Development of a reference database for assessing dietary nitrate in vegetables.
Level 4 - case-series / case-control
Food composition database compilation paired with cross-sectional biomarker validation
PubMed 28105786 · doi:10.1002/mnfr.201600982
What was done
A systematic literature search (1980–2016) was conducted across Medline, Agricola, and Commonwealth Agricultural Bureaux databases to compile nitrate content data for vegetables, herbs, and spices. The resulting database was applied to estimate vegetable nitrate intake from 24-hour dietary recalls (24-HDRs) and food frequency questionnaires (FFQs), comparing these estimates against urinary nitrate excretion and across repeat FFQ administrations.
What was found
The database contains 4,237 records from 255 publications covering 178 vegetables and 22 herbs and spices. Median nitrate content ranged from 4,240 mg/kg fresh weight (FW) in Chinese flat cabbage (range: 3,004–6,310 mg/kg FW) to 12 mg/kg FW in corn (range: 5–1,091 mg/kg FW). Nitrate intake estimated via 24-HDR correlated significantly with urinary nitrate excretion (r = 0.4, P = 0.013). Estimated intake also correlated between 24-HDR and 12-month FFQ (r = 0.5, P < 0.001), and between two 4-week FFQs administered 8 weeks apart (r = 0.86, P < 0.001).
Why it matters
This database provides a comprehensive tool to quantify vegetable nitrate intake from dietary records, facilitating future epidemiological and intervention research on nitrate intake and long-term health outcomes.
Limits
The abstract does not disclose the sample size, demographics, or population characteristics for the human validation cohort. Wide ranges in nitrate concentrations within individual vegetables introduce substantial variability, and the correlation between calculated intake and the urinary biomarker was modest.
Cited by
- context Arugula is the food with the highest concentration of dietary nitrate/nitric oxide precursors, followed by cacao and beetroot juice powder.