And please let Shinga hear some decent testimony before she explodes.
Dr. Glenis Scadding is a consultant allergist with an fine reputation. She has clearly and elegantly stated that IgG tests for the diagnosis of food intolerance are "a waste of money"
. She has criticised the availability of direct-to-consumer IgE tests because they lead to "mis-diagnosis and mis-allergen avoidance".
However, at the same hearing where Dr. Scadding spoke, and earlier in the session, Dr. Hart, a representative of YorkTest
, gave evidence at a meeting of the House of Lords, Science and Technology SubCommittee hearings that are investigating allergy and allergic disease in the UK
In summary, Dr. Hart acknowledged that IgG levels are not necessarily related to either food intolerance or chronic conditions. She also explained that the testing criteria for food intolerance are not as standardised or as high quality as other clinical testing. One might question why it is worthwhile for consumers to spend money on a test that is not agreed to diagnose food intolerance and does not attain the same standard as other clinical tests.
The antibody, the presence of antibodies, and this, I believe is true for IgG and IgE, doesn't necessarily mean disease or no disease.
Unfortunately, in our business, it's not like measuring thyroid function tests, where you've got a beautiful, international reference preparation, all laboratories are controlled, we know exactly what we are measuring, we know the normal ranges. We haven't got the luxury of our higher order standards, the international reference preparations ...so that we, in putting a food down onto the plate, and we have got a wide range of fruits, vegetables and the key foods on the plate. That's what we use.
It can be difficult to understand oral evidence at specialist hearings. However, when the questions are simple it is irritating that an expert's evidence should be so muddled and difficult to follow. I shall comment on Dr. Hart's testimony in follow-up posts. For now, I thought that it might be helpful to post some more of the oral evidence in the House of Lords' investigation in allergy and allergic diseases.
This recording of the SubCommittee meeting on 15 March 2007
is available from the archive for 28 days: thereafter, an authorised transcript will be available. I have used CM to indicate that the speaker is a member of the House of Lords' SubCommittee. Any punctuation, emphases or mistakes in the transcript are mine.
Dr. Gill Hart is the Technical Director of YorkTest Laboratories. Mr. Dillon is the representative for NICE, the National Institute for Clinical Evidence.
: Can you explain to me, as a lay person, how the IgG food allergy tests work given that people who are not allergic to specific foods can still produce an IgG antibody response when they eat those foods?Dr. Hart
: Yes, of course. I think when we consider the antibody response to an antigen challenge we need to really think that the antibody response is only the first part of the whole reaction. The antibody, the presence of antibodies, and this, I believe is true for IgG and IgE, doesn't necessarily mean disease or no disease.
What does make a difference is the complex cascade of events that occurs after that antibody has been raised. And what we find, that the IgG we use as a marker, that a reaction has occurred but that doesn't necessarily mean that the reaction has gone on to provide a cascade of results resulting in disease.
Now, we know that the mechanisms for this are unclear and as a company we have tried to support and collaborate with groups that find out more about these mechanisms. Indeed, we have provided tests to a leading London hospital who have now shown, and this evidence is going to be presented in Digestive Disease Week
in Washington in May, that in inflammatory bowel disease, there is a significantly higher IgG titres than in normal groups and it is the first time this has been shown.
In addition, we've also shown, or the group has also shown independently but using our test, that people's reported food sensitivities, i.e., filling in a questionnaire, saying, "What am I sensitive to?", actually correlates very, very well with the IgG levels and this is particularly in ulcerative colitis. Very preliminary research and it's something that we really hope the team, at this London hospital will build on. We have struggled, working with others, to get grants to do this sort of work. But we really want to encourage the understanding of these mechanisms which we know are not yet clear.CM
: Could I ask you how often you find negative results?Dr. Hart
: Yes, of course. We actually provide a food intolerance indicator test. Bear in mind that the people who come to YorkTest
have chronic conditions. They have...Our recent survey data, which we published, showed that over 70% of the people that come to YorkTest
have suffered for more than three years with their condition. So, it isn't a normal population that comes to YorkTest
. What we find is that between 75 and 80% of those people will have at least one positive scoring to one of our 113 foods.CM
: Perhaps I could ask the other members of the panel...I understand that the IgE antibody tests are an established part of NHS diagnostic routines, is there any evidence to support the use of IgG antibody food tests.
[Silence and confusion.]CM
: Mr Dillon?Mr Dillon
: I'm sorry. I've no information to enable me to answer the question. NICE hasn't looked at that particularly.
: For me, to support the use of IgG tests? Yes, there have been independent clinical trials that have been carried out and published in, this one key one, which is a double-blind placebo controlled trial published in Gut
in 2004 by Atkinson which was actually an independent study but used the YorkTest
test. There has been a study, recently published, in Nutrition and Food Science
. Another in Headache Care
And indeed the recent study that has been carried out using the YorkTest
test commissioned by Allergy UK
and independently audited by the University of York
, used with 5286 of our consumers has shown that people who rigorously adhere to our diet, 3 out of 4 of those people are showing some benefit to their chronic conditions. The considerable amount of data...and we know ourselves as a company that we don't do a lot of aggressive advertising, we can't do that, and the company's grown rapidly, mainly on word-of-mouth, because people are
showing benefit and we see every day that people, there is, as we know, an unmet need and people are suffering and are then seeing benefit by using our service. CM
: Can I just be clear? That with these tests, you're measuring the amount of the molecules of IgG, you're not measuring specific IgG or IgE, are you?Dr. Hart
: We're measuring food-specific IgG in our IgG tests. So we have, so when you talk about...CM
: Sorry, when you say food-specific...what foods? Are you looking at specific...?Dr. Hart
: We are. We have a range of different services but the main one is 113 different foods. You can imagine on a ..The test we use is an ELISA test methodology. So you can imagine that a purified food preparation put onto one of our ELISA plates, is actually a mixture of proteins. Of course, wholemilk would be a mix of different proteins. Unfortunately, in our business, it's not like measuring thyroid function tests, where you've got a beautiful, international reference preparation, all laboratories are controlled, we know exactly what we are measuring, we know the normal ranges. We haven't got the luxury of our higher order standards, the international reference preparations ...so that we, in putting a food down onto the plate, and we have got a wide range of fruits, vegetables and the key foods on the plate. That's what we use.CM
: I don't particularly want to concentrate on Dr. Hart all the time, I apologise to the others. You mention the report commissioned by Allergy UK
, we've got a copy of it here. I wonder if you can tell us, has it been published? Has it been shown in a professional journal yet?Dr. Hart
: It has. It was published at the beginning of February in the Journal of Nutrition and Food Science
: And you talk about chronic medical conditions but it's quite unspecific about these.Dr. Hart
: Yes, that's the interesting area really in terms of the type of people that come to YorkTest
with chronic conditions. As you can see from the paper, it clearly outlines the different sort of conditions that people do come with and I think, because I understand that in the medical community, people are used to looking at specific conditions, it's very difficult to sometimes understand the concept that one or two different factors, like removing food from the diet, could actually benefit a range of conditions.CM
: I think that a lot of conditions will get better with a better diet won't they?Dr. Hart
: That's true. CM
: That is a concern. Dr. Hart
: That's true. But what we do find is that specific combinations of foods do actually show more benefit than removing the typical foods that you might imagine would be responsive to allergy. It's those particular combinations that we can identify using our test. CM
: I'm sorry to keep asking you...Do you ever find that there is such a wide range of IgG reactions when you do your test that the person who sent the kit in is almost on a starvation diet?Dr. Hart
: We're very, very aware of this. As you're probably aware we do provide a nutritionist service with our...nutritional consultation with our...service. We do very unusually find, well not very unusually, we do find people with sometimes which have a high level of reactivity; say, greater than 10 differents foods in our test. We treat these with extreme caution and we always talk to that particular customer and talk through about how they may want to prioritise. We'd never advise removing lots of different foods from one's diet-and that's very irresponsible-but we would suggest that they prioritise and maybe take some of the ones with a particularly high titre out from the diet first and see whether that benefits.
In the end, this is an aid to management of diet. It's a little route-map rather than going through the laborious trials of elimination diet which-elimination diet and challenge which-maybe you're never going to find the exact combination of foods that people are intolerant to. This is an aid to management of diet and a route-map through for the consumer to help them.
End transcript.Related posts:
Food intolerance testing and migraine
Truthiness and referenciness make the case for IgG food intolerance tests
More allergy and intolerance testing nonsense: part 1
More allergy and intolerance testing nonsense: part 2
Quote Mining and Misrepresentation: Poor Ways to Claim Clinical Validation or Sound Science
What is the Significance of IgG Antibodies and Testing?
Why IgG Testing for Food Intolerance Is Not As Simple As ABC or Doh Ray Mi
Labels: allergies, allergy testing, Allergy UK, food allergies, food allergy, food intolerance, Hardman, Hart, House of Lords, IgE, IgG, junk science, Scadding, YorkTest