Day 279 - 12 Jul 96 - Page 22
1 International comparisons, such as those from various
2 sections of China, clearly show advantages to reducing fat
3 intake to levels that are substantially lower than those
4 currently recommended by US health authorities. Those
5 advantages include a reduced risk of heart disease and
6 cancer.
7
8 Diet and Cancer Risk.
9
10 In addition to the extensive information I have
11 already submitted regarding the links between foods of the
12 type sold at McDonald's and cancer risk, I would like to
13 provide a few additional comments. These particularly
14 relate to Professor Naismith's reference to cohort studies.
15
16 Cancer remains a serious and growing problem, and
17 there is no question that diet plays a substantial role in
18 cancer risk. More than 1.2 million Americans are diagnosed
19 with cancer (excluding basal and squamous cell skin cancers
20 and in situ carcinomas except bladder) annually, and more
21 than 500,000 die of the disease, accounting for one in
22 every five deaths in the US. (5) The most common forms of
23 cancer in the United States are prostate, breast, lung and
24 colorectal.
25
26 As noted in my testimony, international and
27 case-control studies have shown a strong relationship
28 between fat intake and breast cancer risk, while most
29 cohort studies have not shown a relationship. This same
30 observation was recently made by Hunter et al. in the New
31 England Journal of Medicine. (6) This observation is not
32 new; rather it reflects the limitations of cohort studies.
33 First, they have typically investigated only a narrow band
34 of fat intake. Secondly, they do not generally account for
35 fat intake during adolescence, which may be the time when
36 fat exerts its greatest effect on breast cancer risk.
37 Third, their follow-up periods are typically short.
38
39 It has long been apparent that a substantial portion
40 of the risk for other cancers is attributable to dietary
41 factors. (7) Colorectal cancer, for example, is diagnosed
42 in 152,000 Americans and kills 57,000 annually (5). Women
43 and men who consume meat frequently have 2.5 and 3.6 times
44 the incidence of colon cancer, respectively, compared to
45 those who consume these products rarely or never. (8-11)
46 The elevated colon cancer risk from diets high in animal
47 products is believed to be caused by the higher levels of
48 cholesterol and bile acids, particularly secondary bile
49 acids, that these products cause in the intestinal tract.
50 (12-16)
51
52 Medical consensus holds that an increased consumption
53 of high-fat, low-fibre foods affects the composition of the
54 diet in such a way that there is a very real risk of cancer
55 of the breast or bowel or heart disease as a result. When
56 the dietary composition is altered in this way, it adds a
57 very real risk of obesity, which, in turn, increases the
58 risk of breast cancer and coronary heart disease; such
59 increased risk is established beyond any scientific doubt."
60
