Iron-rich foods, ranked by milligrams

The RDA is 8 mg/day for men and 18 mg for women aged 19-50, and clams, liver, and fortified cereal top the list, but heme iron from meat absorbs far better than the non-heme iron in beans and spinach. The mg-per-serving ranking, why absorption matters more than the label, and how vitamin C changes the math.

1. 01

   Clams, oysters, and mussels: ~8-24 mg per 3 oz

   Cooked clams are the single densest source by a wide margin at ~24 mg per 3 oz, several times the male target in one serving, with mussels (~6 mg) and oysters (~8 mg per 100 g) close behind (USDA FoodData Central). Crucially this is heme iron, absorbed at 15-35% regardless of the rest of the meal, so the usable dose is far higher than the milligram figure alone suggests. Shellfish also carry B12, zinc, and selenium, so a serving a few times a month meaningfully raises average iron status without any supplement.

2. 02

   Liver and organ meats: ~5-11 mg per 3 oz

   Chicken liver leads at ~11 mg per 3 oz and beef liver supplies ~5 mg, both as well-absorbed heme iron alongside a very high dose of B12, folate, and preformed vitamin A (USDA). Organ meats are the most nutrient-dense common food for iron, which is why they were a traditional remedy for anemia. The vitamin A load is the one caveat: it is high enough that pregnant women are advised to limit liver, so it is a powerful occasional food rather than a daily staple.

3. 03

   Fortified breakfast cereals: up to ~18 mg per serving

   Many fortified cereals are formulated to 100% of the Daily Value, up to ~18 mg of iron per serving, added as ferrous or electrolytic iron (USDA). The catch is that this is non-heme iron absorbed at the low end, often further blunted by the calcium in the milk poured over it, which competes for uptake. Eaten with a glass of orange juice rather than milk, and away from coffee, a fortified cereal becomes a genuinely useful iron source, especially for vegetarians who cannot rely on heme sources.

4. 04

   Legumes: white beans, lentils, and chickpeas, ~4.7-8 mg per cup

   Canned white beans lead the legumes at ~8 mg per cup, with cooked lentils (~6.6 mg) and chickpeas (~4.7 mg) close behind, making them the backbone of plant-based iron (USDA). The iron is non-heme and bound by phytates, so absorption is modest, but the fix is well established: pairing legumes with a vitamin C source such as tomatoes, peppers, or citrus can roughly double uptake. Soaking and sprouting dried legumes reduces phytate further, and legumes double as low-cost protein, so they do several jobs at once.

5. 05

   Red meat: beef and lamb, ~2-3 mg per 3 oz

   A 3 oz serving of beef or lamb supplies ~2-3 mg of iron, less than the plant sources above on paper but far more in practice, because it is heme iron absorbed at 15-35% (USDA). Red meat also enhances the absorption of any non-heme iron eaten in the same meal, the so-called meat factor, so a modest portion of beef alongside beans lifts the iron yield of the whole plate. It arrives with zinc, B12, and complete protein, which is why regular meat eaters rarely fall short on iron.

6. 06

   Spinach and cooked leafy greens: ~4-6.4 mg per cup

   Cooked spinach carries ~6.4 mg of iron per cup and Swiss chard and beet greens are similar, which reads impressively but overstates the usable dose (USDA). The iron is non-heme and greens are high in oxalates, which bind iron and lower absorption, so the Popeye reputation outruns the biology. Greens are still worth eating for the iron, but the yield rises sharply when they are cooked to shrink the volume and served with a squeeze of lemon or another vitamin C source rather than relied on alone.

7. 07

   Tofu, pumpkin seeds, and dark chocolate: ~2.5-3.4 mg per serving

   Firm tofu supplies ~3 mg per half cup, pumpkin seeds ~2.5 mg per ounce, and an ounce of dark chocolate ~3.3 mg, giving plant-based eaters several concentrated top-ups (USDA). All are non-heme, so the vitamin C pairing rule applies, but they stack well across a day and the same pumpkin seeds lead the magnesium-rich foods list too. Their value is convenience: a handful of seeds and a block of tofu built into meals add several milligrams before any main dish, which is how a plant-based day reaches the target.