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
