The ten foods with the highest iron content per 100 grams, ranked using USDA FoodData Central data — including both heme (animal) and non-heme (plant) sources.
Quick answer: 1. Dried Thyme, 2. Spirulina (dried), 3. Pork Liver (cooked), 4. Chicken Liver (cooked), 5. Dark Chocolate (70–85% cocoa), 6. Beef Liver (cooked), 7. Pumpkin Seeds (dried), 8. Hemp Seeds (dried, hulled), 9. Oysters (cooked, Eastern), 10. Tofu (firm, raw).
Iron is a mineral essential for oxygen transport (via hemoglobin), energy metabolism, and immune function. Dietary iron comes in two forms: heme iron from animal foods, which is highly bioavailable (15–35% absorbed), and non-heme iron from plant foods, which is less bioavailable (2–20%) but can be enhanced by eating vitamin C alongside it. This list ranks foods by their total iron content per 100 grams of edible portion, using the USDA FoodData Central database. Dried herbs and spices top the list by weight, but because they are consumed in tiny quantities, the list also highlights which foods are practical everyday sources of iron.
Dried thyme (Thymus vulgaris) has the highest iron concentration of any food at 123.6 mg per 100 g — but it is a dried herb used in pinches, not a food eaten in bulk. A typical 1 g serving (about 1 teaspoon) provides approximately 1.2 mg of iron. Like all dried herbs, it is a concentrated source of minerals because the drying process removes water.
Spirulina is a dried blue-green cyanobacterium that contains 28.5 mg of iron per 100 g. It is also a complete protein and a rich source of B vitamins. A typical serving of 10 g (about 1 tablespoon) provides roughly 2.9 mg of iron, or about 16% of the daily value for adult women.
Pork liver is the most iron-dense organ meat, containing 18 mg of iron per 100 g. It provides heme iron, which is absorbed at 15–35% efficiency — far higher than plant sources. Liver is also exceptionally rich in vitamin B12, vitamin A, and folate, but should be consumed in moderation due to its high vitamin A content.
Chicken liver is slightly lower in iron than pork liver at 13.1 mg per 100 g, but it is more commonly available and frequently eaten. Like other organ meats, it provides highly bioavailable heme iron along with substantial vitamin B12, folate, and vitamin A. It is often used in pâtés and spreads.
Dark chocolate with 70–85% cocoa solids contains 11.9 mg of iron per 100 g, making it one of the highest plant-based iron sources that is also a widely enjoyed food. It also provides magnesium, copper, and antioxidant flavonoids. The iron content rises with cocoa percentage. A typical 30 g serving provides about 3.6 mg of iron.
Beef liver provides 8.8 mg of iron per 100 g, slightly less than pork or chicken liver but still an excellent heme iron source. It is also one of the most nutrient-dense foods overall, providing more than 100% of the daily value for vitamin B12, vitamin A, riboflavin, and copper in a single serving.
Dried pumpkin seeds (pepitas) contain 8.8 mg of iron per 100 g, tying with beef liver. They are one of the best plant-based sources of iron, along with magnesium, zinc, and protein. A 30 g handful (about 1/4 cup) provides roughly 2.6 mg of iron, or about 14% of the daily value for adult women.
Hemp seeds contain 7.95 mg of iron per 100 g, making them a strong plant-based iron source. They also provide complete protein, omega-3 fatty acids, and magnesium. Hemp seeds are versatile — they can be sprinkled on salads, blended into smoothies, or used in baking.
Cooked Eastern oysters (Crassostrea virginica) provide 7.2 mg of iron per 100 g, along with more zinc per serving than any other food. Oysters provide heme iron with high bioavailability. A typical serving of 6 medium oysters (about 85 g) provides roughly 6.1 mg of iron.
Firm tofu made with calcium sulfate contains 5.4 mg of iron per 100 g, making it one of the best plant-based sources of iron for vegetarians and vegans. The iron in tofu is non-heme, but absorption can be improved by pairing tofu with vitamin C-rich foods such as bell peppers or broccoli. Tofu is also a complete protein.
| # | Name | type | food_category | heme_type | typical_serving |
|---|---|---|---|---|---|
| 1 | Dried Thyme | Plant-based | Dried herb | Non-heme | ~1 g (1 tsp) = ~1.2 mg iron |
| 2 | Spirulina (dried) | Plant-based | Dried whole food | Non-heme | ~10 g (1 tbsp) = ~2.9 mg iron |
| 3 | Pork Liver (cooked) | Animal-based | Organ meat | Heme | ~100 g (~3.5 oz) = 18 mg iron |
| 4 | Chicken Liver (cooked) | Animal-based | Organ meat | Heme | ~100 g (~3.5 oz) = 13.1 mg iron |
| 5 | Dark Chocolate (70–85% cocoa) | Plant-based | Confectionery | Non-heme | ~30 g (2 squares) = ~3.6 mg iron |
| 6 | Beef Liver (cooked) | Animal-based | Organ meat | Heme | ~100 g (~3.5 oz) = 8.8 mg iron |
| 7 | Pumpkin Seeds (dried) | Plant-based | Seeds | Non-heme | ~30 g (1/4 cup) = ~2.6 mg iron |
| 8 | Hemp Seeds (dried, hulled) | Plant-based | Seeds | Non-heme | ~30 g (3 tbsp) = ~2.4 mg iron |
| 9 | Oysters (cooked, Eastern) | Animal-based | Shellfish | Heme | ~85 g (6 medium oysters) = ~6.1 mg iron |
| 10 | Tofu (firm, raw) | Plant-based | Soy product | Non-heme | ~100 g (3.5 oz) = 5.4 mg iron |
Foods are ranked by total iron content in milligrams per 100 grams of edible portion, in descending order (rank 1 = highest iron concentration). Values are drawn from the USDA FoodData Central database, which aggregates analytical data from government, academic, and industry sources. Dried spices and herbs are included for completeness, but the FAQ and item blurbs clarify which foods are practical sources in normal serving sizes. Heme and non-heme iron are not distinguished in the ranking — the values shown are total iron. All values reflect the food as typically consumed (cooked for meats, raw for produce, dry for herbs and spices).
Dried thyme has the highest iron concentration at 123.6 mg per 100 g, but it is a dried herb used in very small quantities. Among foods eaten in normal serving sizes, spirulina (28.5 mg/100 g), pork liver (18 mg/100 g), and dark chocolate (11.9 mg/100 g) are the richest practical sources.
The RDA for iron is 8 mg/day for adult men and 18 mg/day for premenopausal adult women. Postmenopausal women need only 8 mg/day. Pregnant women need 27 mg/day. Vegetarians may need up to 1.8 times the RDA because non-heme iron is less bioavailable.
Heme iron from animal foods is absorbed at 15–35% efficiency, while non-heme iron from plants is absorbed at 2–20%. However, you can significantly improve non-heme iron absorption by eating vitamin C-rich foods at the same meal (e.g., squeeze lemon on spinach) or by avoiding tea and coffee with meals.
Yes. Good plant-based sources include pumpkin seeds, hemp seeds, dark chocolate, tofu, lentils, chickpeas, kidney beans, and fortified cereals. Pairing these with vitamin C-rich foods — such as bell peppers, citrus, or broccoli — maximizes absorption.