title: Are nitrates a significant risk factor in human cancer?
abstract: This article focuses on the relationship between exposure to nitrates in the environment and subsequent risk of human cancer. The question of whether or not nitrates represent a cancer hazard is one of the most important public health issues arising from research into N-nitroso compounds. The reason for concern results from the endogenous reduction of nitrate to nitrite and subsequent nitrosation of amines, amides and proteins to give rise to carcinogenic N-nitroso compounds. The human evidence relating nitrate exposure to cancer, especially gastric cancer, has been largely based on geographic correlation studies, a relatively weak form of epidemiological methodology. In sum, this evidence and that from a small number of individually based studies does not support the hypothesis of a straightforward cause and effect association between nitrate exposure and cancer risk. Because many other factors besides nitrate are involved in the endogenous formation of N-nitrosation compounds, it is possible that exposure to nitrate is not a rate-limiting factor in most circumstances. This makes the setting of regulatory standards for nitrate exposure from the environment a complex issue.
authors.affiliation: Imperial Cancer Research Fund, Radcliffe Infirmary, Oxford.
authors.forename: D
authors.initials: D
authors.lastname: Forman
mesh_terms: D002273:Carcinogens; D015984:Causality; D004032:Diet; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D009566:Nitrates / Q000009:adverse effects* / Q000378:metabolism; D015538:Nitrosation; D011159:Population Surveillance; D012306:Risk; D013274:Stomach Neoplasms / Q000139:chemically induced*; D014877:Water Pollution, Chemical / Q000331:legislation & jurisprudence
chemical_list: D002273:Carcinogens; D009566:Nitrates