Your kidneys and iron: what you need to know

Understand why iron is important for your health and why people living with kidney disease may have low iron levels and develop iron-deficiency anaemia.

Your kidneys and iron: what you need to know

What is iron?

“Iron is an important mineral for overall health,” says Amita Godse, Renal Dietitian at the Freeman Hospital in Newcastle upon Tyne and in the Kidney Kitchen.

“Most people can get the iron they need by eating iron-rich foods, but if you have chronic kidney disease (CKD), your body may not absorb the iron it needs from your diet.”

What does iron do?

“You need adequate stores of iron to allow your body to make red blood cells,” explains Dr Richard Hull, Consultant Kidney Specialist at St George's University Hospitals NHS Foundation Trust and New Victoria Hospital in London.

“Iron is one of the building blocks of haemoglobin, a red protein found in red blood cells. Haemoglobin carries oxygen around the body.”

What are the effects of low iron?

People with low iron levels can develop iron-deficiency anaemia.

Symptoms of anaemia can include tiredness, shortness of breath, lethargy and heart palpitations,” says Dr Hull.

Feeling cold all the time or having itchy or ‘crawly’ legs are less-common symptoms. People with anaemia can also experience chest pains or dizziness. “These symptoms are rare,” says Dr Hull.

How do I find out if my iron levels are low?

A simple blood test can show if you have low iron levels.

If you have CKD, your GP or kidney care team will monitor your condition through regular blood tests. Among other things, these tests will show if you have iron-deficiency anaemia.

What anaemia treatments are available for people with CKD?

“There are two main options for treatment of iron-deficiency anaemia,” explains Dr Hull.

Oral iron therapy, taken as a tablet, is often the first line treatment. If patients do not respond or have advanced kidney disease, we often use intravenous iron as it is more effective.”

Intravenous iron therapy can be given by injection or as an infusion or drip. “For most patients on dialysis, we give iron intravenously on the dialysis machine,” says Dr Hull.

What are the potential side effects of anaemia treatments?

People taking oral iron therapy can experience gastrointestinal side effects such as constipation, diarrhoea, nausea, stomach ache or loss of appetite.

“When iron is given as an injection, it can sometimes damage a vein,” says Dr Hull. With intravenous iron there’s a risk of allergic reactions. Some people experience symptoms such as headache, a metallic taste, nausea and vomiting. “These risks are very uncommon and most patients tolerate treatment without a problem,” he adds.

Keep your kidney team updated about any side effects you experience, so you can talk through the treatments available and agree on what would be best for you.

If I eat more iron-rich foods, will my anaemia improve?

Speak to your health care professional or a registered dietitian before making any changes to your diet,” says kidney dietitian Amita Godse. “An iron-rich diet may not help people with CKD to raise their iron levels because people with CKD don’t absorb iron well from the food they eat.”

Many foods that are high in iron are also high in potassium and/or phosphorous. Some people with CKD already have high levels of these minerals in their blood. Your potassium and phosphorous levels will be monitored by your GP or kidney care team as part of your regular blood tests. If you are found to have high levels of potassium and/or phosphorous, your kidney team will give you personalised advice about the best way to bring levels of these minerals down.

This patient information resource has been made possible with a financial contribution from GSK. GSK has had no editorial input into or control over the content which has been independently owned and created by Kidney Care UK.