Dietary exposure assessment of nitrate in Shandong population in China

This study aimed to evaluate the potential health implications associated with dietary nitrate exposure in the Shandong population in China. A total of 979 food samples collected from Shandong Province were analysed for nitrate concentrations using ion chromatography. Dietary consumption data were obtained from the 2015 Shandong Provincial Resident Health Status Survey, which adopted a multi-stage stratified random sampling method. For residents aged 3 years and above, food intake information and body weight (bw) were collected via a combination of consecutive 3-day 24-hour dietary recalls and a food frequency questionnaire (FFQ). Monte Carlo simulations in R software were applied to estimate the probabilistic distribution of nitrate intake across different age groups, while Bootstrap sampling was used to quantify the uncertainty of the evaluation results. The maximum value of average nitrate concentration was 1.37 × 10³ mg/kg, detected in fresh leafy vegetables. The median intake of nitrate from foods by Shandong population was 0.25 mg/kg bw per day, accounting for only 6.76% of the Acceptable Daily Intake (ADI = 3.7 mg/kg bw). The 95th percentile (P95) of daily nitrate intake was 2.62 mg/kg bw, which was well below the ADI. The range of the 95th percentile of daily nitrate intake in each age group was from 2.07 to 3.15 mg/kg bw, with none exceeding the ADI. The maximum exposure of the 95th percentile was that of the 3-6 years group. Only a small number of residents have a dietary nitrate intake exceeding the ADI, which requires attention. Leafy vegetables were the primary dietary source of nitrate, contributing 45.49% to the total nitrate intake of Shandong residents. Overall, the health impact of dietary nitrate intake is relatively low in Shandong population.