Fewer nitrates in hot dogs possibly linked to reduced colon cancer deaths

Issue: December 10, 2011

AACR Frontiers in Cancer Prevention Research

A 33-year-old change in the recipe for hot dogs may have resulted in a reduction in deaths from colon cancer, although new study results do not show a conclusive link.

In 1978, the FDA mandated that levels of sodium nitrate in processed meats, including hot dogs, bacon and ham, be reduced from 150 mg/kg parts per million (ppm) to 120 ppm, and further ordered meat processors to add 500 ppm sodium ascorbate or sodium erythorbate to their products. The change resulted in volatile nitrosamines, primarily N-nitrosopyrrolidine, in fried bacon decreasing from 100 parts per billion (ppb) to about 20 ppb.

Although the incidence rate of colon cancer has remained stable since 1978, deaths have reduced sharply, and Sidney S. Mirvish, PhD, professor emeritus at the Eppley Institute for Research in Cancer and Allied Diseases at the University of Nebraska Medical Center in Omaha, said the reduction of volatile nitrosamines may have played a part.

"It was proposed that N-nitroso compounds in hot dogs and other processed meats can cause colon cancer," he said in a press release. "We found that the level of total apparent N-nitroso compounds in hot dog links prepared in our laboratory fell as increasing levels of sodium erythorbate were included in the hot dog links."

Mirvish presented the results during the 2011 AACR International Conference on Frontiers in Cancer Prevention Research in Boston.

He and colleagues set out to determine what role erythorbate levels had on the N-nitroso compound content of hot dogs. Earlier studies have shown that the apparent non-volatile N-nitro compound fraction can occur in processed meat and, after ingestion, passes down the gastrointestinal tract and induces cancer of the colon. Researchers prepared hot dog patties as "cakes" and determined levels of apparent non-volatile N-nitro compound results and erythorbate per cake.

They found that 500 mg/kg erythorbate reduced the N-nitroso compounds to 2 nmol/g compared with 180 nmol/g when erythorbate was not used.

"When erythorbate was not added, 80% of the apparent N-nitroso compounds were found to be due to nitrosothiols, which are probably harmless, still leaving 40 nmol/g that were attributed to possibly carcinogenic N-nitroso compounds," Mirvish said.

However, if the level of nitrosamines compounds was a significant risk factor, then colon cancer incidence should have decreased along with nitrosamine levels, so Mirvish said the link remains unclear.

For more information:

Mirvish SS. #B111. Presented at: the 2011 AACR International Conference on Frontiers in Cancer Prevention Research; Oct. 22-25, 2011; Boston.

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