JDC reports that he “always thought that Dr John Briffa was like a more grown-up version of Patrick Holford” – and until recently I had rather agreed with him. However, Briffa has now taken up some worrying positions on vaccines and autism. Along with Dr Crippen, “I am worried about Dr John Briffa.”
I have just come across some of Briffa’s claims about food sensitivity testing – they are almost Holfordesque. Writing in the Guardian about Irritable Bowel syndrome, Briffa argues that:
Those with IBS can…benefit from identification of problem foods. Several methods of testing exist, such as kinesiology (muscle testing) and dowsing. I believe all such methods have some validity, though those who are more comfortable taking a more ‘scientific’ approach may have their blood tested for IgG antibodies to specific foods. One study published last year in the journal Gut found that elimination of foods identified by this form of testing was beneficial for IBS sufferers.
Now, Patrick Holford has written positively about health dowsing and Applied Kinesiology (AK), but this was quite a while ago. Briffa’s Guardian article was from 2005. As we’re going to find out below, Briffa gets things badly wrong on food sensitivity testing and on recommendations for dealing with (potential) sensitivities.
John Garrow has shown that AK is not an effective way to diagnose allergy. AK testing thus lacks a plausible mechanism of action, and – in a blinded trial – has failed to do better than one would expect if the practitioners were guessing. Professor Chris Corrigan was thus moved to describe AK – in his testimony to the House of Lords Science and Technology Committee – as
all completely bizarre and, I am afraid, utter nonsense. There is no scientific evidence or mechanistic base to suggest that these tests could be remotely effective.
Putting it politely, this is not a valid way to diagnose food sensitivities.
Quite simply, there is no plausible mechanism through which dowsing might work as a test for food sensitivity, and we have no good evidence that it does work. I cannot see any reason why a competent professional would recommend dowsing for anything other than entertainment.
When recommending IgG testing as a more ‘scientific’ approach to diagnosing food sensitivities, Briffa does point to an article in Gut. Unfortunately, its results indicate that an IgG-guided elimination diet is less effective than a ‘conventional’ elimination diet when you interpret the results using a straightforward Numbers Need to Treat analysis. This is not an effective way to diagnose allergy, intolerance or sensitivity. The House of Lords Science and Technology Committee’s 2007 Report on allergy [PDF, 8.40] have therefore cautioned against the recommendation of IgG testing:
We urge general practitioners, pharmacists and charities not to endorse the use of these products until conclusive proof of their efficacy has been established.
Unfortunate clinical recommendations
This dubious account of food sensitivity testing leads Briffa to make some unfortunate recommendations. Firstly, inaccurate food sensitivity testing can be harmful: both leading patients to avoid foods which they are quite able to eat (false positives) and failing to diagnose genuine allergies and intolerances (false negatives). Secondly, Briffa then suggests a rather haphazard approach to an elimination diet:
there is usually no reason why individuals should not make changes to their diet without testing. I advise trying a diet devoid of wheat (pasta, bread, biscuits, pastries, breakfast cereals) and cows’ milk (another common offender) for a week or two. Better tolerated grains include rice and oats (oat-based muesli, porridge, oatcakes), and rice and oat milks are good swaps for dairy milk, too.
While an elimination diet can be a useful way of diagnosing allergies and intolerances, one would be advised to take a more systematic approach (preferably under medical and/or dietetic supervision). As argued in Allergy: The Unmet Need [PDF, p 53) appropriate advice and supervision is important when a patient is cutting out certain food groups. It is also not entirely clear how Briffa has selected which foods are to be eliminated: for example, while lactose intolerance is relatively common, some milk products (such as some cheeses) contain negligible quantities of lactose.
We should also emphasise that cutting out whole foodgroups from your diet can be harmful, if you fail to adequately substitute alternatives. While eliminating these for 1-2 weeks – as Briffa suggests – is pretty safe in most circumstances, we would have more concerns in the longer term. It is unclear whether Briffa anticipates any kind of challenge protocol being used – for patients to test whether a food which they have eliminated causes problems when reintroduced – or simply expects IBS-sufferers to continue with the exclusion of wheat and cows milk if this exclusion coincides with an improvement in symptoms.
Both milk and wheat are significant sources of calories for many children and adults in the UK. Milk is a significant source of calcium, and some wheat-based products (such as certain fortified breakfast cereals) are a significant source of fibre for many people. Also, fortified wheat-based breakfast cereals and breads can be a useful source of a number of vitamins and minerals. One should therefore not exclude these food groups from the diet without finding suitable alternatives. There are particular concerns with children: Allergy observes [PDF, p11] that “it is harmful to put a child on an extensive exclusion diet that has no scientific basis, because of the risk of nutritional compromise and poor growth.”
This is all rather worrying. Briffa manages to recommend three inappropriate approaches to testing for food sensitivity, and then suggest an haphazard approach to an elimination diet. His clinical recommendations are also unfortunate – failing to take into account the potential harm caused by eliminating whole food groups if this course of action is continued for some time and without appropriate advice and supervision.
As Dr Crippen might put it, this is wibble – damaging wibble.