Iron

What is Iron?

Iron is a mineral found in food in two forms: haem iron (in meat, fish and poultry), which is absorbed well, and non-haem iron (in plant foods and fortified foods), which is absorbed less well.^[1]

Its role in the body

• Part of haemoglobin, the protein in red blood cells that carries oxygen from the lungs to the body, and of myoglobin, which supplies oxygen to muscles.^[1]
• Needed for growth, brain development, energy production and making some hormones.^[1]

Important food sources

• Chicken, mutton, fish and liverProvide well-absorbed haem iron.
• Dals, rajma, chana, lobia and soybeansProvide non-haem iron.
• Green leafy vegetables such as amaranth, drumstick leaves and spinach
• Whole grains, millets and iron-fortified foods (for example fortified atta or rice, where available)
• Sesame seeds and datesContain some iron; portions are usually small.
• TipEating vitamin C-rich foods (such as guava, amla, citrus or tomato) with plant iron sources improves absorption. Calcium, phytate (in grains and beans) and some plant polyphenols can reduce it.

Recommended dietary intake

Signs sometimes associated with low levels

• Iron deficiency develops in stages. When iron stores run out, iron deficiency anaemia can develop, with tiredness, weakness, difficulty concentrating and stomach upset.^[1]
• It can also affect thinking, immunity and body temperature control. In infants and young children, it can affect development.^[1]

Why symptoms alone cannot confirm a deficiency

Signs like tiredness, weakness, hair fall or low mood are very common and have many possible causes, such as poor sleep, stress, infections, thyroid problems or other illnesses.

The same sign can come from several different nutrients, or from no nutrient problem at all.

Only a qualified clinician, using your history, an examination and, when needed, lab tests, can say whether a deficiency is present. This app cannot diagnose a deficiency from symptoms or from BMI.

Anaemia itself has many causes besides low iron, including low B12 or folate, long-term illness, blood loss and inherited conditions such as thalassaemia. Taking iron without knowing the cause can delay the right diagnosis.

Tests a clinician might consider

• Haemoglobin and haematocrit are common screening tests, but they are neither sensitive nor specific for iron deficiency.^[1]
• Serum ferritin, which reflects iron stores, is the most efficient test for diagnosing iron deficiency, though inflammation can raise it. Clinicians may add other iron studies.^[1]

Who is more likely to have low intake

• Pregnant women.^[1]
• Infants and young children.^[1]
• Women with heavy menstrual bleeding.^[1]
• Frequent blood donors.^[1]
• People with cancer, digestive disorders or heart failure.^[1]
• People following vegetarian diets, whose iron needs are estimated to be about 1.8 times higher because plant iron is absorbed less well.^[1]

Potential benefits and quality of evidence

• Iron is essential for making haemoglobin; enough iron prevents iron deficiency anaemia.^[1] Established
• Iron supplements in pregnancy reduce the risk of iron deficiency anaemia in the mother and some problems in the baby; guidelines differ on routine use.^[1] Established
• Iron supplementation or fortified foods reduce iron deficiency in infants and young children, but guidelines vary.^[1] Moderate evidence

Side effects

• Iron supplements can cause stomach upset, constipation, nausea, stomach pain, vomiting and diarrhoea. Taking them with food can reduce these effects.^[1]

Risks of too much

• Iron overload from food is unlikely in adults with normal digestion, but high-dose supplements can cause stomach problems and reduce zinc absorption.^[1]
• Swallowing a large amount of iron at once can be life-threatening. Accidental iron overdose has caused deaths in young children, so iron tablets must be kept out of children’s reach.^[1]
• People with hereditary haemochromatosis absorb too much iron and should not take iron supplements unless their doctor advises it.^[1]

Medicine and supplement interactions

• Levothyroxine (thyroid medicine): Taking iron at the same time can reduce how well the medicine works.^[1]
• Levodopa (for Parkinson’s disease and restless legs): Iron supplements can reduce its absorption.^[1]
• Proton pump inhibitors (e.g., omeprazole): Reduce stomach acid and can reduce absorption of non-haem iron.^[1]
• Calcium supplements: Calcium might reduce absorption of both haem and non-haem iron.^[1]
• Zinc: Iron supplements can reduce zinc absorption.^[1]

Never start, stop or change a prescribed medicine because of this list — talk to your doctor or pharmacist.

Pregnancy and breastfeeding

• Iron needs rise a lot in pregnancy, and anaemia in pregnancy is a concern. Many health services offer screening and iron supplements in pregnancy; the type and amount should be set by the antenatal care team, not self-chosen.^[1]

Kidney and liver cautions

• Anaemia linked to chronic kidney disease and other long-term illnesses is treated mainly by managing the underlying disease, sometimes with iron under medical supervision. People with iron-overload conditions such as haemochromatosis, which can damage the liver, should not take iron unless their doctor advises it.^[1]

Upper intake limits

When to talk to a professional

Talk to a doctor or registered dietitian before starting a supplement, especially if you are pregnant or breastfeeding, have a long-term illness, or take any regular medicines.

Do not start, stop or change a prescribed medicine because of anything you read here.

Supplements sold without a prescription are not automatically safe. Doses, quality and interactions still matter.

Seek medical care promptly if you have severe, sudden or worsening symptoms.

If you think you may be anaemic, ask a doctor for a blood test rather than starting iron on your own.

Keep all iron-containing products locked away from children.

Still being verified

• ICMR-NIN 2020 values for pregnancy/lactation and Tolerable Upper Limit not verified; not stated.
• Indian anaemia programme guidance (e.g., national iron-folic acid supplementation) not yet verified; not stated.

References

1. NIH Office of Dietary Supplements. Iron — Fact Sheet for Health Professionals (opens in a new tab) (2025-09-04). Accessed 9 Oct 2026.
2. ICMR-National Institute of Nutrition (India). A Brief Note on Nutrient Requirements for Indians, the Recommended Dietary Allowances (RDA) and the Estimated Average Requirements (EAR), ICMR-NIN, 2020 (opens in a new tab). Accessed 9 Oct 2026.

Sources checked: 9 Oct 2026