Produce May Protect Against Colon Cancer
WebMD News Archive
Feb. 17, 2000 (New York) -- Spinach, broccoli, lettuce, tomatoes, oranges,
and other fruits and vegetables rich in a carotenoid known as lutein may help
stave off colon cancer, according to research in a recent issue of TheAmerican Journal of Clinical Nutrition.
Carotenoids are the yellow and orange pigments that give sweet potatoes,
winter squash, carrots, apricots, papayas, and other fruits and vegetables
their color. They are also found in broccoli and dark, leafy greens including
spinach, kale, and collards. Carotenoids include alpha-carotene, beta-carotene,
lycopene, lutein, zeaxanthin, and beta-cryptoxanthin.
In the study, researchers compared the diets of nearly 2,000 people with
colon cancer with those of more than 2,400 colon cancer-free control subjects.
Participants who reported eating the most lutein-rich foods were among the
least likely to develop colon cancer, compared with those who reported eating
the least lutein-rich foods. Lutein was most protective against developing
colon cancer at a relatively young age (younger than 67) and developing tumors
in the proximal, or central, part of the colon.
"The major dietary sources of lutein in subjects with colon cancer and
in control subjects were spinach, broccoli, lettuce, tomatoes, oranges and
orange juice, carrots, celery and greens, " the study's authors write.
"These data suggest that incorporating these foods into the diet may help
reduce the risk of developing colon cancer."
Exactly how lutein may reduce the risk of colon cancer is not fully
understood, the authors point out. They 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
To arrive at its findings, the multicenter research team interviewed study
participants about the foods that they consumed and how often they ate them
during a two-year period.
The other carotenoids found in food did not protect against colon cancer,
but lutein was shown to decrease the risk of developing the cancer, the
research team reports.
"The benefit of all carotenoids has not been shown to consistently
reduce risk of colon cancer. However, vegetables are the primary source of
lutein, which has been shown to reduce risk of colon cancer," lead
researcher Martha L. Slattery, PhD, MPH, of the University of Utah Medical
School in Salt Lake City, tells WebMD.
"Many of these vegetable 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," she says, noting
that oranges are also a good source of lutein.
Felicia Busch, RD, a spokesperson for the American Dietetic Association and
a nutritionist in St. Paul, Minn., agrees.
Noting that lutein is a "powerfully potent food," Busch tells WebMD
that "the take-home message is to eat more fruits and vegetables."