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Kerley, Dolan, James and Cormican (2018) describe a randomised placebo (P) controlled, two‐period cross‐over trial of dietary nitrate (N) in 20 patients with known or suspected hypertension. The P and N interventions were delivered in beetroot juice in a nitrogen‐depleted or nitrogen‐enriched form, respectively. Thirteen of the individuals were randomised to receive the sequence NP, that is N in Period I of the trial followed by P in Period II, and the other seven were allocated the sequence PN. Amongst the many endpoints, plasma nitrate and ambulatory blood pressure were recorded prior to randomisation, then 7 days later following the start of treatment in Period I and a further 7 days following Period II. The authors concluded:

Our results support … an anti‐hypertensive effect of dietary nitrate … .

Key features include the following:

 Design: Single‐centre, randomised placebo‐controlled, two‐period cross‐over trial,

 Size: 20 patients with known or suspected hypertension, unequal numbers assigned to the sequences,

 Washout: None included,

 Endpoints: Plasma nitrate and ambulatory blood pressure,

 Analysis: Complex methodology described. All statistical tests were conducted at the two‐sided 0.05 significance level,

 Conclusion: Nitrogen‐enriched has an anti‐hypertensive effect.