Let’s take a deep dive into thyroid health (hypothyroidism)

Autoimmune disease and inflammation Women's Health

1 Jan

Do you have hypothyroidism, and wonder what you can do to help it?

Thyroid issues are becoming increasingly common these days - and are one of the main issues we see in our clinics!

This is a a fairly long post, but we wanted to pack in all the knowledge you need to learn how to optimise your thyroid health through lifestyle medicine - so grab a cuppa and a comfy seat and read on 😉

Hypothyroidism (an underactive thyroid, when our thyroid gland can't keep up with our bodies needs), is the most common type of thyroid issue in our society.

It affects around 5% of women and 1% of men, although some estimates suggest that rates are actually twice this (with many people being undiagnosed).

Up to 15% of women over 60 have 'subclinical hypothyroidism', where one of their thyroid hormones are abnormal (TSH aka thyroid stimulating hormone) - an early sign of thyroid issues, and a signal that the thyroid is not functioning normally 😳

HOW DOES OUR THYROID WORK?

Our thyroid gland is a small organ that’s located in the front of our neck, wrapped around our windpipe (trachea).

It’s shaped like a butterfly, smaller in the middle with two wide wings that extend around the side of our throat.

The thyroid plays a crucial role in metabolism, affecting our energy levels, fat storage, heart rate, and nerve, brain, reproductive and digestive function. There are thyroid hormone receptors in almost every cell in our body!

It also affects hair growth and skin, and is vital for normal brain development and growth in children - which is why iodine is so vital in pregnancy and early childhood.

The thyroid gland produces two main hormones:

thyroxine (T4 - the hormone made by the thyroid gland)
triiodothyronine (T3 - the metabolically 'active' thyroid hormone made from T4, that tells different cells in the body to do their jobs)

It does this in response to thyroid stimulating hormone (TSH) being sent from our pituitary gland (a small gland near our brain) . TSH secretion is pulsatile and has a circadian rhythm ie it varies according to time of day - TSH levels can be up to 50% higher at night and early in the morning than during the rest of the day!

About 90% of the thyroid hormone made by our our thyroid gland is T4, and only 10 percent is T3.

T4 is made by four iodine atoms being mixed with a protein called thyroglobulin. It then has to be converted into T3 for the body to be able to use it
T3 is created when an iodine molecule is removed from T4 via enzymes that remove the excess iodine molecule.
Most of this occurs within our liver, and requires adequate zinc and selenium to occur

T3 works by going into our cells, and activating genes there. Most cells in our body have thyroid receptors, which is why thyroid issues cause such a variety of symptoms!
Our body is constantly adjusting to keep things in balance, and is usually very efficient at converting T4 to T3 as a result.

Certain factors can affect T4 (inactive hormone) to T3 conversion though, these include :

Prolonged calorie deprivation (ie extended fasts)
Low carbohydrate and ketogenic diets
Malnutrition
HIV infection
Severe heart disease
Severe liver disease including fatty liver syndrome
Poorly controlled diabetes
Severe PTSD/Depression
End stage Chronic obstructive pulmonary disease
Any severe illness (such as infections or trauma that require hospital admission, especially ICU admission)

This is because when the body is under stress (physical, or significant emotional stress), it tries to conserve energy for healing, by slowing down metabolism, as a survival response.
In order to do this it starts to convert T4 into reverse T3 (which is an inactive form of T3 aka a 'brake pedal').

This process is often called non thyroidal illness syndrome, or euthyroid sick syndrome - meaning thyroid levels are disrupted, but tend to return to normal when the illness passes (its not due to an issue with the thyroid gland itself, but is the body's way of protecting itself)

Some people can also have high levels of reverse T3 without any thyroid issues - reverse T3 levels and ranges are hugely variable, and testing for reverse T3 is not generally recommended as a result (and is not even available in most labs in New Zealand anyway)

WHAT ARE HYPOTHYROIDISM AND SUBCLINICAL HYPOTHYROIDISM?

Our thyroid is very sensitive, and thyroid hormone levels can fluctuate throughout the day, depending on diet, activity, stress, and illness.

When the thyroid gland works properly, it maintains exactly the right balance of thyroid hormones to keep our metabolism working well.

But when it starts struggling to keep up, our thyroid hormone levels change, and we develop hypothyroidism - an 'underactive thyroid'.

Our TSH level usually rises first, to try get our thyroid cells to work harder. Then eventually our T4 level can drop too (as our thyroid 'runs out of steam') and hypothyroidism is diagnosed.

People may often have a raised TSH but normal T4 for years, and these levels can fluctuate with illness, diet, lifestyle and even medication.

When TSH is elevated but T4 is normal, this is called subclinical hypothyroidism, and it's a 'warning sign' that things aren't going that well - and a good time to intervene from a lifestyle perspective, to try prevent the thyroid failing eventually!!

Not all subclinical hypothyroidism will progress to full blown hypothyroidism however - if you have subclinical hypothyroidism the risk of it developing into actual hypothyroidism (and needing treatment with thyroid medication) is around 2-6% per year (33% to 55% within 10 to 20 years). Subclinical hypothyroidism can resolve spontaneously in half of cases within 2 years, mostly in people with TSH values of 4 to 6 mIU/L..

It's recommended that if you have subclinical hypothyroidism, you should be checked for thyroid antibodies (as this increases risk of progression to hypothyroidism to around 4.3% per year, compared with 2.6% per year in those without this antibody), to determine if you have an autoimmune cause.

Thyroid levels should usually checked annually if you have subclinical hypothyroidism, or with any change in symptoms or health, as untreated hypothyroidism can have health risks.

In general subclinical hypothyroidism does not need treatment with thyroxine (and does not affect the risk of progression), the exceptions to this are in pregnancy or fertility treatment; people who have a high risk of heart disease or a TSH of 7-10 mIU/mL and/or positive thyroid antibodies and are under 70 years of age; or people who have a TSH over 10 but normal T4. This should be discussed with your doctor however as it depends on your personal medical history.

WHAT CAUSES HYPOTHYROIDISM?

Hypothyroidism is usually from an underactive thyroid gland (primary hypothyroidism), but rarely can be from a malfunction in the pituitary gland (secondary hypothyroidism) or hypothalamus (tertiary hypothyroidism) in our brain ie from brain injury or pituitary tumours.

The most common cause of primary hypothyroidism worldwide is iodine deficiency, which usually causes goitre (an enlarged thyroid gland, as the thyroid increases in size to try produce enough thyroid hormone).

This is because iodine is the key component of thyroid hormones, so the thyroid will struggle to make these if it doesn't get enough iodine from our diet, and enlarge in size as it tries to keep up with the bodies needs

As an interesting aside, excess iodine can also cause thyroid problems - either by creating a 'brake' where the thyroid slows down in response to too much iodine (which can sometimes cause hypothyroidism if the brake gets 'stuck'), or by getting overstimulated, and triggering hyperthyroidism (an overactive thyroid, where too much thyroid hormone is made)

This is why we don't recommend mega dosing with iodine to 'boost' your thyroid function, and also don't recommend supplements such as kelp that can contain toxic levels of iodine!

Even mildly to moderately excessive iodine intake (≥ 220 μg/day) through foods, dietary supplements, topical medications, and/or iodinated contrast can increase risk for hypothyroidism.
Like with most things in nutrition, we want enough, but not too much 😉

However, in Western nations, where iodine deficiency is rare, the most common cause of hypothyroidism is Hashimoto’s disease, accounting for 60-80% of hypothyroidism.

Other less common causes of hypothyroidism include medications (in particular lithium and amiodarone, which block thyroid hormone production), genetic mutations, congenital hypothyroidism (from birth) , neck surgery, and radiation damage to the thyroid gland.

WHAT IS HASHIMOTOS DISEASE?

Hashimoto's thyroiditis is an autoimmune disorder that damages the thyroid gland.

In Hashimoto's thyroid disease, our immune cells mistakenly attack our healthy thyroid tissue (instead of protecting it), causing inflammation and damage to the thyroid cells. Over time this can progressively reduce how well the thyroid gland can produce thyroid hormone, leading to a change in thyroid hormone levels.

Often Hashimoto’s will initially be picked up as subclinical hypothyroidism as mentioned above with a high TSH and normal T4), but if T4 levels eventually become low, it is diagnosed as hypothyroidism, and thyroid medication is needed.

If the thyroid gland is totally destroyed, then this is irreversible, and high doses of thyroid hormone medication are needed for life. If it's only partly damaged then lower doses are needed, and lifestyle changes can have more of an effect. Even with total destruction of the thyroid gland lifestyle and nutrition can help though!

Risk factors for autoimmune hypothyroidism include:

being female (especially women who are small at birth and remain small as children)
increasing age (in particular after menopause, due to loss of the protective effect of oestrogen)
pregnancy (the immune changes in pregnancy can trigger Hashimoto’s)
genetics (this is responsible for up to 80% of autoimmune thyroid disease
other autoimmune disease (ie coeliac disease, lupus, rheumatoid arthritis, type 1 diabetes)
potentially environmental toxin exposure such as smoking, plastic water bottles (BPA), organochlorine pollutants (e.g., dioxins, polychlorinated biphenyl [PCB]) which are often found in fish, meat, eggs, and dairy products), triclosan (an antibacterial in soaps), fertilisers that contain perchlorate or thiocyanate, and flame retardants - although the studies on these are still not that clear cut
excess iodine (can trigger Hashimoto’s in people already at risk of it)

Hashimoto’s can only be diagnosed by a thyroid antibody test - this is what differentiates between autoimmune thyroid disease and other causes of hypothyroidism, as with Hashimotos, antibodies to the thyroid gland are detectable in our blood stream

The main test used is a thyroid peroxidase (or TPO) level, which can be requested by most doctors through standard laboratories

A TPO level of greater than 35 IU/mL is generally considered 'positive', meaning thyroid antibodies are present.

The higher your TPO levels, the more 'active' your autoimmune disease is:

TPO levels between 35 and 500 IU/mL indicate minimal risk of the autoimmune disease causing permanent thyroid damage and hypothyroidism
Some guidelines consider TPO levels of less than 100IU/mL to indicate ‘remission’ of Hashimoto’s (ie that the autoimmune process is not active)
TPO levels over 500 IU/mL indicate moderate risk of eventually becoming hypothyroid

It's worth mentioning that having a positive lab results for thyroid antibodies does NOT guarantee you will become hypothyroid or hyperthyroid.
It's a marker that you have antibodies in your blood that react against your thyroid, but it's very possible for these be present but never actually cause enough damage to need thyroid medication

One large study followed 5,783 people with positive thyroid antibodies for for 9.1 years. At the start of the study 10.9% of people already had hypothyroidism, 3.4% had hyperthyroidism (an overactive thyroid, which can occur less commonly with autoimmune thyroid disease), and 62.3% had normal thyroid hormone levels. Follow-up thyroid tests were done at year 3, 6, and 9. At each 3 year interval, people with positive TPO antibodies had a 10-20% likelihood of becoming hypothyroid. This means the majority of them continued to have normal thyroid function, despite having thyroid antibodies in their blood.

TPO levels are also highly sensitive to your lifestyle, including diet, stress, sleep, and exercise, and can vary based significantly due to what's going on in your environment. Routine monitoring of antibodies after initial testing isn't generally recommended as a result, thyroid hormone levels a more accurate reflection of how well your thyroid gland is working

If you have Hashimoto’s, and are wondering how much of your thyroid is still functioning, you can get an idea from the amount of thyroxine medication you take:

If your thyroid function is completely lost, you will usually need around 1.6mcg/kg (of bodyweight) of thyroxine replacement (with a range is 1.5-1.7mcg/kg) .
If you need less than 1.2mcg/kg this suggests there is still some functioning thyroid tissue left

Hypothyroidism can cause a range of non specific vague symptoms, such as weakness, fatigue, weight gain, cold intolerance, depression, muscle aches and weakness, constipation, hair loss, and even raised cholesterol levels

More severe hypothyroidism (or chronic untreated hypothyroidism) can cause goiter, drooping eyelids, hoarse speech, thin dry brittle hair, dry skin, swollen limbs, irregular periods, infertility, slow heart rate,carpal tunnel syndrome, and even numbness and heart problems.

WHAT BLOOD TESTS ARE DONE FOR HYPOTHYROIDISM?

TSH is the main test used to check for thyroid issues, as its very sensitive, and is the first one to change (it rises when the thyroid starts to struggle to produce enough T4).

Ideal levels are 0.5 - 2.5, although some guidelines suggest around 0.8 in younger people is optimal, especially in pregnancy or fertility treatment.
Lab reference ranges are often higher than this however (usually up to 4 will be reported as normal), as this reflects population ranges, However as approximately 80% of adults have a TSH below 2.5mml/L), some experts suggest we should consider TSH above 2.5mml/L as being abnormal. TSH levels higher than 2.5 mIU/L have also been associated with a higher risk of having antithyroid antibodies, and a higher risk of progressing to clinical hypothyroidism

Its worth noting that up to half of older people (ages 50-70) with a TSH between 3.0-5.0 and thyroid antibodies will also eventually develop hypothyroidism!

T4 is usually checked automatically when TSH is abnormal, and the pattern of TSH and T4 levels is used to diagnose thyroid issues, and to adjust thyroid medication

When TSH is high and T4 is low, this is called hypothyroidism
When TSH is high but T4 is normal, this is called subclinical hypothyroidism
If TSH and T4 are both low, this usually means secondary or tertiary hypothyroidism (from lack of TSH hormone)
If TSH is low and T4 is high, this is hyperthyroidism (or too much thyroid hormone medication)
If TSH is low but T4 is normal, this is subclinical hyperthyroidism (most commonly seen when too much thyroxine medication is being given)

T3 doesn't usually need to be monitored, unless there are ongoing symptoms despite a normal TSH, as the body is very good at converting T4 to T3.

However if you have persistent symptoms ie brain fog /fatigue with normal TSH, you may need T3 levels checking to ensure these are adequate, and it's worth asking your doctor about this to get advice specific to your situation.

WHAT NUTRIENTS ARE NEEDED FOR HEALTHY THYROID FUNCTION?

Our thyroid needs several different micronutrients to produce and convert thyroid hormones - these are iodine, zinc, selenium, and iron - so deficiency in any of these can affect thyroid hormone production.

Vit D and magnesium are also important in autoimmune thyroid diseases as they help to regulate inflammation

Selenium:

Selenium plays an important role in the thyroid, as its involved in converting T4 to T3.
It also helps in the production of glutathione (an antioxidant that helps lower oxidative stress in the thyroid, and protect it from damage).
It has been found that rates of autoimmune thyroid disease are also higher in people who are selenium deficient.

One trial of 70 patients with Hashimoto’s showed that supplementing with 200mcg/day with selenium significantly reduced thyroid antibody levels by 25-55% after 3 months.

Luckily, two Brazil nuts a day provides all of the selenium you need! Other sources include whole grains, like whole grain pasta and brown rice, beans and seeds.
Many NZ soils are deficient in selenium so it's essential to get enough of this from imported food. Selenium can be checked a blood test, but a cost usually applies

There is also some evidence that taking selenium with myo-inositol (a type of natural sugar found in foods and also made by our body) can have additional benefits - one RCT of patients with Hashimoto’s subclinical hypothyroidism showed that 600mg/day of myo-inositol in addition to 83mcg/day of selenium resulted in a 33% reduction in TSH levels (compared to the group who received selenium alone), while both groups had around a 40% reduction in TPO antibodies.

Myo-inositol also shows some promise for improving insulin sensitivity and high blood sugar levels, as well as improving depression and anxiety symptoms, all of which are more common in people with Hashimoto’s.

Foods naturally high in myo-inositol include legumes, peas, brown rice, nuts, citrus fruit, rockmelon, berries, and carrots - all great reasons to eat more whole plant foods!

Iodine:

Iodine is an essential nutrient for our thyroid, as it plays a major role in thyroid hormone synthesis. As we mentioned earlier, the thyroid hormones T4 and T3 have iodine as one of their central molecules

Iodine deficiency is rare in Western countries, but is still possible in people who eat a whole food, low salt, plant-predominant diet if its not deliberately included.

Iodine deficiency can rapidly lead to hypothyroidism, and this can be devastating if it occurs in pregnant or breastfeeding women, or in young children, as adequate thyroid levels are crucial for brain development and growth in children

Iodine is easy to find on a plant-based diet, but you need to know where to look!

Iodine comes mainly from the ocean, as well as soils near the ocean. Due to modern farming methods though many soils in NZ are low in iodine, meaning plants grown in these soil will also be low in iodine
Seaweeds such as kelp and nori are good plant based dietary sources of iodine, although it's also found in fish, shellfish, dairy and eggs. 3 sheets of nori contains your daily requirements for iodine
As an aside, the iodine in dairy actually comes from fortified animal feed, and the sanitizing agents used in milk production - ie its not actually 'natural' source of iodine anyway!

In New Zealand (as well as in many other Western countries), table salt is iodized, as a public health measure to prevent goitre and hypothyroidism. 1/2 to 3/4 tsp of iodised salt per day will give you enough iodine.

Bear in mind that most western diets contain way too much salt, and excess salt is linked to increases in blood pressure, heart disease and stomach cancer. However over 70% of this excess salt comes from processed foods (and ironically the salt in processed foods isn't even usually iodised 🙄), so if you eat mostly whole plant foods and limit salt from other sources, small amounts of iodised salt are fine if you prefer to get your iodine this way

Salt intake should be kept to a max of 1500-2300 mg per day.

The recommended dose of iodine is 150 mcg/day for adults, you can get this either as an iodine supplement, or by using kelp powder.

1/16th of a teaspoon of kelp powder per day will give you enough iodine, but remember too much iodine is also harmful!

Some kelp supplements can contain a mega doses of iodine, we do not recommend using them for this reason (when we refer to kelp, we mean pure kelp powder, not concentrated supplements)

Testing for iodide is complex and expensive (it usually requires a 24 hour urine test!) so it's not routinely done, especially as it's so easy to get enough dietary iodine

Iron:

This is needed for an enzyme called thyroid peroxidase (TPO) to work. TPO helps produce T4 and T3 thyroid hormones, so iron deficiency will impact significantly on thyroid function, it's essential for a healthy thyroid.
Iron-deficiency anemia also blunts the effect of iodine supplementation on thyroid function, and iron supplementation improves it (meaning iodine supplements in people who are iodine deficient are less effective when people are also iron deficient)

Iron deficiency is incredibly common, and is important to check for if you have existing thyroid issues, or a strong family history of thyroid problems.
Ferritin is the lab test usually done to check iron levels, and in New Zealand normal ranges for ferritin in adults are technically 15-250

However optimal ranges are higher 50-250 (30 at a minimum) and some guidelines actually suggest aiming for a ferritin of 100 if you have persistent thyroid symptoms despite normal thyroid levels!

Inflammation can also artificially elevate ferritin levels, your doctor can request full iron studies if this applies to you.

Iron rich plant foods include legumes like lentils, beans and chickpeas, as well as whole grains, broccoli, some dark leafy greens, pumpkin seeds and dried fruit (such as figs, apricots, prunes and raisins)

Its also important to mention that if you need to take an iron supplement and are on thyroid hormone medication (thyroxine) , make sure you take these at least a few hours apart, as iron supplements reduce the absorption of thyroid medication

Zinc:

Zinc helps support thyroid function and immunity, and is needed for effective T4 to T3 conversion. It's also important for your immune system to work well.

Plant foods high in zinc include wheat germ, lentils, chickpeas, cocoa powder, oats, cashews, tofu and pumpkin seeds.
Zinc can be checked on a blood test through standard labs, although a cost will usually apply.

Vitamin D:

Vit D plays an important role in immune system regulation (among other roles), and many studies show links between Vit D deficiency and higher rates of various autoimmune diseases. Vitamin D deficiency is relatively common in New Zealand over winter, especially in the South Island, in the elderly, in breastfed babies/toddlers, and in people who are housebound/avoid the sun, have dark skin, or who cover up the majority of their skin for cultural or other reasons.

One trial found that supplementing vit D in people who were Vitamin D deficient also reduced TPO antibody levels ie helped to improve Hashimoto’s levels. The recommended dose is 1000IU-2000IU/day, however Vitamin D is toxic in overdose, so it can be a good idea to check levels before supplementing, and after 3 months, to ensure you are getting the right dose (this test is not funded in New Zealand in most people however, but if you limit supplementation to 1000IU/day then blood tests are not essential). You can also get a monthly vitamin D capsule funded on prescription.

WHAT ABOUT GOITREGENIC FOODS?

You may have heard about foods that can 'block' your thyroid function or are 'bad for your thyroid' as they can cause hypothyroidism.

These are termed 'goitregenic' foods and include soy and cruciferous vegetables (cauliflower, cabbage, kale, broccoli and brussel sprouts)

Cruciferous veges contain compounds called thiocyanate and isothiocyanate, which if eaten in very high amounts can theoretically block iodination of thyroglobulin (T4 production), especially if people are iodine deficient.
However these compounds are also known to protect against cancer as well as other chronic diseases! Cruciferous veges are an important part of an anti-inflammatory healthy diet, and have numerous health benefits (such as reducing the risk of heart disease and cancer, and improving hormone health) so we don't recommend avoiding them - it's all about balance
Steaming or briefly cooking brasiccas can help counteract this effect, and may be a good compromise if you have hypothyroidism or Hashimoto’s and are worried about their effect on your thyroid.

Soy is also slightly controversial from a thyroid perspective, as the isoflavones (compounds in soy that have many health benefits) can block inhibit TPO enzyme activity.
Soy is also known to reduce the absorption of thyroxine medication if eaten at the same time.
There is also some evidence that soy may increase the risk of autoimmune thyroid disease and hypothyroidism in people at high risk of these.

Yet on the other hand, soy protects against heart disease, some cancers (especially breast cancer), improves cholesterol, reduces the risk of diabetes, and protects against osteoporosis - all issues particularly relevant to postmenopausal women (who are also have the highest rates of hypothyroidism!).

One large recent metanalysis showed that soy consumption can potentially cause an increase in TSH levels, but does not affect T4 or T3 levels, and this TSH rise is not generally clinically significant.

Overall the evidence does NOT support avoiding soy (due to its many other health benefits), but it's worth being aware of its potential effects when monitoring thyroid levels, particularly in postmenopausal women.
If you have hypothyroidism or Hashimoto’s, or are at high risk of these, it may also be sensible to avoid taking soy isoflavone supplements, ensure you are getting enough iodine in your diet, and just stick with a maximum of 1-2 servings of whole soy foods per day 😊

OTHER NUTRITIONAL TIPS FOR HYPOTHYROIDISM

Eating an anti-inflammatory diet to help reduce your risk or severity of autoimmune disease is commonly recommended alongside the specific nutrients above, given than the majority of thyroid issues are due to autoimmune problems

We have a detailed post on eating a autoimmune disease in the autoimmune section of our members area, but in general a whole food, plant focused diet rich in colours, fibre, and diversity is the best way to help this!

The key factors in an anti-inflammatory diet are avoiding trans-fats, limiting fats that are high in omega-6 fatty acids (including many saturated ie animal based fats) increasing monounsaturated fats (from plants) and omega-3 in the diet, aiming for 8-10 servings of fruits and vegetables, and eating at least 30 gm of fiber daily, choosing whole grains whenever possible. Limiting or avoiding highly processed foods and those with lots of added sugar, and limiting or avoiding red meat and alcohol is also recommended

Gluten is another area worth mentioning, as there are known links between gluten and autoimmune thyroid disease

This is due to the fact that many people with thyroid disease also have celiac disease - one large longitudinal study found that people with celiac disease have a 4-fold increased risk of hypothyroidism!

People with coeliac disease also have significantly higher levels of thyroid antibodies than the general population, and these levels drop after they start on gluten-free diets. This is thought to be due to a common gene that increases the risk of both issues

Other clinical trials have found that most patients with coeliac disease and Hashimoto’s who strictly followed a gluten-free diet for 1 year find that their subclinical hypothyroidism goes away, and those who are taking thyroxine need less of it - suggesting that gluten is a significant trigger for autoimmune thyroid disease in these people

There is less data in people without coeliac disease, but some specialists suggest a trial of gluten free diets in people with Hashimoto’s due to the potential links- if you choose to do this, then a trial for 3 months with repeat thyroid blood tests at the end is sensible, as well as keeping record of any symptom improvements.

Black cumin seed (Nigella sativa ) is a traditional herbal medicine that has limited evidence in Hashimoto’s hypothyroidism, it has antioxidant, anti-inflammatory and immunomodulatory properties.

One RCT compared 2g/day of black cumin powder with placebo over 8 weeks, and found a reduction in weight, anti-TPO antibodies, and TSH levels in the group treated with black cumin seed. Also, T3 and T4 levels increased significantly in the treatment group. The trial was in a small group over a short time however, so further trials are needed to make firm conclusions.

GENERAL LIFESTYLE TIPS FOR THYROID HEALTH

STRESS :

Significant physical and emotional stress can affect your thyroid health.

This is because our body tends to 'down-regulate' our thyroid activity during stressful conditions as a survival response, meaning T3 and T4 levels decrease, and TSH secretion is inhibited

The conversion of T4 to T3 can also drop, leading to higher levels of reverse T3 and less active T3 hormone as we mentioned earlier.

Even things like calorie restriction (ie dieting), and prolonged emotional stress can have an affect on thyroid function!

Ironically for dieters, this can actually slow metabolism and stop weight loss occurring - another good reason not to follow restrictive diets

Stress can also worsen some symptoms of hypothyroidism (such as fatigue, poor sleep, and brain fog), so stress reduction wherever possible is vital for thyroid health

SLEEP:

If you are sleeping less than 8 hours per night then you may be affecting your thyroid function without realizing it.
TSH is affected by our circadian rhythm (body clock) - it is secreted between 8pm to 3am, and reaches a peak at about 2 to 3am.

Lack of sleep is associated with a nearly two-fold increase in the level of TSH at night, and an increased risk of subclinical hypothyroidism - this is also seen in night shift workers.

Melatonin (the main hormone released during sleep) influences multiple pathways in our body, as well as circadian rhythm

It has anti inflammatory effects due to how it alters our immune cells (inhibits Th1, and promotes T reg), meaning lack of sleep can increase inflammation and potentially worsen autoimmune thyroid disease.

Untreated sleep apnoea can also affect the thyroid, and is associated with higher rates of sick euthyroid syndrome (discussed at the start of this post)

HOW TO TAKE THYROXINE

If you need thyroid hormone replacement due to hypothyroidism, thyroxine (T4) is the recommended treatment.

As our bodies are generally very good at converting T4 to T3, in the majority of people this will result in enough T3, especially in the context of healthy nutrition and lifestyle

You may have heard of desiccated whole thyroid, as this is still used by some functional medicine practitioners.

Due to lack of consistency in the strength and composition with this, there are major concerns about whether its safe to use, and is not recommended by thyroid specialists, as a result
It also contains a higher proportion of of T3 compared to T4 than what humans need, and there have been many reports of hyperthyroidism (thyroid toxicity) in people using dessicated whole thyroid.
We do not recommend using it

A very small percentage of people can also have persistent symptoms of hypothyroidism despite adequate T4 and TSH levels when taking thyroxine.
If this is the case T3 levels can be checked on a blood test, to ensure you are converting T4 adequately (plus don't forget about ensuring you aren't iron deficient, which causes very similar symptoms!)

Research doesn't support routine use of T3 medication however, as many large studies show no difference in thyroid levels and symptoms doing this routinely, and there are also risks with taking T3 medication, such as sleep disturbance, osteoporosis, and heart problems - it should only be done under guidance of an endocrinology specialist as a result

Several other medications also reduce thyroxine absorption, including antacids, calcium, cholesterol drugs, and iron supplements. They should be taken at least 4 hours before or after thyroxine.

Food can reduce thyroxine absorption so it can be helpful to take it before breakfast on an empty stomach if possible

Conditions that reduce stomach acid (ie atrophic gastritis) and infections such as H pylori may also reduce thyroxine absorption

Thyroxine has a very long half life - meaning it lasts around a week in your body, so it doesn't need to be taken at a certain time of the day. If you are getting blood tests for adjusting or monitoring thyroxine dosing, these only need to be done every 4-6 weeks as a result.

Phew, that was a lot of information, but we hope you've found it helpful!

Thyroid issues are complex, but as with many things, lifestyle and nutrition can play a huge role, so are so important to be aware of as well 😊

NOTE: we always recommend talking to your doctor before trying any herbal supplements or vitamin/mineral supplements, as they can be contra-indicated in certain conditions, and can also interact with prescription medicines. This post is not intended to be personal medical advice, it is for educational and reference purposes only.

https://www.ccjm.org/content/86/2/101

https://pubmed.ncbi.nlm.nih.gov/17684054/

https://academic.oup.com/jcem/article/87/2/489/2846568

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2910542

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3148770

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5751186

https://www.ncbi.nlm.nih.gov/pubmed/25758370

https://journals.physiology.org/doi/full/10.1152/ajpendo.90869.2008
https://pubmed.ncbi.nlm.nih.gov/16720655

https://pubmed.ncbi.nlm.nih.gov/28829155

https://www.nature.com/articles/s41598-019-40647-x#ref-CR9
https://www.liebertpub.com/doi/10.1089/thy.2006.16.249

https://pubmed.ncbi.nlm.nih.gov/11932302
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4855971/?_ga=2.162229500.1305076252.1672220824-962210701.1672220823
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2935336/?_ga=2.166740350.1305076252.1672220824-962210701.1672220823

https://academic.oup.com/jcem/article/91/12/4953/2656472

https://www.thelancet.com/journals/landia/article/PIIS2213-8587(14)70225-6/fulltext

https://academic.oup.com/jcem/article/93/10/3915/2627356