Myth: You Can Diagnose Food Intolerance or Allergy with an IgG Blood Test

Professor Patrick Holford of Teesside University and Head of Science and Education at Biocare is a staunch advocate of direct to consumer IgG food intolerance tests and is impressed by the “sound science” that underlies these tests. Holford is convinced that:

The evidence for IgG antibody reactions as a basis for food intolerances continues to grow, including well designed randomised controlled trials, however, some health professionals just haven’t kept up to date. Perhaps it’s because a ‘home test’ takes the power away from the professional and puts it in your hands.

However, Holford is also swayed by the scientific research for a neck pendant that protects wearers from the evil eye of electromagnetic radiation so one might be tempted to generalise from that as to the scientific credibility of some of his endorsements. It is also indisputable that the expert consensus is that these IgG blood tests are of no value in the diagnosis of food intolerance.

Expert Opinion, the House of Lords and the ASA

Professional organisations throughout the world have issued statements about IgG food intolerance testing that make it clear that:

There is no credible evidence that measuring IgG antibodies is useful for diagnosing food allergy or intolerance, nor that IgG antibodies cause symptoms. [ASCIA]

Clinical allergists and immunologists with impeccable research records and many years of clinical experience have explained that there is no scientific support for the role of IgG testing in the diagnosis of food intolerance. One particularly exasperated expert, the redoutable and remarkably compelling Dr Glenis Scadding, Consultant Allergist at the Royal Nose, Ear and Throat Hospital, characterised IgG tests for food intolerance as “a waste of money”:

What I do dispute is that it is worth making any attempt to identify IgG antibodies. We all make IgG antibodies to food….I see no way in which this can be used to guide diet.

I don’t think there’s any point in spending money on IgG antibody tests. You’re better off going to see a dietitian and using an exclusion diet followed by reintroduction. The IgG antibody tests are liable to leave patients on diets that are inadequate and patients often like to think they’re improving. They carry on in the teeth of very little improvement and may end up malnourished.

I think [self-testing kits] should be banned.

Back in 2006, the House of Lords appointed a committee to investigate allergy and allergic disease in the UK. The Committee investigated some important issues with implications for public health and public policy. They heard extensive evidence on the role of appropriate allergy testing and the lack of scientific support for currently available direct to consumer food intolerance or allergy tests.

Well, it rather seems as if the House of Lords Committee has greater confidence in the undisputed expertise of Scadding and other comparable experts rather than Holford who has no original clinical research or even indexed, peer-reviewed publications in this area. In a comprehensive report HL 166-I (pdf from which pg numbers are given), they make a number of good recommendations and provide some useful summaries. Pages 86-88 cover the issue of direct-to-consumer tests such as the YorkTest foodSCAN IgG test for food intolerance and the YorkTestAllergy UK MAST IgE test for allergies to food and airborne allergens, amongst others. The committee noted:

Dr. Gill Hart, Technical Director of YorkTest Laboratories, a company which manufactures such tests, told us that the presence of either IgE or IgG antibodies does not necessarily prove whether a food allergy exists, but claimed that IgG could be used “as a marker that a reaction has occurred” (Q 742). However, there is limited evidence to support this claim.

Furthermore, the EAACI even discredited the use of well validated tests based on IgE antibodies if they are used on a self-testing basis. This was because the tests “cannot be interpreted without a detailed clinical history taken by an allergy-trained individual, thus over the counter and postal testing is open to misinterpretation unless expert opinion is available” (p 70)…

Dr Hart admitted that the mechanisms used in the tests were “unclear…”…

Given the lack of evidence for these services we were concerned to learn that Allergy UK recommended the Yorktest service for food intolerance. The charity acknowledged that a patient’s best option would be to consult a dietician, but noted that “being able to obtain a referral to a dietician who understands food intolerance is extremely difficult on the NHS” (p 303).
[Emphasis added.]

One might imagine that the BDA would argue that dietitians have a considerably better knowledge of food intolerance than people who rely upon the results of a test of no proven scientific or clinical efficacy or who find themselves recommending YorkTest on the rather desperate grounds of faute de mieux:

It’s a lack of other places to send these people to. Err, we would give the YorkTest purely because it’s the only one that has undergone trials-particularly for IBS and that’s what we would say, that we would [be] happy to endorse it for, would be for those kind of symptoms. Eh, but, you know, we wouldn’t recommend any other test.

Desperate people searching for solutions do not need to be fobbed off with expensive tests of no proven efficacy in the hope that it will provide a palliative of dubious duration. It is unfortunate that people who are already in distressed circumstances may restrict their social activities because of the perceived difficulty of living with allergies and intolerances that may be inappropriately diagnosed.

Holford Watch is not optimistic that Holford is heeding expert opinion but the House of Lords 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.

It almost seems gratuitous to add that the House of Lords aligns themselves with clinical experts in their notion of who is qualified to diagnose allergies and allergic disease (hint, it is not the typical holder of a Diploma ION nor an auto-didact nor self-proclaimed expert; pg 89):

An accurate diagnosis is key to treating an allergic condition adequately, and much depends on taking an accurate patient history with details of a patient’s symptoms, home and occupational environment, temporal and geographic features, relevant family history and any physical signs. Diagnostic tests are often based on skin tests, blood tests and challenge tests. But the results of tests are meaningless in isolation; they have to be interpreted in the context of the patient history, a difficult task which requires a solid training in allergy.
[Emphasis added.]

It is important that an evidence-based approached should be used in the managment of allergies and allergic disease that have the potential to be life-threatening and can have a significant impact on quality of life. It is too common, particularly for parents who are desperate to help distressed children, that desperate people seek private testing that have no scientific or clinical support. Professor Gideon Lack specialises in the allergic mechanisms of asthma in children. He was sufficiently concerned about the importance of appropriate advice and testing that he conducted a survey of the allergy advice parents have received before they attended his paediatric allergy clinic: his findings were both eye-opening and alarming.

We found almost 50% had received alternative health care advice about allergies before coming to see us. I would say that of the children who come to our clinic at least 10% and possibly up to 20% have received unsound advice; these children will face nutritional problems.

The redoutable Dr Scadding may not have achieved her tongue-in-cheek wish that such direct to consumer tests as the ones lauded by Holford should be banned but it is a good sign that the House of Lords report makes such strong recommendations urging charities and responsible professionals not to endorse such tests until there is evidence of clinical efficacy.

The ASA recently reproved YorkTest for inappropriate claims that IgG blood tests are diagnostic of food intolerance.

We concluded that the evidence submitted was not sufficiently robust to prove the efficacy of the tests for diagnosing food allergy or intolerance.

Hidden Food Allergies

Patrick Holford and Dr James Braly have written a book: Hidden Food Allergies: Is What You Eat Making You Ill? The book announces:

One in two people, including up to 70% of the chronically ill, suffers from a hidden food allergy. Are you one of them?

The book is a tour-de-force that links common symptoms to IgG food intolerance and ‘allergies’. The statistics are drawn from opinion surveys and audits of people who have used the blood test: there is no support for these numbers in the general clinical literature.

In our experience, the vast majority of people have no idea their health problems may be related to eating specific foods. Most people’s food allergies are truly hidden from them…

Chances are, however, that food intolerances or allergies are adding to your burden, and in many cases, are prroving to be the main cause of any health problems…We’ll let you know about the amazing scientific advances that mean you can now identify food allergies from a pinprick of blood using a simple home test kit…

What’s more, we’ll explain why you become intolerant to certain foods by revealing the underlying causes of most food allergies, and how to eliminate these causes and thereby reduce your allergic potentil. We’ll explain how to ‘desensitise’ yourself to foods you’re allergic to so you can eat them once more, a process that usually takes just three months.

Some types of allergies, of course, are for life. If you have this kind, you can’t desensitise yourself completely – but you can reduce the severity of your allergic symptoms using natural, drug-free methods, and we will show you a range. [pg. viii-ix]

The book is notable for linking IgG food intolerance (or ‘allergies’) and ‘leaky gut syndrome’: there is no support for such a link in the clinical literature.

It wasn’t until the 1980s that published research began to demonstrate that a fundamental mechanism behind IgG food allergy was the penetration of large molecules of incompletely digested food through a leaky intestinal lining into the blood stream… [pg. 86]

Allergies and leaky gut syndrome is one of those chicken-or-egg situations. There’s good reason to suppose that having a more permeable digestive tract is what precipitates food allergies in the first place, while having a food allergy encourages a leaky gut by inflaming the digestive tract wall. While you can test for increased intestinal permeability, it’s highly likely that you have a degree of increased permeability, especially if you have multiple food allergies or digestive symptoms. [pp. 139-40]

The authors inform the reader that it may take the following tests to identify allergies:

tests exist to identify deficiencies in digestive enzymes, leaky gut syndrome, and the balance of bacteria and yeast in the gut. They can be arranged through nutritionists… [pg. 112]

[To identify your allergies you may need] an IgG food allergy test, a coeliac screening test and possibly an IgE food allergy test. [pg. 126]

The authors advise the extensive use of supplements to heal the gut: they caution that the supplements are necessary to reduce allergic potential and that the benefits of an elimination diet may not be possible if the gut is not ‘healed’ first. There is no clinical support for the gut-healing programme that the authors recommend for these ‘allergies’.

The authors attribute too much significance to the slight findings of the scant research that has been conducted for IgG-led elimination diets and IBS: this research has been discussed elsewhere and does not support the authors’ claims for it (cf, Dr Scadding’s comments above). I

More recently, Holford is impressed by the evidence value of an audit of a customer survey for YorkTest. This is particularly poignant in the light of the testimony of one of the authors, Hart, who admitted that IgG levels do not prove that an intolerance/allergy exists (see above). Hardman and Hart acknowledge the equivocal status of IgG as a marker for food intolerance in the introduction to the paper that gives an account of the customer survey:

the exact role of IgG antibodies as markers of food intolerance in general is not clear. IgG antibodies to food antigens are often present in healthy individuals and are generally considered to be part of the normal immune response to food allergens [refs].

The Hardman and Hart audit does not provide support for the value of IgG tests as a diagnosis of food intolerance: Quote Mining and Misrepresentation: Poor Ways to Claim Clinical Validation or Sound Science; More Allergy and Intolerance Testing Nonsense: Part 1; Food Allergy and Intolerance Tests: YorkTest Gives Evidence to the House of Lords . It is rather unfortunate that even though Hardman and Hart understand this about their paper, Patrick Holford does not.


The expert consensus is that there is no clinical or scientific support for the use of IgG blood tests in the diagnosis of food intolerance.

It is inappropriate that people are led to believe that there are clinically validated blood tests available to diagnose such conditions as food intolerance.

The public understanding of the issues of allergy and allergic disease is confused when issues of intolerance, sensitivity and allergy are discussed as if they are equivalent.

53 responses to “Myth: You Can Diagnose Food Intolerance or Allergy with an IgG Blood Test

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  9. Siobhan

    I think the absolute damning of the York blood tests is pretty silly, to be honest, and I speak from experience. I became ill around April 07, initially with what I thought was a rather long-lived bout of hayfever. The symptoms became gradually worse(constantly blocked nose, sinus pains so bad you want to smash your own skull in with a mallet, brain fog/inability to think straight, endless exhauting sneezes etc etc – and my quality of life diminished daily. Various visits to my GP produced reactions ranging from utter disinterest, to running various blood tests, without any helpful results. At Harley Street, a top allergy consultant explained that my IgE test showed only a reaction to grass, and I was assured I had no issue with any of the major food groups. So I was still none the wiser, getting more ill and exhausted, and literally losing the will to live. Unable to think clearly, breathe clearly, with constant pain in my head, I was in a bad way. On yet another visit to my local doctor’s surgery, I saw one of the partners, who was at least interested, but having researched everything he could think of, concluded “I can see you’re ill, but we don’t know why. We’ve done all we can – I’m sorry, but we can’t help you”. THIS, ladies and gents, is the point where your average ill person has no alternative but to look at…an alternative. I asked him about food testing, and he said that the science was not considered sound enough for him to recommend it professionally, but he was aware that some people found it helpful, that was all he could say. I researched further, including Patrick Holford’s book about Hidden Allergies. I remained undecided until one day, where circumstances resulted in only one food being eaten, followed by an acute bought of illness, that I felt food must be playing a part. I sent off for the York test, received a clear report showing intolerance to 2 major food groups, as well as the one single foodstuff that I had eaten on the day that had inspired me to get the test done. Regarding the report as interesting rather than proven fact, I felt I should at least eliminate the listed foods from my diet, to see if there was any improvement to what was by now a miserable, struggling existence. I remember clearly the way in which I woke up, the forth day after changing my diet. The way people wake in up in films, where they’ve been transported to a different place during their sleep, and upon awaking their surroundings are so very different that it takes them a couple of minutes to work out if they’re dreaming, or what is happening. I did the same thing, my eyes looking curiously around my bedroom – then BAM, it hit me joyfully as I told my partner – “I remember THIS! This is what NORMAL people feel like when they wake up!” The tranformation was amazing- I was not 100% myself, but VERY much better. After FOUR DAYS. I continued to improve rapidly, there is simply no comparison now to what my life was a year ago. Without the reference point of Halford’s book, or the results of the York test itself, I wouldn’t like to think how ill I would be now. I TRIED the “science” of our “trusted, proven” health system – on multiple occasions, and it let me down utterly. That is a proven fact. I don’t understand why, when clearly our medical system is so very far from being conclusive or reliable, there is a compulsion to shoot people down in flames when they may have something positive to offer, as clearly Holford does. It may be that some of your criticisms are valid – this is an extensive site & I’d have a lot more reading to do – but I didn’t have to buy any expensive herbal supplements from him, I simply read what he had to say about a subject my own doctor(s) were clearly ignorant of / disinterested in, acted on the results of a York blood test and benefited from an incredible health turnaround in a matter of days after months and months of misery. So go figure. That’s fact. It happened, it’s real. So what’s the problem? PS – thanks Patrick! ;-)

    Admin edit: good to know your health turned around. At some length you have given an anecdote of your personal experience rather than address the science except in the throwaway, “it may be that some of your criticisms are valid”. Please get back to us when you have some science that supports the role of IgG blood tests in the diagnosis of food intolerance or any justification for the too frequent conflation of food allergies and intolerance.
    As far as I can tell, you seem to think it is OK for Holford to offer advice that is allegedly science-based although it demonstrably isn’t as long as it works for you. However, if some medical science doesn’t work for you as an individual, then it is to be roundly condemned.

  10. Tracey Randell

    I am a nutritionist and I have used York allergy tests in my practice. Without question they have proved to benenficial in alleviating IBS symptoms and most notably an extreme case of Hives, whereby an Ig G intolerance to eggs was the culprit. The patient avoided eggs entirely for 6 months and has remained hive free to this day despite re-introducing eggs in to his diet. IgG allergies are a reality.

    Admin edit: you do understand that your personal anecdote here is no substitute for scientific evidence? Or, is there a certain sort of nutritionist, to whom this is really not obvious?

    Why not address some of the research on IgG and foodstuffs and explain why you consider it to be wrong and why you prefer your own comparatively limited experience to the science?

  11. Tracey Randell

    I take your point I do not have a placebo controlled randomised double blinded trial to hand, but I do have clinical experience of food intolerance where I have found IgG tests to have been accurate. I will happily review the research as I am not the ‘certain sort of nutritionist’ to which you refer but at the same time I cannot ignore the evidence of my own eyes and experience.

  12. In that case, we certainly look forward to reading your review of the clinical evidence. We certainly have links to the papers on this blog.

    By the by, it isn’t only double-blind, placebo-controlled RCTs, basic bench research is acceptable – it can be useful to look at, say, a physiology or immunology study that proposes a basic mechanism of action on the basis of outcomes.

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  14. Harissa

    I know people who took this test. They were better for a few weeks and then the symptoms came back. So it made them eat even more restricted way. Still no better. Waste of money and that can never be empowering.

    Admin edit: it is always disappointing when that happens because these tests are so expensive. Sometimes people’s response to advice that tells them to restrict their diet is to restrict it in a way that isn’t helpful over the long-term because there doesn’t seem to be a natural, commonsense point at which people accept that this isn’t working.

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  16. Tim

    I have no interest in Holford – actually I didn’t even know who he is before seeing this website. However, I note the very aggressive tone of the admin towards people who have found specific igg testing useful. In particular you ask for science rather than anecdotal evidence. So I provide here 3 recent and independent studies (independent of Holford for whatever that is worth) demonstrating how avoiding foods testing positive in specific iGg tests is helpful for people with IBS. Actually there are many more but I don’t want to fill up your page with all of them. Please look particularly at the conclusion which DO support the use of this test for improved quality of life.

    Seems that the admin is more interested in attacking this person than the real science issues.

    Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial.Atkinson W, Sheldon TA, Shaath N, Whorwell PJ.
    Department of Medicine, University Hospital of South Manchester, Manchester M20 2LR, UK.

    Gut. 2004 Oct;53(10):1459-64 [Admin edit: do not include an entire abstract, it is copyright issue.].

    Treating irritable bowel syndrome with a food elimination diet followed by food challenge and probiotics.Drisko J, Bischoff B, Hall M, McCallum R.
    University of Kansas Medical Center, Kansas City, KS 66160, USA.

    J Am Coll Nutr. 2006 Dec;25(6):514-22

    [Admin edit: do not include an entire abstract, it is copyright issue.].

    Admin edit: How very odd that you have not noticed that the 1st paper is discussed at length, including the important follow-up correspondence in various of the links.

    Yes, we are aware of the 2nd paper. It seems that we are considerably more au fait with the literature than either you or Holford.

    As for the references – if you want to learn more about what makes a good quality study and what doesn’t then s Evans, Thornton and Chalmers’ Testing Treatments is a free download. You will pick up advice on how to conduct an appropriate literature overview rather than cherry-picking topics you believe to support you if you look through the website of the Cochrane Collaboration.

    We would invite you to sustain your account of why you believe Holford to be correct in the face of the opinion of immunologists or appropriately qualified clinical allergists but it seems that you have no argument other than ad hom. If you do have a better argument that Holford is corrected and it can be grounded in an overview of clincial work that is in a reputable, peer-reviewed journal than please, pose it.

  17. Chemagne

    I have to disagree highly with this article. I have the impression after reading it, that it is a very narrow view of IGG allergy testing.

    From personal experience – (unlike testing in a lab) my two year old daughter took the test (called ELISA) under the guidance of an experienced Naturapathic doctor we realized she had a strong reaction to all gluten containing grains. After eliminating these her eczema has virtually disapeared. She is also a happier child. We hope that the discovery of her IGG allergies will help her to heal and eventually overcome her more serious IGE allergies to nuts and eggs in the long run. It seems the article uses one doctor (and attacks him personally)as an example of someone who endorses IGG testing against the “mainstream” medical doctors and allergists who are not up to date and open to the latest testing methods. The article also does not explore how there are some IGG tests that are more reliable than others. After reading many good things about the ELISA IGG blood test available here in North America and having it reccomended to us by our doctor, we have only positive things to say about our experience with it.

    I am concerned why the author is so bent on attacking anyone who opposes any support of IGG testing. It seems to me that you can learn from these positive personal and professional experiences rather than dismissing them because they don’t fit the “scientific lab results” mold. I am not a doctor and cannot commission a study, but I am so happy my daughter is finally better.

    • We are pleased that you daughter has improved as that is good not only for her but for your family as a whole.

      However, you do not seem to have fully comprehended the article and have certainly not followed up the links or additional material so this may have influenced your understanding and response. FYI, Patrick Holford is neither a doctor nor a qualified nutritionist – he does not have any accredited health qualifications.

      The article does explain IgG within bounds – it would be unhelpful to discuss say IgM or IgG levels in respond to viruses in a piece that addresses food allergy or intolerance.

      There are no certified, accredited, recognised IgG tests for food intolerance in the UK – not even the labs that claims to be testing for the same items achieve anything like the same results. There are no standardised test substances (as we have explained) – so there is no reproducible test result which diminishes any plausible usefulness of this as a biomarker. I believe that there are the same tests in the US?

      We would disagree that:

      the author is so bent on attacking anyone who opposes any support of IGG testing. It seems to me that you can learn from these positive personal and professional experiences rather than dismissing them because they don’t fit the “scientific lab results” mold.

      If you choose to spend your money on those tests then that is fine. However, that is no reason to pay for unevidenced tests that lack any clinical support from central funds or standard health insurance.

      There are appropriate concerns about the usefulness of blood tests even for food allergy (IgE) if they are interpreted by someone who is not appropriately qualified or experienced.

      A couple of papers that you might like to consider that address the issue that high levels of IgG4 may well be protective of children and help them maintain an oral tolerance to appropriate amounts and slow the development of a full-fledged IgE allergy and that even +ve IgE tests do not necessarily indicate a clinically relevant allergy.

      High levels of IgG4 antibodies to foods during infancy are associated with tolerance to corresponding foods later in life.

      Peanut epitopes for IgE and IgG4 in peanut-sensitized children in relation to severity of peanut allergy. You will see that children may have high levels of epitopes but it is not related to the severity of their reaction in this case.

      The next is an abstract so it is subject to confirmation but there are leaving aside tree nut allergies and similar, for children the gold-standard double-blind oral challenge does not confirm blood tests that are interpreted as indicative of an IgE allergy.

      Common blood tests for food-specific serum immunoglobulins are often wrong about allergies and aren’t a good basis for restricting youngsters’ diets, researchers said here.

      Results of supervised oral food challenges in 125 children failed to support most diagnoses of food allergies made on the basis of serum IgE testing.

      • Susan Ursuliak

        OK, epitopes aren’t in the patients’ blood. They are structural moieties on the allergen that are bound by the patients’ antibodies. The peanut antibody study you referenced is actually just saying that diversity of antibody production is not correlated with severity of allergic reaction; however, kids who have a known allergy to peanuts do make a wider range of antibodies to peanut epitopes than do atopic kids who aren’t allergic to peanuts.
        Also, where I’m from (British Columbia, Canada) the medical community generally distinguishes food intolerance from food allergy. Lactose intolerance is not an allergic reaction, while developing anaphylaxis after eating a bowl of strawberries certainly is. I have not noticed a big push here for IgG blood tests, though IgE tests are still available.

  18. Tim

    I supplied 3 peer-reviewed articles in the last few years in respected journals that demonstrate some positive use for igg tests in helping people with IBS.

    These were not “cherry-picked” as you claim but rather just the first three I found in *the* standard resource for biomedical research pubmed used universally by biomedical researchers worldwide. These were the latest papers I found relating to igg and ibs and none of them found igg to not be helpful in some way. Moreover, I found no papers reporting negative utility for igg in diagnosing and treating ibs in the same period. Notice my lack of subjective statements – just what I found.

    A cursory search of pubmed shows many more also in support – so it is up to you to discredit them all and you offer no scientific critique.

    My argument is clear: 3 independent peer-review studies in international science journals showing positive use of igg in ibs diagnosis and treatment
    and no negative studies in the same period across the entire biomedical literature.

    • And you were provided with corrections and guidance that you have chosen not to accept. This is a post about IgG tests for food allergy and intolerance – not for IBS – if you want to look at what we have said about IBS and IgG, then search the blog.

      However, given that you are now somewhat shifting to specify that you meant IBS rather than the general area of food intolerance we would, again, recommend that you read the follow-up by Hunter and the authors’ response to that (follow the links where it is discussed at some length). Note that in the 2004 paper, and the follow-up correspondence that it spawned, the authors agree that that there may be a role for IgG in very limited, circumscribed conditions.
      Hunter made out a good case that the study was premature because there is no answer to the basic research question: “do high levels of IgG against a food predict an adverse reaction to that food?”. Three of the four authors of the original paper replied to Hunter and elaborated their view on how their findings should be interpreted.

      [I]t is entirely possible that IgG antibodies may be important in IBS, where we now know that there is an inflammatory component in some cases, whereas they may not be relevant in food intolerance in general. Furthermore, it is likely that only a subset of patients are likely to have an immuno-inflammatory basis to their condition and these might be the very individuals who respond to dietary exlusion based on IgG antibodies. This would fit with our results where only a proportion of patients responded despite all having antibodies. This, of course, limits the specificity and usefulness of the test unless such subgroups can be identified beforehand. We should also bear in mind that an immunological reaction in the gut, as opposed to other forms of food intolerance, may make the gut more susceptible to other perturbing stimuli, such as stress, rather than necessarily causing symptoms directly.

      You may be interested in a recent newspaper item by Prof. Peter Whorwell (one of the authors of the 2004 Gut paper you reference). Prof Whorwell recommends several useful interventions that might be attempted by people with IBS – not one of them is the IgG test for the diagnosis of food intolerance.

      Again, we recommend Testing Treatments in order to understand what constitutes an acceptable paper and what doesn’t. It may also demonstrate that it is unwise to rely upon papers that make a case for something on the basis of a test that has no evidence to support its role in the diagnosis of food intolerance. It may also (along with Ben Goldacre’s Bad Science) illuminate why an small-scale open-label study such as the Drisko et al may be interesting but not carry much evidential weight).

      It might be helpful if you set yourself an exercise of searching PubMed to find a paper that demonstrates that the results from IgG diagnosis of food intolerance can be replicated from one lab to another. As some guidance, you might find it useful to look at the outcome from tests that were run by a consumer programme and for which the results were assessed by various well-respected experts.

      Another hint – don’t assume that you can search PubMed in a cursory manner – the results can be misleading, or more accurately, can be misinterpreted by those who don’t understand them.

    • As a matter of interest – why have you chosen to ignore Hunter and the follow-up correspondence to the 2004 Gut paper? Not only the Hunter but also the Mawdsley et al:

      we wonder whether their conclusion that assay of IgG antibodies may have a role in identifying candidate foods for elimination to treat patients with IBS may be a step too far…

      It is not clear whether the difference in improvement in symptoms seen in the current study between true and sham groups can be explained simply by the omission of these foods. This could in practice eliminate the need for antibody testing.

      What do you find so relevant about Drisko et al.’s open-label study with 20 participants that was drawn from a tertiary-level clinic for people with IBS for a discussion of IgG diagnosis of food intolerance in general?

      Sticking to the topic of this page rather than your de-rail about IBS, where is your evidence that IgG diagnosis of food intolerance out-performs food diaries, elimination and challenge?

  19. UK dietitian

    Hi Tim
    Your Whorwell reference in Gut is a valid reference about IgG testing for food exclusion in IBS, but if you had access to the comments regarding this article, or had any background dietetic training, you would realise that the study was severely flawed by having an ‘active’ placebo. Telling IBS sufferers on the ‘sham’ diet to take more lactose, fermentable fibres, caffeine and fat is to actually increase the risk of symptoms in the so-called ‘control’ group, thus creating a greater ‘difference’ between symptoms in the IgG vs the ‘sham’ diet. Rather like standing next to your ugly best friend to make yourself look more attractive.
    Whorwell is a gastroenterologist and like Kumar, a surgeon who did an equally appalling study on IBD (a different set of conditions) and IgG testing, neither have much practical knowledge of dietary symptoms and IBS. Thats why their studies ‘worked’ for the very short time followed up. Pity the volunteer patients left in the nutritional wilderness with nutritionally inadequate diets, long after the ‘trial’ finished.

    and Chemagne
    no doubt your daughter has improved, but she is young, and still growing, and you really should get a conventional assessment of TTG antibodies and other recognised allergy tests to make sure she is not a coeliac. Merely avoiding wheat may improve symptoms but not the underlying damage, and excluding wheat, rye, oats and barley makes for a very limited diet. Formal diagnosis will allow you expensive gluten free items free on prescription. False diagnosis means a lifetime of unnecessary food restriction and nutritional compromise. Please follow this up with a conventional approach. No reason for alt and conventional not to be considered in parallel. If your naturopath considers otherwise he does not have you or your childs best interest at heart…….

  20. Pingback: Allergy UK Wants YorkTest IgG Food Intolerance Tests Available on NHS « Holford Watch: Patrick Holford, nutritionism and bad science

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