Day 036 - 13 Oct 94 - Page 40
1 MR. RAMPTON: It is not terribly important. You were going to
2 make a comment?
3 A. There are a number of items that came to my
4 attention. I did not want to forget to provide something
5 to you, so I was making a note on my own pad, hopefully,
6 for your benefit. It is certainly fair to say that no one
7 line of investigation alone is conclusive. In addition to
8 that, regarding his criteria that must be satisfied in
9 order for fat enhancement of mammary carcinogenesis to be
10 expressed, it is simply perhaps worth noting his first one
11 is carcinogens administrated at a time when the animal is
12 particularly sensitive to mammary induction. That does
13 apply to human populations. We are exposed to carcinogens
14 quite regularly, although not only at times when we are
15 exquisitely sensitive to them, but at all times. I would
16 certainly argue that there is no time when we are
17 insensitive to them, at least that I am aware of.
18
19 His second one is that animals are maintained on a
20 purified diet. My truncated comments earlier went to this,
21 my reference to Dr. Burkitt's writings, that, regrettably,
22 human beings on what some have described as indeed a
23 purified diet. By "purified" one means removing
24 components that would naturally be in the diet. Fibre is
25 one that has gotten the most discussion but, in addition,
26 one can easily strip a diet of vitamins and important
27 minerals. Regrettably, that is exactly what has happened
28 when one makes a hamburger bun, for example, one will not
29 find the same -----
30
31 MR. JUSTICE BELL: You made this point before. What does a
32 "purified" diet mean so far as the laboratory rats are
33 concerned?
34 A. It is an imprecise term and can be used in different
35 ways by different experimenters.
36
37 Q. Do you know how Dr. Burkitt was using it?
38 A. I take it to mean in this context a diet which is more
39 restricted than that which would be normal for a rat in a
40 laboratory; perhaps would not provide the full range of
41 nutrients in their full amounts which, regrettably, is
42 exactly analogous to the human situation. Human beings do
43 not get ----
44
45 Q. I am not at all sure it is the same. I appreciate that
46 you say we have restrict our diet, it is not as wide as it
47 might be, but that may or may not be the equivalent of a
48 purified diet in rats. You may be right, but until we
49 know what a purified diet means, it is difficult to say,
50 is it not?
51 A. Yes. The third point being ad libitum feeding
52 necessary which, obviously, is typical of human
53 populations. Again, he is not speaking here of human
54 populations. He is speaking of how to do a rat study in a
55 way he is satisfied with. I am simply trying to point out
56 that at least those, the three that I have discussed so
57 far, do have parallels in the human population.
58
59 Finally, it is worth again emphasising, although the point
60 seems to get lost, that even in the presence of an agent
