The possible link between low iron levels and low thyroid function

Ongoing trials, research and studies regularly reveal new information - some confirm what we already believe, some contradict long held opinion and others remain inconclusive.  

One body of research that has yet to be confirmed is the link between hypothyroidism and low iron levels.

We do know that normal thyroid hormone metabolism requires trace elements of iodine, iron, selenium and zinc and that imbalance in the usual combination can impair thyroid function. However we don’t conclusively know whether thyroid levels directly influence iron metabolism

Iron/hypothyroidism links in pregnancy

In 2015 researchers from Saint Pierre University Hospital in Brussels tested 1900 women in their first trimester and discovered that just over a third had low iron levels. Amongst those 20% had subclinical hypothyroidism and 10% showed signs of immune-system damage to their thyroid gland.

In those women with normal iron levels 16% had low thyroid levels and 6% had high thyroid antibody levels.  The researchers at the time said it was too soon to tell whether the low iron led to hypothyroidism or the other way round.

For full details of the research as presented in the European Journal of Endocrinology please click here

Graves’ disease and iron metabolism

In September this year research was carried out to see whether Grave’s Hyperthyroidism interferes with iron metabolism and raises the levels of ferritin (an iron-containing protein)

The researchers themselves acknowledged that the sample was small (31 patients) and that only a fraction of the factors that influence the proteins involved in iron metabolism were actually measured but the conclusion was that hepcidin (a key iron metabolism regulator) was affected by Graves’ disease and that the chief functional cells within the liver known as hepatocytes were being directly affected by thyroid hormones. See the more detailed article on this research just here 

This research demonstrates the particular challenge in finding clear cause and effect links…something which is further complicated by the fact that iron deficiency symptoms closely match the symptoms in hypothyroid patients for example:

• Tiredness
• Weakness
• Shortness of breath
• Cold hands and feet
• Brittle nails
• Headaches

What is perhaps more clear is that hypothyroidism is worse when you also have an iron deficiency.  So if, having allowed a reasonable time for your medication to take effect, you still feel unwell despite being treated for hypothyroidism you may want to request  a check for iron deficiency.

The link between heavy periods and hypothyroid patients

It is generally acknowledged that heavy periods and hypothyroidism is linked but which is the cause?

• Is it that heavy periods lead to low iron levels and anaemia which then affects the thyroid function?
• Or is that hypothyroidism causes low levels of thyroxine which then leads to heavy menstrual periods?

 First do no harm

In all areas of medicine, not only does research provide different answers, but the interpretation of that research can also vary - which is why many areas of endocrinology do not have black or white answers and why the risk of harm will always outweigh the unproven benefits.

This is of course most frustrating for patients who believe they can absolutely prove their own belief one way or another.  

As a specialist it is my job to consider their perspective as well as determining what relevant information is already on hand and then to help solve the underlying needs of my patients using experience, expertise and current best practice.

I hope you have found this helpful.

Although every effort is made to ensure that all health advice on this website is accurate and up to date it is for information purposes and should not replace a visit to your doctor or health care professional.

As the advice is general in nature rather than specific to individuals Dr Vanderpump cannot accept any liability for actions arising from its use nor can he be held responsible for the content of any pages referenced by an external link