MONDAY, Oct. 24 (HealthDay News) -- A U.S. government requirement that vitamin C or one of its close relatives be added to hot dogs, to reduce the amount of nitrites found in this popular food, may not have lowered the rate of colon cancer cases after all, a new study suggests.
Back in 1978, the U.S. Food and Drug Administration mandated that the meat industry include vitamin C (ascorbate) or its close cousin, erythorbate, in hot dogs to offset the amount of nitrites. Nitrites are added to cured, processed meats such as hot dogs to enhance their flavor and color, and to extend their shelf life. The problem is that during the cooking process, nitrites combine with amines in meat to form cancer-causing nitrosamines.
Since vitamin C was added to hot dogs, the researchers found that there has been a sharp drop in the number of people who die from colon cancer, but the incidence of colon cancer has not changed that much.
The findings were presented Monday at the American Association for Cancer Research annual meeting in Boston.
"The amount of nitrites in hot dogs were reduced as a result of these changes," said lead researcher Dr. Sidney Mirvish, professor emeritus at the Eppley Institute for Research in Cancer and Allied Diseases at the University of Nebraska Medical Center in Omaha. But, "if it were true that these changes reduced risk for colon cancer, it possibly should have been evident by now," he said. "It's not."
Dr. David Bernstein, chief of the division of gastroenterology at North Shore University Hospital in Manhasset, N.Y., said that the decrease in death rate from colon cancer was likely due to earlier detection and improved treatment, not changes in the nitrite content of hot dogs.
"The hot dog issue is a tough one to study," he said. "Not everyone eats a ton of hot dogs, so it is a difficult risk factor to control for. Nitrites are probably bad and cause all sorts of problems, but colon cancer may not be one of them."
In a related study presented at the same meeting, researchers at Simmons College in Boston found that women who consumed diets rich in foods that increase blood levels of C-peptide may be at higher risk for colorectal cancer. C-peptide is a blood marker of insulin secretion.
In the study, women who ate high amounts of red meat, fish and sugar-sweetened beverages and consumed lower amounts of high-fat dairy, coffee and whole grains had a 35 percent increased risk for colorectal cancer, the study showed. Also, those women who were overweight or sedentary were more vulnerable to the cancer-causing effects of this diet. The researchers suggest that high levels of insulin may promote cell growth and multiplication.
While the study found an association between this kind of diet and colorectal cancer, it did not prove a cause-and-effect.
Because these studies were presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.
The American Cancer Society provides a wealth of information on early detection and treatment of colon cancer.
SOURCES: Sidney S. Mirvish, Ph.D., professor emeritus, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha; David Bernstein, M.D., chief, division of gastroenterology, North Shore University Hospital, Manhasset, N.Y.; Oct. 24, 2011, presentation, American Association for Cancer Research annual meeting, Boston
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