Day 017 - 25 Jul 94 - Page 49


     
     1        "uncertainty factor".  There is a mention of calcium in
              this column.  Can I just read the paragraph beginning "The
     2        promoting effects of faecal bile acids".  Do you have that
              one?
     3        A.  Yes.
 
     4   Q.   It is after reference 45.  "The promoting effects of
              faecal bile acids are thought to be due to cytotoxic
     5        injury leading to regeneration with accompany increased
              cell turnover.  Ionized fatty acids of dietary origin will
     6        also irritate colonic epithelium; a high fat diet might
              therefore be linked in a more direct way with  colorectal
     7        carcinogenesis.  Similarly, dietary cholesterol has been
              proposed as a direct tumour promoter.  In the presence of
     8        calcium ions the toxic effects of  ionised fatty acids and
              faecal bile acids would be abolished through their
     9        conversion to insoluble calcium soaps.  Abnormal patterns
              of cellular proliferation in high risk individuals for
    10        colorectal cancer disappeared when their diets were
              supplemented with calcium carbonate." What conclusion
    11        might we draw from that passage?
              A.  I think that his choice of words is very apt.  For
    12        example, he talks about the promoting effects of faecal
              bile acids are thought to be due to cytotoxic injury.
    13        What he is saying is that there are these theories which
              have been put forward to try to explain why there might be
    14        a relationship between bile acids, fat in the diet and the
              possible causation of colorectal cancer. But what he is
    15        saying is that we cannot go any further forward than
              that.  We have not the evidence to say there is a direct
    16        causal relationship.  These are purely theories which have
              been put forward to try to explain what some people have
    17        suggested is an effect.
 
    18   Q.   Does it follow from that that he is not suggesting that
              the popular media should come out with headlines saying:
    19        "Drink more milk and you will not get colorectal cancer"?
              A.  Well, I think the media have a lot to answer for in
    20        the -----
 
    21   Q.   I am not going to ask you about that, not more the moment
              at least.  Can you just pass your eye across to the column
    22        on the opposite side of the page where there is a
              reference after reference 52 to selenium.  Do you see
    23        that?
              A.  Yes.
    24
         Q.   Selenium a rare trace element reduces the incidence and
    25        progression of cancer in animals exposed to carcinogens.
              Low blood selenium levels have been correlated with a 
    26        reduced activity of glutathione"? 
              A.  Yes, glutathione perioxidase. 
    27
         Q.   Failure to remove perioxdase may lead to oxidated damage
    28        of DNA.  Dietary deficiency of selenium has been linked to
              the increasing incidence of right-sided colonic cancer."
    29        Pausing there, but not to left, so ascending but not
              descending?
    30        A.  That is absolutely right.
 

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