Iron: functions, foods, deficiency and supplements

Find out all about iron, including what it does, how much you need, where to find it and who might need to supplement their diet

Overview

What is iron and what does it do?

Iron is an essential mineral that’s needed for making haemoglobin, a protein found in red blood cells that helps transport oxygen around the body. It plays a key role in supporting the immune system, too.¹ Iron also helps maintain our energy levels, regulate body temperature and may even improve athletic performance.² If you don’t get enough iron, you can feel tired and may be more susceptible to infections.³ A severe lack of iron could even lead to iron deficiency anaemia, which causes pale skin, feeling out of breath and heart palpitations.⁴

Function of iron

What does iron do in the body?

Iron is important for making haemoglobin in red blood cells, which carries oxygen around the body into our muscles and tissues. Iron is also found in muscle cells as myoglobin, which accepts and stores oxygen for later use.⁵ You also need iron to support your immune system. If you’re not getting enough in your diet, you may be more susceptible to illnesses and infection.⁶

How much iron do I need?

Women aged 19-50 need 14.8mg a day, and men 8.7mg a day. Women need more iron than men due to menstruation, pregnancy and breast-feeding. After 50, women need 8.7mg of iron a day.⁷ If you’re not getting enough iron from non-meat sources in a vegan or vegetarian diet, if you experience heavy periods or have a stomach ulcer that may cause internal bleeding, you will need more iron.⁸

How much iron do children need?

• 0-3 months – 1.7mg a day
• 4-6 months – 4.3mg a day
• 7-12 months – 7.8mg a day
• 1-3 years – 6.9mg a day
• 4-6 years – 6.1mg a day
• 7-10 – 8.7mg a day
• 11-18 years – girls 14.8mg, boys 11.3mg a day⁹

Iron foods

Which foods are the best sources of iron?

The best animal-based sources of iron include:¹⁰

• red meat, including pork and lamb
• fish and shellfish
• liver or liver paté – avoid during pregnancy, due to high levels of vitamin A
• eggs

The best plant-based sources of iron include:¹¹

• dried fruits, particularly figs and apricots
• dark green leafy vegetables
• nuts and seeds
• chickpeas
• beans
• fortified breakfast cereals

Iron from animal sources (haem iron) is more easily absorbed by the body, but you can increase absorption of non-haem iron from plant sources by eating them with a source of vitamin C.¹² So, you could have a glass of orange juice along with a veggie curry but avoid having a cup of tea, as it can stop your body absorbing non-haem iron.¹³ Leave at least an hour either side of eating before your cuppa.

Iron deficiency

What are the symptoms of iron deficiency?

If your body doesn’t get enough iron, you won’t have enough haemoglobin for your tissues and muscles to function normally. This leads to a condition called iron deficiency anaemia.¹⁴ Symptoms of iron deficiency anaemia¹⁵ include:

• fatigue
• feeling weak or tired
• pale skin
• shortness of breath
• heart palpitations
• headache
• sore tongue
• hair loss
• mouth ulcers

More than two billion people across the globe have iron deficiency anaemia, making it the world’s most common nutritional deficiency.¹⁶ Women are particularly at risk, due to periods, pregnancy and breastfeeding. Vegetarians, vegans or those who don’t eat a lot of meat may also have low iron levels.

What happens if I have too much iron?

If you consume too much iron (more than 20mg a day) either through food or supplements, you may experience:¹⁷

• stomach ache
• nausea or vomiting
• constipation

In very high doses, iron can be toxic or even fatal for young children.

Iron supplements

When should I take iron supplements?

You may need to take iron supplements if you are:

• anaemic
• have heavy periods
• vegan or vegetarian
• don’t eat enough iron-rich foods¹⁸

Always talk to your GP before taking iron supplements. The NHS advises taking no more than 17mg a day, unless advised by your doctor.

Should children take an iron supplement?

Breast-fed babies usually get enough iron from their mother’s milk for the first six months, while bottle-fed babies will typically consume a formula fortified with iron.¹⁹ Children should get all the iron they need from a healthy balanced diet. However, if they’re vegetarian, vegan or a fussy eater, they may need to consider a supplement. Always talk to their doctor before giving them any iron supplements, as high doses can be fatal in young children.²⁰

Should women take an iron supplement in pregnancy?

Pregnant women do need more iron, but should be able to get the amount they need from their daily diet. Iron supplements are only recommended if blood tests show the mother is anaemic.²¹

What are the potential benefits of taking an iron supplement?

The major benefit of taking iron supplements is to help prevent iron deficiency anaemia. But they may also be useful if you exercise regularly – we lose iron through our sweat, which could be a problem if your iron levels are already low²² – and can help maintain healthy skin, hair and nails, too.²³ Shop Minerals Advice is for information only and should not replace medical care. Please check with your GP before trying any remedies. Written by Nic Hopkirk on December 4, 2018 Reviewed by dietitian and nutritionist Azmina Govindji on December 10, 2018 Sources 1. British Dietetic Association. Iron. Available from: https://www.bda.uk.com/foodfacts/iron 2. Megan Ware. Medical News Today. Everything you need to know about iron. Available from: https://www.medicalnewstoday.com/articles/287228.php 3. As Source 1 4. NHS. Iron deficiency anaemia. Available from: https://www.nhs.uk/conditions/iron-deficiency-anaemia/ 5. University of California San Francisco. Haemoglobin and Functions of Iron. Available from: https://www.ucsfhealth.org/education/hemoglobin_and_functions_of_iron/ 6. Dr Mary Jane Brown, PhD. Healthline. 10 signs and symptoms of iron deficiency. Available from: https://www.healthline.com/nutrition/iron-deficiency-signs-symptoms 7. NHS. Iron. Available from: https://www.nhs.uk/conditions/vitamins-and-minerals/iron/ 8. As Source 4 9. As Source 1 10. British Nutrition Foundation. Iron. Available from: https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/minerals-and-trace-elements.html?start=8 11. As Source 1 12. As Source 10 13. Zijp IM, Korver O, Tijburg LB. Effect of tea and other dietary factors on iron absorption. Available from: https://www.ncbi.nlm.nih.gov/pubmed/11029010 14. As Source 4 15. As Source 4 16. As Source 10 17. As Source 7 18. As Source 2 19. Scientific Advisory Committee on Nutrition. Feeding in the First Year of Life. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/725530/SACN_report_on_Feeding_in_the_First_Year_of_Life.pdf 20. As Source 7 21. Southampton Children’s Hospital. How to increase your child’s iron intake. Available from: http://www.uhs.nhs.uk/Media/Controlleddocuments/Patientinformation/Childhealth/Ironintake-patientinformation.pdf 22. Ottomano C, Franchini M. Sports anaemia: facts or fiction? Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3417720/ 23. Wright JA, Richards T, Srai SKS. The role of iron in the skin and cuteaneous wound healing. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3417720/