Effect of betel-quid chewing on nitrite levels in saliva

Abstract

A study was made of the effects of chewing betel quid, alone or with tobacco, on salivary levels of nitrite and other factors of importance in the formation of nitrosamines, and the possible relevance of the findings to the development of oral cancer was assessed. When a betel quid was chewed after ingestion of a lunch that was not rich in nitrates, saliva samples taken 1 hr later showed an increase in nitrite level, except in habitual chewers of tobacco. Subsequent studies confirmed that a substantial rise in salivary nitrite followed betel-quid chewing by volunteers who never chewed tobacco, but no such increase occurred when tobacco and betel quid were chewed together. Basal levels of salivary nitrite were also lower in habitual tobacco chewers than in non-chewers. Free amino-nitrogen levels in the saliva were not affected significantly either by habitual tobacco chewing or by the experimental chewing of betel quid or betel with tobacco. However, salivary pH was increased by both types of test chew, and particularly by the betel quid alone, while thiocyanate levels were significantly higher in habitual tobacco chewers than in non-chewers and were further increased after the chewing of betel quid with tobacco.