CARCINOGENIC EFFECTS OF NITRITE

It is believed that after nitrate is converted to nitrite in the body, it can react with certain amine containing substances found in food to form nitrosamines, which are known to be potent cancer causing chemicals. Nitrosamine formation is inhibited by antioxidants that may be present in food such as Vitamin C and Vitamin E. In some laboratory studies in which rodents were given high levels of nitrites along with amine-containing chemicals, cancers of the lung, liver, andesophagus were observed. However, cancer was not observed in animals given either nitrate plus amines or nitrite alone without amines. A few epidemiological studies of human populations have shown a correlation between gastric cancer and nitrate levels in drinking water. However, many similar studies have not found any association between drinking water nitrate and cancer. In 1995, a committee from the National Academy of Science reviewed the scientific data available for nitrate. They concluded that "…exposure to the nitrate and nitrite concentrations found in drinking water in the United States is unlikely to contribute to human cancer risk."One recent study conducted in the US found an association between nitrate exposure in drinking water and non-Hodgkin's lymphoma (NHL). 

However, the same study found that a higher dietary intake of nitrate decreased the risk for NHL. Although occupational exposure topesticides was taken into account in this study, pesticide exposure in drinking water was notmeasured. Pesticide exposure has been associated with an increased risk for NHL.There is no strong evidence that nitrate and nitrite can cause cancer in the absence of the amine containing substances necessary for the formation of nitrosamines in the body. Therefore, nitrate and nitrite would be classified in Group D, inadequate evidence to determine carcinogenicity,under the old U.S. Environmental Protection Agency cancer categorization scheme. Under the new EPA cancer guidelines, it would be appropriate to classify them into the "inadequate information to assess carcinogenic potential" category.

N-Nitrosamines are potent mutagenic and carcinogenic compounds in humans and animals and are widespread in the environment. Their existence has been confirmed in food products cosmetic products, tobacco smoke,soil, ground water etc. In general, it is well known that N-nitrosamines are formed by a nitrosation reaction between secondary amines and nitrite and Dimethylamine Hydrochloride is a secondary amine.