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Vitamins & minerals health centre

Dietary iron and iron supplements

Iron is a mineral that is necessary for life. Iron plays a key role in the making of red blood cells, which carry oxygen through the body.

Iron uses

Iron supplements are most often used to treat certain types of anaemia. Anaemia is a low level of red blood cells, which can cause fatigue and other symptoms. Anaemia can be a sign of another disease or health condition. There is good evidence that iron supplements can treat iron deficiency anaemia caused by:

Iron supplements are often recommended for infants and toddlers, teenage girls and women who are pregnant or of childbearing age. Ask your doctor about other uses of iron supplements.

Iron doses and instructions for use

The recommended daily intake includes the iron you get from both the food you eat and any supplements you take. In the EU, the recommended daily amount of  iron for women is 14.8mg per day, and for men it is 8.7mg a day. 

When they are recommended, take iron supplements with a full glass of water and food. At high doses iron is toxic, especially for children. The NHS advises that 20mg or less of iron supplements a day is unlikely to be harmful for adults.

Iron food sources

For most people, a good diet provides enough iron. Natural food sources of iron include:

  • Meat, fish and poultry
  • Vegetables, such as spinach, kale and broccoli
  • Dried fruits and nuts
  • Beans, lentils and peas

Iron is also added to many fortified foods, such as cereals and enriched breads.

Iron supplement information

Iron often comes in tablet, capsule or liquid forms. Iron is a standard ingredient in many multivitamin products. As with any supplement, keep iron supplements in a cool, dry place, away from humidity and direct sunlight, and out of reach of children.

Iron warnings

Side-effects. Taken at normal doses, iron supplements may cause upset stomach, stool changes and constipation.

Risks. Do not start taking iron supplements unless your healthcare professional advises you that you need them. That is especially true if you have a chronic health condition. Women who are, or plan to become pregnant should also check with their doctor before they start daily iron supplements.

Interactions. Iron can interact with many different drugs and supplements, including antacids, anti-inflammatory painkillers, antibiotics, calcium and others. If you take regular medicine, ask your doctor or pharmacist if it is safe for you to take iron supplements.

Overdose. Signs of an iron overdose include severe vomiting and diarrhoea, stomach cramps, pale or bluish skin and fingernails, and weakness. Iron overdose is a common cause of poisoning in children. It can be fatal. Treat these signs as a medical emergency. Call 999 and get immediate medical help.

WebMD Medical Reference

Medically Reviewed by Dr Rob Hicks on December 19, 2016

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