
Our thyroid gland is one of the most crucial parts of the body that helps to ensure balance. When looking at health from a functional medicine perspective, we recognize that health is a multi-disciplinary approach with various factors. One often overlooked factor is the impact of heavy metals on thyroid function. As functional medicine practitioners, we work to uncover the root causes of health issues, and understanding the relationship between heavy metals and the thyroid is a crucial piece of the puzzle.
Today, we will explore this connection and shed light on how heavy metal exposure can disrupt thyroid health. We will also identify what proactive steps can be taken to address this concern.
The Crucial Role of the Thyroid
It is widely accepted that thyroid hormones, secreted from the thyroid, play important roles in energy metabolism, energy production, and maintaining overall homeostasis in the body (1). The thyroid plays a pivotal role in our well-being. When considering a functional medicine approach to help rebalance the thyroid, we go beyond treating symptoms; rather, we aim to identify and address the underlying imbalances that may be contributing to health issues.
Heavy Metals as Thyroid Disruptors
1. Enzyme Inhibition and Hormone Conversion
Within the body, there are certain enzymatic pathways that play a pivotal role in converting inactive thyroxine (T4) into its active form, triiodothyronine (T3). This conversion primarily occurs outside the thyroid gland and in our liver. The interference of heavy metals interrupts these enzymatic processes. Mercury and lead, in particular, have been shown to inhibit the activity of enzymes critical to the conversion of T4 to T3 (2).
The disruption in the conversion of thyroid hormones due to heavy metal interference can have metabolic consequences.
This includes:
- Decrease in energy production
- A slower metabolic rate
- Challenges in weight management
- Fatigue
- Cold intolerance
- Mood disturbances
2. Mineral Imbalances
As functional medicine practitioners, we also identify key vitamin and mineral deficiencies. Believe it or not, each vitamin and mineral is crucial to the function of different systems within the body. Some of the key vitamins and minerals related to the thyroid are selenium, calcium, iodine, zinc, and potassium.
If you suspect a thyroid imbalance, it is important to ensure that you work with a practitioner to understand how to rebalance your body properly. Taking supplements in isolation can be incredibly dangerous!
Selenium is a micronutrient recognized for its role in thyroid function; it is crucial for converting thyroxine (T4) to the more active triiodothyronine (T3). However, heavy metals, such as mercury, are recognized for their potential to act as competitors for binding sites that would otherwise host essential minerals like selenium (3). When heavy metals displace selenium, it interferes with the ability to convert T4 to T3, compromising thyroid hormone synthesis.
3. Functional Testing and Personalized Approaches
We recommend a Hair Tissue Mineral Analysis to understand your heavy metal toxicity. This is the best test to understand the depths of your exposure because it looks at your load from a 3-4 month period. It also provides a more well-rounded picture of what is happening inside the body as well. Using a hair sample can help pick up on imbalances that bloodwork can often miss. Understanding your toxic load can help you identify individualized and targeted nutrition support, detoxification protocols, and lifestyle modifications.
In acknowledging heavy metals’ impact on thyroid conversion, we can ensure that we are taking proactive measures to address the root causes of our thyroid concerns and begin to use targeted interventions from qualified practitioners to restore balance and promote optimal well-being for each individual. If you’d like to learn more about Hair Tissue Mineral Analysis testing, reach out to us!
- Chaoran Chen, Zhenxing Xie, Yingbin Shen, Shu Fang Xia, “The Roles of Thyroid and Thyroid Hormone in Pancreas: Physiology and Pathology”, International Journal of Endocrinology, vol. 2018, Article ID 2861034, 14 pages, 2018. https://doi.org/10.1155/2018/2861034
- Ivo Iavicoli, Luca Fontana & Antonio Bergamaschi (2009) The Effects of Metals as Endocrine Disruptors, Journal of Toxicology and Environmental Health, Part B, 12:3, 206-223, DOI: 10.1080/10937400902902062
- Schomburg, L. and Köhrle, J. (2008), On the importance of selenium and iodine metabolism for thyroid hormone biosynthesis and human health. Mol. Nutr. F

