The Study
Effect of Spinach, a High Dietary Nitrate Source, on Arterial Stiffness and Related Hemodynamic Measures: A Randomized, Controlled Trial in Healthy Adults
This study gave people spinach soup one week and asparagus soup another week and measured their blood pressure. It found a small change when they ate spinach, but it doesn't prove spinach fixes heart problems — just that it might help a little for a short time in healthy people.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study tested if eating a lot of spinach every day for a week helps your blood vessels relax and lowers your blood pressure.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 578 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — a 3–4 mmHg drop in central blood pressure is clinically meaningful and comparable to the effect of some blood pressure medications.
- 2After eating spinach with 845 mg of nitrate daily for 7 days, participants had 6.9% less arterial stiffness and their central blood pressure dropped by 3.4 mmHg after 3 hours — effects that didn't fade over the week.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Clinical Nutrition Research
Year
2015
Authors
E. Jovanovski, L. Bosco, K. Khan, F. Au‐Yeung, H. Ho, A. Zurbau, A. Jenkins, V. Vuksan
Related Content
Claims (5)
Consuming nitrate from spinach reduces central blood pressure and arterial stiffness more than it reduces blood pressure in the arm, showing a stronger effect on large arteries than on overall systemic pressure.
Healthy adults aged 18–50 who consume 845 mg of dietary nitrate from spinach daily for 7 days experience a 6.9% reduction in arterial stiffness and a 3.4–3.5 mmHg decrease in systolic blood pressure at 180 minutes after consumption.
Eating 845 mg of dietary nitrate from spinach every day for 7 days does not reduce arterial stiffness more on day 7 than on day 1 in healthy young adults.
Consuming 845 mg of nitrate from spinach in one meal lowers arterial stiffness and central blood pressure within three hours in healthy young adults, and the reduction is as large as what occurs after seven days of daily nitrate intake.
Consuming spinach for 7 days improves blood vessel function more than consuming asparagus, even though asparagus has other compounds that might affect blood vessels, because spinach contains more nitrate.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.