Compounds which are formed from nitrates and other naturally present substances. May occur naturally and are usually concentrated upon cooking.
End products of the combination of nitrites and nitrates with amines in meat have been shown to produce cancer in test animals.
Formed outside or inside the body from precursors like amines, amides, and nitrites. The fundamental requirements are a secondary amino nitrogen and nitrous acid. Three types of nitrosamines can be distinguished: (1) dialkyl nitrosamines (e.g., dimethylnitrosamine, diethylnitrosamine), (2) cyclic nitrosamines (e.g., N-nitrosopiperidine, N-nitrosopyrrolidine), and (3) acylalkyl nitrosamines or nitrosamides (different types of nitrosoureas, thioureas, carbamates, carboxamides, and guanidines). The conditions in the alimentary tract from the mouth to the anus are conducive to nitrosamine formation. The most important factor inhibiting nitrosamine formation is ascorbic acid, which rapidly reacts with nitrite to form nitric oxide and dehydroascorbic acid. Other inhibitors are gallic acid, sodium sulfite, cysteine, tannins, and urea. Occurrence of different nitrosamines has been reported in several foodstuffs: dimethylnitrosamine (e.g., fried bacon, luncheon meat, salami, sausages, fish [raw sable, salmon, and shad; smoked sable and salmon; smoked and nitrate or nitrite-treated sable, salmon, shad and salted marine fish], fish sauce, cheese, baby foods, dried shrimps, shrimp sauce, squid, uncooked canned meats, uncooked ham and other pork products, uncooked beef products, light and dark beers, and Scotch whisky); diethylnitrosamine (e.g., fried bacon, luncheon meat, salami, and wheat flour); nitrosopiperidine (e.g., fried bacon); and nitrosopyrrolidine (e.g., fried bacon, fish sauce, dried shrimps, and squid). In animals, a large number of N-nitroso compounds have been shown to be carcinogenic. Factors enhancing the carcinogenicity of N-nitroso compounds are hormones, other carcinogens or toxicants, viral or bacterial infections, metals, and nutritional factors. The inhibitory factors can be identified as those that decrease the metabolism of the carcinogen (e.g., aminoacetonitrile [affects dimethyl¬ nitrosamine], dibenamine [affects dimethylnitrosamine], and phenobarbitone [affects diethylni-trosamine]); and those that retard or interfere with the formation of the carcinogen (e.g., ascorbic acid, tannins, sulfite, and cysteine). Since no animal species that has been tested so far is resistant to dimethylnitrosamine or diethylnitrosamine, it is expected that humans are not resistant to the nitrosamines either. When the amounts of total nitrosamines in food, water, and other sources are added to those formed throughout the alimentary tract, the total nitrosamine load could be considerable.
Chemical compounds that may have a role in cancer cell formation. Nitrosamines are formed in the stomach and intestines through reactions of nitrites and proteins. Nitrites are produced from nitrates that are naturally present in vegetables or added as preservatives to meat, poultry, and fish. Antioxidants, which interfere with the formation of nitrosamines, can prevent this conversion from taking place and may offer protection against some cancers.
Nitrosamines are highly carcinogenic ingredients found in tobacco products.