Abstract
Purpose
Dietary nitrate supplementation increases nitric oxide (NO) bioavailability and reduces blood pressure (BP). Inter-individual differences in these responses are suspected but have not been investigated using robust designs, e.g., replicate crossover, and appropriate statistical models. We examined the within-individual consistency of the effects of dietary nitrate supplementation on NO biomarkers and BP, and quantified inter-individual response differences.
Methods
Fifteen healthy males visited the laboratory four times. On two visits, participants consumed 140 ml nitrate-rich beetroot juice (~ 14.0mmol nitrate) and, on the other two visits, they consumed 140 ml nitrate-depleted beetroot juice (~ 0.03mmol nitrate). Plasma nitrate and nitrite concentrations were measured 2.5 h post-supplementation. BP was measured pre- and 2.5 h post-supplementation. Between-replicate correlations were quantified for the placebo-adjusted post-supplementation plasma nitrate and nitrite concentrations and pre-to-post changes in BP. Within-participant linear mixed models and a meta-analytic approach estimated participant-by-condition treatment response variability.
Results
Nitrate-rich beetroot juice supplementation elevated plasma nitrate and nitrite concentrations and reduced systolic (mean:-7mmHg, 95%CI: -3 to -11mmHg) and diastolic (mean:-6mmHg, 95%CI: -2 to -9mmHg) BP versus placebo. The participant-by-condition interaction response variability from the mixed model was ± 7mmHg (95%CI: 3 to 9mmHg) for systolic BP and consistent with the treatment effect heterogeneity t = ± 7mmHg (95%CI: 5 to 12mmHg) derived from the meta-analytic approach. The between-replicate correlations were moderate-to-large for plasma nitrate, nitrite and systolic BP (r = 0.55 to 0.91).
Conclusions
The effects of dietary nitrate supplementation on NO biomarkers and systolic BP varied significantly from participant to participant. The causes of this inter-individual variation deserve further investigation. Trial registration: https://clinicaltrials.gov/study/NCT05514821.
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More Information
Divisions: | School of Health |
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Identification Number: | https://doi.org/10.1007/s00394-025-03616-x |
Status: | Published |
Refereed: | Yes |
Publisher: | Springer Science and Business Media LLC |
Additional Information: | © The Author(s) 2025 |
Uncontrolled Keywords: | Beetroot juice; Blood pressure; Dietary nitrate; Hypertension; Individual differences; Inter-individual variation; Humans; Male; Nitrates; Cross-Over Studies; Blood Pressure; Double-Blind Method; Adult; Beta vulgaris; Dietary Supplements; Nitrites; Fruit and Vegetable Juices; Young Adult; Biomarkers; Nitric Oxide; 1111 Nutrition and Dietetics; Nutrition & Dietetics; 3210 Nutrition and dietetics; 4202 Epidemiology |
SWORD Depositor: | Symplectic |
Depositing User (symplectic) | Deposited by Griffiths, Alexander |
Date Deposited: | 17 Mar 2025 15:33 |
Last Modified: | 27 Mar 2025 08:19 |
Item Type: | Article |
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