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.
