Hashimoto’s and Low Iron Levels: Navigating the Complex Relationship

August 22, 2023

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I'm a Nutritionist, Metabolic Balance coach, foodie, Mamma & Hashimoto's thriver. A few years ago Hashi's was kicking my in the butt. Now I help other women to regain their energy & maintain a healthy weight with ease. 


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If you’re on this journey to reclaim your health and vitality, you already know that Hashimoto’s disease can be quite the puzzle! There is one puzzle piece that is very common amongst my clients, so many Hypothyroid women are iron deficient. I would wager that it is the most common deficiency I see in clinical practice.

So today we’re going to dive deep into the realm of iron deficiency and iron deficiency anemia, sadly a very common companion to Hashimoto’s and one that exacerbates one of the most debilitating symptoms Hashi’s sufferers experience, fatigue. A word of caution, treating iron deficiency is not as simple as popping a pill! Read on to find out more.

A note on anemia: Anemia is when you have too few healthy red blood cells. This can be due to severe iron deficiency as well as deficiencies in B12, folate and general blood loss. You can be iron deficient or suboptimal without being anemic.


The Iron-Thyroid Connection

Your two main thyroid hormones, thyroxine (T4) and triiodothyronine (T3), require iron for synthesis and conversion into active forms that get sent all throughout the body to influence everything from your heart rate to your digestion and metabolism. So your thyroid can have quite a handicap without adequate iron stores. Iron plays crucial roles in many other related systems, particularly immune function and energy production.


Why Iron Deficiency and Hashimoto’s Go Hand in Hand

When there isn’t enough T3 making it to cell receptors in systems like your gastrointestinal tract it can also impact iron stores as there is a breakdown in digestive function, particularly the acidity of your stomach that impedes absorption of this all important mineral. You need a lot of stomach acid to properly digest and absorb iron but in those with Hashimoto’s and Hypothyroidism the stomach environment tends to be more alkaline. If the small intestine where iron is absorbed is inflamed due to indirect consequences of Hashimoto’s like a SIBO infection or intestinal permeability then iron absorption will suffer.

Iron absorption can also take a hit due to the inflammation caused by Hashimoto’s. During times of inflammation, the body might sequester iron as a protective mechanism. This means that iron might be stored in a way that reduces its availability for use by pathogens, including bacteria, that could potentially thrive in an inflamed environment. This leads to lower levels of iron in your blood, setting the stage for that constant fatigue you’ve been grappling with.

FYI iron isn’t the only nutrient deficiency associated with Hashimoto’s & Hypothyroidism. Vitamin D, A, magnesium, selenium, iodine, B12, B1 and zinc are also often deficient.


Other root causes of low iron

Other causes of iron deficiency include heavy menstrual bleeding, another common symptom in Hashimoto’s. Chronic gastrointestinal bleeding due to gastritis, ulcers, inflammatory bowel disease will also deplete iron stores. This will often change the colour of stools to very dark brown to black and can be confirmed via a fecal occult stool test with your GP.

Undiagnosed or poorly managed celiac disease can also cause iron deficiency. Always rule this out if you have an autoimmune disease like Hashimoto’s because you are at higher risk of celiac disease. SIBO infections or anything affecting digestion in the small intestine will also impede iron levels. Low dietary intake of heme iron, including vegetarian or veganism. Proton Pump Inhibitor medication suppresses stomach acid and therefore leads to nutrient deficiencies like iron. Check out the blog I wrote about PPI’s.


Signs and symptoms

I bet by now you’re wondering if your iron might be low. Iron is needed to form hemoglobin, part of red blood cells that transport oxygen into cells, when there isn’t enough oxygen to go around you can start to feel pretty symptomatic. Here are some of the signs and symptoms that some can experience with iron deficiency:

  • Fatigue, even after adequate rest.
  • A feeling of weakness and a sense of low stamina may occur due to reduced oxygen delivery to tissues and muscles.
  • Pale pallor due to a decreased amount of hemoglobin in red blood cells, especially noticeable in the face, lips, and inside the lower eyelids.
  • Shortness of Breath, reduced oxygen-carrying capacity of the blood can result in shortness of breath. For example if you can’t climb a set of stairs without puffing that wouldn’t normally be a problem.
  • Headaches and Dizziness.
  • Cold Hands and Feet due to poor circulation.
  • Brittle Nails that can break easily and may develop into a concave or spoon shape in severe cases.
  • Rapid Heartbeat.
  • Unusual cravings, pica is a craving for non-nutritive substances such as ice, dirt, or paper.
  • Difficulty Concentrating.
  • Mood changes, including irritability and feeling low.
  • Heavy menstrual bleeding (more than 40ml per cycle) can cause low iron and also be a symptom.
  • Hair loss.

Sound familiar? Many of these symptoms overlap with hypothyroidism/Hashimoto’s. That’s why having thorough pathology semi-regularly is important if you’re trying to get your health into the best shape possible.



To have a proper iron level assessment you need to look at inflammatory markers, full blood count and iron studies. No one marker can tell you whether your iron is replete. If inflammation has been ruled out and your ferritin, transferrin saturation, Haemoglobin, MCV and MCH are low then it’s time to start looking at why your iron levels might be affected.


So should I supplement?

It’s not always appropriate to reach straight for an iron supplement. In fact it’s not ideal due to how inflammatory high doses of iron can be on your system. If you already have inflammation or a current infection then you need to hold off on supplementation.

Another factor to consider is the state of your digestion. If you tend towards constipation then iron can make things much worse. This is part of the reason why I never recommend retail brands of iron available in pharmacies (I’m looking at you Ferrograd C!) as they are often forms of iron that constipate, cause GI inflammation and aren’t even that bioavailable. Meaning your body can’t digest much of it. When necessary I only ever prescribe iron bisglycinate as it is much gentler on tummies and far more bioavailable than forms such as ferrous sulfate.

If you can identify what may be causing the low iron from the list above then now is the time to start taking steps to address it. If your iron is very low and you’re working on your underlying cause then you will likely need a supplement to help you get your levels up as it can be quite difficult with food alone. But don’t DIY it, see a practitioner or iron savvy GP to get the right dose and directions for optimal absorption. If taken in too high doses or too rhythmically then Hepcidin (a liver protein) will also become elevated and bind to iron, preventing absorption. I’ve seen iron stores go DOWN with inappropriate supplementation eeek!

In some cases an iron infusion may also be necessary. Due to the very large dose and inflammatory potential they really should be a last resort though and sadly they don’t always deliver the relief from fatigue one is expecting.

Sorry I don’t have a straightforward answer but I did warn you that treating iron deficiency can be complicated! There are a few habits and interventions you can adopt to help it on its way below.


Improving digestion of iron

I’ll first explain the difference between heme and non-heme iron. Heme iron is found exclusively in animal proteins, particularly red meats & some seafood. Non-heme iron is found in vegetarian sources like dark leafy greens and legumes. Non-heme iron needs to be converted by the body into heme iron to be utilised in red blood cells. Unfortunately we are not able to absorb as much non-heme iron from the food we eat (up to 10%) whereas heme iron is more readily absorbed (up to 35%). As long as there is no breakdown in the digestive function you will absorb more if your iron stores are low. Pretty nifty!

So when consuming foods rich in either non-heme or heme iron and trying to improve your iron stores it’s important you avoid the following within two hours as they inhibit iron absorption:

  • Dairy products
  • Calcium supplements
  • Tannin rich tea and coffee
  • Zinc supplements.

If you consume animal proteins plan to have roughly 3 red meat, 3 fish meals per week and seafood such as octopus, clams, oysters and mussels as convenient in addition to a broad variety of vegetables, leafy greens, legumes, nuts, seeds and eggs. If you can manage the strong taste, liver is rich in iron and highly bioavailable due to its high Vitamin A content too. Add small amounts to beef dishes like spaghetti bolognese or have chicken liver pate 3 times per week.

If you are a vegan or vegetarian then you need to be very intentional about planning your meals to ensure you are getting enough iron and really focusing on improving digestion while working on any other underlying causes of iron deficiency.

Regardless you should be doing what you can to improve your digestion by stimulating stomach acid and digestive power. You can do this by:

  • Ensuring your zinc levels are good
  • Being properly hydrated
  • Taking minimum 4 hour breaks in between meals
  • Chewing well
  • Eating consciously
  • Avoid eating when stressed
  • 1-2 tsp of apple cider vinegar diluted in water before meals
  • Avoiding drinking water during meals.


Helpful supplements (other than iron)

Lactobacillus Plantarum (299v) a probiotic strain clinically shown to help with iron absorption and my favourite place to start as a less inflammatory and gentler way to coax those iron levels up through your diet.

Lactoferrin is a protein found in breastmilk that helps with iron absorption specifically. You’ll find some practitioner only iron supplements contain lactoferrin. It is believed that lactoferrin can help with the increase of hepcidin that can block iron absorption.

Freeze dried Liver capsules with meals are a great option for those who can’t stomach eating liver but want to use food to boost iron levels. Rich in vitamin A which can help improve iron stores.

Vitamin C via supplement or food alongside an iron rich meal aids in absorption. Think an orange (or the juice of 1-2 freshly squeezed oranges), kiwi fruit, strawberries, cruciferous vegetables, capsicum.

B12 & folate are also important for healthy red blood cells so get them checked too if you suffer from the symptoms above. These two will often be deficient if iron is too.

In summary, if your iron is low or you have iron deficiency anemia then it’s important you find the underlying cause and start working on that while you work to increase your intake and absorbability of iron whether that be via a supplement or optimising your daily food intake and habits.

If you made it this far you deserve a medal! Thanks for bearing with me as we explore this not-so-simple but all-too-common problem. We deserve to feel fantastic and have abundant energy despite our Hashimoto’s diagnosis and I hope this helped you gain a clearer understanding of how you can help your iron stores.

Get in touch if you have any questions.



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