Contents
What it is
Spinach is the leaf of an annual in the goosefoot family, a relative of beet and chard, native to western Asia. It is fairly high in oxalate, which is why eating a lot of it raw leaves a dry, chalky feel in the mouth; blanching draws a good share of that oxalate into the water, and the blanching Korean cooking does before dressing it as namul takes care of this as well. Anyone with a history of kidney stones may want to keep that in mind. Spinach that has been through cold weather is sweeter.
Scientific name Spinacia oleracea
Spinach iron is non-heme iron, absorbed at only 2–20%, and the plant's own oxalate binds much of what is there. As an iron source it is ordinary, cartoons notwithstanding.
Other columns are outstanding, though. 100 g delivers four times the daily requirement for vitamin K and half of it for folate. Its lutein content is among the highest of any common vegetable.
Key benefits
- Nutrition data
Folate drives cell division and fetal development
194 µg per 100 g, about half an adult's requirement. Folate is needed for DNA synthesis and red blood cell formation, and it is directly tied to preventing neural tube defects in early pregnancy.
- Nutrition data
Lutein and zeaxanthin accumulate in the retina
These two carotenoids deposit selectively in the macula, where they filter blue light. Numerous observational studies find lower rates of age-related macular degeneration among people with higher intakes.
- Moderate evidence
Nitrates improve blood pressure and exercise efficiency
Spinach's natural nitrates convert to nitric oxide, which widens blood vessels. A meta-analysis found systolic pressure fell by an average of 4.1 mmHg, alongside better oxygen efficiency in endurance exercise. The drop showed up only in clinic readings, though — 24-hour ambulatory monitoring did not confirm it.[1][2]
- Nutrition data
Magnesium supports muscle and nerve function
79 mg per 100 g is high for a vegetable. Magnesium is a cofactor in more than 300 enzyme reactions.
How to eat it well
- Blanch briefly and discard the water. Much of the oxalate leaches out, reducing its interference with calcium and iron.
- Add fat. Lutein and beta-carotene are fat-soluble, so a little sesame or olive oil raises absorption.
- Pair with vitamin C to absorb more iron — lemon juice or peppers alongside will do it.
- If eating it raw, choose baby spinach, which is lower in oxalate and more tender.
- Long simmering destroys folate and vitamin C. Add it to soup at the very end.
How to read the grades
Each benefit carries a label showing how far research on people supports it. Grades differ between items even within the same ingredient.
- Nutrition data
- A fact verifiable from food composition databases or health authorities. This is a different kind of statement from a clinical effect.
- Strong evidence
- Consistently confirmed across randomised controlled trials or meta-analyses.
- Moderate evidence
- Human studies exist, but effect sizes are small or results are mixed.
- Early research
- Cell or animal work, or small preliminary studies.
- Not established
- Commonly claimed, but not confirmed in studies on people.
What to watch out for
- High in oxalate: with a history of calcium oxalate kidney stones, moderate the amount and always blanch it.
- On warfarin, keep vitamin K intake steady. Spinach is unusually high in it.
- If you restrict potassium for kidney disease, check your portions.
- Large amounts are not recommended for infants because of the nitrate content.
Nutrition
Approximate values per 100 g edible portion.
- Calories
- 23 kcal1%
- Carbohydrates
- 3.6 g1%
- Fiber
- 2.2 g8%
- Protein
- 2.9 g6%
- Vitamin K
- 483 µg403%
- Folate
- 194 µg49%
- Beta-carotene
- 5,626 µg
- Vitamin A
- 469 µg52%
- Vitamin E
- 2.03 mg14%
- Iron
- 2.7 mg15%
- Magnesium
- 79 mg19%
- Potassium
- 558 mg12%
Percentages are of the US FDA Daily Value for adults and children 4 and over. National reference intakes differ by sex and age.
Calculate this alongside other ingredients →
Key nutrients
By health concern
Dishes with this ingredient
- Korean spinach namul10 min
- Spinach scrambled eggs10 min
- Strawberry and spinach salad10 min
- Roasted pumpkin salad40 min
- Quinoa and grapefruit salad30 min
- Clear kelp and tofu soup20 min
- Cheese and spinach omelette10 min
- Clam and buckwheat noodles30 min
- Quail egg and spinach salad15 min
- Macadamia and spinach pesto15 min
- Guava and lentil bowl30 min
Compare with
Sources
The databases and health authorities this article's nutrition figures and health statements draw on.
- 1Medium-term effects of dietary nitrate supplementation on systolic and diastolic blood pressure in adults: a systematic review and meta-analysisMeta-analysisAshor AW, et al. J Hypertens 2017PMID 28319596
- 2Effect of food sources of nitrate, polyphenols, L-arginine and L-citrulline on endurance exercise performance: a systematic review and meta-analysisMeta-analysisd'Unienville NMA, et al. J Int Soc Sports Nutr 2021PMID 34965876
- 3USDA FoodData CentralFood composition database
- 4NIH Office of Dietary SupplementsHealth authority
- 5PubMedResearch literature
