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

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