Hydroponic vs Conventional Spinach Smoothies for Salivary Nitrate and Blood Pressure
Official title: Acute Effects of Hydroponically vs. Conventionally Grown Spinach Smoothies on Salivary Nitrate Bioavailability and Blood Pressure: A Randomized Controlled Crossover Trial
Run by University of Plymouth · NCT07665944 · Data updated 2026-11-12
This study tests whether smoothies made from hydroponic spinach vs conventional spinach change saliva nitrate levels and blood pressure after a single serving in healthy adults.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 18 Years to 60 Years |
| Sex | All |
| Enrollment | 12 (estimated) |
| Sponsor | University of Plymouth Academic / other |
| Locations | 1 site (Plymouth, Devon) |
| Status | Recruiting |
| Started | May 22, 2026 |
| Main results expected | June 19, 2026 |
| Study ends | July 31, 2026 |
| Registry record updated | June 24, 2026 |
| Trial ID | NCT07665944 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Healthy adults aged 18-60 who are non-smokers, not on interfering medications, and without chronic illnesses or spinach allergies.
✕Probably not a fit
Individuals with chronic cardiovascular or metabolic diseases, who are pregnant or lactating, or who use medications or supplements affecting nitrate metabolism may not receive expected benefits.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This randomized, double-blind, crossover study compares the acute effects of hydroponic spinach and conventional spinach smoothies on vascular-related biomarkers. Participants consume each smoothie on separate days with a washout period, while researchers measure salivary nitrate and blood pressure before and after consumption. The smoothies are matched for volume and appearance to maintain blinding. The trial aims to see if the cultivation method affects nitrate bioavailability and immediate blood pressure responses in adults without chronic disease.
Why it matters
Potential benefit: If successful, the findings could clarify whether spinach grown by hydroponic methods provides different vascular benefits compared with conventional farming.
How similar studies have gone: Similar research has explored nitrate from leafy greens and short-term vascular responses, with mixed results depending on sources and methods; this crossover design adds within-subject comparison.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Adults aged 18-60 years * Generally healthy individuals (no diagnosed chronic disease) * Non-smokers and non-vapers * Not currently taking medications known to affect cardiovascular function or nitrate metabolism * Able and willing to provide informed consent * Willing to comply with study procedures and attend both study visits Exclusion Criteria: * Presence of chronic disease (e.g., cardiovascular, metabolic, renal, or respiratory conditions) * Use of pacemakers or implanted medical devices * Pregnant or lactating individuals * Known allergy or intolerance to spinach * History of gastrointestinal disorders or pathology affecting digestion or absorption * Use of nitrate or nitrite supplements * Use of antibiotics within the past 3 weeks * Use of antibacterial mouthwash or oral products within the past 2 weeks * Current participation in another clinical trial or recent participation that may interfere with outcomes
Where it's running
-
University of Plymouth
Plymouth, Devon, United Kingdom Recruiting
Study contacts
- Study coordinator: Raul Bescos, PhD
- Email: raul.bescos@plymouth.ac.uk
- Phone: +44 1752 587585
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.