Report 9 of the Council on Scientific Affairs (A-04)

Labeling of Nitrite Content of Processed Foods

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Summary

Objectives. To summarize the scientific literature on the risks to public health due to the presence of nitrites in food, describe the regulations governing the use of nitrites in food production, and present recommendations.

Data Sources. Literature searches were conducted in the MEDLINE database for English-language articles published between 1966 to 2003 using the search term "dietary nitrite and human health." The Lexis/Nexis news databases were searched with the search term "nitrite AND food safety." The World Wide Web was searched using the Google search engine with the search term "nitrite AND food safety."

Results. Data are irrefutable that when ingested in high concentrations nitrites can cause methemoglobinemia. Additionally, certain populations such as infants may be particularly vulnerable. However, the human body can tolerate fairly high levels of methemoglobin before toxemia sets in. Thus, there have been no reports of methemoglobinemia caused by nitrites present in food, although disease caused by contamination of water and food by sodium nitrite has been reported. The scientific evidence is clear that N-nitroso compounds (NOCs) have carcinogenic effects in animal models. Thus, it must be assumed that at the right concentrations, NOCs are likely to be carcinogenic in humans as well. The primary source of NOCs in the human diet is the nitrosation of secondary amines and amides by nitrites present in food. However, epidemiological studies cannot confirm any association between the presence of nitrites (or nitrates) in food and the formation of NOCs and the causation of human cancer. In fact, studies that suggest a link between nitrites in food and cancer have largely been disputed due to these studies’ inability to exclude confounding factors, such as recall bias. Data linking nitrites present in the human diet to type 1 diabetes remain limited and inconsistent. Regardless, the use of nitrites in the preparation and preservation of meats and poultry has been substantially reduced from the time when these studies were first performed. Over the 22 years from 1975 to 1997, residual nitrite levels on finished meat products have dropped more than 80%. Additionally, the use of erythorbate and/or ascorbate with nitrites has been shown to inhibit the formation of NOCs. The United States Department of Agriculture (USDA) requires addition of such nitrosamine inhibitors during the production of bacon and does not permit detectable NOC levels on bacon.

Conclusions. Given the current Food and Drug Administration (FDA) and USDA regulations on the use of nitrites in food production, the risk of methemoglobinemia due to residual nitrites on food and of developing cancer as a result of consumption of nitrites-containing foods is negligible. The American Medical Association supports the current FDA and USDA regulations, including current labeling requirements, for nitrites in food and encourages continued research and surveillance of the safety of the use of nitrites in foods, with particular attention to its effects on type 1 diabetes.

RECOMMENDATIONS

The following statements, recommended by the Council on Scientific Affairs, were adopted by the AMA House of Delegates as AMA directives at the 2004 AMA Annual Meeting:

1. The AMA supports the current Food and Drug Administration and United States Department of Agriculture regulations, including current labeling requirements, for nitrites in food. (Directive)

2. The AMA encourages continued research and surveillance of the safety of nitrite use in foods, with particular attention to its possible effects on type 1 diabetes. (Directive)