Day 254 - 22 May 96 - Page 58


     
     1        when we were in the cororectal section, but on page 18 in
     2        the second column under "Major Risk Factors" the third
     3        paragraph says:
     4
     5        "The major risk factor in colorectal carcinogenesis that
     6        has excited most interest is diet.  Higginson 1968 use the
     7        lowest incidence found in any population as representing
     8        that due to unavoidable factors estimated, that more than
     9        90 per cent of colorectal cancers could potentially be
    10        prevented principally by the choice of the right diet."
    11
    12        Are you aware of that study?
    13        A.  I am not particularly aware of that individual study
    14        but it is certainly the sort of argument which was being
    15        put forward around that time, as I have already said to
    16        you.
    17
    18        These sorts of studies followed very closely on the result
    19        of the analysis of smoking and lung cancer in British
    20        doctors and these were the sorts of statements which were
    21        made.  Richard Doll, who is well known, made similar ones,
    22        that 80 to 90 per cent of cancers could be prevented
    23        possibly by modification of one's diet, and that was the
    24        position at that time.
    25
    26        What I am saying is that that hypothesis, having been
    27        proposed, needed further investigation which has taken
    28        place over the last 30 years, nearly.  What has become
    29        clear with the scientific studies, as we have available to
    30        us, is that the position regarding this is much less clear.
    31
    32   Q.   In terms of different dietary components?
    33        A.  Yes, you know, exactly what the relationship between
    34        diet and the development of cancer is.
    35
    36   Q.   Potentially it is still the case that more than 90 per cent
    37        of colorectal cancers could be prevented by using the right
    38        diet?
    39        A.  No, I think that is probably not true today.  I think
    40        we are less sure about that statement today than we were in
    41        1965/68 and, as I said earlier, there is a growing feeling
    42        that genetic aspects may be more important and what the
    43        inter-relationship between diet and other aspects of life
    44        and the genetics is, I think people are unsure and are
    45        beginning to question very much today.  I do remember that
    46        a lot of the genetic studies which are possible today were
    47        not possible in 1968.
    48
    49   MR. MORRIS:  If you look on page 19, there is a chart dated 1991
    50        and at the top of the page there seems to be some kind of 
    51        review of case control studies of diet and colorectal 
    52        cancer; yes? 
    53        A.  Yes.
    54
    55   Q.   The total is in a column of different studies on different
    56        components of a diet, yes, and the causal relationship
    57        seems to apply to fat and meat especially with some showing
    58        no effect but none showing any protective effect, and the
    59        protective relationship of the dietary components seem to
    60        apply to dietary fibre and vegetables with some showing no

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