Hydroponic vs Conventional Spinach Smoothies: Effects on Salivary Nitrate Bioavailability and Blood Pressure
Acute Effects of Hydroponically vs. Conventionally Grown Spinach Smoothies on Salivary Nitrate Bioavailability and Blood Pressure: A Randomized Controlled Crossover Trial
University of Plymouth
12 participants
May 22, 2026
INTERVENTIONAL
Conditions
Summary
The goal of this clinical trial is to determine whether hydroponic spinach (HS) versus conventional spinach (CS) smoothies produce differential post-consumption effects on salivary nitrate availability and blood pressure in adults. The main questions it aims to answer are: Do hydroponic spinach (HS) and conventional spinach (CS) smoothies produce differential post-consumption salivary nitrate availability responses in adults when consumed in equal volumes? Do hydroponic spinach (HS) and conventional spinach (CS) smoothies produce differential post-consumption blood pressure responses in adults when consumed in equal volumes? Participants will: Consume hydroponic spinach (HS) and conventional spinach (CS) smoothies on two separate study days. Attend two laboratory visits at the university, scheduled within a 1-2 week period. Undergo check-ups and study measurements during each visit (e.g., blood pressure and saliva sampling).
Eligibility
Inclusion Criteria6
- 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 Criteria9
- 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
Interested in this trial?
Get notified about updates and connect with the research team.
Interventions
Standardized smoothie prepared with hydroponically grown spinach, matched for volume and appearance.
Standardized smoothie prepared with conventionally grown spinach, matched for volume and appearance.
Locations(1)
View Full Details on ClinicalTrials.gov
For the most up-to-date information, visit the official listing.
NCT07665944