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
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.
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.
Nitrates improve blood pressure and exercise efficiency
Spinach's natural nitrates convert to nitric oxide, which widens blood vessels. Trials report modest drops in blood pressure and better oxygen efficiency during endurance exercise.
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.
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 kcal
- Carbohydrates
- 3.6 g
- Fiber
- 2.2 g
- Protein
- 2.9 g
- Vitamin K
- 483 µg
- Folate
- 194 µg
- Beta-carotene
- 5,626 µg
- Iron
- 2.7 mg
- Magnesium
- 79 mg
- Potassium
- 558 mg
Key nutrients
- Vitamin K
- Folate
- Lutein
- Iron
- Magnesium