Spinach is one of the most nutrient-dense foods you can eat. A 100-gram serving (roughly two-thirds of a cup raw) contains just 23 calories, yet delivers 402% of your daily vitamin K, 52% of your vitamin A, 49% of your folate, and 31% of your vitamin C. Few foods pack that much nutrition into so few calories.
How Spinach Scores on Nutrient Density
The Aggregate Nutrient Density Index (ANDI) rates foods on a scale of 1 to 1,000 based on how many vitamins, minerals, and phytochemicals they contain per calorie. Spinach scores 707, placing it in the top tier of all foods. Only a handful of greens score higher: collard greens, kale, Swiss chard, and watercress all hit 1,000, while bok choy lands at 865. Spinach still outranks arugula (604), green leaf lettuce (585), and most other vegetables by a wide margin.
What makes that score remarkable is context. Spinach beats virtually every fruit, grain, nut, and protein source on the list. It sits comfortably among the most concentrated packages of micronutrients in the entire food supply.
What You Get in a Serving
Per 100 grams of raw spinach, the nutritional profile looks like this:
- Vitamin K: 483 micrograms (402% of daily value)
- Vitamin A: 469 micrograms (52% DV)
- Folate: 194 micrograms (49% DV)
- Vitamin C: 28 milligrams (31% DV)
- Magnesium: 79 milligrams (19% DV)
- Iron: 2.7 milligrams (15% DV)
You also get 3 grams of protein, 3.6 grams of carbohydrates, and zero fat or cholesterol. The vitamin K content alone is extraordinary. A single cup of raw spinach (30 grams) provides about 121% of the recommended daily intake, more than almost any other common food.
How Spinach Compares to Kale
Kale often gets the “superfood” spotlight, but a cup-to-cup comparison tells a more balanced story. One cup of raw spinach (30 grams) delivers 121% of the daily value for vitamin K, compared to 68% for the same volume of kale. Spinach also provides nearly three times as much vitamin A (16% vs. 6%) and five times as much folate (15% vs. 3%). It edges ahead on iron, magnesium, and potassium too.
Kale wins on vitamin C, offering 22% of the daily value per cup compared to spinach’s 9%. It also has slightly more fiber and calcium. Both vegetables clock in at 7 calories per cup. The practical takeaway: they’re both excellent, with different strengths. Eating both regularly covers more nutritional ground than relying on either one alone.
Eye-Protecting Antioxidants
Spinach is one of the richest dietary sources of lutein and zeaxanthin, two pigments that concentrate in the retina. These compounds filter harmful blue light and neutralize damaging molecules in the eye. Higher dietary intake of both is associated with reduced risk of age-related macular degeneration, the leading cause of vision loss in older adults, and cataracts. A multi-center study across five ophthalmology centers in the U.S. found that people with higher lutein and zeaxanthin intake had measurably lower rates of macular degeneration.
Green leafy vegetables contain far more lutein relative to zeaxanthin than other food sources. Spinach, kale, and parsley top the list. Because these pigments are fat-soluble, eating spinach with a small amount of oil or fat improves absorption.
Nitrates and Blood Pressure
Spinach is naturally high in inorganic nitrates, compounds your body converts into nitric oxide, a molecule that relaxes blood vessels. In a randomized controlled trial, healthy adults who consumed spinach soup containing roughly 845 milligrams of nitrate per serving saw meaningful reductions in blood pressure after seven days. Central systolic blood pressure dropped by about 4 mmHg, and a measure of arterial stiffness improved by nearly 7%. These effects appeared as soon as three hours after intake on day one and strengthened over the week-long study period.
That 845-milligram dose falls within the range estimated for people following the DASH diet, a well-studied eating pattern for blood pressure management. Spinach is one of the most concentrated vegetable sources of these nitrates, which partly explains why leafy green consumption is so consistently linked to cardiovascular benefits.
Raw vs. Cooked: What You Keep
How you prepare spinach changes which nutrients survive. Vitamin C is the most vulnerable. Boiling spinach cuts true vitamin C retention to about 40% of what raw spinach contains. Blanching preserves around 58%, and steaming holds roughly 45%. Microwaving stands out as the gentlest method, retaining over 91% of the original vitamin C content. The difference is significant: microwaved spinach actually measures higher in vitamin C concentration per kilogram than raw spinach because of water loss during cooking.
On the other hand, cooking spinach has advantages. Heat breaks down cell walls, which makes certain fat-soluble nutrients like vitamin A and lutein easier to absorb. Cooking also reduces the volume dramatically, so you end up eating far more spinach in a cooked serving than a raw one. A half-cup of cooked spinach started as several cups of raw leaves, concentrating the minerals and fat-soluble vitamins in each bite. The best strategy is variety: eat it both raw and cooked.
The Oxalate Factor
Spinach contains oxalates, naturally occurring compounds that can bind to calcium and iron in the digestive tract. This has long raised two concerns: that spinach’s minerals are poorly absorbed, and that oxalates contribute to kidney stones. The reality is more nuanced than the reputation suggests.
For iron absorption, a study comparing spinach and kale meals found that iron absorption from spinach was about 24% lower than from kale, but the difference was not statistically significant. The researchers concluded that oxalic acid in fruits and vegetables is “of minor relevance in iron nutrition.” You’re still absorbing meaningful amounts of iron from spinach, especially if you eat it alongside vitamin C-rich foods, which enhance iron uptake.
Kidney stones are a more relevant concern for people who are already prone to them. Oxalates can combine with calcium in the kidneys to form the most common type of stone. If you have a history of calcium oxalate stones, limiting high-oxalate foods like spinach is a standard recommendation. For everyone else, the oxalate content of spinach does not pose a meaningful risk, particularly when consumed as part of a varied diet with adequate hydration and calcium intake. Calcium from other foods actually binds oxalates in the gut before they reach the kidneys, reducing rather than increasing stone risk.