Spinach deserves some of its iron reputation, but the story is more nuanced than a ranking. Several leafy vegetables are close, and the amount in a table is not the same as the amount your body absorbs.
Approximate raw values per 100 g
| Vegetable | Approx. iron |
|---|---|
| Spinach | ~2.7 mg |
| Beet greens | ~2.6 mg |
| Asparagus | ~2.1 mg |
| Swiss chard | ~1.8 mg |
| Kale | ~1.5 mg |
| Broccoli | ~0.7 mg |
Values are rounded and vary by cultivar and preparation.
Vegetable iron is nonheme iron
NIH explains that nonheme iron has more variable absorption than heme iron. Phytates and some polyphenols can inhibit absorption, while vitamin C consumed in the same meal improves it.
Serving size changes the number
A salad containing 50 g of spinach provides about 1.3 mg iron, not 2.7 mg. Adding red pepper, tomatoes, or vitamin-C-rich fruit can improve use of that nonheme iron.
Absorption matters as much as the number in the table
Plant iron is non-heme iron, and its absorption varies more than heme iron from animal foods. Pairing vegetables or legumes with a vitamin C source can improve absorption, while large amounts of certain inhibitors in the same meal can reduce it.
That does not make the ranking useless, but it changes how to read it. A vegetable containing 2 mg per 100 g does not automatically mean 2 mg is absorbed, and a large serving of legumes can provide more total iron than a small side serving of the vegetable at the top of the list.
Legumes are a different category
If the comparison expands beyond vegetables, lentils, beans, chickpeas, and soy are important plant iron sources and often provide more per realistic serving.
Spinach contains useful iron, but portion size, bioavailability, and the rest of the meal matter as much as the per-100-g number.
“High in iron” depends on portion as well as 100-gram values
Vegetable rankings can be misleading when cooked and raw foods are mixed. Cooking reduces water and volume in leafy greens, so a 100 g serving of cooked spinach represents much more plant material than 100 g of raw spinach. That can make cooked greens look dramatically richer in iron. The comparison is not wrong, but it answers a different question from “what will I get from a normal side dish?” Portion-based values are often easier to apply at the table.
Legume-type vegetables such as green peas can contribute meaningful iron along with protein and fiber, while leafy greens provide folate, vitamin K, carotenoids, and other nutrients. There is little reason to select vegetables on iron alone. A mix of greens, peas, broccoli, and other vegetables spreads nutritional benefits across the diet.
Plant iron is not absorbed at the same rate as heme iron
The iron in vegetables is non-heme iron. Its absorption changes with the rest of the meal, especially vitamin C and compounds such as phytates and polyphenols. Adding lemon juice to greens, serving broccoli with beans and tomatoes, or pairing a vegetable dish with fruit can improve the conditions for absorption. This is particularly helpful when plant foods provide most of a person’s iron.
Oxalates in spinach are sometimes discussed as if they make its iron useless. Absorption is indeed limited, but spinach still contributes iron and many other nutrients. The sensible response is variety rather than avoiding it. Other greens, legumes, tofu, seeds, and fortified foods can supply additional iron through different food matrices.
Vegetables work best as part of an iron-rich meal
For most people, vegetables alone are not the easiest way to reach a full day’s iron target. Their strength is that they can complement more concentrated sources. A lentil bowl with roasted peppers and greens, tofu with broccoli, or beans with tomato salsa combines iron-rich staples with vitamin-C-rich produce. This approach increases both total intake and the chance that some of the non-heme iron will be absorbed.
People with diagnosed iron deficiency or unusually high requirements should not rely on a vegetable ranking as treatment. Laboratory results, the cause of low iron, and individualized advice matter. For routine eating, however, regularly including leafy greens and other vegetables alongside legumes, whole grains, seeds, and fortified foods is a strong strategy.
Sources
- USDA FoodData Central — Iron values for vegetables.
- NIH Office of Dietary Supplements — Iron Fact Sheet — Heme and nonheme iron and absorption factors.