December 28, 2005

Meats differ in effect on colon cancer risk

NEW YORK (Reuters Health) - People who eat a lot of
processed meats may have a higher risk of developing
pre-cancerous growths -- polyps -- in the colon, while the
opposite may be true for fans of chicken, a new study suggests.

Researchers found that among 1,520 adults with a history of
colon polyps, those who ate a diet heavy in processed meats had
a higher risk of polyp recurrence than those with the lowest
intake. On the other hand, patients who favored chicken had a
lesser risk of new polyps than those who ate the least.

Colon polyps are growths that, while usually benign, can
become cancerous. Patients in the current study had all had
polyps removed and were then followed for 4 years to detect any

Overall, the one-quarter of patients with the highest
intake of processed meat were 75 percent more likely to develop
an advanced polyp compared with the one-quarter of patients who
ate the least processed meat, the researchers found.

In contrast, those with the highest chicken intake were 39
percent less likely than those who ate the least to develop an
advanced polyp.

"Our data indicate that intake of specific meats may have
different effects on risk," the study authors state in the
American Journal of Gastroenterology.

Dr. Douglas J. Robertson of the VA Medical Center in White
River Junction, Vermont, led the study.

A number of studies have linked heavy consumption of red or
processed meats to a higher risk of colon cancer, while diets
high in fiber from fruits, vegetables and whole grains have
been tied to a lower risk of the disease.

But not all studies have found these relationships. And in
the current study, high fiber intake was not clearly tied to
the overall risk of polyp recurrence.

Patients who ate the most fruit, vegetables and whole
grains were, however, less likely to develop polyps in the
upper part of the colon. Red meat, meanwhile, was not linked to
polyp risk.

Despite that latter finding, the overall results are in
line with advice to eat red and processed meats sparingly,
Robertson and his colleagues write.

In theory, they note, processed meats could contribute to
the development of colon cancer because processing may increase
levels of potentially cancer-promoting substances called
N-nitroso compounds.

SOURCE: American Journal of Gastroenterology, December