Paper about the relationship of iron deficiency... - Thyroid UK

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Paper about the relationship of iron deficiency and thyroid function

diogenes profile image


Front. Endocrinol. | doi: 10.3389/fendo.2021.629831

Iron deficiency, a risk factor of thyroid disorders in reproductive-age and pregnant women: a systematic review and meta-analysis

Jingyi Luo1, Xiaoxia Wang1, Li Yuan2* and Lixin Guo1*

1Beijing Hospital, China

2University of Chinese Academy of Sciences, China

Background: Iron deficiency (ID) is concerned as the most common nutritional deficiency worldwide. The effects of ID on thyroid function and autoimmunity in pregnant women and reproductive-age women are controversial. The aim of the current study was to summarize the evidences and evaluate the relationship between ID and thyroid disorders.

Methods: In this systematic review and meta-analysis, Studies published on the Cochrane, Embase, Medline and PubMed databases by October 2020 were searched. 636 studies discussed the correlation between ID and thyroid disorders were eligible in the initial search. Pooled mean differences (MD) and 95% confidence intervals (CI) were calculated for the assessment of thyrotropin (TSH) and free thyroxine (FT4) levels. Combined odd ratios (OR) and 95% CI were calculated for the assessment of the prevalence of overt and subclinical hypothyroidism, positive thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb).

Results: For women of reproductive age, ID could significantly increase the risk of positive TPOAb ( and both positive TPOAb and TgAb). The meta-analysis of pregnant women showed that pregnant women with ID had increased serum TSH levels and decreased FT4 levels Meanwhile, the prevalence of overt and subclinical ) hypothyroidism in pregnant women with ID was significantly increased.

Conclusions: ID may adversely affect thyroid function and autoimmunity of pregnant and reproductive-age women and it is very necessary for monitoring iron nutritional status and early treatment of ID for them.

13 Replies

Thanks. Not published yet . Just a meta-analysis?

They appear to have just studied associations. I looked at a number of studies some time ago and from memory there were associations but nothing showing moderate iron deficiency (ID) caused thyroid disorders. (There was a study in rats that demonstrated this but I suspect they invoked severe ID). On the other hand it did look like hypothyroidism caused iron deficiency which was somewhat refractory to supplementation and resolved when the patient was adequately treated with thyroid hormone.

I have noticed a few other posters mention their iron levels raise when their thyroid medication is optimum.

Notice the work is again Chinese. They use this approach to get as many papers out as possible to justify their existence

SlowDragon profile image

Personally I think the emphasis is the wrong way around

It’s perhaps not Iron deficiency that CAUSES thyroid issues.....but thyroid disease that RESULTS in iron deficiency

jgelliss profile image
jgelliss in reply to SlowDragon

I beg to differ.From my personal experience. I was infact overdosed with T4 after my TT for suppression purposes and had all sorts of symptoms including palpitations anxiety hair loss etc.My Iron always tested low. Supplementing with Iron made a huge difference for me.

SlowDragon profile image
SlowDragonAdministrator in reply to jgelliss

Yes, it’s true we need optimal vitamin levels in order to utilise thyroid hormones as well

So it’s a mix of both

With hypothyroidism as initial cause of thyroid disease.....iron deficiency is often present. Is the iron deficiency results or cause ? Or a mix of both

jgelliss profile image
jgelliss in reply to SlowDragon

Your very right. Nutrients are very essential to make our thyroid meds work well for us. Personally I was convinced once my nutrients where up to par my thyroid meds worked so much better too . Take home lesson is that nutrients are not to be taken lightly.

Mostew profile image
Mostew in reply to SlowDragon

Which comes first . Chicken or egg !!!

shaws profile image
shawsAdministrator in reply to jgelliss

I really do not know why those who've had their thyroid gland removed altogether aren't prescribed - at the very least - a combination of T4/T3. There used to be the original replacement 'called NDT (natural dessicated thyrid hormones) made from animals' thyroid glands and saved lives from 1892 but now withdrawn due to False Statements made about it. Its safety was well established as there were no blood testsin 1892 but restored health to those who would have died prematurely. It also contains the thyroid hormones a healthy thyroid gland would have produced.

I have only read your summary but I would like to tell you my experience. I am 72 and when I was 47 I was admitted to a psychiatric unit in our local hospital owing to worsening symptoms, leading to screaming and panic attacks. On admission I had blood tests and was found to be so low in iron I had iron injections. Even after those they thought I was bleeding internally as the iron must still have been low and I had to have camera investigations down throat and in rear end. I was in there 4 months and 3 months the following year. I wonder if this was thyroid and/or B12 related. Things seemed to change with me in the 3rd pregnancy - mental things and I also put on loads of weight. I didn't think anything of it at the time, just thought as my 3rd pregnancy was in my early 30's and the previous two were early twenties that it was my age causing me to put on weight. I think all my problems started from that point onwards but I never went to the doctors about it until my problems in my 40's.

shaws profile image

I doubt few doctors are aware of signs/symptoms and U believe quite a number of people could have been diagnosed with a psychiatric problem. when they actually had an undiagnosed problem with their thyroid gland.

They still do not test Free T4 and Free T3 often enough and concentrate upon TSH alone.

Many people who're hypothyroid gain weight but it usually that their thyroid hormone replacement i.e. levo, doesn't raise their metabolism high enough so weight is gained. I assume that the medical professionals then believe we eat the 'wrong type of food' that causes weight gain whereas it is due to being hypothyroid (hypo meaning low). So our metabolism is lowered quite a lot, thus weight is gained.

Chicken and the egg!

I have a mild Haemophilia not diagnosed until after my two pregnancies although I lost a lot of blood during both deliveries and bled for 10 months afterwards.

I have been clinically anaemic, despite constant iron tablets which really upset my stomach, since the first birth at 22 until menopause.

I went to work in NZ for a time and when my NZ Consultant got my first blood results he wrote an angry letter to my UK GP to say I had been neglected by the British NHS. Sheffield Haemophilia Centre had told me there was nothing could be done and it wasnt until I went to NZ that I was told about Transanamic Acid!

Anyway I’m the only one in my family that has this Haemophilia gene and the only one now with a Thyroid problem x

shaws profile image
shawsAdministrator in reply to MichelleHarris

I'm sorry you have several autoimmune diseases. If we've got one we can develop others.

I hope you can resolve your hypo symptoms quite soon. You had an awful time after the delivery of two babies and I'm surprised you didn't have an appointment with a specialist to resolve your awful symptons.

Hopefully, with the advice from members on the forum, you will be able to resolve your thyroid symptoms and you reach an optimum dose of thyroid hormones. Hopefully your GP is aware how to do so. If not members will be able to help.

Unfortunately in the UK they seem to be poorly traine

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