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:

• pregnancy
• heavy menstrual periods
• kidney disease
• chemotherapy

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 supplements have also been studied for treatment of ADHD (attention deficit hyperactivity disorder). While early data has suggested a benefit, more study is needed before iron can be recommended for ADHD.

Iron doses and instructions for use

The recommended daily amount (RDA) includes the iron you get from both the food you eat and any supplements you take.  In the EU, the RDA for iron is 14mg per day. Strict vegetarians and vegans, as well as pregnant and breastfeeding women, may need to take in higher levels of iron. 

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 FSA advises that 17mg 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. It is possible that iron can increase the risk of heart disease, although this is by no means proven. The findings are inconsistent and more research is needed. 

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.