Nitrosamine

Nitrosamines, more N- Nitrosamines are a class of organic chemical compounds of the general structural formula R.sup.1R.sup.2N -NO, while R1 and R2 are carbon-containing radicals. Nitrosamines be carcinogenic.

Formation

Nitrosamines are formed for example from nitrites and amines. They are formed only under certain conditions, especially in the acidic environment such as exists about the human stomach.

Nitrite initially forms HNO2. This splits after re- protonation in a nitrosyl cation (NO ) and water (see (1)). The nitrosyl cation reacts with an amine to nitrosamine on ( see (2) ).

Occurrence

Evidence for the presence of nitrosamines in foods of plant origin, in soils or groundwater does not exist. They come - usually in non- harmful doses - in many foods, such as beer, fish, cured meat products or cheeses. N-nitroso amines are the reaction products of nitrite and secondary amines (such as in proteins ), which are formed especially under heat. When heated, salted foods, and the reheating of spinach, its intracellular nitrate deposits were converted microbially to nitrite, there is also the risk of nitrosamine formation.

Nitrosamines can also be detected in latex mattresses, balloons and tobacco.

Nitrosamines in water -mixed cooling lubricants - from converted into nitrite nitrate from the preparation water and entrained amines ( food scraps, cigarette ) - arise. Key component is N -nitroso -diethanolamine ( NDELA ).

Health effects

In animal experiments, a highly carcinogenic effect at 90 % of the investigated nitrosamines has been demonstrated. There is still no known species, in which the substance can not induce tumors. Nitrosamines are precancerous, that is, they must be activated in the body, so that they can develop their harmful effect. This is done by a cytochrome P450 -catalyzed reactions. In subsequent reactions the very reactive formaldehyde and carbenium ions are released, which have a strong genotoxic effect.

Epidemiological studies indicate a positive correlation between nitrite and nitrosamine intake and gastric cancer, as well as between the consumption of meat and meat products and stomach and esophageal cancer.

Further epidemiological studies also see a correlation between the increasing use of nitrate and nitrite in agriculture (fertilizers ) and food industry ( preservative), the resulting increased exposure to nitrosamines and the increasing number of Alzheimer's, Parkinson's and diabetes cases.

Nitrosamines have also caused damage to the liver and the genetic material in animal experiments.