Demystifying Iron: What Plant Contains the Most Iron?

November 13, 2025 •

5 min read

While spinach is famously known for its iron content, its non-heme iron is less bioavailable than animal sources. Finding out which plant contains the most iron involves not just measuring raw content but also understanding concentration and how to maximize absorption for a truly iron-rich diet.

Quick Summary

This article explores and compares the highest plant-based sources of iron, including concentrated options like blackstrap molasses and dried seaweed, and common foods like lentils and seeds. It also discusses absorption tips.

Key Points

Concentrated Sources: Dried seaweed, blackstrap molasses, and sesame seeds contain the highest concentration of iron per 100g among plants.
Everyday Iron: Legumes like lentils and chickpeas, along with dark leafy greens such as spinach and kale, are excellent and practical daily sources.
Boost Absorption: Pairing plant-based iron (non-heme) with Vitamin C-rich foods like bell peppers and citrus fruits significantly improves absorption.
Beware of Inhibitors: Compounds like phytates in grains and legumes, and polyphenols in tea and coffee, can inhibit iron absorption, so timing consumption is important.
Balanced Approach: A combination of highly concentrated sources used sparingly and common iron-rich plants ensures a robust and consistent intake of this vital mineral.
Practicality Over Purity: While dried seaweed may be the densest source, a varied diet with easily accessible foods like lentils and spinach is often a more sustainable strategy.

Iron is a vital mineral that supports numerous bodily functions, including oxygen transport and red blood cell production. For those following plant-based diets or simply seeking to diversify their iron intake, understanding which plant foods offer the most iron is crucial. The answer isn't a single food, but rather a collection of powerful contenders, some more concentrated than others.

The Highest Contenders: Gram for Gram

When assessing which plant contains the most iron, it's essential to look at the iron density per 100 grams. This perspective often reveals some unexpected and highly concentrated sources that can be added to your diet in smaller amounts.

Dried Seaweed

Dried seaweed, particularly species like dulse, often stands out with some of the highest iron content per 100 grams, with figures ranging from 11.6 to 19.6 mg. Used frequently in Asian cuisine, types like nori, wakame, and kombu are rich in minerals and offer a savory, umami flavor. Dried seaweed can be a potent iron booster when added to soups, salads, or consumed as a snack. Some varieties of green seaweed, such as Ulva lactuca (sea lettuce), have also been found to have high iron concentrations.

Sesame Seeds

Another extremely dense source is sesame seeds. Per 100 grams, these tiny seeds pack a powerful punch, with iron content reported as high as 14.6 mg. They are a versatile addition to many dishes. When ground into a paste to make tahini, sesame seeds offer an easy way to incorporate this mineral into dressings, hummus, and sauces. However, it's worth noting that consuming 100g of seeds in one sitting is impractical for most people.

Blackstrap Molasses

As a byproduct of the sugar refining process, blackstrap molasses becomes a highly concentrated source of vitamins and minerals, including iron. A single tablespoon can provide a significant portion of the recommended daily value, sometimes up to 20%. Because of its strong, slightly bitter flavor, it is best used sparingly as a sweetener in recipes, sauces, or oatmeal rather than consumed alone. Its concentrated form and surprisingly high bioavailability for a non-heme source make it a standout option.

Everyday Plant-Based Iron Powerhouses

While some plants boast extremely high iron density, other common plant foods are staples of an iron-rich diet due to their practicality and nutrient profile. Including these regularly is a sustainable way to meet your daily iron needs.

Legumes: Lentils, Chickpeas, and Beans

Legumes are among the most accessible and popular sources of plant-based iron. A single cup of cooked lentils, for example, can provide around 6.6 mg of iron. Similarly, cooked chickpeas and soybeans are also excellent sources. Legumes are versatile, affordable, and high in fiber and protein, making them a cornerstone of many healthy diets.

Dark Leafy Greens: Spinach, Kale, and Swiss Chard

Spinach earned its reputation for a reason. One cup of cooked spinach contains approximately 6.4 mg of iron. Other dark leafy greens like Swiss chard, kale, and collard greens also contain substantial amounts. It is important to note that these greens also contain compounds like oxalates that can inhibit iron absorption, but this can be mitigated through preparation and pairing with other foods.

Seeds and Nuts

Beyond sesame seeds, other nuts and seeds contribute significantly to iron intake. Pumpkin seeds are notably high, with a single cup offering a substantial amount. Cashews, almonds, and flaxseeds also provide good quantities of iron along with healthy fats and other minerals.

Maximizing Non-Heme Iron Absorption

Plant-based iron (non-heme) is not as readily absorbed by the body as heme iron from animal products. This is not a reason to avoid plant-based sources, but it does mean a mindful approach to diet is required. Proper pairings can significantly boost absorption.

Enhancers of non-heme iron absorption:

Vitamin C: This is the most effective enhancer of non-heme iron absorption. Eating iron-rich plants with foods high in Vitamin C, like citrus fruits, bell peppers, tomatoes, and strawberries, can dramatically increase bioavailability. For example, a spinach salad with strawberries and a lemon vinaigrette is an excellent combination.
Organic Acids: Lactic, malic, and tartaric acid found in various fermented foods, berries, and vegetables can also aid absorption.

Inhibitors of non-heme iron absorption:

Phytates: These compounds are found in whole grains, cereals, and legumes. Soaking, sprouting, and fermenting can reduce their content.
Polyphenols: Found in coffee, tea, and some cereals and legumes, polyphenols can inhibit iron absorption. It's often recommended to consume tea or coffee between meals rather than with them.
Calcium: High amounts of calcium can also interfere with iron absorption. Spacing out the consumption of high-calcium foods and iron-rich foods can be beneficial.

Comparison of Top Plant-Based Iron Sources

To put these options into perspective, here is a comparison of some of the top plant-based iron sources, normalized per standard serving size for easy comparison.


Food (Cooked)	Standard Serving	Iron per Serving	Notes on Absorption
Lentils	1 cup	~6.6 mg	Phytates may inhibit absorption; pairing with Vitamin C is key.
Spinach	1 cup	~6.4 mg	Contains oxalates; cooking reduces them. Pair with Vitamin C.
Soybeans	1/2 cup	~4.4 mg	Contains phytates; sprouting can help.
Blackstrap Molasses	1 tbsp	~3.6 mg	Excellent source, high concentration, use sparingly due to sweetness.
Dried Apricots	1/2 cup	~3.5 mg	Dried fruits are concentrated but also high in sugar.
Pumpkin Seeds	1 ounce	~4 mg	Great snack source; contains phytates.
Dried Seaweed	30g	3.5-6 mg	High concentration; excellent mineral source.

The Final Verdict on the Most Iron-Rich Plant

Ultimately, there is no single plant that universally holds the title for the most iron. The highest iron concentration per 100 grams is found in dense foods like dried seaweed, sesame seeds, and blackstrap molasses. However, for most diets, a balance of highly concentrated sources and everyday powerhouses is more practical. A well-rounded diet incorporating legumes like lentils, dark leafy greens such as spinach, and various seeds provides a steady and substantial source of non-heme iron. The key to successfully leveraging plant-based iron is to combine these foods with Vitamin C-rich sources to maximize absorption, ensuring your body can effectively utilize this essential mineral.

For more detailed nutritional information and daily reference values, consult the Office of Dietary Supplements at the National Institutes of Health.(https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/)

Frequently Asked Questions

Cooking generally does not destroy the iron itself, as it is a mineral. However, preparation methods can influence the overall bioavailability. For example, boiling leafy greens can reduce oxalate content, a compound that inhibits iron absorption. Cooking legumes also makes their nutrients more accessible.

No, non-heme iron is not absorbed as efficiently as heme iron. While your body absorbs about 25% of heme iron from animal sources, it absorbs a smaller percentage of non-heme iron from plants. This is why combining plant-based iron sources with enhancers like Vitamin C is crucial.

Yes, it is possible to get enough iron from a plant-based diet by consistently including a variety of iron-rich plant foods and using strategies to maximize absorption. Planning meals that pair non-heme iron with Vitamin C is the most effective approach.

To enhance iron absorption from oatmeal, which contains phytates, try adding a handful of berries or a sprinkle of sliced strawberries. These fruits are rich in Vitamin C and will help your body better absorb the iron present in the oats.

Yes, fortified foods like certain breakfast cereals and plant-based milks can be excellent sources of iron, as the mineral is added to them. Many cereals are fortified with a bioavailable form of iron, making them a convenient option.

To maximize iron absorption, it is best to avoid consuming coffee and tea with iron-rich meals. The polyphenols found in these beverages can inhibit iron absorption. Instead, enjoy your cup between meals.

While highly nutritious, blackstrap molasses is a concentrated sugar product. It should be used in moderation due to its sugar content. It also has a strong, bitter taste that is not suitable for all recipes or palates.