Survey of the daily intake of nitrate and nitrite in school children by the duplicate portion method

The daily intake of nitrate and nitrite in school children (n = 100) in Hiroshima Prefecture was estimated directly by the duplicate portion method. The daily intake of nitrate was 68.42 +/- 77.49 mg. The daily intake of nitrate/kg body weight was 2.06 +/- 2.24 mg, which is about 56% of the acceptable daily intake (ADI). The daily intake of nitrite was 0.953 +/- 0.869 mg. The daily intake of nitrite/kg body weight was 0.027 +/- 0.021 mg, which is about 45% of the ADI. The daily intake of nitrite/kg body weight was significantly different between the obese group and the non-obese group in boys (p < 0.05, Mann-Whitney U-test). The rates of children whose daily intakes of nitrate and nitrite were above the ADI were 16% and 7%, respectively.