Nitrate and nitrite in vegetables on the Danish market: content and intake

The contents of nitrate and nitrite in lettuce, leek, potato, beetroot, Chinese cabbage and white cabbage on the Danish market were determined for 3 years in the period 1993-1997 as part of the Danish food monitoring programme. These vegetables are supposed to provide the major contribution to the intake of nitrate from the diet. Results for nitrate and nitrite in fresh and frozen spinach are also shown. The highest content of nitrate was found in lettuce followed by beetroot, Chinese cabbage, fresh spinach, leek, frozen spinach, white cabbage and potatoes. For all the products a great variation in the content of nitrate was found. For lettuce a characteristic variation throughout the year is clearly seen with the highest content in the winter period the lowest content in the summer period. Generally, the content of nitrite was low but in spinach high contents were found, probably due to improper storage conditions during transportation. The intake of nitrate and nitrite from these vegetables is calculated on the basis of two different consumption surveys. For both surveys the average intake of nitrate from the vegetables included in the monitoring programme is estimated to be approximately 40 mg day-1, whereas for nitrite the average intake is approximately 0.09 mg day-1. The total intake of nitrate and nitrite is estimated to be respectively 61 mg day-1 and 0.5 mg day-1.