charities will seek funding and support from the pharmaceutical industry and there is no doubt that such a relationship can be mutually beneficial. But I would hope that conflicts of interest between charity staffers and commercial partners were made clear. I would also hope that medical charities pay due attention to scientific evidence before offering endorsements.
I may be naive in assuming that Allergy UK think the same.
August 23, 2008 at 1:39 pm
Dr Aust – afaik, no ‘sensible’ people were in attendance at the presentation.
Surely the strictures of Miller fall into abeyance when one considers that Patrick Holford and Chris Steele are impressed by the sound science of YorkTest. Stop the head-banging – it’s a bad example for Aust (most) Jnr. Dr Steele even launches YorkTest’s WebTV service for them and chats to a YorkTest client about her IBS (sorry, they don’t allow a direct link – and that doesn’t include the interview but this does).
There is some discussion of lab accreditation for particular tests and Dr Gill Hart admitted that there are still no standardised reference samples of IgG tests for food during her House of Lord’s testimony.
August 23, 2008 at 3:28 pm
dvn
Have you and the other H’watch folks ever tried summarizing the iffy nature of the tests, and the relationship between Yorktest and AUK, in a short article? I would write one and send it to the BMJ if I were you. They are running an occasional “debate feature” so you could even debate: “Are OTC tests for food intolerance worthless?” or “Should health charities promote tests which best evidence says are useless?” Perhaps you sign Catherine Collins up as a co-author?
August 23, 2008 at 4:13 pm
Dr Aust, interesting suggestion. We do know someone who is working on an unbelivably detailed review but by its nature it is fantastically detailed and will probably not be that accessible to read.
In the interim, a shortish sharpish piece in BMJ would probably be a good idea if Catherine Collins and others were game.
August 23, 2008 at 4:46 pm
They call me Mr Obvious for a reason but it would look like Dr Chris Steele is also choosing to ignore the House of Lords’ recommendation that GPs etc. should not promote the use of these tests.
Has he ever said why? Or is this counted as interfering with the right to freedom of religious expression – such as the blandishments of Mammon?
August 24, 2008 at 12:22 am
Ah, we have just learned that the fantastically-detailed systematic review may be rendered null and void. Apparently, YorkTest is producing their own review.
That’s the same industry magazine that published the previous YorkTest customer audit.
Hardman G & Hart G, 2007: Dietary advice based on food-specific IgG results (pdf). Nutrition and Food Science: 37,16-23
March 28, 2009 at 10:56 pm
I am keen to contribute some ammunition to any review of the links between YorkTestand Allergy UK. I’d be very grateful if you’d put me in touch with the relevant person(s).
I think there may be grounds for a complaint to The Charity Commission about Allergy UK’s behaviour and governance.
Thanks
August 24, 2008 at 11:52 am
Publishing in ‘Nutrition and Food Science?’ A journal one small sciencey step above the BBC ‘Good Food’ magazine. Sounds about right.
Also of interest is another offshoot of Allergy UK, and another chance to promo Yorktest (TM) unreservedly.
And another example of ‘take one media doc, plus a couple of interested medico’s , then voila! the dodgy nutritionists gain kudos-by-association http://www.foodintoleranceawareness.org/experts.htm
Admin edit: we discussed the make up of the FIA expert panel: My paid friend says this product is really good.
August 24, 2008 at 1:52 pm
I still think someone should write a piece for the BMJ pointing out that “Big Quacka” uses exactly the same tactics as Big / Evil Pharma: inter alia, vanity publications and company lit masquerading as independent published papers; charities which are thinly disguised promotional fronts and/or corrupted by financial ties; biddable “experts”, plus others whose names get used even though they probably don’t understand what the “charity” is really about etc etc.