Listen again while you can: BBC Radio 4′s You and Yours on Which?‘s Investigation into Food Intolerance Testing with participation from Dr Mike Walker of Cambridge Nutritional Sciences Ltd.
One note that should be of particular interest to Patrick Holford, given his claims for IgG testing in the diagnosis of food intolerance, is a significant change in stance by the companies who promote, distribute and carry out such tests. We shall write more about this at a later date but Walker was at pains to stress that the Cambridge Nutritional Sciences’ IgG test is indicative of food intolerance but not diagnostic of food intolerance. The tap-dancing on this point was painful and brought a similar episode to mind involving Patrick Holford and his qualifications.
The interviewer challenged Walker about what scientific evidence is available to support the use of IgG tests for food intolerance. Walker mentioned the papers with which regular readers are already familiar (listed here: IBS, migraine) to which the interviewer responded, “So, you’re saying that your test can detect those conditions?”. Walker then said:
No. I think we need to be very clear here. We’re not diagnosing intolerance. What our test does is measures the presence of a particular sort of antibody which is called IgG antibody. This is in contrast to the IgE antibody which is associated with allergies and we’re showing that these antibodies are present in the blood.
What the patient can then do is select the foods that are giving a strong response – they select those foods first to eliminate from their diet.
Possibly this may read differently to other people, but it really did sound to us as if Walker were claiming that there is a validated connection between the measurement of IgG antibodies to foodstuffs and food intolerance with a correlation between the IgG levels and the severity of symptoms. Yet, somehow, this is not intended as diagnostic for food intolerance.
YorkTest also has some interesting flip-flopping on this point: Zero Tolerance: Exploring the Burden of the UK’s Food Intolerance Problem (pdf). The brochure repeatedly refers to food intolerance and praises its IgG test for their self-evaluated supporting science and validation. However, they also state:
The presence of food-specific IgG antibodies in a FoodScan113 test indicates:
- that the person has had a reaction to that particular food
- that the person may benefit by eliminating that food from their diet
The test is not diagnostic of any condition; rather, it is a strategy for identifying foods to which the subject may be sensitive. [Emphasis added; pg. 8]
However, this does not prevent them from calling upon the Dept. of Health to take a “proactive approach” in:
• Providing training to GPs that will help doctors recognise food intolerance and direct sufferers to testing and treatment that works.
• Making food intolerance screening available as a part of patients’ check-up procedures where appropriate
So, help us out here. It seems as if both YorkTest and Cambridge Nutritional Sciences are denying that their respective IgG food intolerance tests are, you know, diagnostic of food intolerance. If somebody knows what else tests that measure IgG antibodies against samples of foodstuffs should be used for then we are agog with curiosity. In the interim, shouldn’t someone from YorkTest be sending Allergy UK and Patrick Holford a memo?
Related Reading
YorkTest, Hardman & Hart: there’s a difference between the BMJ and Nutrition and Food Science.
Which?, YorkTest and Cambridge Nutritional Sciences Ltd.
Update on Which?, YorkTest and Selective Quoting in Google Sponsored Links.
Pingback: Update on Which?, YorkTest and Selective Quoting in Google Sponsored Links « Holford Watch: Patrick Holford, nutritionism and bad science
Pingback: Which?, YorkTest and Cambridge Nutritional Sciences Ltd « Holford Watch: Patrick Holford, nutritionism and bad science
Pingback: YorkTest, Hardman & Hart: there’s a difference between the BMJ and Nutrition and Food Science « Holford Watch: Patrick Holford, nutritionism and bad science
Hmm, that’s not the only thing that’s wrong with the IgG tests. They also tend to have a significant percentage of misses, because they test only a limited ammount of allergens.
I took two IgG tests, because I would sometimes respond rather extremely to certain foods, and rather then risk hospitalization (again) by randomly trying what it was, my parents took me for a foodtests. It found nothing.
Some time later, I got sick again (swollen throat, difficulty breathing, horrible nausia etc), so another test. Again, no result. I was officially not allergic to any food. Until I got sick again.
Now, I was getting a little paranoid, but I was starting to see a pattern, after all, there are only so many ingredients in the food that aren’t in normal, everyday consumption. After some carefull DIY testing, it turned out I was allergic to Rhubarb. Yes, really.
Apearently, both tests didn’t check for rhubarb, because “Most european people aren’t allergic to rhubarb”…. Isn’t that what the test is for? to determine unlikely allergies?
So, if you’re unfortunate enough to have an allergy that affect less then 1 in 200.000 people, odds are that a normal foodtest won’t even look for it.
Sanity, now that you’ve mentioned it, I’ve never seen an IgG panel include the Polygonaceae family. Probably because reactions to rhubarb are thought to be so unusual which is a pest for people like you. Do you have a similar problem with buckwheat (with it being from the same family)?
I’ve never tried it, but it is on my list of things to avoid. I might be allergic to it, but there are several substances in rhubard that aren’t in buckwheat, and it’s a completely different part of the plant.
So, I might be, but all things considering, I don’t plan on finding out any time soon.
The rest of the Polygonaceae family isn’t (as far as I know) edible, so that’s not much of a worry.
I consider myself rather lucky to be allergic to rather obscure foodtypes, you’d be hard pressed to find any store that sells either buckwheat or rhubarb anywhere near where I live. If my parents didn’t grow it in their garden, I would probably never have found out.
Without wishing to denigrate Sanity’s obvious problem it is important not to conflate or confuse intolerance with allergy. Sanity obviously has an allergy to rhubarb not anything like an intolerance.
I am not up on the IgG story, I self diagnosed as gluten intolerant (mild) 15 years ago using good old fashioned exclusion diets. My money was on dairy and I was surprised at the gluten results but a repeat made the issue incontrovertible.
Fortunately I can eat pasta or something like pizza once a week and I have some good bread machine recipes for extremely palatable GF bread. There are some who are keen to tell me I am allergic and the supermarket shelves heave with expensive products to allow me to wallow and pander if I was so inclined. Some people want such things as they then give them an identity and it is this which makes me sceptical of much of the modern fad to be intolerant to something. We used to call such people fussy eaters, now we have to be sensitive to their suffering. Bah Humbug!
“…Some time later, I got sick again (swollen throat, difficulty breathing, horrible nausia etc), so another test. Again, no result. I was officially not allergic to any food. Until I got sick again…”
IANAD but these symptoms sound like anaphylaxis so, like Musclguy, I did wonder about why IgG food tests were used. If Sanity was hospitalized after these symptoms (it’s not entirely clear to me) I should hope that some kind of referral was made rather than leaving him/her to self-diagnose.
Sorry to make this request, but does anyone know how I might be able to listen to the You and Yours program now that it seems to have been taken down?
Admin edit: we’ll ask about but after the audio file is gone it seems like there is a delay of up to 4 weeks and then they post the transcript – not the same but better than nothing.