Hypothyroidism: Is Your Thyroid Ruining Your Health?

How a functional medicine approach to hypothyroidism can change your life...

Hypothyroidism (low thyroid function) affects millions of people around the world and is one of the most commonly treated hormone conditions.

Unfortunately, conventional medicine doesn’t have much to offer in cases of hypothyroidism. 

Hypothyroidism

Hypothyroidism can have a real impact on your daily quality of life.

The functional medicine approach to hypothyroidism offers a more comprehensive analysis of the root causes of low thyroid function.

In our clinical experience, this approach can deliver life changing results.

Table of Contents

What does the thyroid gland do?

The thyroid is a butterfly shaped gland that sits at the base of the neck, wrapped around the trachea (windpipe). 

It secretes hormones that play critical roles in processes that are influenced by ‘speed’ and every cell in the body can use thyroid hormones.

Thyroid hormones control factors such as;

What are the sign & symptoms of hypothyroidism?

The most common signs and symptoms of low thyroid function, that we see in our clinic are;

A more comprehensive list of signs and symptoms is provided by Thyroid UK, click here.

Low thyroid function can affect us in different ways – mood, energy, body weight, digestive function, aches & pains, hair loss, and fertility issues.

What hormones are the thyroid responsible for producing?

The thyroid gland secretes a number of different hormones but the primary hormone secreted is thyroxine (T4), the inactive form of thyroid hormone.  

T4 can then be converted to the most biologically active form, triiodothyronine (T3), as and when required.

T3 is important as it is this active hormone that regulates metabolism.

Normal thyroid function infographic with images of tissues, and hormone pathways

The thyroid gland secretes around 80% T4 and around 20% T3 (4). 

Levels of these hormones are tightly controlled by signals from areas of the brain called the hypothalamus and pituitary gland.

Imbalances in these signals from the hypothalamus or pituitary, or in the ability of the thyroid gland to make thyroid hormones, or in the body being able to use these hormones, can cause thyroid function problems.

So what is hypothyroidism?

Hypothyroidism, also referred to as low thyroid function or under-active thyroid, is when the thyroid gland doesn’t produce enough thyroid hormone (or the thyroid hormone isn’t binding to thyroid receptors).

However, there are various potential underlying reasons – especially in a functional medicine approach to hypothyroidism – why someone may be suffering with hypothyroidism. 

This is important to understand in order to support optimal thyroid function (and in some cases to avoid medication or help the medication to work more effectively).

How common is hypothyroidism?

Hypothyroidism affects up to 5% of the general population, with a further estimated 5% being undiagnosed (5), and is ten times more common in women than in men (6).

Levothyroxine (a synthetic form of T4), a medication used to treat hypothyroidism, is the third most commonly prescribed drug in the UK – a huge 29 million prescriptions (in 2014) (7) and an estimated 33 million in 2021.

Hypothyroidism is 10 times more common in women than in men.

Why is hypothyroidism a silent epidemic?

The real number of people suffering with hypothyroidism could be (and we’d go as far as to say we’re quite sure it is) much higher than the official figures suggest.

In our clinics, we commonly work with clients who have low thyroid function and who were previously unaware that they had a problem.

Of more importance clinically, low thyroid function can help us to understand why someone may be experiencing certain (often unexplained) symptoms.

Overt vs subclinical hypothyroidism

Now just to be clear; there is a significant difference between the incidence of overt (clearly defined) hypothyroidism and subclinical hypothyroidism.

Overt hypothyroidism is clear hypothyroidism, with lab results that show an increased TSH and a decreased T4 level, as per the conventional lab ranges used by doctors.

Subclinical hypothyroidism is where the TSH may be ‘sub-optimally high’ or normal, where the T4 may be ‘sub-optimally low’ or normal, and people are still experiencing signs and symptoms of low thyroid function, due to other thyroid imbalances.

In our clinical experience, additional in-depth thyroid testing (the kind used in our functional medicine approach to hypothyroidism) can reveal imbalances and therefore the reason(s) for symptomatic, sub-optimal thyroid function. 

This results in a situation where you suffer from symptoms despite test results being normal, or not clinically relevant, according to conventional lab ranges.

As doctors often ‘treat the test rather than the person’, this can often result in your doctor telling you that there’s nothing wrong with you, despite you definitely knowing that there is.

Don’t worry, you’re not going mad, it’s just that, as we’ll discuss, the testing used by the vast majority of doctors is not up to the job, and the ranges used don’t identify problems until they’re much more advanced.

Sub-clinical hypothyroidism (where the TSH is only ‘mildly elevated’) can still cause symptoms and be clinically relevant (e.g. increases cardiovascular risk and fertility issues), and may be more common than Type II diabetes!

‘Normal’ thyroid test results

At Coho Health, our practitioners frequently discover a ‘subclinical’ state of hypothyroidism during our investigations – even where standard testing has come back ‘normal’.

This is often where the TSH level is within the ‘normal’ range and a diagnosis of hypothyroidism is not made.

Despite a ‘normal’ test result, and the patient being told there is no thyroid problem, the imbalance can still be significant enough to manifest in low thyroid symptoms, sub-optimal quality of life and sadly, fertility issues.

Why do results come back ‘normal’ when I still have symptoms?

There are several key issues to consider;

Firstly, in conventional medicine, a hypothyroidism diagnosis is fundamentally flawed.

It’s based on TSH and T4 levels only.

And the ranges used in this testing are often too broad (if you keep reading you’ll learn why these ranges just don’t cut it).

Secondly, subclinical hypothyroidism is both very common and under-diagnosed (due to inadequate test quality and other factors).

One study reported that almost 11% of women may have subclinical hypothyroidism (8).

And some hormone experts suggest that, in their opinion, thyroid insufficiency affects 20% to 50%  (20 to 50 people in every 100) of a standard population (9).

The lack of comprehensive testing means that thyroid hormone imbalances aren’t always picked up (unless you’re working with a Functional Medicine or Naturopathic practitioner who has access to, and is able to correctly interpret, the most accurate testing).

Thirdly, the underlying cause of thyroid hormone imbalance is not considered – and this can alter the clinical approach taken in helping to restore thyroid hormone balance.

Lastly, for a diagnosed hypothyroid case, the prescribed treatment is always the same.

Levothyroxine (synthetic form of T4), is prescribed (usually for life). 

The problem is that there are some cases where the underlying issue isn’t a T4 deficiency.

A functional medicine approach to hypothyroidism takes a much broader range of factors and test results into account.

Sub-clinical hypothyroidism may be affecting 20-50% of the population, is significantly under-diagnosed and usually not treated.

And why don’t I feel any better despite taking thyroid medication?

But what if low thyroid function isn’t due to low T4?  

There are several other reasons why someone may have low thyroid function, despite producing good levels of T4.

If you’re taking thyroid medication and still don’t feel any better for it, keep reading.

The cause of  low thyroid function, may not be a levothyroxine (T4) deficiency.

TSH and T4 ‘normal’ ranges

The conventional range used for TSH levels is broad.

This means that most of the population fall within a ‘normal’ range, and therefore most patients are informed that their results are ‘normal’ and they do not have a thyroid issue.

However, when applying the same test result to an optimal (functional) test result range (the kind we use at Coho Health), the interpretation can be different.

Very different.

In a Functional Medicine approach to hypothyroidism, optimal ranges are applied to test results. 

The question considered in defining these ranges is: 

how much of a nutrient / hormone etc is required for processes in the body to function at 100%, i.e. to function optimally.

In hypothyroidism, we know that imbalances in metabolism can occur long before a lab test result for TSH is above the standard NHS upper limit.

Better quality testing, with a greater number of parameters analysed, and ‘functional’ ranges applied to these results, gives us a more clinically accurate picture of underlying imbalances.

What does regular thyroid testing cover?

‘Standard’ thyroid testing, which is commonly available in the UK through the NHS and private health insurance is usually limited to:

The TSH is produced by the pituitary (in the brain) and acts as a signal to the thyroid gland.

TSH says ‘hey, my body needs more thyroid hormones, so make some more’.

The lower the perceived level of thyroid hormones, T4 and T3, the louder (higher) this signal is.

So, when the body senses there isn’t enough thyroid hormones, the TSH goes up.

Usually, in subclinical and overt hypothyroidism, the TSH released from the pituitary is higher, signalling to the thyroid gland to produce more hormones.

TSH ranges: Coho Health vs conventional testing

At Coho Health we consider the upper limit of the optimal range for TSH to be 2.5 mU/l (milliunits per litre).

If your TSH level has been tested, is above 2.5, and you are displaying signs or symptoms of low thyroid function, we recommend you work with a Functional Medicine practitioner to have a full thyroid screen performed.

This way, we can begin to understand where the imbalance is coming from – and how to address it.

The NHS upper limit for TSH is usually around 5.0 mU/l

However NHS guidelines currently state ‘‘Consider levothyroxine for adults with subclinical hypothyroidism who have a TSH of 10 mlU/litre or higher on 2 separate occasions 3 months apart.’ (10).

You read that right – treat hypothyroidism when TSH is higher than 10!

But guidelines also state to start treatment where there is;

‘a TSH above the reference range [so above the usual 4 or 5] but lower than 10 mlU/litre on 2 separate occasions 3 months apart, and symptoms of hypothyroidism’  (11).

Thats better, but still not great;

The ‘Thyroid UK’ organisation states:

‘In America and some other European countries, they have reduced the TSH level to 2.5 which means that anyone above that figure will be treated if they have symptoms of underactive thyroid.’ (12).

So, you could have hypothyroidism in one country, but cross the border, and then you don’t – it’s like magic!

That’s the problem with treating the test. 

It’s also a big problem for patients who have total faith in test results and the conventional interpretation guidelines.

Hypothyroid and other health problems

Recent studies suggest that a TSH greater than 2.5 increases the risk of infertility and miscarriage (13, 14, 15).

There is also a strong correlation between heart disease and sub-clinical hypothyroidism.  

A study following 1365 patients with pre-existing heart failure found that a TSH ≥7 and low T3 levels was associated with poor prognosis (various end points were considered including death) (16).

Infographic of how hypothyroidism can cause depression, cardiovascular risk, fertility and miscarriage, with images

One reason for the increase in cardiovascular risk are the changes in lipids (cholesterol profile) that can be seen in sub-clinical and overt hypothyroidism.

In these cases, it’s worth asking yourself; is it best to treat high LDL cholesterol with statins, or to address the root cause of the high LDL – for example sub-clinical hypothyroidism?

The TSH take-home

We see clients weekly at our clinic who have a TSH over 2.5, and who are displaying symptoms of hypothyroidism.

We also see ‘normal’ TSH results, alongside other thyroid hormone imbalances that we identify through additional testing.

Together with the presentation of symptoms, this makes it necessary to address thyroid hormone balance.

The take home is this – if your TSH is above 2.5 and you’re displaying signs and symptoms of low thyroid, or have a family history of thyroid issues, please go and speak with someone who understands thyroid function.

Someone who can help with ordering comprehensive testing that can pinpoint where the imbalance is, and who can help you to bring your hormones back into balance.

Free T4 testing

The next thyroid hormone that is tested (in some cases along with the TSH, but in other cases only if the TSH is out of range), is free T4.

The thyroid gland makes and releases thyroxine, i.e. T4.

However, not all of the T4 is ‘free’.

Thyroid hormones, like many other hormones, can be bound to proteins (17), this allows the body to carefully regulate the amount of hormone that is ‘free’ to be used by cells.

So, the ‘free’ portion is often tested by doctors to help understand the amount of ‘usable’ thyroid hormone.

The ‘Free T4’ normal range is usually 12 – 22 pmol/L.

What about Free T3?

Conventional testing will include TSH and free T4, but that’s usually all you’re going to get.

In some cases, free T3 may be tested. 

And in our clinical experience, measuring levels of free T3 is very useful, as this is the active hormone available to bind to the receptors on all of our cells to control the speed of cellular function.

The conventional ‘Free T3’ ‘normal’ range is usually around 3.1 – 6.8 pmol/L.

Subclinical hypothyroidism: why a full thyroid screen can be life changing

Let’s say TSH and Free T4 levels are within the ‘normal’ range.

But you still suspect hypothyroidism.

Maybe it’s because you have many of the associated symptoms.

Or maybe there’s a family history of hypothyroidism (and therefore you have a higher risk).

And maybe your doctor has told you that there’s no problem, or even that your symptoms are all in your head (yes, it shouldn’t happen, but it does).

Hypothyroidism testing

What next? Our experience suggests that a full screen is hugely beneficial. 

This is the kind of full screen we use in our functional medicine approach to hypothyroidism and Hashimoto’s.

Good thyroid health testing should ideally include:

Why test Free and Total T3?

T3 is the metabolically active thyroid hormone.

It allows us to check your ability to convert T4 to T3.

This conversion is dependant on enzymes called deiodinases, which require the minerals, zinc (18) and selenium (19).

The levels of deiodinase enzymes we produce can be influenced by our microbiome.

A diverse microbiome can also help to create a ‘reservoir’ of thyroid hormones which may reduce fluctuations in thyroid hormone levels and the need for thyroxine medication (20).  

Gut health plays a key role in supporting thyroid hormone balance.

Free T3 is the amount of active thyroid hormone ‘free’ to be used by cells.

Low T3 is a hormone imbalance we frequently identify with our clients and is linked to symptoms of low thyroid function, as well as to a significantly increased risk of heart attack (21, 22).

Remember that the conventional treatment for hypothyroidism is synthetic T4.

If your body isn’t converting T4 to T3 then this could be one reason why your medication isn’t working and you’re not feeling better.

Low T3 (hardly ever tested) is associated with an increased risk of cardiovascular disease.

What is Reverse T3?

T4 should be converted to T3 as and when the body requires it.

But under some situations, T4 can go down a different path and be converted to the ‘mirror image’ of T3 –  Reverse T3.

This can happen when:

The increase in Reverse T3 is a consequence of alterations in thyroid hormone metabolism.

It is one reason why chronically restricted calorie intake or carbohydrate restriction can actually slow down metabolism in the long run.

If TSH, T4 and T3 all look fine, but you still suspect low thyroid function, then it’s time to check reverse T3.

T3 uptake

When thyroid hormones are not ‘free’, it’s because they are bound to proteins.

The main binding protein is Thyroxine-binding globulin (TBG) (24).

Other hormones can also affect TBG levels, such as oestrogen and testosterone.

The TBG marker is helpful in understanding if there are issues around levels of TBG, which could cause either higher, or lower, levels of ‘free’ thyroid hormones (T3 and T4).

When there are these types of imbalances, the issue isn’t around how much T4 or T3 the body is making, but how the hormones are being bound to TBG.

Let’s take a look at some test results…

1/ In this test result, we see the elevated levels of thyroglobulin possibly causing the low free T4, and the low iodine, selenium and high mercury…

2/ In this test result, we can see low free and total T4, and sub-optimally low free and total T3, is this nutrient insufficiencies affecting T4 and T3 synthesis…

3/ In this test result, we can see high thyroid peroxidase and thyroglobulin antibodies. This client was being over prescribed with levothyroxine  – this person doesn’t need more T4 (you can see that TSH is too low), but there is a need to reduce the antibodies (identify and remove triggers and address inflammation, immune modulation and intestinal permeability)…

4/ In this test result, we see a high TSH and high thyroid peroxidase antibodies. The antibodies are beginning to affect thyroid hormone levels…

As you can see, each test result shows something different – different root causes and different systems at play.

Based on each individual test result and case presentation, our team would devise an individual plan to address the factors at play.

What’s the root cause of hypothyroidism?

The root cause of hypothyroidism can involve a range of factors. 

As we’ll discuss below, these factors include a number of nutrient deficiencies.

But chief amongst the root cause factors involved in hypothyroidism, are autoimmune antibodies.

Autoimmune

Studies suggest that up to 90% of hypothyroidism may have an autoimmune cause (25) – specifically Hashimoto’s thyroiditis disease.

This is where the body is producing antibodies (an immune response) that are destroying the thyroid gland and therefore reducing thyroid hormone synthesis.

Often these antibody levels are not tested by the doctors, so many people who have a diagnosis of hypothyroidism, may actually have Hashimoto’s but they just don’t know.

 

Thyroid auto-antibodies infographic with images of factors and hormone pathways

On the other hand, thyroid antibodies may be present but the person may not be presenting with symptoms of hypothyroidism.

In this case it’s still relevant to know about the antibodies, as the risk of developing hypothyroidism at some point in the future is increased.

For doctors, it’s usually a case of ‘watch and wait’ for the antibodies to cause enough damage to throw the TSH and T4 out of range.

This approach doesn’t sit well with us.

That’s because we have a body of evidence suggesting that nutrition and lifestyle interventions can reduce antibody levels and prevent or delay the onset of thyroid problems.

Addressing underlying factors such as infections (epstein bar virus and helicobacter pylori, for example, have been implicated in the development of Hashimoto’s), chronic stress or environmental chemicals would be part of the Functional Medicine approach.

Why ‘watch and wait’ for things to get worse, when we can intervene earlier, and delay or completely prevent what’s about to happen.

That seems crazy to us, and it probably does to you as well.

Iodine

An iodine (mineral) deficiency is another common cause for hypothyroidism (26).

The reason for this is that thyroid hormones are synthesised from iodine molecules and the amino acid tyrosine.

In T4, the ‘4’ denotes the four iodine molecules present in the thyroid hormone.  

So it goes without saying that a deficiency or insufficiency of iodine, influences levels of thyroid hormones.

Iodine deficiency is a worldwide problem – iodine content in soil is low and amounts of fish (a source of iodine) consumed varies significantly. 

Seafood and sea plants, such as nori, kelp, wakame and kombu are the best sources of iodine (but levels can vary significantly, potentially also leading to dangerously high levels of iodine).

Iodine supplementation should be avoided in autoimmune thyroiditis as there is an increased risk of free radical damage to the thyroid gland and an increase in thyroid antibodies (potentially made worse by a selenium insufficiency).

Other nutrient deficiencies

Other nutrient deficiencies can also interfere with thyroid function.

Selenium is required for the conversion of T4 to T3 (27). Selenium is needed to produce the deiodinase enzymes that drive this conversion.

Iron a component of the enzyme, thyroid peroxidase, involved in the early stages of thyroid hormone synthesis (28).  

Thyroid hormones infographic with nutrient factor images and hormone pathways

It is common to find a low iron status in people with hypothyroidism (29).  We consider a ferritin level of 50ug/L as an absolute minimum (30), most conventional lab ranges are set much lower than this.

Zinc has a complex role in thyroid hormone regulation. 

Zinc plays a role in the metabolism of thyroid hormones by regulating deiodinase enzymes, and also plays a role in the synthesis of thyrotropin releasing hormone (TRH) (31), secreted from the hypothalamus and TSH (in the pituitary gland).

Vitamin D deficiency is more common in autoimmune thyroid disease. The sunshine vitamin has an immune modulating role and a correlation has been found between higher blood vitamin D levels, and lower thyroid antibodies (32).

A range of nutrients support optimal thyroid function. Vitamin and mineral insufficiency, could be affecting thyroid hormone levels.

What about thyroid medication?

In Functional Medicine, we’re looking to identify and address the root cause(s) of thyroid signs and symptoms.

Providing medication is not always the answer, because it corrects the end result – the hormone imbalance, without addressing the root cause, which is often an autoimmune problem.

Without addressing the ‘autoimmune’ aspect of the condition, it’s difficult to see how there can be long term improvement in thyroid health.

The underlying immune dysregulation can manifest in other ways.

In Hashimoto’s disease there is an increased risk of having additional autoimmune conditions, such as coeliac disease (33, 34, 35, 36).

Often with coeliac disease, the symptoms can be so mild that the condition remains undiagnosed.

However, where coeliac is present, the damage caused to the intestinal cells can mean that Levothyroxine isn’t well absorbed, and a higher dose is required. 

But be aware that medication can be the best option if your condition is more advanced or for your individual circumstances – there is definitely a time and place for medication

And never change your medication dose or stop taking it without consulting your doctor.

Note: we often find that thyroid medication is not being taken correctly. There are several interactions with this medication, as it can easily bind to foods and drinks and its absorption is then reduced (meaning it is less effective). 

It must be taken away from foods and caffeinated drinks likes tea or coffee, and ideally taken around the same time daily (unless your doctor has advised differently).

In our clinical experience, thyroid medication alone, does not always lead to complete resolution of low thyroid symptoms – a root cause, multifactorial, individualised approach is required. For example, medication may be necessary, but in Hashimoto’s disease we also need to understand what is driving the immune response for each client. For instance, is it:
Thyroid hormone infographic with environment and lifestyle factor images and hormone pathways

Other reasons for hypothyroidism can include:

Are you taking medication for hypothyroidism but still feeling the symptoms of low thyroid function?

There can be multiple causes for low thyroid function as seen above.

To recap, it could be due to:

However, despite the range of root cause factors that can be behind hypothyroidism, in conventional medicine, the standard treatment for all cases is usually Levothyroxine.

This may not solve your problem.

Levothyroxine, is simply synthetic T4: inactive thyroid hormone.

What if that T4, being taken as a pill every morning, isn’t being converted to active thyroid hormone, T3?

This is something we see frequently in our functional medicine clinic and in our functional medicine approach to hypothyroidism.

Where T4 isn’t being converted, someone with hypothyroid symptoms is likely to still experience symptoms of hypothyroidism

Even when their lab test for free T4 is within the normal range.

This is one reason why you can still feel terrible despite your lab test results being normal.

The conversion of Levothyroxine (T4) to T3 needs to be supported in order for it to be effective.

Additionally, there may be ‘normal’ levels of T4 and/or T3 in the blood, but high levels of Reverse T3, which blocks the action of thyroid hormone, again causing symptoms of low thyroid function.

There are several other reasons for hypothyroidism too, as mentioned above, but you get the picture. 

Comprehensive testing and employing optimal testing ranges – the functional medicine approach to hypothyroidism – is a must in order to understand thyroid function.

Concerned about your thyroid health?

Our Functional Medicine team can help!

The clinic team at Coho Health can help you at our clinics, or wherever you are in the world through our online consultations:

You don’t have to feel ‘stuck’ with hypothyroidism, there is a better option!

Further thyroid health resources

Book your free 15 minute Discovery Call with Dee Brereton-Patel now

We hope you found this article useful, if you suffer from some of the problems highlighted here, or know someone who does, please feel free to share this post so we can reach and help more people!

If you’re looking for a Functional Medicine Nutritional Therapist delivering real health transformation, you’re in the right place.

We’d love to help you.

To your optimised, healthy future,

Dee & the Coho Health team

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