Studies on the gastrointestinal absorption of N-nitrosamines: effect of dietary constituents.

Studies on the intestinal absorption of N-nitrosodimethylamine (DMN) in the rat have shown that the presence of dietary constituents such as fat markedly reduced the rate of disappearance of this nitrosamine whereas the presence of protein and carbohydrate had little effect on the absorption rate. Fat was also found to reduce the absorption rate of N-nitrosodiethylamine (DEN), N-nitrosopyrrolidine (NPY) and N-nitrosopiperidine (NPIP). Further it was confirmed that the small-intestinal tract of the rat has the ability to degrade DMN. The implications of these findings are discussed in terms of the biological fate of orally ingested nitrosamines.