Dietary nitrate and nitrite levels in an endemic upper gastrointestinal (esophageal and gastric) cancer region of Turkey.

Abstract The aim of this study was investigate nitrate and nitrite levels in some traditional foods and drinking water in Van, an endemic upper gastrointestinal (esophageal and gastric) cancer region of Eastern Turkey. Cheese with added herbs, drinking water, bread baked by wood fire and bread baked by burning animal manure specimens collected in the Van region were analyzed by Stahr's modification method. Nitrite was reduced to nitrate by the following three reagents: hydrazine sulphate ((NH2) 2SO4), CuSO4 and NaOH. Nitrate was then determined by coupling reagent containing sulphanlyamide, phosphoric acid and N-1-naphtyl ethylendiamine dihydrochloride. Nitrate and nitrite levels of all traditional foods and nitrite levels of drinking water were very significantly elevated compared to standard values (p