Abstract
The authors previously observed that one of the sources of nitrite was human saliva and its amount significantly increased after ingestion of salted Chinese cabbage which contained high amounts of nitrite and nitrate.
In the present study, the concentrations of nitrite and nitrate in saliva after taking other vegetables containing high amount of nitrate such as lettuce, spinach, and dried-cut radish were determined. The results obtained were the same as in the case of salted Chinese cabbage. Furthermore, 200 and 600mg of sodium nitrate dissolved in 200ml of boiled milk were taken and the amounts of nitrite and nitrate in saliva were determined. In this case, the same results were also obtained. So, it was suggested that the increase of nitrite in saliva after taking the foodstuffs containing high amount of nitrate was caused by in vivo reduction of nitrate.
