Iron — how to spot deficiency, get more from food, and use supplements safely

Do you feel tired, pale, or short of breath climbing stairs? Those are common signs of low iron. Iron powers your red blood cells so they can carry oxygen. When stores run low you notice fatigue, brain fog, fast heartbeat, and sometimes restless legs. A simple blood test (hemoglobin and ferritin) tells the real story. If you feel off, get tested before starting supplements.

Best food sources and how to boost absorption

Choose iron-rich foods first — they’re safer and give other nutrients too. Heme iron from animal products absorbs best: beef, lamb, chicken liver, and shellfish like clams and oysters. Plant sources include lentils, chickpeas, tofu, spinach, and fortified cereals. Plant iron (non-heme) absorbs less, but you can help it:

- Eat vitamin C with meals (orange juice, bell peppers, strawberries). It can double plant-iron absorption.
- Avoid coffee or tea at meals — tannins block absorption. Wait at least an hour after eating.
- Calcium and some antacids reduce absorption. If you need calcium or antacids, space them apart from iron-rich meals.

Iron supplements: which type, how much, and safety tips

Over-the-counter iron pills are common but take them carefully. Ferrous sulfate is the usual choice; one 325 mg tablet contains about 65 mg elemental iron. For treating iron-deficiency anemia doctors often aim for roughly 100–200 mg elemental iron daily, split into two or three doses. For prevention (like in pregnancy) smaller doses — often around 30–60 mg elemental — are typical. Always follow your clinician’s advice.

Common side effects are stomach upset, nausea, and constipation. To reduce these, try taking iron with a small snack, switch to ferrous gluconate (lower elemental iron) or a slow-release form, or split the dose. Expect dark stools — it’s normal, not dangerous. If you get severe stomach pain, vomiting, or black tarry stools, stop and seek care.

If you have a condition like hemochromatosis (genetic iron overload) or repeated blood transfusions, extra iron can be harmful. Don’t take supplements without testing if you have a family history of iron overload.

Some medicines interact with iron. Take iron at least 2 hours before or 4 hours after levothyroxine, some antibiotics (like tetracyclines and fluoroquinolones), and bisphosphonates. Ask a pharmacist if you’re unsure.

Severe or resistant iron deficiency may need IV iron given by a clinic or hospital. That’s for people who can’t tolerate pills, have poor absorption, or have heavy ongoing blood loss. It’s effective but should be done under medical supervision.

Bottom line: If you suspect low iron, get tested. Try food first, use supplements only as directed, and watch for interactions and side effects. When in doubt, talk to your doctor — they’ll guide testing and the safest treatment for you.