Nutrient glossary
What is iron?
Iron carries oxygen in your blood; low iron means tiredness, and women lose enough monthly to need nearly double the male amount.
Reviewed 20 July 2026. General information, not medical advice.
The short version
Iron sits at the centre of haemoglobin, the protein that moves oxygen from lungs to muscles and brain. Run low and everything runs slow: iron deficiency is the most common nutrient deficiency in the world, and tiredness, breathlessness and poor concentration are its signature.
Meat iron (haem) absorbs at roughly 15 to 35%, plant iron closer to 2 to 20%. Vitamin C eaten in the same meal multiplies plant iron absorption, while tea and coffee with meals cut it.
Daily reference
8.7 mg a day
The reference is 8.7 mg a day for men and 14.8 mg for women aged 19 to 49, dropping to 8.7 mg after periods stop.
This is the fixed adult reference used across these pages. In the app, your amount adjusts to your body and way of eating.
Best food sources of iron
Full ranking| Food | Per serving | Per 100g |
|---|---|---|
| Oysters | 7.8 mg | 9.2 mg |
| Mussels | 6.7 mg | 6.7 mg |
| Lentils (cooked) | 6.5 mg | 3.3 mg |
| Duck Breast | 6.3 mg | 4.5 mg |
| Beef Liver | 5.6 mg | 6.5 mg |
| Pizza (cheese) | 5.4 mg | 2.5 mg |
| Cannellini Beans | 4.8 mg | 3.7 mg |
| Chickpeas (cooked) | 4.8 mg | 2.9 mg |
Common questions
- Why do women need more iron than men?
- Monthly blood loss removes iron that has to be replaced from food, so the reference for women 19 to 49 is 14.8 mg against 8.7 mg for men.
- How can I absorb more iron from plants?
- Pair iron-rich plants with vitamin C in the same meal, peppers with lentils, orange with fortified cereal, and keep tea and coffee away from mealtimes.