Increased nitric oxide in exhaled air after intake of a nitrate-rich meal

Respir Med. 2001 Feb;95(2):153-8. doi: 10.1053/rmed.2000.1010.


Exhaled and nasal NO (ENO, NNO) have been suggested as markers for inflammation in lower and upper respiratory tract respectively. It is still unknown how a number of factors, apart from airway inflammation, can influence NO levels. The aim of this study was to determine the effect of a nitrate-rich meal on ENO and NNO. Sixteen healthy subjects were observed during 1 week on normal diet before a nitrate-restricted diet was introduced in the next. On day 3 of the second week they were made to ingest a nitrate rich meal. ENO, NNO, plasma nitrate and plasma L-arginine were followed before the meal and afterwards for 3 h. ENO and NNO as well as plasma nitrate and plasma L-arginine were significantly elevated after the nitrate-rich meal. The median maximal increase of ENO and NNO was 47% and 13% respectively. We found a moderate but significant correlation between the rise in plasma nitrate and ENO (r(s)=0.57, P=0.027) but none between plasma nitrate and NNO (r(s)=-0.02, P=0.95). As nitrate in the diet seems to substantially influence the levels of ENO it is important either to restrict or register the intake of nitrate-rich food prior to measuring ENO.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Arginine / blood
  • Biomarkers / analysis
  • Breath Tests
  • Female
  • Humans
  • Male
  • Nitrates / administration & dosage*
  • Nitrates / blood
  • Nitric Oxide / analysis*
  • Postprandial Period
  • Sensitivity and Specificity


  • Biomarkers
  • Nitrates
  • Nitric Oxide
  • Arginine