Western Diet and the Risk of Colon Cancer
by Jennifer Wider, M.D.
Women who fill their diets with red or processed meats, french fries, white
bread and sugary desserts may have an increased risk of colon cancer, according
to Major Dietary Patterns and the Risk of Colorectal Cancer in Women from the
February 10, 2003 issue of the Archives of Internal Medicine.
Researchers followed more than 76,000 women for 12 years to determine how their
dietary patterns affect the risk for colon and rectal cancers. They identified
two main patterns: the "prudent" diet consisting primarily of fruit,
vegetables, fish and whole grains and the "Western" diet consisting
mainly of red meat, fried foods, refined grains and desserts. The results revealed
a significant association between the Western diet and the risk of colon cancer.
The "Western diet" has been linked to an increased risk of colon
cancer for several reasons. According to Teresa Fung, ScD, RD, LDN, lead researcher
and assistant professor at the department of nutrition at Simmons College, in
Boston, Massachusetts, "Red meats are cooked in high heat and may generate
nitrosamines, which may be carcinogenic. Many processed meats are preserved
with nitrites, and may also be converted to nitrosamine in the gut." In
other words, the processes of cooking or preserving meat may produce cancer-causing
chemicals.
In addition, consuming white bread rather than whole-wheat may make a difference.
Dr. Fung explains, "Refined grains may increase insulin levels. Insulin,
being a mitogen, may promote the carcinogenic process if transformed cells already
exist." More simply, the consumption of refined grains like pasta or white
bread can raise insulin levels in the body. Insulin can cause cell division
and potentially turn pre-cancerous cells into cancerous ones.
While other studies have suggested an association between dietary habits and
colorectal cancer, none have the scientific validity of this current study.
"This is the first, large prospective study to look at dietary patterns
and colon cancer," explains Walter Willett, MD, DrPH, one of the key researchers
and Professor of Epidemiology and Nutrition and Chair, Department of Nutrition,
at the Harvard School of Public Health. A prospective study means that the data
about dietary patterns was collected while the participants were healthy, before
any diagnosis of cancer was made. According to Dr. Willet, because the study
was "prospective and large, the findings are more credible than the findings
of prior studies."
Colon cancer is the third most common cancer among men and women in the United
States and the second leading cause of total cancer death in the U.S., according
to data from the American Gastroenterological Association. More women over the
age of 75 will die of colorectal cancer than from breast cancer. Despite these
numbers, many women do not consider colorectal cancer a major threat to their
health.
The American Cancer Society recommends a variety of screening tests in the
prevention of colorectal cancer. For women and men over the age of 50, an annual
fecal occult blood test should be performed at the doctor's office to look for
blood in the stool. Every five years, a flexible sigmoidoscopy is recommended,
and every ten years, a colonoscopy should be performed. Colorectal cancer is
highly treatable if detected in the early stages. Employing proper screening
methods can not only find the disease early but also prevent it by finding and
removing pre-cancerous polyps.
The findings of this study underscore the importance of dietary habits, along
with regular screening, in the prevention of cancer. According to Dr. Willett,
patients can also: "reduce the risk of colon cancer by staying lean and
exercising regularly, avoiding cigarette smoking and high alcohol consumption
(greater than 2 drinks per day)." Dr. Willett also points out that "there
is quite strong evidence that a RDA multiple vitamin will reduce the risk, probably
by ensuring adequate intake of folic acid."
The Society for Women's
Health Research is the nation's only not-for-profit organization
whose sole mission is to improve the health of women through research. Founded
in 1990, the Society brought to national attention the need for the appropriate
inclusion of women in major medical research studies and the resulting need
for more information about conditions affecting women. The Society advocates
increased funding for research on women's health, encourages the study of sex
differences that may affect the prevention, diagnosis and treatment of disease,
and promotes the inclusion of women in medical research studies. Dr. Donnica
Moore has been a member of the Society since 1990 and is a past member of its
Board of Directors.
Created: 3/6/2003 - Jennifer Wider, M.D.
Reviewed: 3/6/2003 - Donnica Moore, M.D.
