Iron is an essential trace mineral needed for oxygen transport, energy production, cognitive performance, and normal immune function. This page explains what iron does, the difference between haem and non-haem iron, who is more likely to run low, how iron is tested, and why unnecessary supplementation can backfire.
Plain-English summary: iron helps carry oxygen around the body and supports normal energy production. Too little iron can leave people flat, pale, short of breath, or mentally foggy. Too much iron is not harmless either. Iron is one of those nutrients where guessing is stupid. Testing matters.
Iron is central to haemoglobin, the protein in red blood cells that carries oxygen. It also helps form myoglobin, which stores oxygen in muscle, and supports enzymes involved in cellular energy production.
Haem iron comes from animal foods such as red meat, poultry, and seafood. It is generally absorbed more efficiently.
Non-haem iron comes from plant foods, eggs, fortified foods, and supplements. Its absorption is more affected by meal composition, gut environment, and inhibitors such as tea, coffee, and phytates.
Iron absorption is highly variable. That is why two people can eat similar food and end up with very different iron status.
A rough rule: absorption tends to be lower in vegetarian patterns than in mixed diets, and inflammation can distort both absorption and lab interpretation.
Low iron does not just affect oxygen carrying capacity. It can affect concentration, work capacity, exercise tolerance, mood, and day-to-day function. In infants and pregnancy, iron status matters even more because of rapid growth and higher physiological demand.
Iron can come from both animal and plant foods. Haem iron is generally easier to absorb. Non-haem iron can still contribute meaningfully, especially when paired with vitamin C-rich foods and sensible meal planning.
| Food | Type | Typical serve | Approx. iron | Notes |
|---|---|---|---|---|
| Beef | Haem | 100 g cooked | ~2.5–3.5 mg | Well-absorbed compared with most plant sources. |
| Lamb | Haem | 100 g cooked | ~1.5–2.5 mg | Useful contributor in mixed diets. |
| Chicken thigh | Haem | 100 g cooked | ~1.0–1.5 mg | Lower than red meat but still useful. |
| Oysters / mussels | Haem-rich seafood | 100 g | Variable, often high | Can be excellent sources depending on species. |
| Lentils | Non-haem | 1 cup cooked | ~3–6 mg | Pair with tomato, capsicum, or citrus to help absorption. |
| Chickpeas | Non-haem | 1 cup cooked | ~4–5 mg | Useful plant source, but absorption varies. |
| Tofu | Non-haem | 100 g | ~2–5 mg | Depends on brand and processing. |
| Fortified breakfast cereal | Non-haem / fortified | 1 serve | Variable | Check the actual label. Fortification levels differ a lot. |
| Spinach | Non-haem | 1 cup cooked | ~3–6 mg | Contains iron, but absorption is limited by oxalates and meal context. |
| Pumpkin seeds | Non-haem | 30 g | ~2–3 mg | Good addition, not a magic fix. |
| Eggs | Mixed / lower absorption | 2 eggs | ~1–2 mg | Contributes some iron, though not the strongest source. |
Values are approximate and vary by food type, cut, brand, fortification, and cooking method. The amount of iron in food is not the same thing as the amount actually absorbed.
Iron deficiency can exist before full iron-deficiency anaemia develops. That means someone can feel awful even before haemoglobin crashes.
Too much iron is not a harmless wellness strategy. The body has limited ways to actively excrete iron, so overload can matter.
Iron status is not assessed well by one number alone. A decent iron work-up usually looks at storage, transport, red blood cells, and clinical context.
| Test | What it helps show | Key limitation or note |
|---|---|---|
| Ferritin | Iron stores | Low ferritin strongly supports iron deficiency, but ferritin can rise with inflammation, infection, liver disease, and other stress states. |
| Full blood count (FBC) | Anaemia pattern and red cell indices | Useful, but iron deficiency can exist before anaemia shows clearly. |
| Transferrin saturation | Circulating iron availability | Helpful in deficiency and overload work-ups. |
| Serum iron | Current circulating iron | Can fluctuate and is usually not enough on its own. |
| CRP or inflammatory context | Whether inflammation may distort ferritin interpretation | Important when ferritin looks “normal” but clinical suspicion remains. |
| Haemochromatosis genetics | Inherited overload risk | Relevant in the right family or lab context. |
Iron interpretation should be based on symptoms, ferritin, full blood count, transferrin saturation, inflammation status, and the likely cause of deficiency or overload. The number is only part of the story.
Iron supplements can interfere with the absorption of some antibiotics and other minerals such as zinc and calcium. Dose spacing matters. That is basic supplement hygiene, not optional detail.
Haem iron comes mainly from animal foods and is usually absorbed more efficiently. Non-haem iron comes from plant foods, fortified foods, eggs, and supplements, and its absorption is more affected by meal composition.
Yes. Iron deficiency can exist before full iron-deficiency anaemia develops. That is one reason ferritin and broader iron studies can matter even when haemoglobin is not dramatically abnormal.
It can, especially for non-haem iron. Tea and coffee are best separated from iron-rich meals or iron supplements when absorption is a concern.
No. Fatigue has many causes. Taking iron without checking your status first can be pointless or even harmful, especially if iron overload risk is present.
Yes. Ferritin is useful, but it also rises with inflammation, infection, liver issues, and other stress states. That is why interpretation needs context.
Common groups include menstruating women, pregnant women, frequent blood donors, endurance athletes, people with restrictive diets, and people with gastrointestinal conditions or possible blood loss.
TGA-compliant note: This page is educational and describes normal physiological roles, dietary sources, testing concepts, and evidence-informed safety considerations. It does not claim to diagnose, treat, cure, or prevent disease.