Can Iron Affect Blood Sugar?

An Overview of Haemochromatosis

Haemochromatosis is an inherited condition in which sufferers experience a build-up of iron in their bodies, termed ‘iron overload’.1 It is most commonly caused by a genetic mutation of the homeostatic iron regulator (HFE) gene. This affects the absorption of iron from food. 2

Usually, the body will alter how much iron it should absorb from food depending on its requirement. However, this does not happen in people with haemochromatosis; instead, too much iron is absorbed, causing the overload. This can be dangerous as excess iron can affect the function of several organs and glands, including the heart, liver, and pancreas. Sufferers may also experience joint issues. 

According to the National Organisation for Rare Diseases, 3 if left untreated, haemochromatosis causes an increased risk of: 

  • Liver Disease
  • Insulin Resistance, Which Can Later Lead To Type 2 Diabetes
  • Heart Disease

Once diagnosed, patients with haemochromatosis will be treated using venesection. This involves regularly drawing about 450ml of blood at a time, which stimulates the body to produce new red blood cells, causing any excess iron in the glands, organs, and joints to enter the blood.4 This is done until the levels of serum ferritin and transferrin saturation (which are two blood tests used to determine if someone has haemochromatosis and how severe it is) are at an acceptable level. From there, patients will be asked to control their iron levels by avoiding foods like shellfish and not eating vitamin C or iron supplements.1

Some people with particular difficulties in drawing blood may be offered chelation therapy,2 which involves taking medication that draws iron out of the organs, glands, and joints and into the urine or stool and having it removed that way.

Can Haemochromatosis Cause Diabetes?

As mentioned above, haemochromatosis can affect glands in the body, particularly the pancreas. When the level of iron in the blood is too high, it will be stored in different organs and glands to achieve homeostasis (this is also known as the body’s ‘normal’). 

Normally, the pancreas will receive signals indicating whether blood sugar levels are too high or too low. This then stimulates the pancreas to release different hormones, for example, glucagon, if the blood sugar is too low, and insulin if it is too high. These hormones will act on different parts of the body and facilitate the movement of sugar into or out of the blood.5 If iron is stored in the pancreas, it can cause damage. This is because free iron (iron that is not bound to another structure, like the red blood cells) takes part in a reaction called the ‘Fenton reaction’, which produces hydrogen peroxide. Hydrogen peroxide is dangerous for the cells of the pancreas, causing them to become impaired or die. 6 This affects the pancreas’ ability to produce and release its hormones. The pancreas then fails to release enough insulin causing the person to become diabetic. 

Diabetes caused by haemochromatosis is known as ‘secondary diabetes’ as it is not caused by diet or an inherent issue with the pancreas but rather another disease that affects the function of the pancreas. 7

Preventing Diabetes Caused by Haemochromatosis

Diabetes UK, a charity that supports people who suffer from diabetes regardless of what caused it, states that the best way to prevent secondary diabetes caused by haemochromatosis is to receive the appropriate treatment for haemochromatosis.7

The Link Between Diabetes and Anaemia

Diabetes and anaemia are both common disorders affecting millions of people worldwide. Diabetes occurs when the body's ability to control the amount of sugar in the blood is compromised. Anaemia occurs when there are insufficient red blood cells or haemoglobin (chemical-carrying oxygen). Low haemoglobin could also be due to iron deficiency in the blood. 

The two are not intrinsically linked, meaning that one does not necessarily cause the other. However, diabetes can increase the risk of a person developing anaemia. This is because diabetes can damage the blood vessels in the kidneys resulting in kidney damage.8 The kidneys play a crucial role in the release of the hormone erythropoietin, which binds to red blood cells to protect them from damage that could lead to anaemia. It can also stimulate the bone marrow stem cells (which are cells that have not ‘grown up’ and do not have a job yet) to become red blood cells. 10  It is believed that some diabetes medicines may decrease the amount of iron that is absorbed from food.

The Causes and Symptoms of Anaemia:

According to World Health Organisation (WHO), anaemia can have many causes, 11 including:

Created by Avantika Pandey

 Anaemia has the following symptoms 12

Created by Avantika Pandey

Testing for Anaemia

Initially, anaemia does not produce very noticeable symptoms. However, as anaemia worsens, deficiency increases and a person’s symptoms become more severe. Some cases of anaemia are discovered by accident when doctors are looking into something else.

 Testing is done usually via a full blood count,13 which measures:

  • how much haemoglobin (or iron) there is in the blood (to diagnose iron deficiency anaemia)
  • the size of the red blood cells (which can be useful in diagnosing non-iron deficiency anaemia)
  • how much vitamin B12 is there in the blood

When to Worry and When to Visit a Doctor

If you or someone you love is experiencing unexplained tiredness, a lack of energy or exhibiting any other symptoms of anaemia, it is best to get this checked by a doctor. In the beginning stages, anaemia does not have any lasting damage. However, as it progresses, there is an increased risk of long-lasting damage.12 This may include issues with your immune system or heart. It can also worsen any other illnesses you may suffer from.

Typically, people with anaemia will be given iron supplements to increase their iron levels, as well as a list of iron-rich foods to add to their diet. More severe anaemia may require blood transfusions or an intravenous supply of iron. If the anaemia is caused by hormonal issues or is secondary to kidney disease, erythropoiesis-stimulating agents may be given to help signal to the bone marrow stem cells to grow into red blood cells. 14

It is advised to see your doctor as early as possible. The sooner you are diagnosed, the sooner you can receive treatment and lifestyle advice to reverse anaemia.


  1. Hemochromatosis | niddk [Internet]. National Institute of Diabetes and Digestive and Kidney Diseases. [cited 2022 Oct 12]. Available from:
  2. Haemochromatosis - causes [Internet]. 2019 [cited 2022 Oct 12]. Available from:
  3. Classic hereditary hemochromatosis [Internet]. NORD (National Organization for Rare Disorders). [cited 2022 Oct 12]. Available from:
  4. Treatment & care [Internet]. Haemochromatosis UK. [cited 2022 Oct 12]. Available from: 
  5. Röder PV, Wu B, Liu Y, Han W. Pancreatic regulation of glucose homeostasis. Exp Mol Med. 2016 Mar 11;48:e219. 
  6. Kresser C. Does iron overload cause diabetes and heart disease? [Internet]. Kresser Institute. 2017 [cited 2022 Oct 12]. Available from:
  7. Haemochromatosis and diabetes [Internet]. Diabetes UK. [cited 2022 Oct 12]. Available from: 
  8. CDC. Make the connection [Internet]. Centers for Disease Control and Prevention. 2021 [cited 2022 Oct 12]. Available from:
  9. BSN NJ RN. Diabetes and anemia: are they related? [Internet]. 2017 [cited 2022 Oct 12]. Available from:
  10. Erythropoietin | you and your hormones from the society for endocrinology [Internet]. [cited 2022 Oct 12]. Available from:
  11. Anaemia [Internet]. [cited 2022 Oct 12]. Available from:
  12. Vitamin B12 or folate deficiency anaemia - Symptoms [Internet]. 2017 [cited 2022 Oct 12]. Available from:
  13. How is anemia diagnosed? [Internet]. Hematology-Oncology Associates of CNY. [cited 2022 Oct 12]. Available from:
  14. Anemia - iron-deficiency anemia | nhlbi, nih [Internet]. [cited 2022 Oct 12]. Available from: 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Aisha Hayat

Bachelor of Science - BS, Biomedical Sciences, General, University of Bristol

Aisha is a Biomedical Sciences graduate with an understanding about research techniques, the pharmacology of drugs and the pathophysiology of illnesses. She is currently working as a healthcare assistant and has experience of research being used in a clinical setting, as well as the process of diagnosing and treating illnesses.

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