Probiotic lactic acid bacteria detoxify N-nitrosodimethylamine. - GreenMedInfo Summary

Humans can be exposed to N-nitroso compounds (NOCs) due to many environmental sources, as well as due to endogenous formation. The main nitrosamine which is found in food products and is also synthesized in vivo by the intestinal microbiota is N-nitrosodimethylamine. It can cause cancer of the stomach, kidney, and colon. The effect of four probiotic Lactobacillus strains on NDMA was studied under different culture conditions (24 h in MRS, 168 h in modified MRS N, and 168 h in phosphate buffer). HPLC and GC-TEA methods were used for NDMA determination in supernatants. The influence of lactic acid bacteria on NDMA genotoxicity was investigated by means of the comet assay. Additionally, the effect of NDMA (2-100 µg/mL) on the growth and survival of the probiotic strains was studied. Our results indicate that the bacteria decreased NDMA concentration by up to 50%, depending on the culture conditions, time of incubation, NDMA concentration, pH, and bacterial strain. Lactobacillus brevis 0945 lowered the concentrationand genotoxicity of NDMA most effectively, by up to 50%. This could be due to either adsorption or metabolism. The growth and survival of the bacteria was not affected by any of the tested NDMA concentrations.