Author: Jacqueline Newson, BSc (Hons) Nutritional Therapy

How to tell if you have an underactive thyroid

How to tell if you have an underactive thyroid

One of the major issues of modern day life seems to be constant fatigue and lack of energy.

While there can be many reasons for experiencing chronic fatigue it may be worth focussing on your thyroid.

If you have a thyroid gland that is 'sluggish' or under-functioning, fatigue is one of many symptoms it is likely to present with.

In this article, we will take a look at the causes of low thyroid function, what the common symptoms are, how to diagnose it and some top tips for regaining thyroid hormone balance. 

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Understanding the thyroid gland 

The thyroid, a butterfly-shaped gland is located in the front of the neck below the larynx.

It is controlled by the master glands the hypothalamus and pituitary and is regulated by thyrotropin-releasing hormone (TRH) and thyroid stimulating hormone (TSH).

It produces inactive thyroxine (T4) which is converted into the active form of triiodothyronine (T3) within the tissues and liver. (1)

The thyroid works like a tiny factory operating on the instructions of TSH.

It takes in iodine and tyrosine and produces large quantities of thyroxine (T4).

Thyroxine is transported through the blood to specific cells and organs where it is transformed into the more active thyroid hormone T3 with the help of a selenium-dependent enzyme called deiodinase. (1)

Both hormones are present in blood serum either in the free-state or bound to proteins.

The amount of free T4 and free T3 is important for the biological effects of the thyroid hormones. (1)

This is because only the free fractions can cross the cell membranes and exert an effect on metabolism within the cell.

T3 is less tightly bound to plasma proteins than T4 and is, therefore, more readily taken into the cells, making it approximately 10 times more active than FT4. (2)

T4 may also be converted into a substance called reverse T3 (rT3).

Unlike T3 this compound does not stimulate thyroid hormone receptors; however, it does still bind to these receptors subsequently blocking the action of T3.

Some research suggests that rT3 may also directly interfere with the generation of T3 from T4. (11)

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The thyroid controls many functions in the body, (2,12) including :

  • The metabolism of every cell of the body
  • Blood glucose levels
  • Growth and development
  • Nervous system activity
  • Calcium balance
  • Cholesterol levels
  • Heart rate
  • Blood pressure
  • Appetite
  • Mental function
  • Reflexes
  • Libido

An under-active thyroid (hypothyroid) occurs when the thyroid gland doesn't produce enough thyroxine (T4) and triiodothyronine (T3).

These hormones control the metabolic rate of all cells throughout the body. (3)

It's commonly believed that the thyroid is all about weight gain or loss, but in fact, because it controls metabolism it has an impact on every system, organ and muscle in the body.

A thyroid with diminished activity decreases your metabolic rate, affecting every cell in your body and will, therefore, influence virtually all bodily functions.

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Common Symptoms of Low Thyroid Function 

Since thyroid hormones affect every cell of the body a deficiency will usually result in a large number of symptoms.

Low thyroid function is more common than people realise, but some of the tell-tale signs include:

  • Fatigue
  • Headaches
  • Cold feet and hands
  • Eczema
  • Acne
  • Menstrual disorders
  • Constipation
  • Chronic recurrent infection
  • Atherosclerosis
  • Sensitivity to cold
  • Psychological problems
  • Low libido
  • Muscle weakness
  • Dry skin
  • Brittle nails
  • Course hair
  • Low mood/depression
  • Erectile dysfunction
  • Slow heartbeat/palpitations
  • Poor memory and concentration
  • Infertility/miscarriage
  • Unexplained weight gain and inability to lose weight
  • Hair loss

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Factors affecting thyroid health

Stress - chronic stress is characterised by raised cortisol levels (Cortisol is a steroid hormone). (5)

Excess cortisol inhibits the conversion of T4 to T3. It also increases the production of rT3 and hinders TSH production.

This can lead to lower overall levels of both T4 and T3

Calorie restriction - can reduce TSH levels and negatively alter the balance between T4 and rT3 (4) particularly when carbohydrate is also restricted.

The fall in thyroid hormones seems to be most significant in the early stages of fasting.

Liver function - conversion of T4 to T3 and the metabolism of spent thyroid hormones happens mainly in the liver.

As a result, compromised liver function is associated with increased rT3 and reduced T3 levels. (6)

Heavy metals - animal studies show that cadmium lead and mercury impairs type II, 5'-deiodinase enzyme activity. (13)

A free radical load can inhibit certain liver deiodinase enzymes, interfering with T4 to T3 conversion.

Medications - certain medications including corticosteroids and beta-blockers can decrease levels of T3 and increase levels of rT3. (8)

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How can you be sure you have an under-active thyroid? 

Thyroid function tests (blood measurements of T3, T4, TSH and TRH) are used to diagnose thyroid disorders. (9)

However, it is known that milder forms of these disorders are much more difficult to detect using such tests.

As a result, many individuals are currently undiagnosed.

Also, it may well be that the thyroid hormones present are not accessible to the tissues due to other imbalances within the body such as elevated cortisol and oestrogen levels (oestrogen competes with thyroxine preventing it from exerting its effects). (10)

Before the use of blood tests, low thyroid function diagnosis was based on resting temperature and Achilles heel reflex (reflexes are slowed by hypothyroidism).

In fact, checking the Achilles reflex is still accepted and used by mainstream medicine today as an indicator of thyroid function. (11)

Metabolic rate is reflected in the body’s resting temperature.

Thyroid function can, therefore, be determined by using the following procedure:

  • On waking, place a thermometer in your armpit for a full ten minutes.
  • It is important to make as little movement as possible. Lying and resting with your eyes closed is best. Do not get up until the ten minutes is completed.
  • After ten minutes, read and record the temperature and date.
  • Record the temperature for at least three mornings (preferably at the same time of day).
  • Menstruating women should perform the test on the second, third and fourth day of menstruation. Men and post-menopausal women can perform the test at any time.

Your basal temperature should be between 97.6 and 98.2 degrees F or 36.4 to 36.7 degrees C.

Lower than this may indicate hypothyroidism.

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Low thyroid Support

Stress, poor diet, environmental toxins (fluoride, chlorine), pesticides, paint, food additives, poor digestion and absorption, food intolerance, candidiasis, hormonal imbalances and lack of exercise can all contribute to thyroid disorders.

Tackling these factors involves a multi-pronged approach and should ideally start with good nutrition.

Including high protein foods such as chicken, turkey and nuts are essential as they are a good source of the amino acid tyrosine.

This, together with the mineral iodine found in kelp (seaweed) is important to help make thyroxine.

A selenium dependant enzyme converts thyroxine into triiodothyroxine, so selenium-rich foods such as Brazil nuts, yellowfin tuna and sardines(22) are also important.

Whole grains, fresh fruit and plenty of green vegetables are also recommended as B vitamins, vitamin C, zinc, iron and magnesium play a key role in thyroid function.


Other top tips for supporting your thyroid: 

  • Eliminate as much physical, and emotional stress as possible
  • De-clutter and simplify your life
  • Create a regular relaxation routine
  • Avoid gluten (barley, wheat, rye and oats)(20)
  • Supplement with iodine, zinc and selenium
  • Consider taking herbs that support thyroid function such as Guggul. (14)
  • Support adrenal function with Ashwaganda, Siberian ginseng Rhodiola and holy basil. (15)(16)(17)
  • Take part in short bursts of high-intensity cardiovascular exercise for a few minutes every day. (18)
  • Also, add in some resistance training (yoga, isometric, or weights) for a few minutes every day. (19)
  • Support toxin elimination by sweating profusely 3 times a week (up to an hour at a time). Infrared saunas are particularly beneficial. (21)
  • Avoid processed foods and added sugar
  • Eat organic
  • Get plenty of rest

If you recognise any of the symptoms suggested in this article and would like to be sure about your thyroid function, Amchara can provide Thyroflex testing.

This amazingly accurate testing method uses an instrument that measures the speed of your brachiradialis reflex, located in the forearm.

The Thyroflex test provides information about what’s happening inside your cells, rather than what’s happening outside your cells (in your blood).

With the Thyroflex you can find out how your body is utilising its thyroid hormone.

For a Free, Hormone Health Consultation click on the image.

Book your free hormone health consultation today

Written by: Jacqueline Newson BSc (Hons) Nutritional Therapy


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