Day 035 - 12 Oct 94 - Page 40


     
     1   Q.   I am understanding what you are saying.
     2        A.  But if one reduces fat intake from, say, 35 per cent
     3        of calories down to 25 per cent of calories, and finds
     4        that that affects the rates of colon cancer but does not
     5        affect the rate of breast cancer, just to take an
     6        hypothetical example -- I am not suggesting that this is
     7        necessarily the case -- that does not mean that breast
     8        cancer is not also caused by excessive dietary fat.  It
     9        simply means that we are not yet at the level where that
    10        is meaningful.
    11
    12        This is precisely what we have seen with heart disease.
    13        There is no question that elevated fat intake increases
    14        the risk of heart disease.  However, if you reduce the fat
    15        in your diet and the cholesterol in your diet to a rather
    16        modest degree, the changes in heart disease, death rates,
    17        are virtually nil.  So, what I am suggesting is that
    18        responsiveness is quite different from cause and they are
    19        both important but they have to be distinguished.
    20
    21   Q.   I entirely follow that.  I think what you are saying is
    22        this (which is an inevitable failure of cohort or
    23        prospective studies within homogenous populations) that
    24        very often the interval of fat intake in the study is not
    25        wide enough, so you do not study people within your cohort
    26        who are consuming, let us say, 10 per cent of their energy
    27        intake as fat?
    28        A.  If the cohort is homogenous, you cannot work with that
    29        population.
    30
    31   Q.   Exactly.  That is a criticism, if it can be called that,
    32        which has been made of some of Dr. Willett's own results,
    33        is it not?
    34        A.  Correct.
    35
    36   Q.   Yes.  What we cannot infer from that, can we, Dr. Barnard,
    37        is that if you went down as far as 10 per cent as your
    38        lower limit any different result would be produced?
    39        A.  That is right.
    40
    41   Q.   It is right, is it not?  Can I ask you to look then over
    42        the other side of the page:  "Risk factors for breast
    43        cancer" -- this is page 389 of the magazine -- "Risk
    44        factors for breast cancer.  As early as 1700, Ramazzini
    45        observed that child-bearing reduces the risk of breast
    46        cancer".
    47
    48        May I pause there, in your book, Dr. Barnard, you do not
    49        mention parity as one of the factors which are influential
    50        in reducing the risk of breast cancer, do you? 
    51        A.  I would have to refer to it again, but I presume I did 
    52        not. 
    53
    54   Q.   May we do it now because we can get it out of the way?
    55        A.  That is quite all right.  I would be glad to concede
    56        that the book has nothing to do with child bearing.
    57
    58   Q.   No, but it had to do with the risk of breast cancer, in
    59        part at least, did it not?
    60

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