Thyroid's impact on overall health is a complex subject with a lot of deviations. From hair loss and brain fog to inability to lose weight and extreme fatigue. Here we will look at the thyroid function from a bird's eye view.
Feeling flat and at times even exhausted is becoming the new "norm" alongside increased BMI (weight). According to recent statistics over 50% of Australian population is feeling tired, and over 65% are overweight. Mental health follows with 45% of our fellow citizens Australia wide. It is also estimated that over 45% of Australians are living with a sub-clinical thyroid dysfunction. Coincidence? Think not.
The thyroid gland is a small butterfly-shaped organ located in the neck. It plays a crucial role in regulating all bodily functions, making it a powerhouse of metabolic control and overall well-being. From the speed of your metabolism to the lightness of your mood, digestion to fertility, the thyroid influences various aspects of health, often flying under the radar until imbalances occur.
Think of the body in terms of corporate hierarchy: the brain is the founder, thyroid is the C.E.O. and the rest of the organs are managers and employees. When the thyroid gland is sub-optimally functioning the rest of the organs do not receive correct "orders" to operate at the right rate.
Thyroid Hormones
Under the influence of the hormone from the brain - T.S.H. - Thyroid Stimulation Hormone, the thyroid gland produces two main hormones: triiodothyronine (T3) and thyroxine (T4). These hormones are synthesized from the amino acid tyrosine and iodine, essential components derived from the diet. T3 is the biologically active form of thyroid hormone, while T4 serves as a precursor that is converted into T3 as needed by tissues throughout the body.
How Thyroid Hormones Impact The Body
Metabolism
Thyroid hormones play a central role in regulating metabolism—the process by which the body converts food into energy. This is the process that allows us to remain in our optimal weight. In order to stimulate metabolism (think rhythm, burn, speed) T3 and T4 stick to the receptors on the cells, which in turn increase the production of proteins and enzymes involved in energy production and utilisation. Here glucose, lipids and proteins are metabolised to provide overall metabolic efficiency and calorie expenditure. You have eaten and the thyroid hormones switched the process of utilising what you have eaten into energy. When people have underactive thyroid function the metabolism is slowed down, sometimes to the point where you barely eat yet you are not losing any weight - your body is able to sustain its slowed down function on very little calories. And on the opposite side, when the thyroid overactive we see people rapidly losing weight without any psycial effort or food deprivation on their part.
Digestion
Thyroid hormones T4 & T3 influence gastrointestinal motility, secretion, and absorption, helping to regulate bowel movements and ensure proper digestion of nutrients. They stimulate the secretion of digestive enzymes and bile acids, promote intestinal motility, and enhance nutrient absorption in the small intestine. Imbalances in thyroid function can disrupt digestive processes, leading to symptoms such as constipation, bloating, and malabsorption in cases of underactive thyroid. And diarrhoea, bloating, vigirous appetite and malabsorption in case of hyperthyroid. In clinical practice I have witnessed both spectrum of the imbalance: bowel motions once a week, and stool frequency increased to 12 times per day. Here we also see sluggish liver, high cholesterol and insulin resistance.
Cognition & Mood
Brian fog is one of the most common complaints in people with underactive thyroid (alongside fatigue and weight increase). Optimal thyroid function is essential for cognitive function, memory, and concentration. Thyroid hormones support neuronal growth, synaptic transmission, and neurotransmitter synthesis in the brain, promoting cognitive clarity and mental acuity. They also play a role in mood regulation and emotional well-being, influencing neurotransmitter activity in areas of the brain involved in mood regulation, such as the amygdala and prefrontal cortex. I often witness how on optimal thyroid treatment people feel happier, brighter and less worried.
Energy Levels and Adrenals
Thyroid hormones modulate energy metabolism and the stress response, working in concert with the adrenal glands to maintain consistent energy levels throughout the day. They increase basal metabolic rate, enhance energy production from carbohydrates, fats, and proteins, and promote glycogenolysis and gluconeogenesis to mobilize energy reserves during periods of increased demand or stress. Thyroid hormones also help regulate adrenal function, influencing cortisol secretion and adrenal responsiveness to stressors. If the thyroid is functioning "well" the adrenals will pick up the speed delivering you sustained energy throughout the day.
Temperature Regulation
Wearing socks and jackets whilst everyone around you is in T-shirts and flip flops is one of the signs of thyroid dysfunction. Thyroid hormones play a key role in regulating body temperature by influencing heat production and dissipation. They increase basal metabolic rate, leading to greater heat production, and enhance peripheral vasodilation and sweating to facilitate heat loss. Hypothyroidism, characterized by low thyroid hormone levels, can lead to feeling cold and difficulty tolerating cold temperatures, while hyperthyroidism may result in feeling excessively warm or experiencing heat intolerance.
Hair, Skin, and Nail Growth
Dry skin and hair loss are some of the concerns my clients express on their initial appointment. Thyroid hormones promote cellular metabolism, protein synthesis, and tissue regeneration, contributing to healthy hair, skin, and nails. They stimulate hair follicle growth, sebum production, and collagen synthesis, helping to maintain skin hydration, elasticity, and integrity. Thyroid dysfunction can lead to hair loss, dry skin, brittle nails, and other dermatological issues. When we address the root cause the quality of skin, hair and nails is one of the obvious signs of health.
Immune System
Thyroid hormones modulate immune responses and inflammation, influencing the activity of immune cells and cytokines involved in innate and adaptive immunity. They enhance immune surveillance, phagocytosis, and antibody production, promoting defense against pathogens and foreign invaders. Thyroid dysfunction can disregulate immune function, leading to increased susceptibility to infections, autoimmune disorders, and inflammatory conditions. As the body slows down under the lack of influence from the thyroid gland, it accumulates toxins, which increase systemic inflammation. When the thyroid is in top shape the immune system is also strong.
Reproductive System
heavy menstrual cycle, irregular menstruation, sore and tender breasts, ovarian and breast cysts, fertility issues (miscarriages), rough menopause in women and erectile dysfunction, infertility and lack of libido in men are also traced back to the thyroid. Thyroid hormones are essential for reproductive health in both men and women. They regulate ovarian and testicular function, menstrual cycles, and fertility by influencing sex hormone production, gonadotropin secretion, and follicular development. Thyroid dysfunction can disrupt menstrual cycles, impair fertility, and affect libido. During pregnancy, adequate thyroid function is essential for fetal development, maternal well-being, and successful pregnancy outcomes. Having healthy thyroid function also ensures mother does not experience post-partum depression.
This is just to name a few!
As you can now see, the thyroid gland and its hormones play a central role in regulating absolutely every aspect of health. When I see an individual presenting with several health concerns we always perform in-depth thyroid testing to find the root cause of the issues and address those rather than do the guess work and stick "band-aid" treatment. We find solutions that have a long-lasting beneficial health impact. And in most cases understanding how the thyroid impacts overall health is the key to finding the right solutions.