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Thyroid function imbalance

The thyroid hormone is incredibly important because it controls the rate at which our cells burn energy - our metabolic rate.

Every cell in the body has receptors for thyroid (and cortisol) hormones and as such, these regulate heart rate, blood pressure, body temperature, weight, metabolism and growth. Like an accelerator pedal, turn it up and your metabolism will speed up, slow it down and you, quite literally, start to slow down.

Production of thyroid hormones
Under the control of a clever feedback loop the “master gland” in the brain (the hypothalamus) is constantly measuring blood levels of thyroid hormone – commonly termed thyroxine and when levels are low, it secretes a substance called Thyrotropin Stimulating Hormone (TRH).This affects a second gland, the pituitary, causing it to release Thyroid Stimulating Hormone (TSH) which triggers the thyroid gland to produce thyroxine. When a certain level has been reached, the feedback loop ceases production of TSH, until such time when levels begin to dip and so the process continues. In hypothyroidism, the body has inadequate levels of thyroxine. Hyperthyroidism is a less common condition that exists when excess thyroid hormones are present. So because every cell of the body is affected by thyroid hormones, symptoms of imbalances are often varied and affect multiple body systems.

Symptoms of low thyroid function

Symptoms of high thyroid function

  • Brittle hair and nails
  • Cold temperature intolerance
  • Cold hands and feet
  • Constipation
  • Decreased sweating
  • Depression
  • Dry skin
  • Fatigue
  • Inability to lose weight
  • Low libido
  • Menstrual irregularities
  • Shortness of breath
  • Sluggishness
  • Weight gain
  • Anxiety
  • Diarrhea
  • Eye/vision changes
  • Fatigue
  • Hair loss
  • Insomnia
  • Palpitations
  • Rapid heart beat
  • Sweating
  • Weakness
  • Weight loss

Not quite that simple
The thyroid gland actually produces two very similar hormones called T4 & T3 and strictly speaking when we talk about thyroxine, we are talking of just T4. T4 is made up of the amino acid tyrosine and 4 iodine atoms, T3, just has the three atoms of iodine attached. Now, although T4 is produced in more plentiful amounts in the blood, it has little effect on our cells. Enzymes, predominately in our liver and kidneys convert T4 to T3 which IS the most active hormone and able to stimulate our cells’ thyroid receptors and thereby affect out metabolism.

Testing for thyroid function
Most GP’s run tests for thyroid-stimulating hormone (TSH), Total T4 (TT4) and free T4 (FT4). As just mentioned, T3 is actually the most active thyroid hormone at the cell receptor level and this isn’t routinely checked at all. In addition, there could be a number of reasons that your immune system has started to produce antibodies against the thyroid gland and negatively impacting its function, but these are not checked either. Finally, on this point, under certain conditions, the conversion of T4 to T3 can be impaired resulting in high levels of a hormone called reverse T3 (rT3). Although chemically similar, reverse T3 is completely inactive and lowers the amount of active T3 available to the cells. The way I describe it to patients is as though you are driving a car with the handbrake on!  This can all occur in the face of “normal” TSH FT4 and even FT3 readings. Here are two quotes direct from Thyroid UK:-


We at Thyroid UK believe that you need to know your Free T3 level too because this will often show low if you are not converting, and high if you have blocked receptor cells. Even if you are converting, the body needs the extra T3 that a normal thyroid produces”.

Note on TSH as A Measuring Tool for Hypothyroidism
Authorities in USA now suggest that 2.7mU/L should be the cut-off point and treatment should be offered above this. In this country recent suggestions, sadly approved by the British Thyroid Foundation and certain senior endocrinologists, have placed the cut-off point now at 10mU/L, well above previous levels of 4 or 5mU/L, which were far too high anyway. The thinking behind these proposed guidelines is beyond rational explanation; and the amount of illness and suffering which will result is heartbreaking. A problem with interpreting TSH results is that, firstly, it assumes that the hypothalamus and pituitary are working normally, and secondly, that the thyroid status is normal and is not being influenced by medication or other illness.”


What can cause Hypothyroidism?
Stress
One of the most important factors that I see in clinic that leads to hypo and sub-clinical hypothyroid is chronic stress. As I have written about in detail under adrenal imbalance & stress, chronic stress, be it physical or emotional is characterised by raised cortisol levels. Excess cortisol can inhibit both thyroid-stimulating hormone (TSH) and the conversion of thyroid hormone T4 to T3. That’s not all; too much cortisol can cause the tissues to no longer respond to the thyroid hormone signal. It creates a condition of thyroid resistance, meaning that thyroid hormone levels can be normal, but tissues fail to respond as efficiently to the thyroid signal. This inhibition of your thyroid and hormone receptors often takes place quietly behind the scenes for years without causing overt symptoms, but just gradually, over time, more and more symptoms begin to arise.

Nutrients
To manufacture thyroid hormones, we require a number of key nutrients:- Vitamins E, A, C, B2, B3, B6 and the minerals selenium,  iron, zinc, and the amino acid tyrosine derived from protein rich foods and iodine. Deficiencies in any of these will impact upon thyroid hormone production.

Toxic metals
Exposure to environmental toxins such as pesticides, which act as hormone disruptors can interfere with thyroid hormone metabolism and function. In fact, one study found that as people lost weight (toxins have an affinity to fat) they released pesticides from their fat tissue. This then interfered with their thyroid function and caused hypothyroidism. Heavy metals such as mercury can also affect thyroid function.

Yo- Yo dieting
Crash dieting, specifically the type that involves a significant restriction in calories, such as popular “packet meal” diets, can reduce TSH levels and subsequent T4/T3 production.

Female hormones
A typical form of hormone imbalance is the "oestrogen dominance" syndrome when there is not enough progesterone produced in the female cycle to balance the effects of oestrogen. This is very common in the lead up to the menopause, when progesterone production slows far quicker than oestrogen production does and can often lead to hypothyroidism.

Clearly, there are many things to consider but any approach to correcting poor thyroid function must address the endocrine system in its entirety- maybe not just prescribing "a pill for an ill" - but looking a bit deeper in order to understand what caused the body to tip out of balance... wouldn't this be more of a proactive and lasting approach?

Tests
Functional tests I may use at Nutritional Values to aid treatment protocols in this area are:-
Adrenal Stress Profile
Thyroid plus panel (includes total T3, free T3 Reverse T3 & antibodies, together with TSH&FT4)
Iodine screen
Rhythm (female hormone profile over course of menstrual cycle)

The whole picture
At Nutritional Values I use the Functional Medicine model to assess your health. This means seeking to identify interactions between different systems in the body through comprehensive case history taking, your presenting signs and symptoms and on occasion functional laboratory testing. The goal is to identify and address the triggers and underlying causes of your health problems, that often then cause imbalances in body systems, rather than simply focusing on symptoms.

To book an appointment or speak to Tanya click here.

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