When you think about the nutrients you need for a healthy thyroid, you’ll probably be first thinking about iodine, selenium, and tyrosine. And you wouldn’t be wrong, but one of the essential minerals for thyroid function that often gets overlooked is iron.
Iron is an essential nutrient that helps us to carry the oxygen around in our red blood cells, and one of the most common symptoms experienced with iron deficiency (anemia) is fatigue, which funnily enough, is also a common symptoms of hypothyroidism, alongside heart palpitations, hair loss, and shortness of breath, difficulty concentrating and low mood.
Iron deficiency is found in up to 60% of patients with hypothyroidism, and a correlation has been found between low levels of iron and hypothyroidism in women. (1)
A point to consider is that if you have thyroid problems, the normal reference ranges for what healthy iron levels are will be a bit different. I will go into what I consider to be an ideal iron profile for hypothyroidism below.
Being deficient in iron can affect thyroid function, and poor thyroid function can affect iron levels.
Iron is part of the thyroid team
Iron has a huge role to play in the health of our thyroid hormones, which I will go into more detail about below. A coexisting deficiency of iron alongside other nutrients can have an added effect, stopping those nutrients from working effectively – this is particularly so in the case of iodine (2) (3).
Several studies have found that supplementing with iron alongside iodine produces a greater effect on thyroid health than with iodine alone, in those who are deficient (4).
How Iron affects the thyroid
There’s a few key areas where iron is involved in keeping thyroid levels happy:
If you are iron deficient the thyroid hormone can’t get properly transported into the cells where it can do it’s thing. This will still show as having normal levels of T3 in blood tests, but you’ll be experiencing symptoms of underactive thyoid.
One of the main enzymes you need to synthesise the thyroid hormones, thyroid pyroxidase, is heme-dependant, which means that it requires iron to work effectively. If you are deficient in iron this enzyme can be reduced by 30-50%, which slows the conversion of T4 to T3 (2).
Iron deficiency can also disrupt adrenal health, which is another area that when out of balance can cause thyroid problems (5).
How your Thyroid affects Iron Levels
In women with hypothyroidism, your periods are more likely to be heavier (a condition called menorrhagia) and this can result in an increased blood loss and consequently losing iron as well (5) (6) (7).
Your thyroid hormones affect your gastric acid secretion, and so having hypothyroidism can result in lower absorption of nutrients, in particular iron which requires plenty of acid to be absorbed(8) (9).
People with thyroid problems often have difficulty digesting wheat and this can cause inflammation in the digestive system, impairing nutrient absorption.
It’s not uncommon for people with thyroid problems to be inflamed and/or overweight (especially in hypothyroidism) and this can affect how much iron you can absorb via a hormone called Hepcidin. This hormone increases when you’re inflamed, which can be from a result of things like when you’re stressed, worn out, have an infected, on certain medications and inflammation also increases when you’re overweight.
It’s quite normal for our body to lock iron away and stop absorption when we’re sick, as this is one of our innate mechanisms for starving infections. But when this message gets skewed and iron absorption is affected long term, that
Testing for Iron deficiency
Before undergoing an iron test, you will need to stop any iron supplements at least 5 days before, as the supplements can skew the test. It’s also a good idea to ensure you’re properly hydrated.
When testing iron studies there are a few markers performed. Below I give the normal reference ranges, however please remember that different labs have different values that they work with so always check with your practitioner before starting any changes based on these results, I have included the reference ranges to give you an example of where in them you would want to approximately aim to be.
Ferritin (how much iron you have stored).
This has a huge reference range and it’s different for men and women. For women the labs will say normal is anywhere between 12-200ug/L, however I say aim for this to be 70-90, and about 100 for men.
It’s important to take this marker into consideration with the other readings, because situations like inflammation or an infection will cause your ferritin levels to appear much higher, and if associated with a high level of serum iron and saturation it may indicate haemochromotosis (a condition that affects iron excretion) or another genetic imbalance such as MTHFR.
Very low levels of ferritin can also indicate heavy metal toxicity, a common issue in thyroid problems.
Serum iron (how much iron is floating around your blood stream bound by transferrin).
Normal reference range is between 5-30.
This will drop lower in acute infections, and will be low in chronic iron deficiency and blood loss.
You want to aim to be in the lower 20s, men slightly higher.
TIBC (Total Iron Binding Capacity)
This goes higher in iron deficiency and
Normal reference ranges 45-72
Saturation % (essentially it’s serum iron divided by total iron binding capacity).
A few notes on improving iron levels
- Be careful of which type of iron you use, as some can be constipating. Recently, topical iron has become available as an option, which may be worthwhile discussing with your practitioner.
- Take iron supplements with a glass of water on rising before other supplements by 30 minutes. Ok to take at the same time as thyroxin.
- Iron is best absorbed alongside vitamin C.
- Consider your intake of drinks which may reduce iron absorption such as tea (these contain tannins which can bind to the iron).
- Check other reasons for iron deficiency such as iron loss through bleeding (e.g. with heavy periods) or digestive issues.
VIDEO – Nutrients for optimal thyroid health.
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- Interacting effects of selected trace and toxic metals on thyroid function. Jain, R B and Choi, Y S. 1, s.l. : International Journal of Environmental health research, 2015, Vol. 19.
- The impact of iron and selenium deficiencies on iodine and thyroid metabolism: biochemistry and relevance to public health. Zimmermann, M B and Köhrle, J. 10, s.l. : Thyroid: official journal of the American Thyroid Association., 2002, Vol. 12.
- The influence of iron status on iodine utilization and thyroid function. Zimmermann, Michael B. s.l. : Annual Review of Nutrition, August 2006, Vol. 26, pp. 367-89.
- The impact of common micronutrient deficiencies on iodine and thyroid metabolism: the evidence from human studies. Hess, Sonja Y. 1, s.l. : Best Practice and Research. Clinical endocrinology & metabolism., 2010, Vol. 24.
- Menorrhagia–a pragmatic approach to the understanding of causes and the need for investigations. Fraser, I S. 11, s.l. : British Journal of Obstetrics and Gynaecology, 1994, Vol. 101.
- Profound hypothyroidism-induced acute menorrhagia resulting in life-threatening anemia. Moragianni, V A and Somkuti, S G. 2, s.l. : Obstetrics and Gynecology, 2007, Vol. 110.
- Menorrhagia and hypothyroidism. Weeks, Andrew D. 649, s.l. : BMJ, 2000, Vol. 320.
- Gastroprotective effects of Nigella Sativa oil on the formation of stress gastritis in hypothyroidal rats. Abdel-Sater, Khaled A. 2, s.l. : International Journal of Physiology, Pathophysiology and Pharmacology., 10 March 2009, Vol. 1, pp. 143-149.
- Effects of thyroid hormones on basal and stimulated gastric acid secretion due to histamine, carbachol and pentagastrin in rats. Rafsanjani, F N, et al. 4, s.l. : Saudi Medical Journal, 2003, Vol. 24.