Day 038 - 19 Oct 94 - Page 24
1 that may or may not be so, at the end of the day I have to
2 judge the allegation which is made against the compound
3 itself.
4
5 MR. MORRIS: Just on that trade secret angle, the actual
6 processes that a manufacturer may wish to not reveal in
7 their submissions, could they have an impact on the safety
8 of an additive or are they largely irrelevant?
9 A. As I have tried to indicate, since I do not see the
10 information, I do not know. My starting assumption is they
11 are very unlikely to be relevant to safety.
12
13 MS. STEEL: Just to move on: Professor Walker suggested that
14 you make the mistake of treating ADI's, acceptable daily
15 intakes, as if they were a threshold of toxicity; is that a
16 fair criticism?
17 A. No, I do not think it is. As I tried to indicate
18 earlier in an answer I gave, I am less comfortable than
19 Professor Walker is to rely on the notion of a threshold.
20 If there is a threshold for particular compounds in
21 particular populations, my working assumption is that
22 threshold might be conceivably higher than the ADI or lower
23 than the ADI or should be characterised in other units and
24 other terms.
25
26 So, I do not treat it as a threshold of toxicity. However,
27 since these ADI's are published and articulated by these
28 key advisory committees, it seems to me they do provide a
29 benchmark against which it is reasonable for somebody, such
30 as myself, to seek to judge estimates of intake.
31
32 So I, for example, have been doing a great deal of work on
33 the consumption of artificial sweeteners. One of the ways
34 in which I record reported intakes is as a proportion of
35 the ADI for particular compounds, but I do not treat it as
36 a threshold of toxicity, no.
37
38 Q. Professor Walker also asserted that hypersensitive
39 reactions to food colours and other additives are
40 relatively rare and that the true incidence of intolerance
41 is probably significantly lower than is claimed. Is that
42 something you would agree with and if not why not?
43 A. No, I most certainly do not agree with that. I have
44 done some work on this matter. The way I proceeded was as
45 follows: I have attempted to gather all the documents
46 I can find in the published literature which purport to
47 provide estimates of the rate or the incidence of the
48 frequency of intolerance to additives, and I find many of
49 them very seriously flawed.
50
51 For example, some of the key studies have deliberately, in
52 choosing the test population, excluded -- in one case
53 everyone under the age of 16; in another case all people
54 already diagnosed as suffering from allergies, and so on.
55 Now, if you systematically exclude from your test
56 population, test sample, the groups most vulnerable, then
57 you are going to generate an underestimate.
58
59 Moreover, actually trying to estimate the frequency, the
60 genuine authentic frequency, of intolerance to food
