Formation in vivo of volatile N-nitrosamines in man after ingestion of cooked bacon and spinach

Abstract

N-NITROSAMINES, which are thought to be causally related to human cancer¹, have been found in μg kg⁻¹ concentrations in polluted air^2,3, in water⁴ and in tobacco products⁵. Foodstuffs such as cooked bacon, preserved with nitrite, have long been known to contain μg kg⁻¹ amounts of volatile N-nitrosamines formed during cooking⁶. In vivo formation of N-nitrosamines, after ingestion of suitable amine precursors and nitrite, has been demonstrated in laboratory animals⁷. In vivo formation in human subjects with hypoacidity, gavaged with relatively massive amounts of diphenylamine plus nitrite, has been demonstrated through detection of N-nitrosodiphenylamine in the stomach contents⁸. In vivo nitrosation after ingestion of conventional foods has not been demonstrated so far, either in animals or man. We now report in vivo formation of volatile N-nitrosamines in man after ingestion of a midday meal consisting of a bacon, spinach and tomato sandwich and beer.