Do you know that there is a link between iron deficiency and thyroid function? Yes, it has been proven that iron deficiency may be one of the reasons why your thyroid symptoms cannot be controlled, even while you’re on thyroid medication.

Most hypothyroid patients suffer from iron deficiency, making it one of the most prevalent nutrient deficiencies in this group. It frequently occurs alongside deficiencies in magnesium, B12, and vitamin D. Doctors typically check for anemia by measuring hemoglobin and hematocrit levels, which assess the amount of iron in the blood. (1) While they diligently diagnose anemia, they often overlook testing for ferritin levels, which measure the body’s iron stores. This means that even if a patient does not have anemia, they could still have low iron stores affecting their thyroid function.

Iron plays a vital role in thyroid hormone function [2], and hypothyroid patients with depleted iron stores deserve special treatment and attention. Addressing iron deficiency can significantly improve thyroid function and alleviate symptoms.

In this article, we’ll get to learn all about Iron deficiency and thyroid  function :

• The importance of iron in thyroid function
• What ferritin is and how it affect thyroid function
• The importance of knowing your iron levels and ferritin levels
• The health implications of a very low or extremely high ferritin level
• Symptoms of low and high iron levels
• The link between low iron or high/ferritin levels and hair loss
• How can your diet contribute to a high or low iron level?
• What you can do if you have too little iron.

The Importance of Iron in Thyroid Function

Iron is a vital mineral that plays a crucial role in overall health, particularly in oxygen transport and red blood cell production. It is also essential for thyroid function, as it supports the production of key thyroid hormones such as triiodothyronine (T3) and thyroxine (T4). Iron deficiency can disrupt hormone levels, leading to symptoms of hypothyroidism, including fatigue, weight gain, and a slowed metabolism. Maintaining adequate iron levels is fundamental for proper thyroid health and supporting the body’s metabolic processes.

1. Connection Between Iron and Thyroid Function

Iron is indispensable for thyroid hormone production. It enables the synthesis of T3 and T4, hormones responsible for regulating metabolism and energy levels. Research from the American Thyroid Association emphasizes that iron deficiency impairs this process, particularly by reducing free T3 levels. This deficiency can exacerbate hypothyroid symptoms such as chronic fatigue, cold intolerance, and weight gain.

2. Impact of Iron on Hypothyroidism Treatment

T3 is the most active thyroid hormone, and insufficient iron hinders the body’s ability to produce it effectively. This may explain why many hypothyroid patients experience persistent symptoms even while on thyroid medication. Monitoring iron levels alongside thyroid hormone levels is crucial for effective treatment and symptom management.

3. Iron’s Role in Enzyme Activation for Thyroid Hormone Production

Iron is essential for activating thyroid peroxidase (TPO), an enzyme critical for thyroid hormone synthesis. TPO facilitates the iodination of tyrosine, a key step in producing T3 and T4. Without sufficient iron, this process becomes less efficient, leading to reduced hormone levels. Adequate iron intake supports optimal enzyme activity, ensuring healthy thyroid function and balanced metabolism.

Things to keep in mind about iron deficiency and thyroid function

When TSH levels are high, it indicates low thyroid hormone levels, and when TSH levels are low, it indicates high thyroid hormone levels.

When TSH levels are high, it indicates low thyroid hormone levels; when TSH levels are low, it indicates high thyroid hormone levels. Transferrin, a protein your liver produces, binds and transports iron in blood serum. It shuttles ingested iron from your food throughout your body via your bloodstream. The transferrin saturation test checks how many places on your transferrin can hold iron and how many are doing so. A low transferrin saturation indicates low iron levels in your serum.

Iron is essential for thyroid hormone production because it affects thyroid peroxidase, an enzyme in the thyroid gland. Since iron is heme-dependent, it means that iron is necessary for proper thyroid function. Studies have shown that low-iron alters the effects of iodine supplementation [5]. When this happens, some patients may believe that iodine supplementation doesn’t work, but the real issue is their low iron levels.

Most healthcare providers miss iron deficiency because they only check iron levels if they detect abnormal hemoglobin or red blood cell levels, which are clear indicators of iron deficiency anemia. Since iron studies are not routinely carried out, many patients with hypothyroidism do not realize that sub-optimal iron levels impair their thyroid function.

What is ferritin and how does it affect thyroid function?

Ferritin is a protein that binds with iron and acts as the body’s primary form of iron storage. The body regulates its iron levels by utilizing these stores until they are exhausted. Once the iron stores are depleted, normal iron levels cannot be maintained, leading to anemia.

On the contrary, ferritin levels may decrease before iron levels decline, indicating that intervention is necessary to prevent anemia.

The normal range of ferritin varies by gender, typically ranging from 30 to 300 ng/mL for men and 10 to 200 ng/mL for women [8], although these ranges can vary between laboratories.

The healthy serum ferritin range is typically between 20 and 80 ng/ml, with the ideal range being 40 to 60 ng/ml. Levels below 20 ng/ml strongly indicate iron deficiency, while levels above 80 ng/ml indicate excess iron. Healthcare providers often recommend iron supplementation for individuals below 20 ng/ml of ferritin.

Elevated ferritin levels can signal various conditions, including:

• Porphyria
• Hemochromatosis
• Taking excess iron supplements
• Hyperthyroidism
• Alcohol abuse
• Multiple blood transfusions
• Liver disease
• Hodgkin’s lymphoma

The link between low ferritin and thyroid function

It is important to note that hypothyroidism causes reduced levels of hydrochloric acid in the stomach, which in turn leads to poor iron absorption [9].

Low ferritin levels are problematic for hypothyroid patients for several reasons.

Firstly, an adequate supply of iron is necessary for normal thyroid hormone metabolism [6]. Normal thyroid hormone metabolism also depends on adequate supplies of zinc, selenium, and iodine [6]. It is important to note that zinc and iron interact in the intestine. This interaction is highly competitive. An excess of iron inhibits zinc absorption, while an excess of zinc inhibits iron absorption as well.

It is also important to note that symptoms of anemia bear a close semblance to symptoms of hypothyroidism, so the patient may believe that they are not taking adequate thyroid medication or that what they are taking isn’t effective.

For instance, hair loss is a symptom of hypothyroidism, but it may also be caused by iron deficiency [10, 11]. Many patients may believe that their hair loss is a sign of hypothyroidism completely unaware of the fact that they may have very low levels of iron/ferritin. It is mandatory that all hypothyroid patients get tested for ferritin/iron.

Thirdly, iron deficiency may result in the deactivation of the thyroid peroxidase enzyme. The thyroid peroxidase enzyme is iron-dependent, so its deactivation may reduce thyroid hormone production. There may be an alteration of thyroid metabolism as well, while the conversion of thyroxine (T4) into triiodothyronine (T3) may be slowed down, and the binding of T3 modified. There may also be an increase in the circulating levels of thyroid-stimulating hormone [5].

Clinical studies have also shown that levothyroxine treatment may be beneficial to patients with anemia and subclinical hypothyroidism [12].

So, it is important that patients with hypothyroidism undergo regular checks on their ferritin and iron levels as a deficiency in this mineral can cause complications for these patients [13].

The importance of knowing your levels of iron and ferritin for your thyroid health

Monitoring your iron and ferritin levels is essential for maintaining optimal thyroid health. These levels directly influence thyroid function, and understanding them can help prevent and manage thyroid-related symptoms. Here’s why it’s crucial:

1. Understanding Ferritin Levels

Ferritin is a protein that stores iron in your body. By measuring ferritin levels, healthcare providers can assess your overall iron status. Low ferritin suggests depleted iron stores, leading to iron deficiency, while high ferritin indicates either sufficient iron reserves or iron overload. For thyroid patients, especially those with hypothyroidism, low ferritin levels can worsen symptoms. Therefore, tracking ferritin levels regularly is vital.

2. Symptoms of Low Ferritin

When ferritin levels drop, a variety of symptoms may arise that affect daily life. These include dizziness, chronic headaches, irritability, shortness of breath, and fatigue. For hypothyroid patients, these symptoms may be mistaken for thyroid issues alone. However, they could also indicate iron deficiency. Replenishing ferritin stores is crucial for improving thyroid function and boosting overall energy levels.

3. Symptoms of High Ferritin

Elevated ferritin levels can also pose health risks, such as joint pain, stomach discomfort, and even chest pains or heart palpitations. These symptoms may suggest iron overload, a condition where excess iron is stored in the body’s organs, potentially leading to liver damage and other complications. Individuals with inflammatory conditions, such as autoimmune disorders, should be especially vigilant about monitoring ferritin levels.

4. Health Monitoring and Recommended Tests

These tests give your healthcare provider a clearer picture of your iron levels and storage, helping to identify conditions such as inflammation, anemia, hair loss, or thyroid-related issues linked to high or low iron and ferritin levels. They include;

• Complete Blood Count (CBC): This helps monitor iron status and detect potential health issues, such as inflammation or infection.
• Iron Test: This measures the iron level in your blood, helping to assess your overall iron status.
• Ferritin Test: This test reflects your body’s iron stores and is crucial for identifying iron deficiencies or overload.
• Transferrin Test: This measures the level of transferrin, a protein that binds to iron and helps transport it through your bloodstream. It provides insight into your iron metabolism.
• Total Iron-Binding Capacity (TIBC): This measures how well the body can transport and utilize iron, providing additional context about iron levels.

How a high or low ferritin level can affect your health

Hyperthyroidism and high levels of ferritin

An overactive thyroid interferes with iron metabolism and produces high ferritin. So, if you have hyperthyroidism, it is likely that your ferritin levels are on the high side.

Hypothyroidism and low levels of ferritin

We have established that most conventional doctors rarely order the ferritin test so many patients are left with the symptoms of hypothyroidism when in fact their health problems are caused by low ferritin levels. The first problem with iron is that one may be having severe iron deficiency but blood markers such as the red blood cell count and hemoglobin may be normal. and so many patients, mostly women are left misdiagnosed as non-anemic.

What causes iron deficiency and low ferritin?

Iron deficiency and low ferritin are caused by a lifelong history of blood loss mainly attributed to blood donations, menstrual bleeding, surgeries, pregnancies, atrophic gastritis, accidents, celiac disease, and antacid medications (calcium carbonate). If you have issues with your gut that are causing nutrient malabsorption, then your ferritin levels may be low as well. A vegan/vegetarian, or high-level athlete may also be at risk for low iron. These can cause excessive iron loss and poor iron absorption, resulting in low ferritin levels.

Do you know that high or low levels of iron and ferritin can cause hair loss?

We have established that iron is involved in many vital bodily processes including the creation of red blood cells.

Red blood cells help transport oxygen to various tissues and organs of the body. This can cause several problems including hair loss.

A study published in the Journal of Korean Medical Science found that generally, people who had pattern hair loss were deficient in iron compared to those who did not [10].

This claim has been backed up by other smaller studies. For example, a study published in the Indian Journal of Health Sciences and Biomedical Research found low serum ferritin levels in women with hair loss problems, implying that they were deficient in iron [14].

One reason why iron deficiency leads to hair loss is that when your iron level is low, the body takes the ferritin stored in the hair follicles and uses it in another part of the body. The reduced level of ferritin causes the hair to weaken, leading to hair loss.

Iron is an essential nutrient. This means that it can only be obtained through the diet. So, a person’s risk of low ferritin levels increases if they do not eat iron-rich foods. So, diet is an important factor in the link between iron deficiency an thyroid function.

Factors that may affect the concentration of ferritin in the serum include:

• Exercise habits
• Smoking
• Ethanol (alcohol) intake
• Diet

Does increasing ferritin levels help?

If your hair loss is due to low ferritin levels, then theoretically, upping your iron intake should replenish the ferritin in your hair follicles. Your healthcare provider will prescribe iron supplements and then observe your symptoms.

Conversely, raising ferritin levels will not have any positive effect on hair growth in healthy people who have normal ferritin and iron levels.

It is also worth knowing that too much iron may have side effects, including iron poisoning as well as tissue and organ damage, and may trigger inflammatory processes in the body.

Metals in dental work can also contribute to high iron and ferritin levels

Heavy metal poisoning is attributed to the accumulation of certain metals in the body due to exposure to industrial chemicals, water, food, or other sources.

Yes, the human body needs small amounts of specific metals (manganese, iron, chromium, copper, and zinc) to function normally, but these metals become harmful in toxic amounts.

If the soft tissues of your body accumulate an excess of these substances, the resulting toxicity can cause serious health problems.

As you know I am a hypothyroidism patient. I have been experiencing high levels of Iron and ferritin for some time, and my naturopathic doctor recommended I donate blood to lower my levels. Every time I donate blood, my levels drop too low, resulting in hair loss.

My doctor couldn’t identify why I had these high iron levels until I went to the dentist for a check-up. They discovered that I had a small cavity hidden inside a crown made of a combination of porcelain and metal. In total I had five dental crowns in my mouth that were leaching the metals into my blood, causing high levels of Iron and ferritin. I am in the process of replacing all my crowns and looking forward to testing my Iron again to see if my levels are optimal.

How can your diet contribute to a high or low iron level?

Recommendations to reduce high iron levels

1. Foods that block Iron from your food

• Organic low-fat yogurt or grass-fed raw cheese (feta cheese, parmesan cheese, goat cheese)
• Foods with tannins: coffee, tea, etc
• Foods that contain phytates or phytic acids, such as brown rice and whole-grain foods.
• Decreasing your intake of iron-rich foods like red meats from cow, lamb, and seafood, and eliminate iron-rich fortified foods.
• Avoid taking foods high in vitamin C or supplements with meals high in Iron

2. Other recommendations to reduce the iron and ferritin levels:

• Change your cookware to ceramic.
• Take turmeric supplements after your meals with iron-rich foods.
• Donate blood if you have too high levels of Iron and Ferritin

What you can do if you have too little Iron

• Taking supplements or eating foods with high vitamin C content with your meals will help absorb Iron.
• Eat foods high in iron: lean red grass-fed meats, organic chicken, wild salmon, seafood, organic dark green leafy vegetables, beans, lentils, and spinach. Boost iron absorption by consuming foods rich in vitamin C, such as citrus fruits, berries, apples, figs, apricots, bell peppers, and broccoli, with your meals.

Conclusion

Hypothyroid patients frequently experience low iron levels.

Iron plays a crucial role in thyroid function, and insufficient iron levels can lead to symptoms similar to hypothyroidism. Therefore, it is crucial to assess your iron levels within the optimal ranges.

If you have hypothyroidism and you also think that your iron levels are below optimal, then start by getting a full iron lab test panel.

Iron supplementation may help boost thyroid function by increasing T4 to T3 conversion and enhancing the effect of your thyroid medication.

And while checking your iron levels, also remember to check whether you’re deficient in other nutrients, such as vitamin B12, D, selenium, zinc, and magnesium. They are also common in hypothyroid patients.

References

1. Warner MJ, Kamran MT. Iron Deficiency Anemia. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448065/
2. Li S, Gao X, Wei Y, Zhu G, Yang C. The Relationship between Iron Deficiency and Thyroid Function in Chinese Women during Early Pregnancy. J Nutr Sci Vitaminol (Tokyo). 2016;62(6):397-401. doi:10.3177/jnsv.62.397
3. National Institutes of Health Office of Dietary Supplements. Iron.
4. Johnson Wimbley TD. Diagnosis and management of iron deficiency anemia in the 21st century. Therp Adv Gastroenterol. 2011; 4(3): 177-184. doi: 10.1177/1756283X11398736
5. Zimmermann MB, Köhrle J. The impact of iron and selenium deficiencies on iodine and thyroid metabolism: biochemistry and relevance to public health. Thyroid. 2002;12(10):867-878. doi:10.1089/105072502761016494

Eftekhari MH, Keshavarz SA, Jalali M, Elguero E, Eshraghian MR, Simondon KB. The relationship between iron status and thyroid hormone concentration in iron-deficient adolescent Iranian girls. Asia Pac J Clin Nutr. 2006;15(1):50-55.