Which Leafy Green Has More Iron? A Deep Dive into Nutrition

November 6, 2025 •

4 min read

While many assume spinach is the ultimate iron champion, recent studies highlight that wild and less common leafy greens, like amaranth, can contain significantly higher amounts. This raises the critical question of which leafy green has more iron not just in total quantity, but also in terms of how well the body can actually absorb it.

Quick Summary

Comparing the iron content and bioavailability of common leafy greens like spinach, kale, and chard, with lesser-known varieties such as amaranth and beet greens. It also explores factors that affect iron absorption and provides tips for maximizing intake from plant-based sources.

Key Points

Amaranth leaves contain the highest concentration of iron among many leafy greens, especially certain wild varieties.
Iron in leafy greens is non-heme, which is less bioavailable than the heme iron from meat sources.
Cooking leafy greens reduces oxalates, which are compounds that inhibit iron absorption.
Pairing greens with vitamin C enhances the body's ability to absorb non-heme iron effectively.
Beet greens offer a higher iron count than spinach with potentially better absorption due to lower oxalate levels.
Cooking in a cast-iron skillet can boost the available iron content of leafy vegetables.
Kale contains less iron than spinach per raw serving, but its lower oxalate concentration might mean more of that iron is absorbed.
Dietary diversity is key, as a mix of different leafy greens provides a broader range of nutrients and benefits.

Demystifying the Iron Content in Leafy Greens

Iron is an essential micronutrient vital for carrying oxygen in the blood and supporting overall energy metabolism. While leafy greens are often praised as a source of iron, the reality of their iron content and how our bodies process it is more complex than simple folklore, like the famous "Popeye effect".

For example, while 100 grams of raw spinach contains around 2.7 mg of iron, this is non-heme iron, which is not absorbed as efficiently as the heme iron found in animal products. Furthermore, spinach contains high levels of oxalic acid, a compound that can bind with iron and inhibit its absorption in the gut. This means the total iron figure doesn't tell the whole story.

Beyond Spinach: Unearthing Other Iron-Rich Greens

While spinach is readily available, many other leafy greens offer comparable or even higher iron content, sometimes with better bioavailability due to lower levels of inhibiting compounds like oxalates. A closer look reveals some surprising champions.

A closer look at different leafy greens:

Amaranth Leaves: Studies on wild variants show exceptionally high iron content, with one report indicating up to 509 ppm (parts per million) in the plant's crown and root sections, significantly higher than cultivated spinach. While iron concentration varies, amaranth is consistently ranked highly.
Beet Greens: Often discarded, the leafy tops of beets are a powerhouse of nutrition. Some analyses show they can contain more iron per serving than spinach, along with other key nutrients.
Swiss Chard: Belonging to the same family as beets, Swiss chard is a great source of minerals, including iron. It is recognized for its thick, crunchy stalks and nutrient-dense leaves.
Kale: This popular cruciferous vegetable contains a respectable amount of iron, but generally less than cooked spinach. However, its lower oxalate content may improve overall absorption for some people.
Fenugreek Leaves: Known in many parts of the world for their distinctive flavor, fenugreek leaves are also a very good source of iron.

Comparison Table: Raw Iron Content in Common Leafy Greens


Leafy Green	Iron Content (per 100g raw)	Notes on Bioavailability
Amaranth Leaves	~1.5 - 25.5 mg (highly variable)	High content, but still non-heme; wild varieties can be exceptionally high.
Spinach	~2.7 mg	Iron absorption is inhibited by high levels of oxalic acid.
Beet Greens	~2.7 mg (cooked)	Similar iron content to spinach, but lower oxalate levels can aid absorption.
Swiss Chard	~1.8 mg (cooked)	Decent source, but generally lower than spinach or amaranth in concentration.
Kale	~1.7 mg	Lower oxalate content than spinach, potentially allowing for better absorption.
Fenugreek Leaves	~16.5 mg (some studies)	High reported iron content in some regional studies, non-heme form.

Maximizing Iron Absorption from Leafy Greens

Since plant-based non-heme iron is less bioavailable, it's crucial to optimize its absorption. Fortunately, there are several effective dietary strategies you can employ.

Tips for improving iron absorption:

Combine with Vitamin C: Eating leafy greens with a source of vitamin C, like bell peppers, tomatoes, or a squeeze of lemon juice, can significantly boost non-heme iron absorption.
Cook Your Greens: The cooking process helps break down oxalates, the inhibitors found in many leafy greens, including spinach, thereby increasing the amount of iron your body can absorb.
Pair with Heme Iron Sources: For those who are not vegetarian, combining plant-based iron with a small amount of heme iron from meat or fish can also improve overall absorption.
Use Iron Cookware: Cooking with a cast-iron pot or pan can increase the iron content of your food. Studies have shown that the total and available iron in greens can increase significantly when prepared this way.
Avoid Inhibitors: Try not to consume high-oxalate foods like spinach at the same time as high-calcium foods or drinks like milk, as calcium can also inhibit iron absorption. Coffee and tea can also interfere with absorption, so it is best to drink them between meals.

Conclusion

While spinach is a well-known source, it does not necessarily contain more bioavailable iron than other leafy greens. Amaranth leaves and beet greens often possess a higher raw iron concentration, and lower oxalate levels in some alternatives like kale and Swiss chard can improve absorption. The key takeaway for anyone focusing on a nutrient-rich diet is not just to count milligrams but to employ smart cooking and pairing strategies to get the most out of your food. By diversifying your intake and following these tips, you can effectively boost your body's iron supply from a variety of delicious green sources.

For a deeper dive into the factors affecting non-heme iron absorption and to learn more about nutritional strategies, consult an expert or visit a resource like the NIH Office of Dietary Supplements for reliable health information.

Learn more about iron and absorption from the National Institutes of Health: Office of Dietary Supplements - Iron

Frequently Asked Questions

While raw spinach has a higher volume per serving, cooked spinach contains more usable iron because the heat reduces the levels of oxalic acid, which can inhibit iron absorption.

The non-heme iron in spinach is poorly absorbed primarily due to its high concentration of oxalic acid, a compound that binds to iron and prevents its uptake by the body.

Amaranth leaves have been reported to contain higher concentrations of iron than spinach, and beet greens also offer a comparable or higher iron count per cooked serving.

Yes, consuming leafy greens with a source of vitamin C, such as citrus fruits or bell peppers, significantly increases the absorption of non-heme iron.

Yes, beet greens are an excellent source of iron and contain a lower level of oxalates compared to spinach, which can improve iron availability.

No, spinach typically has a higher overall iron content per raw serving than kale. However, kale's lower oxalate levels may mean better absorption for some people.

Sautéing greens in a cast-iron skillet with a squeeze of lemon juice or other vitamin C source is an effective way to maximize both the iron content from the pan and the absorption from the greens themselves.