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Ageing modifies the effects of beetroot juice supplementation on 24-hour blood pressure variability: An individual participant meta-analysis
Individual-participant meta-analysis collating four RCTs (n=85 adults 55–76 y): pooled effects on overall 24-hour BP means were not significant, but younger (<65 y) participants showed lower nocturnal systolic BP variability with beetroot juice, and larger plasma nitrite responses were associated with lower nocturnal SBP mean and variability.
Design
- IPD meta-analysis of 4 independent RCTs
- n = 85; age 55–76 y; beetroot juice vs placebo
- Outcomes: 24-h ABPM means and variability, dipping, morning surge
Headline null (abstract)
Pooled effect across all BP outcomes: not significant overall.
Nuanced signals
- Nocturnal SBP variability: significant decrease in <65 y cohort (−2.8 mmHg weighted variability metric; 95% CI −4.5 to −1.0; p = 0.002) vs not significant in ≥65 y.
- Nitrite responsiveness: larger NO₂⁻ increases associated with favourable shifts in nocturnal mean SBP and variability (see abstract CIs).
Evidence hygiene
This is variability / circadian physiology as much as clinic BP—pair with office BP beetroot RCTs on dietary-nitrate-supplementation without flattening into a single headline.
Publication
Siervo M, et al. Nutr Res. 2015 Oct;35(10):865-882. PMID 25937622.
Outcomes
- Systolic Blood Pressure-2.8mmHg (Millimetres of Mercury)
- Overall pooled effect across listed BP outcomes was not statistically significant; nitrite-responsiveness associated with nocturnal SBP mean/variability shifts per abstract.