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Heavy metals are naturally occurring elements that have a density at least 5 times greater than that of water.[1]  The 5 main heavy metals that pose the most significant risk to our health are arsenic, lead, cadmium, mercury, and chromium.  This is due to their high degree of toxicity, even at lower levels of exposure. Elevated chromium rarely occurs, but the other four do, and these heavy metals pose significant effects on the thyroid.

Heavy metals are hard to avoid in modern life. We literally live in a toxic soup. We come in contact with environmental toxins virtually every day. A 2005 study found that 287 chemicals were detected in umbilical cord blood; 180 of those cause cancer in humans or animals, 217 are toxic to the brain and nervous system, and 208 cause birth defects or abnormal development in animal tests.[2]  Even if we lived in a bubble, I’m sure the BPA’s, phthalates, and polycyclic aromatic hydrocarbons from the plastic would do us over. We can’t escape it. I’ve written briefly before about heavy metal toxicity and its effect on the microbiome.  But thyroid function has become a new focus for heavy metal toxicity.
Ubilical toxins

What do heavy metals do to your thyroid?


Mercury accumulates in the thyroid and reduces iodide uptake at the sodium/iodide symporters by binding to iodide.[3]  Studies show this causes T4 depletion (iodide is needed to create T4), although it does not have the same bearing on T3 levels.  That said…  T4 converts to T3, so there is a functional deficit caused by mercury exposure.

Mercury fillings Thyroid Toxic
Mercury exposure is associated with a 2.4 x increase in Thyroglobulin antibodies.[4]  Studies do not show that mercury increases TPO antibodies, which causes Hashimotos thyroiditis.  While this is good news, about 25% of patients with autoimmune disease still have a tendency to develop additional autoimmune diseases,[5] so a high Tg-Ab is nothing to be sneezed at.


Even at low levels, Arsenic has been shown to affect thyroid function in various ways. Individuals exposed to Arsenic have both increased TSH and Thyroglobulin (Tg) levels, leading to slowed thyroid function.[8] As Tg is the main protein component of thyroid follicles, it is possible that the increase in Tg may be a compensatory response by the thyroid gland due to the increase in TSH. In addition, Arsenic may further contribute to increased TSH by inhibiting TPO activity, in turn, reducing thyroid hormone synthesis.  Arsenic exposure can also destroy thyroid hormone receptors through gene-mediated mechanisms, which are crucial for normal development and reduced disease risk.[9]


Aluminium exposure is common and typically in the spotlight due to its potential in the development of Alzheimer’s disease. However, it can also alter pituitary endocrine regulation of the thyroid gland.[10] Exposure decreases TSH levels and may indirectly alter thyroid function by disrupting the sodium-iodide symporters (NIS), which is the transport system responsible for moving iodine from the blood to the thyroid. Like Cadmium, Aluminium is a Copper antagonist (which means it can deplete Copper) and due to Copper’s importance in thyroid function, imbalance of this mineral can lead to hyperthyroidism and Grave’s Disease. As previously mentioned, Zinc and Copper also have a close relationship and fortunately OligoScan reads Al, Zn and Cu levels.  This enables you to look directly at the relationships within your body and to treat accordingly without upsetting the apple cart.

Thyroid Aluminium


Cadmium is considered a category 1 carcinogen. It accumulates in the liver, pancreas, kidneys, and also in the thyroid. Blood levels of Cadmium correlate with concentrations in the thyroid. Smoking decreases Tg-Ab and TPO antibodies and prevents hypothyroidism by 40%.  This may be due to activation of nicotine receptors, but possibly also due to the cadmium content of cigarettes.  This is obviously not a reason to take up the ole cancer sticks.  Especially considering cigarette smoking increases the risk of Graves’s disease by two-fold.  Cadmium is associated with decreased TSH levels, and increases in both T3 and T4.[11], [12]

Cadmium cigarette
Cadmium sits right next to Zinc on the periodical table of elements, which means it can have an affect on this mineral.  Zinc is needed for the conversion of T4 to T3, so may have bearing on elevated T4, which banks up due to poor conversion. Low zinc can cause issues with copper, adrenal fatigue, and all sorts of other issues. Sorry ladies, estrogen can act as an accelerator of mineral uptake into the body, so it may act to enhance cadmium absorption more than males.[13]

How can you get tested for heavy metal toxicity?

Hair tissue mineral analysis (HTMA) is an accepted method for assessing heavy metals and the balance of minerals in the body. The person must have open detox pathways for metals to show up, as the hair shows excretory levels only.

Provocation testing is another option for those open to the medical route.  This involves taking a chelating agent such as DMSA or EDTA, which mobilises the toxic metals, and then measuring excretion levels in the urine. 

Where are we getting exposed to heavy metals?

Metals are hard to avoid in modern life. Everyone will have some burden of heavy metals, no matter how careful you are. They’re virtually impossible to avoid.  Many of us are born with heavy metals, obtained in utero courtesy of our mothers’ own heavy metal load.  Some report that a mother’s first child will receive 2/3 of the mothers’ body burden of mercury. Having a baby is the most effective detox!

Much of our heavy metal exposure comes from our environment


Can be found in dental amalgams (silver fillings), paints, bleaches, batteries, some diuretics, fungicides, fluorescent lamps, cosmetics, hair dyes, contaminated seafood, and petroleum products. Vaccines such as tetanus toxoid contain thimerosal, which is a mercury compound.


Can be found in our environment due to use in fertilizers, batteries, LED televisions, pigments and some plastics. It can also be released from mining and smelting plants. Of course cadmium is also a problem for cigarette smokers.

Cadmium Battery


Can be found in drinking water, food additives, baking powder, spices, brewed tea, buffered aspirin, vaccines, antacids, aluminum pots and pans, cans, foil packaging, antiperspirants and deodorants, and polluted air.


Can be found in dust, cigarettes, lead cookware, some Ayuervedic remedies, PVC products, leaded paint, ground water, and like other toxic metals, from foetal exchange.


Can be found in found in chicken (they receive anti parasitics that contain arsenic), fish, mushrooms, rice, cigarette smoke, glass blowing, pigments, leather, insecticides, farming chemicals, and lead smelters.

How can you detox from heavy metals?

When it comes to treating thyroid issues that arise from heavy metal toxicity, a personalised approach is best. Normally treatment would include optimising gut function, improving methylation, looking at mineral balance: treating deficiencies as they relate to metals (for example, zinc can detox mercury, manganese detoxes cadmium, silica reduces aluminium). Each person’s protocol is unique. Many practitioners will detox their patients for 3 months, but it often takes much longer.  The half-life of Mercury is 32 years, so levels can be quite high and embedded deep into tissues; much like other heavy metals. 3 months wont scratch the surface.  Acute detoxification can take longer than 6 months, but really, detoxing is for life due to our continued exposure. Detoxification can be done using diet, sauna (or general sweating), using binders, regular colonics or enemas, minimizing our exposure by eating organic, avoiding chemicals and pharmaceutical drugs (which often contain high levels of Aluminium and other metals), and choosing to live in an area with less exposure (avoid airports or flight paths, heavily sprayed agricultural areas, mining areas etc).
Adelaide Flight path

An important note about Glutathione and metals

Glutathione is a master antioxidant. When your body produces glutathione, it helps to prevent pollutants from hurting your body. People who are glutathione deficient are less able to defend against heavy metal toxicity, often storing heavy metals in their brain, muscles, organs and other tissues.  There is a very close realtionship between the thyroid and glutathione in its own right. In order to optimise your body’s’ ability to produce glutathione, and help your body rid itself of metals, you’ll need to ensure the methylation cycle is performing well, and sulphation is also adequate.  This can often be treated by increasing sulphur containing foods, such as onions, garlic, eggs, broccoli, cauliflower, leeks, asparagus, cabbage, and artichokes etc. 


So you’re full of metal.  Just like me.  Unfortunately not in an X-Men type way; we have no super powers.   Heavy metals can have quite substantial effects to your thyroid, and are unavoidable in our modern life.  The best strategy to deal with this is to find out which metals your body has accumulated, address environmental exposure, and beginning (and never ending) a detox strategy to help reduce these harmful metals.

If you are Looking for a Functional Medicine practitioner or a Chronic Fatigue Specialist in Adelaide? Contact Elemental Health and Nutrition to help you with your needs.  We’re committed to empowering you on your wellness journey. Our holistic approach focuses on integrating nutritional medicine with cutting-edge testing techniques. 

Heavy Metal Thyroid