Preventing Colon Cancer: What You Can Do
April 19, 2000 -- Two new studies published in The New England Journal of
Medicine go against conventional wisdom, indicating that high-fiber diets
may not protect us from colon cancer. But across the country, doctors like
Shanthi Sitaraman, MD, say they won't change the dietary advice they have been
"Fiber in the diet is still good for preventing many diseases -- heart
disease, cancer," Sitaraman, an assistant professor of medicine and
digestive diseases at Emory School of Medicine in Atlanta, tells WebMD. Low-fat
foods are also important, she says, because they offset obesity -- another risk
factor for many diseases.
Colorectal cancer is second only to lung cancer as a leading cause of cancer
deaths in the US. Yet as Sitaraman tells her patients, colon cancer is probably
preventable if you "eat five servings of fruits and vegetables every day,
get regular exercise, don't smoke, and drink only a little alcohol. One glass
of wine daily is plenty."
"Also, if a woman is postmenopausal and at risk for osteoporosis, I
would advise taking calcium supplements with vitamin D -- it has been shown to
decrease incidence of polyp formation and colorectal cancer," Sitaraman
says. Regular screenings for colorectal cancer after age 50 are also essential,
doctors say. Some experts say more than 50% of colon cancer cases are
Research is yielding other clues to preventing this disease.
Take the fruits/vegetables issue: another study has shown that a type of
nutrient found in spinach, broccoli, lettuce, tomatoes and oranges is
what helps protect against colon cancer. These foods are rich in a carotenoid
known as lutein.
Carotenoids are the pigments that give certain fruits and vegetables their
yellow and orange colors. They are also found in broccoli and in dark, leafy
In the lutein study, published in The American Journal of Clinical
Nutrition, researchers compared the diets of nearly 2,000 people with colon
cancer with those of more than 2,400 without the disease. Participants who
reported eating the most foods rich in lutein were much less likely to develop
colon cancer than those consuming the least lutein-rich foods.
Exactly how lutein may reduce the risk of colon cancer is not fully
understood, says researcher Martha L. Slattery, PhD, MPH, of the University of
Utah Medical School in Salt Lake City. She and her colleagues speculate that
this occurs because carotenoids are antioxidants, which may destroy the free
radicals that are believed to accelerate aging and contribute to the formation
of cancers and heart disease.
"Many of these vegetables are also high in folate, another nutrient that
may protect from colon cancer, [so] an easy tip is therefore to eat more
vegetables, especially dark green vegetables or broccoli," Slattery tells