Thyroid function

What Causes Low Thyroid Function

With 12% of women experiencing low thyroid function at some stage of their life, and with 60% of these going undiagnosed this can often be the cause of why you feel less than optimal.

It is important to look out for the signs and symptoms of low thyroid function and look at what causes low thyroid function.

If you have been told that your thyroid is “normal” this may not be the case as most doctors only test for TSH and don’t do a full thyroid test.

Symptoms of Low thyroid function

You don’t need to experience all of these symptoms but even 2-3 could indicate a low thyroid function
  • Difficulty losing weight, or even gaining weight despite a good diet and exercise program
  • Tired and fatigued
  • Depression, anxiety or just feeling unmotivated
  • Poor quality sleep
  • High cholesterol levels
  • Digestion problems such as constipation/ diarrhea, bloating, reflux, gallstones, or other IBS symptoms
  • Feeling the cold or poor circulation
  • Poor quality hair, skin, or nails
  • Muscle or joint pain
  • Menstrual cycle problems.

What causes low thyroid function

While the medical treatment is to wait until your TSH and T4 levels are out of balance and then prescribe medication, if you can catch low thyroid symptoms early and treat the cause often you can reverse low thyroid function.

There are 3 main causes of low thyroid function and they all will not respond to thyroid medication, a comprehensive thyroid test measuring TSH, T4, T3, Reverse T3, and thyroid antibodies can help to identify the cause.

Looking at adrenal function will also help to identify stress and inflammation as a cause and help with a specific treatment plan.

What causes low thyroid function

1/ Low Pituitary Function

This can be caused by high levels of cortisol which cause the pituitary to try and down-regulate thyroid function, if someone has adrenal dysfunction their TSH levels may be reduced.

Rather than treating the thyroid, it is important to also treat adrenal function through diet, lifestyle, and specific herbs and nutrients.

Toxicity caused by heavy metals will also affect pituitary function. In particular, there is a strong association with high levels of mercury and thyroid disorders and this can be diagnosed through a mineral analysis test.

Knowing the cause will help with treatment. Other common heavy metals such as chlorine and fluoride can also affect thyroid function.

Inflammation caused by diet and in particular gluten and excess sugar can disrupt the pituitary function and eliminating the trigger foods 100% can often reverse this damage.

Doing a 30-day challenge where you cut out gluten, dairy and sugar is a great starting point, particularly with the autoimmune Hashimoto’s thyroid.

2/ Low Thyroid Function

Nutrient deficiencies can also cause low thyroid function and this includes zinc, selenium, iron, iodine, tyrosine, vitamin D, and B vitamins.

Not everyone with low thyroid needs all of these nutrients, and in fact, some people with autoimmune low thyroid should avoid or reduce their iodine intake.

The best option is to do a vitamin and mineral blood test to check your levels.

Even with a good diet, it is possible to have nutrient deficiencies if you also have digestion problems like IBS, Helicobacter pylori, SIBO, or a parasite infection that has not been identified.

The foods that you are eating can also reduce thyroid function, in particular the same ones that affect pituitary function like gluten, dairy, and excess sugar from processed foods.

Excess omega 6 fats from processed oils such as canola oil, rice bran oil, and soybean oil are also inflammatory to your body, the only way to avoid these oils is to avoid processed foods.

3/ Poor T3 Conversion

Elevated estrogen levels and low levels of progesterone will increase levels of Thyroid binding globulin which as the name suggests binds to T3, stopping it from getting into the cell.

This is where taking thyroid medication or minerals such as iodine is not going to help, as you have to identify the cause which in this case would be elevated estrogen levels.

Poor digestion will also affect thyroid function in a number of different ways, as we have already discussed poor absorption will lead to low levels of nutrients that affect T4 to T3 conversion.

Also, imbalance in gut bacteria will decrease the conversion of T4 to the active T3 thyroid hormone and also lead to an increase in toxins that the liver has to process which can also affect the T4 to T3 conversion.

Infections like Helicobacter pylori and parasitic infections can also lead to an autoimmune response against the thyroid.

So as you can see digestion and what you eat which is so important for health and wellbeing in general is also vital for healthy thyroid function.

The number one problem that I see in clinical practice is adrenal function issues leading to either high or low cortisol levels which will inhibit the T4 to T3 conversion and lead to higher levels of reverse T3.

This is why I always test reverse T3 and adrenal function through the DUTCH hormone test when assessing thyroid function.

What to do next

The first step is to get a comprehensive thyroid test which includes TSH, T4, T3, reverse T3 and the thyroid antibodies, if you have never had these markers tested then you have never had your thyroid properly assessed.

I would also recommend getting the DUTCH hormone test to assess adrenal function.

These tests are available through Planet Naturopath and can be done anywhere in Australia and most parts of the world.

If you suspect that low thyroid or adrenal function issues might be behind your health problems you can order your tests from the Functional Medicine Test Page

Do you need help with “what causes low thyroid function”?

If you would like more information or would like to schedule a consultation to find what is the best option for you, then you can book an appointment here

About the Author Michael

Michael is head consultant at Planet Naturopath - Functional Medicine and Nutrition Solutions. He is a registered naturopath with the Australian Natural Therapists Association (ANTA) and works with clients from all over the world via video or phone consultations. He is a degree qualified naturopath from the Endeavour College of Natural Medicine in Australia with 18 years of experience. He uses advanced testing methods, nutritional medicine, herbal medicine, and lifestyle advice to help you stay healthy. He is a Kalish Method-trained practitioner that keeps updating his education with Chris Kresser. Michael completed Dr. Terry Wahls practitioner training program, a 12-month program with ongoing training that helps understand the underlying cause and treatment of MS and autoimmune conditions. He keeps up to date with the latest research into health and natural medicine through the Metabolic Fitness Pro course with Dr. Bryan Walsh.

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Leave a Comment:

Tinika McNamara says April 26, 2015

I have had my left thyroid gland removed about 22 months ago. I had a nodule on it that came back with a inconclusive result for cancer. I was diagnosed with Harishimoto auto immune disease also. I am taking thyroxine 100mg week day, and 50mg weekend. I am not eating gluten, sugar or processed foods. I am making my own Kefir milk which I have daily. But I feel like there is something wrong still. I have not had a saliva test at any point. Any ideas or suggestions?

    michael says April 26, 2015

    It sounds like you are doing many of the right things for the Thyroid Hashimoto auto immune condition but you may still not be converting the Thyroxine (which is T4) into the active T3. When you are on thyroid medication the doctors usually do not test for T3 and reverse T3 which can indicate how your thyroid is really working. Testing adrenal function with a saliva cortisol test would also be a good idea as adrenal issues have very similar symptoms to thyroid problems. Let me know if you need help with adrenal testing

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