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What is Selenium?

By Lucy Rose Clinic

October 12, 2021

Selenium element

Selenium is an amazing nutrient that activates thyroid hormones in your body, but it also does so much more! One of the most fundamental cellular processes, DNA synthesis, depends on the presence of Selenium.

Unlike Iron, Magnesium, and Zinc, the clinical signs of selenium deficiency are not obvious. Insufficient stores of Selenium can allow toxic mineral accumulation, particularly Mercury, Arsenic, and Cadmium. Mercury, in particular, can deplete Selenium and prevent its cellular uptake, even though that Selenium may be circulating in the blood supply.

Selenium is an anti-oxidant mineral

Selenium is an important antioxidant and is vital for normal immune function, as well as an essential tool in the auto-chelation of heavy metals. Selenium is important for preventing free radicals from accumulating in our tissues. Smokers and people on medication have a higher need for selenium due to the oxidative damage these substances wreck in the body.

Unfortunately, if you do have a heavy metal blockage, adding more selenium-rich foods to your diet may not have many benefits.

However, if toxic substance levels are in acceptable ranges, these foods will be of great health benefit:

  • Brazil nuts – organic preferred 1 oz (6-8 nuts): 544 mcg (over 100% DV)
  • Yellowfin tuna 3 oz: 92 mcg (over 100% DV)
  • Halibut, cooked 3 oz: 47mcg (67% DV)
  • Sardines, canned 3 oz: 45mcg (64% DV)
  • Grass-fed beef 3 oz: 33 mcg (47% DV)
  • Turkey, boneless 3 oz: 31 mcg (44% DV)
  • Beef liver 3 oz: 28 mcg (40% DV)
  • Chicken 3 oz: 22 mcg (31% DV)
  • Egg 1 large, 15 mcg (21% DV)
  • Spinach 1 cup: 11 mcg (16% DV)

Can you have too much Selenium?

Australia has low selenium in our soils, and while much progress has occurred in fertilising livestock pastures to prevent deficiencies in animals, the same level of research has not yet been done on human food production. Therefore, it is likely that many Australians are low in selenium. If you are reading articles that warn that you can get too much selenium, check the source. Many American articles warn of overdoing selenium because they have good levels of selenium in the soils, therefore, it is more likely that people living there require little or no supplementation.

At the Lucy Rose Clinic, you may find that you are taking beyond the recommended daily requirement of selenium. This is fine short-term while deficiencies and toxicities are being addressed. However, if you have concerns, speak with your practitioner.

To give you an idea, a reported toxic dose was 200 times the RDI taken for an undisclosed amount of time. This particular incident was caused by an incorrectly manufactured American vitamin product! This is a great example of why we recommend specific products with stringent testing and quality control.

Signs of an overload of Selenium are: 

  • nausea; vomiting; nail discoloration, brittleness, and loss; hair loss; fatigue; irritability; and foul breath odour (often described as “garlic breath”)


Enzymes responsible for the activation of thyroid hormones in the liver, kidney, skeletal muscles, and other peripheral tissues are called deiodinases. The enzymes are selenium hungry – without adequate selenium, they can’t work. There are 3 types – D1, D2, and D3, and their job is to convert T4 to T3.

Would you like to know more about our testing? Book an appointment here

Thyroid hormones

Standard hypothyroidism involves high levels of thyroid-stimulating hormone (TSH) and low levels of the thyroid hormones T4 and T3. Symptoms are very classic, with fatigue, weight gain, and hair shedding being the top three complaints – but there are over 20 symptoms you can have when you have this type of hypothyroidism.

Low T3 syndrome is where the TSH is sitting normal, the T4 is normal, but the T3 is low.

And considering that T3 is the ACTIVE form of thyroid, this is significant.

If you have ever had your thyroid tested and it was said to be fine, then this could relate to you. The only way to find out for sure is with a thorough thyroid test, as well as checking the status of other vital body systems that work with the thyroid hormones.

Low T3 Syndrome

Medically, this is also called Euthyroid Sick Syndrome (ESS), Non-thyroidal Illness Syndrome (NTIS), and Low T3 Syndrome.

The main difference between Low T3 Syndrome and classic hypothyroidism is that it is NOT an issue with the thyroid gland.


Most studies have been done on people in extreme circumstances, such as admittance to ER – Emergency Room, and people dealing with life-threatening illnesses.

But luckily there is more interest in understanding the role of T3 in the arena of wellness and preventative health, and also in chronic disease.


Often T4 and T3 are tested, rather than free T4 and free T3. While total T4 and T3 give us important information about what the thyroid gland itself is producing, free T4 and T3 tell us how much thyroid hormone is actually available at the cellular level to exert its metabolic effects.

Of importance, reverse T3 must also be tested as a part of the picture, and other tests may be needed depending on your situation.


Diet is the most powerful friend or foe in your health. This is even more important if you have a thyroid problem.

Understanding exactly what is driving your symptoms is the key to empowerment on the healing path, and helps you to understand why you may need to eat in a certain way.

At the very least, adopting a diet that supports less inflammation is a good start – no processed foods, no sugar, no additives. Lots of fresh organic fruit, vege and clean protein sources, and lots of filtered water.

We really help people get their health sorted faster when they run food intolerance testing to accurately remove foods from the diet that are causing inflammation.

As we mentioned earlier, inflammation is the bane of all health issues, so taking control by reducing drivers of inflammation as much as is feasibly possible is important. This includes stress, sleep, personal purpose, and self-talk as well – as they can all trigger a stress response in the body when out of balance.


One interesting study was done with 22 women, aged 30 to 40, with medicated hypothyroidism completed a six-month yoga practice. Each session lasted one hour, and sessions were held four times per week.

At the end of the study, the participants had significantly reduced total cholesterol, LDL cholesterol, and triglycerides, and increased HDL cholesterol levels. Although TSH levels were not significantly different from baseline, they trended downwards, and seven of the 22 women were able to reduce their hormone medication dosage.

This shows the influence of mindfulness, conscious breathing, and movement on the body.

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“I would highly recommend … the Lucy Rose Clinic for anyone who is wanting answers and help with their health. I have struggled with constant exhaustion and gut issues for some time now and it got to the point that I just started to think that they were just ‘normal’ for my body. Well I was wrong! I have never felt so good since diagnosing and starting treatment for my gut and thyroid along with multiple deficiencies and intolerance’s I never knew I had!” – J.T.

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If you are ready to get your thyroid properly assessed, book your first call now.


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