Nitrosamines and amides are carcinogens of interest because of the possibility that they are formed in the gastrointestinal tract of humans and so may contribute to the induction of some forms of cancer, particularly gastric carcinoma.
Nitrosamines and amides are derived in the stomach from the reaction of nitrostable amines and nitrate used as a preservative, which is converted to nitrites by bacteria. Concerns about these agents have led many to shun processed food containing nitrate preservatives.