Dietary nitrate, mutagenic concentrations of NO at the GE junction.
Now this is a convoluted pathway…we eat processed meats high in nitrates. This gets absorbed in the GI tract and makes it back to the saliva where bacteria in the mouth convert the nitrate to nitrite. The nitrite is swallowed and turned to nitric oxide by gastric juice. This elevated nitric oxide is believed to be a contributing factor to cancer risk in the upper stomach and lower esophagus. Talk about a physiology/biochemistry lesson!! Just remember this next time you are about to take a bite of processed meat…
Gastroenterology Online –