Spinach is one of the most vitamin-dense leafy greens you can eat. A single cup of raw spinach delivers more than your entire daily need for vitamin K, meaningful amounts of vitamins A and C, folate, and several B vitamins. Here’s a closer look at each one and what affects how much your body actually absorbs.
Vitamin K: The Standout Nutrient
Vitamin K is where spinach truly shines. One cup of raw spinach (about 30 grams) contains 145 micrograms, which is 121% of the daily value. That makes spinach one of the richest food sources of this vitamin, which plays a central role in blood clotting and bone health. If you’re taking blood-thinning medication, this is worth paying attention to, since large or inconsistent amounts of vitamin K can interfere with how those drugs work.
Vitamin A and Beta-Carotene
Spinach provides about 16 micrograms of vitamin A (as retinol activity equivalents) per cup of raw leaves. That number sounds modest, but there’s more to the story. Spinach is loaded with beta-carotene, the orange pigment masked by its green chlorophyll. Your body converts beta-carotene into usable vitamin A, which supports vision, immune function, and skin health.
The catch is that spinach isn’t the most efficient delivery system for beta-carotene. Research from Wageningen University found that the bioavailability of beta-carotene from spinach is only about 7%, compared to 18 to 26% from carrots. Cooking helps significantly. Heat breaks down the plant cell walls that trap carotenoids, so your body absorbs more beta-carotene from sautéed or steamed spinach than from a raw salad. Adding a small amount of fat (olive oil, butter, or cheese) further improves absorption, since beta-carotene is fat-soluble.
Folate (Vitamin B9)
One cup of raw spinach provides 58 micrograms of dietary folate equivalents, about 15% of the daily value. Folate is essential for DNA synthesis and cell division, making it especially important during pregnancy. Unlike folic acid (the synthetic form found in supplements and fortified foods), the natural folate in spinach can be partially lost through cooking in water, since it leaches into the liquid. Steaming or quickly sautéing preserves more than boiling does.
Vitamin C
A cup of raw spinach contains about 9 milligrams of vitamin C, roughly 10% of the daily value. That’s a helpful contribution but far less than citrus fruits or bell peppers. Vitamin C supports immune function and helps your body absorb iron from plant foods, which is a useful pairing since spinach also contains non-heme iron.
The problem is that vitamin C in spinach is fragile. It breaks down with heat, so cooking reduces levels noticeably. It also degrades quickly after harvest. Research published in the Journal of Agricultural and Food Chemistry found that fresh-cut spinach loses about half its vitamin C within just three days of storage, even when refrigerated. After a week, levels drop further. If vitamin C is your goal, eat your spinach as fresh as possible and raw.
Other B Vitamins
Beyond folate, spinach contains small but measurable amounts of three other B vitamins per cup: 0.02 milligrams of thiamin (B1), 0.06 milligrams of riboflavin (B2), and 0.06 milligrams of vitamin B6. These aren’t blockbuster amounts on their own, but they add up when spinach is part of a varied diet. B vitamins collectively help convert food into energy and support nervous system function.
Lutein and Zeaxanthin for Eye Health
Spinach is one of the top food sources of lutein and zeaxanthin, two carotenoids that concentrate in the retina and help protect against age-related macular degeneration. A cup of raw spinach contains about 3.7 milligrams of these compounds. Cooked spinach concentrates them dramatically: a cup of canned spinach contains over 20 milligrams, simply because cooking and packing compresses far more leaves into the same volume. Like beta-carotene, these carotenoids are fat-soluble and absorb better when eaten with dietary fat.
Raw vs. Cooked: Which Is Better?
Neither is universally better. It depends on which vitamins you’re prioritizing. Raw spinach preserves heat-sensitive nutrients like vitamin C and folate. Cooked spinach increases the bioavailability of fat-soluble carotenoids like beta-carotene, lutein, and zeaxanthin, because heat breaks open the plant cells that trap them. Cooking also lets you eat a much larger volume of spinach in one sitting, since it wilts down considerably, which means more of every nutrient per serving.
A practical approach is to eat spinach both ways. Toss raw leaves into salads and smoothies for vitamin C and folate. Sauté or steam them with a little olive oil when you want to maximize carotenoid absorption.
What Can Block Absorption
Spinach contains oxalates, naturally occurring compounds that bind to calcium and iron and reduce how much your body absorbs. According to USDA research, oxalates can significantly inhibit mineral uptake, which is why spinach isn’t actually a great source of calcium despite containing some on paper. However, oxalates primarily affect minerals, not vitamins. Your body still absorbs the vitamins in spinach effectively, particularly the fat-soluble ones when eaten with a source of fat.
Baby Spinach vs. Mature Spinach
If you’ve wondered whether baby spinach and full-grown spinach differ nutritionally, the answer is simple: their vitamin profiles are essentially the same. Baby spinach is just harvested earlier, so the leaves are smaller and more tender. Choose whichever you prefer to eat, since you’ll get the same nutritional benefit either way.
Getting the Most From Your Spinach
Freshness matters more than most people realize. Buy spinach that looks vibrant and unwilted, and try to use it within a few days. Vitamin C levels drop by half in just three days of refrigeration. Store it in a sealed bag or container to slow nutrient loss. When you cook it, steaming or quick sautéing preserves more nutrients than boiling, which leaches water-soluble vitamins into the cooking water. Pairing spinach with a source of fat, even just a drizzle of olive oil, meaningfully improves absorption of its most valuable compounds.