Iron is essential for oxygen transport (hemoglobin), energy metabolism, and immune function. There are two forms: heme iron (animal sources, well absorbed) and non-heme iron (plant sources, absorption influenced by dietary factors). For guidelines and safety, see the NIH ODS professional fact sheet on iron.
Top 15 — iron-rich foods (heme vs non-heme)
Indicative values (mg/100 g or per serving); variations depending on cut, preparation, and cooking. For precise values, use the USDA FoodData Central and Ciqual table.
Heme iron (animal sources)
- Liver (beef/chicken/pork): ~5–15 mg/100 g
- Oysters/clams/mussels: ~5–10 mg/100 g
- Beef (steak, braised): ~2–4 mg/100 g
- Sardines (canned): ~2–3 mg/100 g
- Turkey/chicken (dark meat): ~1–2 mg/100 g
- Pork/lamb: ~1–2 mg/100 g
Non-heme iron (plant sources)
- Fortified cereals: ~4–18 mg/serving (check label)
- Lentils/chickpeas/beans (cooked): ~2–4 mg/100 g
- Tofu (firm): ~2–3 mg/100 g
- Spinach (cooked): ~2–4 mg/100 g
- Quinoa (cooked): ~1.5–2.5 mg/100 g
- Pumpkin seeds/sesame seeds: ~3–15 mg/100 g
- Dark chocolate (70–85%): ~5–12 mg/100 g
- Dried apricots/prunes: ~2–3 mg/100 g
- Cashews/almonds: ~2–4 mg/100 g
Common portions: 120–150 g cooked meat/fish, 150–200 g cooked legumes, 30 g nuts/seeds, 1 serving fortified cereal.
Optimizing absorption
- Heme vs non-heme: heme iron (animal) is better absorbed (15–35%) than non-heme iron (plant, 2–20%).
- Vitamin C: enhances non-heme iron absorption; combine legumes/grains with citrus, bell peppers, tomatoes, strawberries. See our vitamin C-rich foods guide.
- Inhibitors: phytates (whole grains, legumes), polyphenols (tea, coffee), calcium (dairy) can reduce non-heme iron absorption. Space out consumption if iron status is low.
- Cooking: use cast iron cookware to increase iron content; soaking/sprouting legumes/grains reduces phytates.
- Timing: take iron supplements on an empty stomach for best absorption (if tolerated); with food if gastric upset occurs.
Daily guidelines (recommended intakes)
Usual guidelines: ≈ 8 mg/day (men), ≈ 18 mg/day (premenopausal women), ≈ 8 mg/day (postmenopausal women). See the NIH ODS professional synthesis and EFSA dietary reference values.
| Population | Daily guideline |
|---|---|
| Adult men | ≈ 8 mg/day |
| Premenopausal women | ≈ 18 mg/day |
| Postmenopausal women | ≈ 8 mg/day |
| Pregnancy | ≈ 27 mg/day |
| Breastfeeding | ≈ 9–10 mg/day |
Risks, interactions and precautions
- Iron deficiency: anemia (fatigue, pallor, shortness of breath), impaired immunity, cognitive difficulties. See our iron deficiency symptoms guide.
- Iron overload: hemochromatosis (genetic), excessive supplementation; can cause liver damage, heart problems, diabetes. UL (adults): 45 mg/day (from supplements/fortified foods), according to the NIH ODS fact sheet.
- Interactions: iron supplements can reduce absorption of thyroid medications (levothyroxine), antibiotics (tetracyclines, quinolones), bisphosphonates; space doses by 2–4 hours.
- Gastric upset: iron supplements often cause constipation, nausea, dark stools; start with lower doses, take with food if needed.
Prioritize food sources (meat, fish, legumes, fortified cereals, nuts, seeds). If deficiency is documented, supplement under medical guidance and monitor ferritin/hemoglobin. Avoid self-supplementation at high doses.
Sources and further reading
- Mechanisms, needs, safety: NIH ODS professional fact sheet – Iron.
- Composition tables: USDA FoodData Central, Ciqual table (ANSES).
- EU reference values: EFSA dietary reference values for iron.
