Hi Liza,

the abstract you posted illustrates how difficult it is to reach a
consensus among scientists... For many years, some studies found no
correlation between fiber intake while others found a protective
effect. The problem is, many of these studies were prospective, and
thus poorly controlled (do _some_ types of fiber have a protective
effect? If a plant protects against colon cancer, is it due to the
fiber or to other factors? Could people who eat more fiber have
increased risks due to other reasons?).

By the way a former study in the NEJM found a positive correlation
between colon cancer and animal fat intake; seems like it involves the
same women (see below).

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N Engl J Med 1990 Dec 13;323(24):1664-72

Relation of meat, fat, and fiber intake to
the risk of colon cancer in a prospective
study among women.

Willett WC, Stampfer MJ, Colditz GA, Rosner BA, Speizer FE

BACKGROUND. The rates of colon cancer in various countries are
strongly correlated with the per capita consumption of red meat and
animal fat and, to a lesser degree, inversely associated with the
consumption of fiber.

METHODS. We conducted a prospective study among 88,751 women 34 to 59
years old and without a history of cancer, inflammatory bowel disease,
or familial polyposis who completed a dietary questionnaire in
1980. By 1986, during 512,488 person-years of follow-up, 150 incident
cases of colon cancer had been documented.

RESULTS. After adjustment for total energy intake, animal fat was
positively associated with the risk of colon cancer (P for trend =
0.01); the relative risk for the highest as compared with the lowest
quintile was 1.89 (95 percent confidence interval, 1.13 to 3.15). No
association was found for vegetable fat. The relative risk of colon
cancer in women who ate beef, pork, or lamb as a main dish every day
was 2.49 (95 percent confidence interval, 1.24 to 5.03), as compared
with those reporting consumption less than once a month. Processed
meats and liver were also significantly associated with increased
risk, whereas fish and chicken without skin were related to decreased
risk. The ratio of the intake of red meat to the intake of chicken and
fish was particularly strongly associated with an increased incidence
of colon cancer (P for trend = 0.0005); the relative risk for women in
the highest quintile of this ratio as compared with those in the
lowest quintile was 2.49 (95 percent confidence interval, 1.50 to
4.13). A low intake of fiber from fruits appeared to contribute to the
risk of colon cancer, but this relation was not statistically
independent of meat intake.

CONCLUSIONS. These prospective data provide evidence for the
hypothesis that a high intake of animal fat increases the risk of colon
cancer, and they support existing recommendations to substitute fish
and chicken for meats high in fat.


--Jean-Louis Tu <[log in to unmask]>