Image shows some facts on iron and why it is important for the thyroid.

Top Thyroid Nutrients – Iron

Our thyroid glands are very nutrient hungry.  Alongside making sure you eat balanced meals (you can download the free balanced meal planner for hormonal harmony here) thise series covers my top 4 Micronutrients for optimal thyroid function.  There are some tips on how you can maximise these in each meal too and some signs that you may be deficient too.  I hope you find this series helpful and the links to the other micronutrients are below.


An Iron deficiency can cause your TSH to go up. It is a very common deficiency in hypothyroidism and a common deficiency in menstruating women in general. It is often undiagnosed too. Even being on the low end of normal it can affect the activated thyroid hormone (T3) getting into your cells. During menstruation adolescent girls and premenopausal Women lose considerable amounts of iron.  Low iron can lead to heavy bleeding and of course heavy bleeding can lead to low iron so it can be a vicious cycle.

Iron in my opinion is a huge topic so I will do my best to summarise. Iron is present in foods in 2 forms – Haem iron (ferrous iron) and non-haem iron (ferric iron). Around 40% of iron in meat, fish and poultry is haem iron and the rest is non-haem iron. Haem iron is well absorbed (around 25%) while non haem is poorly absorbed (2-20%). Non-haem iron is what is present in plant foods and processed (fortified) foods. Non-haem iron absorption is inhibited by plant chemicals like phytates. Non-haem iron is more efficiently absorbed alongside vitamin c, but it can also increase the very common side effects of iron supplements.

Black tea and coffee can reduce absorption of both dietary and supplemental iron so consume it away from iron containing meals and iron supplements. Don’t underestimate this, tea can reduce iron absorption by 90%! Iron can also effect a lot of medications in various ways, including thyroid medication. Take your meds at least 2 hours away from your iron or iron rich meals. On the flip side stomach acid medication like omeprazole and antacids can interfere with iron absorption.

Also please note that high ferritin can be a sign of high inflammation levels in the body. It may be used by your GP to monitor a known deficiency or as routine pregnancy screening, but otherwise the full panel should be looked at, not just ferritin. 

Leafy greens are the best plant source of iron and you can also use concentrated plant sources if avoiding animal products and not at the point of needing a supplement. Kelp, blackstrap molasses and brewers yeast are all good examples of this.

Check out the other top 3 nutrients I recommend for thyroid health below:


Vitamin D



If you want a personalised take on the best nutrients are for you right now, consider booking your very own Health and Hormone audit. 

If you suspect a thyroid disorder I can give you recommendations for testing, supplements and nutrition to help you get clear on what is going on and get you started on the path to feeling much better.

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Julie McGill

Perimenopausal mother to 4 and holistic clinical nutritionist helping women thrive through perimenopause, naturally.

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Hi, I'm Julie

I help Women thrive through perimenopause, naturally.  I’m a qualified & holistic clinical nutritionist, mum to 4 and also navigating my way through second puberty.

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