To understand the thyroid, we need to first quickly look at hormones and how they work in the body. A common misconception is that the only hormones in the body are reproductive hormones, such as testosterone, estrogen and progesterone. But in fact hormones are constantly working in our bodies to send messages to all our organs to start or stop different functions or processes. All hormones are designed to keep our bodies in balance, or homeostasis, and therefore well balanced hormones are key to a healthy body.
Hormones that constantly work to keep you healthy include;
Insulin and glucagon which balance our blood sugar levels.
Cortisol which is a hormone that helps us focus in a stressful situation, but cause issues in long term stress.
Serotonin and melatonin help us get up in the morning and fall asleep at night.
Plus many others
Some hormones have one specific task, whilst others are more complicated and affect the body in a multitude of actions. The thyroid and it’s hormones are good examples of complex hormones with a wide range of interactions in the body, which is why thyroid problems can lead to so many different issues; weight issues, fatigue, sleeplessness, trouble with the female cycle, and heart health, to name a few.
How the thyroid works
As a major player on our hormonal landscape, the thyroid gets its signals from a gland in the
brain called the pituitary. This in turn gets hormonal messengers from the hypothalamus.
The hypothalamus is responsible for much of the hormonal balancing in the body by measuring the blood and looking for abnormalities.
It then sends messages to the pituitary to correct or restore balance.
It's the pituitary’s role to release the hormones for distribution through the blood stream to stimulate different organs to produce their own hormones which will affect the function of the body. Still with me?
The messenger from the pituitary which stimulates the Thyroid is called TSH or thyroid stimulating hormone. This is usually the first hormone your GP will test for when he/she suspects there might be something amiss with your thyroid. This hormone tells the thyroid to produce its own hormones; T4 and T3.
How T4 and T3 are produced
T4 and T3 are made up from tyrosine (an amino acid) and iodine (a mineral). As the iodine changes molecular structure to enable itself to stick together, to form T4 or T3, it goes through an oxidation process. To protect the thyroid from oxidative damage, selenium is used as an anti-oxidant in the shape of Glutathione peroxidase (Ventura, Melo, & Carrilho, 2017).
Once T4 and T3 are produced they enter the blood stream and since most cells in the body have receptors for T4 and T3, they will affect almost every tissue in the body. Both T4 and T3 are fat-soluble, which means they can easily enter the cells and directly affect the processes inside the cell. Even though we have more T4 in the blood stream, T3 is much more potent and has a stronger effect. T4 is commonly converted to T3 once inside the different cells. (Tortora & Derrickson, 2014)
Overview of how T4 and T3 work in the body
Thyroid hormones increase our base metabolic rate (BMR), which means we use our energy faster and break down our fats, carbs and proteins quicker. Hence we will often see weight gain and fatigue in clients with low thyroid hormones as they don’t have enough T4 and T3 to stimulate energy production. Skinny people that can’t gain weight may have a high thyroid function with too much of these hormones, but this comes with other problems, so not an enviable way to lose weight. As you can see, an imbalance here can definitely make it harder to lose weight. (Tortora & Derrickson, 2014)
As the T4 and T3 stimulate the energy to be produced in our cells, this gives off more heat, and through this process the thyroid has an impact on our body temperature. So we often see cold intolerance in people with low levels of hormones, and heat intolerance in people with high levels of hormones. (Tortora & Derrickson, 2014)
T4 and T3 also impact our fat metabolism and enhance cholesterol excretion, and as such have a direct impact on cholesterol levels. The hormones tell the cells to take up more cholesterol, so if there are not enough T4 and T3, less cholesterol is cleared from the blood stream. Low hormones can also increase the amount of cholesterol which is reabsorbed in the gut, which also leads to an increase of cholesterol in the blood. (Tortora & Derrickson, 2014)
T4 and T3 also up-regulate the “beta” receptors which respond to our stress hormones, epinephrine and nor-epinephrine. This means that we get a bigger response when we get stressed. These receptors are mostly present in our heart tissue, and can therefore be seen as increased blood pressure or palpitations in our clients with high levels of T4 and T3.
The thyroid hormones also work with insulin and the Human Growth Hormone (HGH) to accelerate body growth. Particularly important in the growth of the nervous system and the skeletal systems. Therefore it’s extra important to have well balanced thyroid hormones when you are pregnant to ensure normal growth of your baby.
To understand how the body re-balances hormones, let’s go back to the hypothalamus that decides how much we produce of each hormone. So if there is a lot of T4 and T3 in our blood, the hypothalamus will reduce the signal to produce TSH, which will reduce the production of T4 and T3 until we are at a good level again. Same if the hypothalamus picks up a low number of T4 and T3 in the blood, it will signal for an increase in TSH to up the production. These fluctuations are normal and will look normal on a blood test.
However, if there is something not working properly in the thyroid, and it’s not producing enough T4 and T3 the hypothalamus will continue to signal for higher production. This will lead to an increased TSH, but without the increase in T4 and T3. The system will be malfunctioning and the hypothalamus will continue to push for more without the resulting increase in T4 and T3.
Thus, when we have a raised TSH, but not enough T4 and T3 is produced, it’s called HYPO-thyroidism, if the TSH is raised but T4 and T3 are normal its called sub-clinical hypothyroidism.
If instead our thyroid is set to producing too much T4 and T3, the hypothalamus will read the high levels and reduce the signal for production, and less TSH will be sent out by the pituitary. If this reduced signal doesn’t stop the over production and our thyroid continues to produce too much T4 and T3, it is called HYPER-thyroidism.
How thyroid function interacts with other commonly seen problems
Stress and the thyroid
Cortisol is as mentioned a hormone which the body produces in response to stress. It helps us in acute situations when we need to “run away from a blood thirsty animal”. Epinephrine and norepinephrine are two other stress hormones also involved in this process. In our modern world we seem to live in a state of constant fear and running around, and many of us have a constant high production of cortisol.
However, chronically raised cortisol may lead to hypothyroidism. There are also indications that hypothyroidism may cause increased cortisol as the hormones affect each other. (Walter et al., 2012)
As mentioned above, in hyperthyroidism, the effect of epinephrine and nor-epinephrine is enhanced and can lead to heart palpitations or high blood pressure (Tortora & Derrickson, 2014).
Thus when we look at a stressed person, we need to always consider the link to the thyroid, whether is clear or not. We might have a person who is trying to lose weight, but can’t. This may be due to chronic stress and this effect on the thyroid.
Cortisol, insulin and the thyroid – type 2 diabetes
Type 2 diabetes mellitus (T2DM) is a complex disorder which is caused by an unhealthy lifestyle, which has led to abdominal obesity. This in turn causes the body to not be able to utilise glucose efficiently with high insulin levels (insulin resistance).
Many factors lead to this situation and there are several issues that often co-exist; heart disease, obesity, high blood pressure, high cholesterol and problems with the thyroid. (Sarris & Wardle, 2014)
Studies also show that insulin resistance is directly related to TSH levels. That means that your thyroid issues can lead to weight gain, which can then later lead to insulin resistance and T2DM (Adhau, Girish, & Kansara, 2015).
Female cycle and the thyroid
Another interaction which is commonly seen is the correlation hypothyroidism has with menstrual problems. It has been found that many people that suffer endometriosis also suffer hypothyroidism. In severe cases hypothyroidism can be implicated in infertility. Hyperthyroidism can be a cause of late onset of your period. (Ajmani et al., 2016)
General signs the thyroid isn’t working well
Even the smallest change in thyroid hormones can make a difference to how we feel. Slightly raised TSH, but with T4 and T3 still within “normal” range can affect your well-being. This is called sub-clinical hypothyroidism and is the kind of problems us Naturopaths look for.
In this scenario the most common symptoms are dry skin, poor memory, slower thinking, weakness and muscle cramps, swollen face with some swelling around the eyes, fatigue, hoarseness, deep voice and constipation. (Cojic & Cvejanov-Kezunovic, 2017)
Causes of thyroid disturbance
Most commonly in women, normal thyroid function is disrupted by pregnancy. Other situations which may affect the thyroid is inflammation from a viral disease or an autoimmune attack (this is when the body mistakes its own tissue to be a foreign invader and attacks it). An inflammatory episode can lead to overproduction of hormones, which is then over-corrected and leads to lowered production. This is called a thyroid storm. Any of these issues can become more or less permanent if the reason for the disturbance isn’t removed.
Each case is different and we all arrive at our state of health or disease in different ways, and due to different problems. As discussed above, the disruption to a normal thyroid function can be due to a viral infection, stress or pregnancy. Other reasons can be a lack in the minerals which make up the thyroid hormones.
Naturopaths will look at your health history, your diet and lifestyle and help you find the best path to your healing. The most important thing to remember is that there is no one-size-fits all solution to your complex health problems. In addition to diet and lifestyle, there are also herbs which may support your recovery.
Most important to remember, is that a happy thyroid will most probably make you a happier, more well-balanced person.
Adhau, S., Girish, S., & Kansara, G. (2015). Insulin resistance in sub clinical hypothyroidism. International Journal of Research in Medical Sciences, 4(9), 1420–1425. https://doi.org/10.18203/2320-6012.ijrms20150159
Ajmani, N. S., Sarbhai, V., Yadav, N., Paul, M., Ahmad, A., & Ajmani, A. K. (2016). Role of Thyroid Dysfunction in Patients with Menstrual Disorders in Tertiary Care Center of Walled City of Delhi. Journal of Obstetrics and Gynecology of India, 66(2), 115–119. https://doi.org/10.1007/s13224-014-0650-0
Cojic, M., & Cvejanov-Kezunovic, L. (2017). Subclinical hypothyroidism - Whether and when to start treatment? Macedonian Journal of Medical Sciences, 5(7), 1042–1046. https://doi.org/10.3889/oamjms.2017.195
Sarris, J., & Wardle, J. (2014). Clinical Naturopathy 2e. Chatswood, NSW: Elsevier.
Tortora, G. J., & Derrickson, B. H. (2014). Principles of anatomy and physiology (14th ed.). Wiley.
Ventura, M., Melo, M., & Carrilho, F. (2017). Selenium and thyroid disease: From pathophysiology to treatment. International Journal of Endocrinology, 2017. https://doi.org/10.1155/2017/1297658
Walter, K. N., Corwin, E. J., Ulbrecht, J., Demers, L. M., Bennett, J. M., Whetzel, C. A., & Klein, L. C. (2012). Elevated thyroid stimulating hormone is associated with elevated cortisol in healthy young men and women. Thyroid Research, 5(1), 1. https://doi.org/10.1186/1756-6614-5-13