title: Serum nitrate and nitrite levels in patients with hypertension and ischemic stroke depend on diet: a multicenter study.
abstract: OBJECTIVE
  Nitric oxide, NO, is the key vasorelaxing agent produced by vascular endothelium. Stable end products of NO oxidation, nitrate and nitrite (NOx), are considered as markers of endothelial dysfunction associated with hypertension. Our goal was to compare NOx levels in patients with hypertension on controlled low nitrate diet with NOx levels in general population without dietary restrictions.
  
  
  METHODS
  The study included 1005 participants split into 8 groups: healthy subjects (n=28) and patients with moderate (n=37) and malignant hypertension (n=24) on low nitrate diet; healthy subjects (n=9) and patients with stroke (n=44) on low nitrate diet; normotensive subjects (n=354) and patients with elevated blood pressure (n=430) and severe hypertension (n=79) without dietary restrictions.
  
  
  RESULTS
  In groups with controlled low NOx diet, patients with moderate and malignant hypertension had significantly (p<0.01) higher serum NOx versus healthy subject (66.9±18.8μM and 75.3±22.7μM versus 52.8±28.8μM, respectively). Patients with stroke had significantly (p=0.02) higher serum NOx levels versus corresponding group of healthy subjects (106.3±58.4μM versus 71.2±18.1μM, respectively). In the absence of dietary control, differences in serum NOx levels between normotensive subjects and patients with elevated blood pressure and severe hypertension were not significant (p>0.1).
  
  
  CONCLUSIONS
  Differences in serum NOx concentrations are associated with severity of hypertension only in patients on low nitrate diet. The highest concentrations of NOx were observed in patients with stroke. In the absence of dietary control, NOx levels were not associated with presence or severity of hypertension.
authors.affiliation: Biochemistry Department, National Research Center for Preventive Medicine, Moscow, Russian Federation. Electronic address: gumanova@mail.ru.
authors.forename: Nadezhda G
authors.initials: NG
authors.lastname: Gumanova
authors.affiliation: Cardiology Department, Pirogov Medical University, Moscow, Russian Federation.
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Teplova
authors.affiliation: Medical Department, Orenburg State Medical Academy, Orenburg, Russian Federation.
authors.forename: Alexander U
authors.initials: AU
authors.lastname: Ryabchenko
authors.affiliation: Medical Department, Orenburg State Medical Academy, Orenburg, Russian Federation.
authors.forename: Eugene N
authors.initials: EN
authors.lastname: Denisov
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000097:blood* / Q000150:complications; D004032:Diet; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000150:complications; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000097:blood*; D009573:Nitrites / Q000097:blood*; D020521:Stroke / Q000097:blood* / Q000150:complications
chemical_list: D009566:Nitrates; D009573:Nitrites
keywords: Hypertension; Low nitrate/nitrite diet; NOx; Nitric oxide; Serum nitrate; Serum nitrite; Stroke