Selenium & your Thyroid

After a long time being absent from blogging due to completing my masters, I’m finally back and so excited to have time again for Nutritious Roots. Lots of exciting plans ahead so watch this space.


Selenium deficiency is considered a major health problem for 1 billion people worldwide. The selenium content of all UK soils is desperately low and intake is half what it should be due leaching by the sulphate in acid rain and ammonium sulphate fertilizers, a shortage of uptake by plants, over-cultivation of soil and lack of crop rotation.


A healthy functioning metabolism and protection of the thyroid gland is largely dependent on selenoproteins called glutathione peroxidases (GPx) and deiodinases. As selenoproteins are selenium-dependent, availability of this mineral is vital for thyroid function and for many systems that are crucially linked to thyroid health. For this blog I am going to focus on GPx and I will cover deiodinases in my next post.


GPx enzymes require selenium and are highly expressed in the thyroid gland acting as antioxidants to protect the thyroid gland from oxidative damage. Hydrogen peroxide (H2O2) is a form of reactive oxygen species (ROS). A high amount H2O2 is produced during the natural synthesis of thyroid hormones. This is a wonderful example of how the body’s natural systems are designed to rebalance and create homeostasis, if we provide the nutrients needed for these processes through a nutrient-dense diet and appropriate supplements.

Selenium deficiency reduces GPx activity which impairs oxidative protection leading to an excess of H2O2. This can cause thyroid tissue destruction, hyper (over-active) and hypothyroidism (under-active), goitre, nodule formation, autoimmunity, cell damage and apoptosis (cell death).

H2O2 is typically low in a healthy individual but in patients with Graves’ Disease and Hashimoto’s Thyroiditis GPx is too low, leading to higher H2O2. Selenium supplementation has the potential to modulate H2O2 generation in these instances, via increased GPx activity. This can help to protect the thyroid during autoimmune disease. 

The selenium content of all UK soils is desperately low and intake is half what it should be.

Selenium deficiency can lead to an increase in thyroid antibodies. A significant reduction in Thyroid Peroxidase antibodies (TPOAb) and Thyroglobulin antibodies (TgAb) with 200mcg/day selenium supplementation has been shown in a number of studies. In cases with higher antibodies the reductions were most promising.

In conclusion a healthy level of selenium through diet and supplementation can help to protect your thyroid. Don’t forget to check your antibodies as part of your thyroid blood test. Companies such as offer tests for as little as £69 which include TSH, T4, T3 and TPOAb and TgAb. They can add on reverse T3 (rT3) but this is a little more expensive.

If you are thinking about having a Nutritional Therapy appointment please visit my home page to read about what I offer during a consultation. I offer all potential clients an informal free 10 minute conversation over telephone. This is not a consultation but an opportunity to understand how and the process works and ask any questions you may have. It is also a chance to hear my voice and get a sense of my practice style. You are in no way obligated to book afterwards.

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October 9, 2017 5:19 pm Published by