spinach
A nutrient-dense leafy green packed with nitrate, lutein, folate, and a striking dose of vitamin K.
Strong evidence
🥦Vegetables
Evidence tier
Strong
Research weight
Citations
10 verified / 10
Classification
Vegetables
❝
What the evidence says. Multiple high-quality RCTs / meta-analyses with consistent effects.
Nutrition per serving 1 cup, raw (30 g)
- Sugars 0.1 g0%
- Fibre 0.7 g2%
- Other carbs 0.3 g1%
- Protein 0.9 g3%
- Other 28.1 g94%
6.9 kcal0.86 g protein0.66 g fiber0.13 g sugar
| Nutrient | Per serving | % daily value |
|---|---|---|
| Vitamin C | 8.4 mg | 9% |
| Fiber | 0.66 g | 2% |
| Potassium | 167 mg | 4% |
| Folate | 58 µg | 14% |
| Vitamin A | 141 µg | 16% |
| Vitamin K | 145 µg | 121% |
| Vitamin B6 | 0.06 mg | 4% |
| Manganese | 0.27 mg | 12% |
| Copper | 0.04 mg | 4% |
| Vitamin E | 0.61 mg | 4% |
| Magnesium | 24 mg | 6% |
| Calcium | 30 mg | 2% |
Composition data: USDA FoodData Central ↗
What is spinach?
spinach is a vegetable used for supports healthy blood pressure via dietary nitrate. NutriDex grades the human evidence as Strong. Spinach is among the most studied dietary sources of inorganic nitrate and the macular carotenoids lutein and zeaxanthin. Meta-analyses of randomized trials show dietary nitrate produces dose-dependent reductions in blood pressure and meaningful improvements in endothelial function, while lutein supplementation raises macular pigment optical density in age-related macular degeneration. Large cohorts further link higher nitrate-rich leafy-green intake to lower cardiovascular disease risk and slower cognitive decline.
Purported Benefits
✓Supports healthy blood pressure via dietary nitrate
✓Improves vascular endothelial function
✓Builds macular pigment for eye health
✓Linked to slower age-related cognitive decline
✓Very low energy, high micronutrient density
Dosing & Compounds
Typical Dose
Standard serving: 1 cup, raw (30 g). Eat whole (with skin where edible); favour whole fruit over juice.
Active Compounds
Safety & Cautions
High in oxalate (~750 mg/100g raw) — relevant for calcium-oxalate kidney stone formers, who may prefer cooked spinach and adequate fluid/calcium. Very high vitamin K1 content can interfere with warfarin dosing; patients should keep intake consistent. Nitrate content is the basis of cardiovascular benefit, not a concern at dietary levels. Educational only — always check with your doctor or pharmacist before combining spinach with any medicine.
Key Studies ★ 10 studies
Systematic review & meta-analysis of RCTs
Norouzzadeh 2025
✓ Full text
GRADE-assessed dose-response meta-analysis (75 RCTs, n=1,823): dietary nitrate produced dose-dependent reductions in systolic BP (medium-term -0.48 mmHg per mmol NO3, 95% CI -0.71 to -0.25) and diastolic BP, alongside rises in plasma nitrate/nitrite.
Systematic review & meta-analysis of RCTs
Jackson 2026 (Nutr Rev)
✓ Source
Systematic review and meta-analysis of RCTs found inorganic nitrate improves flow-mediated dilation by a clinically relevant magnitude (>1%) versus control, with the effect abolished by antibacterial mouthwash.
Systematic review
Vegetable Nitrate Systematic Review 2024
✓ Full text
Systematic review of 5 cohort studies (63,155 participants) found habitual vegetable nitrate intake inversely associated with CVD incidence and mortality, with benefit from ~one daily portion (e.g., 80 g spinach or lettuce).
Systematic review & meta-analysis of RCTs
Liu 2022
✓ Full text
Meta-analysis of RCTs (n=429): lutein supplementation significantly increased macular pigment optical density in AMD (WMD 0.07, 95% CI 0.04-0.10), with greater effect at 20 mg/day and >6 months.
RCT
DINO3 Trial 2024
✓ Full text
In an exploratory double-blind RCT in early-stage hypertension, 16 weeks of high-nitrate vegetable powder (60% beetroot, 28% kale, 12% spinach) produced no significant BP difference versus low-nitrate vegetable supplementation.
RCT
Liddle/Inter-individual RCT 2025
✓ Full text
A randomized double-blind placebo-controlled replicate crossover trial examined inter-individual variability in the BP-lowering response to dietary nitrate, finding heterogeneous individual responses to nitrate supplementation.
Randomized controlled trial
Jovanovski 2015
✓ PubMed
Randomized controlled trial in 27 healthy adults: 7-day high-nitrate spinach lowered central and brachial systolic blood pressure and reduced carotid-femoral pulse wave velocity (arterial stiffness) versus low-nitrate control.
Randomized controlled crossover trial
Rebello 2015
✓ PubMed
Randomized controlled crossover trial in 60 overweight/obese adults: a 5 g concentrated spinach-thylakoid dose reduced hunger and longing for food over 2 hours versus placebo (p<0.01).
Prospective cohort study
Bondonno 2021
✓ Full text
Danish Diet, Cancer and Health cohort (n=53,150; 23-y follow-up): moderate vegetable-nitrate intake (~60 mg/day) was associated with ~15% lower CVD incidence (HR 0.85, 95% CI 0.82-0.89) and lower systolic BP.
Prospective cohort study
Morris 2018
✓ Full text
Memory and Aging Project prospective cohort (n=960, mean 4.7 y): highest green-leafy-vegetable intake (~1.3 servings/day) was associated with slower cognitive decline equivalent to being 11 years younger.