Evaluation of nitrate daily intake in parsabad and varzeqan cities and its relationship with the prevalence of gastrointestinal cancers(stomach)

Abstract

Introduction: Nitrate is one of the essential parts of plants and soil. Nitrate contamination occurs when plants absorb nitrates higher than their need. Although nitrate is not toxic to humans under standard level, it may convert to nitrite and nitrosamine compounds in the body and react with amines and amides to produce nitrosamine compounds which increases the risk of stomach cancer. Allowable daily intake of nitrate established by WHO is between 0-3.7 mg per kilogram of body weight per day. Many studies have shown the relationship between nitrate and nitrite intake from drinking water and food, and gastrointestinal cancers. On the other hand, Some other studies have shown, there is no relationship between these parameters. With this in mind, more studies about this subject is requaired.Therefore, aim of this study was the determination of nitrate input to the body in Varzaghan city that ranked third in the incidence of gastrointestinal (stomach) cancer and Parsabad with low gastrointestinal (stomach) incidence of cancer in the country. Material and methods: To determine nitrate at food in Varzaghan and Parsabad cities, 3 to 5 retailer center in the autumn and spring were chosen randomly for food sampling which included: breads and cereals, vegetable crops, fruit and protein, dairy, Fats, sugar and tea. Food samples were brought to the environmental chemistry laboratory, health and nutrition school, Nitrate was measured after extraction with colorimetric method using a spectrophotometer (a total of 196 food samples in two cities and 20 water samples). Results: The results of this study show that the total amount of nitrate intake in Varzaghan is 597.53 mg per day and with considering average weight of a person70 kg, intake per person per kg of body weight per day is 8.53 mg. Daily nitrate intake per person in Parsabad is 572.11 mg (or 8.17 mg per kg of body weight). Conculasion: The average Daily intake of nitrate in both cities are more than the amount established by the FAO/WHO and the results of other studies. Relationship between the daily intake of nitrate in Varzaghan with high rate of stomach cancer and Parsabad with low stomach cancer rates were analyzed by spss software with two sample t-test analysis. Only difference between the total intake of nitrate from drinking water showed a significant relationship between the two cities. And nitrate intake of most of other food samples showed no significant relationship. In total, the amount of nitrate in the two cities is very high, therefore food control and monitoring is necessary.