Document Type
Journal Article
Publication Title
Free Radical Biology and Medicine
Volume
222
First Page
519
Last Page
530
PubMed ID
38972612
Publisher
Elsevier
School
Nutrition and Health Innovation Research Institute / School of Medical and Health Sciences
RAS ID
71196
Funders
Austrian Science Fund
Grant Number
KLI 858
Abstract
Background: Vascular oxidative stress and low-grade inflammation are important in the pathology of cardiovascular disorders, including hypertension. Cell culture and animal studies suggest that inorganic dietary nitrate may attenuate oxidative stress and inflammation through nitric oxide (NO), and there is a need to investigate whether this translates to humans. Aim: In this randomised, placebo-controlled crossover study, by measuring a combination of multiple blood biomarkers, we evaluated whether previously reported benefits of dietary nitrate translate to a reduced oxidative stress and an improved inflammation status in 15 men and women (age range: 56–71 years) with treated hypertension. Methods: We investigated the effects of a single ∼400 mg-dose of nitrate at 3 h post-ingestion (3H POST) and the daily consumption of 2 × ∼400 mg of nitrate over 4 weeks (4WK POST), through nitrate-rich versus nitrate-depleted (placebo) beetroot juice. Measurements included plasma nitrate and nitrite (NOx), oxidised low-density lipoprotein (oxLDL), F2-isoprostanes, protein carbonyls, oxidised (GSSG) and reduced glutathione (GSH); and serum high-sensitive C-reactive protein (hsCRP), chemokines, cytokines, and adhesion molecules. Flow cytometry was used to assess the relative proportion of blood monocyte subsets. Results: At 4WK POST nitrate intervention, the oxLDL/NOx ratio decreased (mainly due to increases in plasma nitrate and nitrite) and the GSH/GSSG ratio (a sensitive biomarker for alterations in the redox status) increased, compared with placebo (for both ratios P < 0.01). The relative proportion of classical (CD14+CD16−) monocytes decreased at 4WK POST for placebo compared to nitrate intervention (P < 0.05). Other oxidative stress and inflammatory markers were not altered by increased nitrate intake relative to placebo. Conclusions: The data from this study point toward a subtle alteration in the redox balance toward a less pro-oxidative profile by a regular intake of inorganic nitrate from plant foods. Clinical trial registry number: NCT04584372 (ClinicialTrials.gov).
DOI
10.1016/j.freeradbiomed.2024.07.004
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Comments
Fejes, R., Pilat, N., Lutnik, M., Weisshaar, S., Weijler, A. M., Krüger, K., ... & Neubauer, O. (2024). Effects of increased nitrate intake from beetroot juice on blood markers of oxidative stress and inflammation in older adults with hypertension. Free Radical Biology and Medicine, 222, 519-530. https://doi.org/10.1016/j.freeradbiomed.2024.07.004