Chance of Colon Cancer Connected to Copper Consumption

Take some oysters, liver, nuts and seeds, wash them down with a little cocoa, and top them off with a chocolate bar for dessert. While this combination may not appeal to your taste buds, including these foods in a well-balanced diet may reduce your risk of colon cancer, according to recent animal studies by Agricultural Research Service scientists.

These foods are all high in copper--an essential trace element that is below the new recommended intake (0.9 milligram per day) in about one-quarter of U.S. diets.

Studies of mice and rats--led by ARS nutritionist Cindy D. Davis at the Grand Forks, N.D., Human Nutrition Research Center--add to evidence that a low-copper diet significantly increases risk of colon cancer. Copper joins selenium, calcium, carotenoids and fiber as being important for a healthy colon.

Colon cancer is the second leading cause of cancer mortality in the United States and the fourth worldwide. Diet is thought to be the single greatest contributor to colon cancer in humans, possibly accounting for 35-45 percent of the disease risk.

Davis and colleagues found that rats raised on only one-fifth of their copper requirement had significantly more precancerous lesions in their colons than the animals that got adequate copper after both groups were given a cancer-causing chemical. And copper-deficient colon cells showed enzyme abnormalities that have been reported in precancerous lesions in both humans and rats.

Davis also looked for a copper connection in mice with a genetic predisposition to develop intestinal tumors. Since the mouse mutation is similar to one found in some human families, these animals make a good model for testing the effects of dietary changes. Not surprisingly, the mice fed the copper-deficient diet had significantly more and bigger tumors than the animals fed adequate copper.

Earlier this month, ARS honored Davis as the "outstanding early career research scientist of 2000" (link to news release). ARS is the U.S. Department of Agriculture’s chief scientific research agency.

Scientific contact: Cindy D. Davis, ARS Grand Forks Human Nutrition Research Center, Grand Forks, N.D., phone (701) 795-8380, fax (701) 795-8220, cdavis@gfhnrc.ars.usda.gov.