How your thyroid works and how you can keep it healthy

Your thyroid gland produces hormones that impact such fundamental aspects of your life as sleep, body temperature, metabolism, fertility and mood. With one in three Australians suffering from low thyroid hormone levels, we dig into how your thyroid works and how you can keep it healthy.

The thyroid gland is one of the most important glands in the human body. It controls nearly all of your cells and is vital for healthy metabolism, growth and development. This tiny butterfly-shaped gland, which makes up part of your endocrine system, produces hormones that help regulate many vital functions in the body. A disturbance in thyroid function can greatly impact your physical and mental health and wellbeing. This is why, when the thyroid is not working optimally, it can affect the functioning of almost every system of the body, including your emotional state.

Thyroid hormone regulation

Located at the base of the neck, the thyroid gland is regulated by what is called a negative feedback loop, which includes the hypothalamus, pituitary gland and the thyroid gland. The hypothalamus secretes thyrotropin-releasing hormone (TRH), which stimulates the pituitary gland to produce thyroid-stimulating hormone (TSH), which in turn stimulates the thyroid gland to make and secrete thyroid hormones.

The thyroid produces two main types of hormones: triiodothyronine (T3) and thyroxine (T4). T3 is the active form of thyroxine. The liver, gut and kidneys convert T4 into its active T3 form that can be used by cells in the body. There is a third hormone produced by the thyroid called calcitonin, which is involved in calcium and bone metabolism.

If your T3 or T4 levels are too high the hypothalamus and pituitary gland will stop secreting hormones. If your T3 and T4 levels are too low the hypothalamus and pituitary gland will increase thyroid hormone secretion to help bring the body back into balance. If your thyroid function test results show high TSH levels, this may indicate that your thyroid is underactive and not producing enough thyroid hormones. Low TSH on the other hand may indicate that your thyroid is overactive and producing too much thyroid hormone.

Role of thyroid hormones

Thyroid hormones play a major role in metabolism and how nutrients from the foods you eat are converted into energy to fuel the body. They regulate body temperature, heart rate and digestive function, and they can also affect fertility.

Thyroid hormones influence your sleep, and your brain function and development. They also help regulate your “feel-good” neurotransmitters like serotonin and dopamine that control your mood.

Additionally, these hormones also play a role in maintaining healthy bones, and they assist the liver with breaking down cholesterol and controlling triglyceride levels.

Hypothyroidism

Hypothyroidism is the most prevalent thyroid disorder in Australia, affecting one in three Australians. Hypothyroidism is a condition where the thyroid gland is unable to make and release enough thyroid hormones. Women, particularly women over 60, are more vulnerable to developing hypothyroidism than men. People with pre-existing autoimmune diseases such as rheumatoid arthritis, coeliac disease and type-1 diabetes are at a greater risk of hypothyroidism.

Common causes of hypothyroidism

In Australia, Hashimoto’s thyroiditis is the most common cause of hypothyroidism. Hashimoto’s is an autoimmune disease where the immune system starts mistakenly attacking the thyroid gland, causing inflammation and thyroid cell destruction.

Other causes of hypothyroidism include poor diet lacking in iodine and selenium, radiation therapy or surgery and genetic disorders. Issues with the pituitary can affect TSH production and can result in hypothyroidism.

Common symptoms of hypothyroidism

One of the most notable symptoms of hypothyroidism is sluggish metabolism. When your metabolism slows down you put on weight easily and feel tired all the time.

The thyroid gland helps regulate important neurotransmitters including serotonin, so if the thyroid is under-functioning symptoms such as moodiness and depression are often experienced.

Some other common symptoms of hypothyroidism include being sensitive to cold, constipation, changes in skin (dry, rough and cracked), brittle hair and nails, hair loss, poor concentration, joint and muscle aches and pains, frequent colds and flu (resulting from poor immune health), fluid retention, sleep issues, goitre (enlarged thyroid gland), slow heart rate and breathing difficulties.

Heavy and irregular periods and difficulties falling pregnant are also seen in women with hypothyroidism.

People with hypothyroidism can also develop thyroid nodules. This is caused by a build-up of cells within the thyroid that causes a lump. Thyroid nodules are generally benign; however, some can turn cancerous over time.

During and after pregnancy women can start producing high amounts of thyroid hormones, and then can experience a rapid drop. This is called post-partum thyroiditis. TSH plays a role in the development of a healthy foetus, so it is very important that women’s hormones are balanced throughout their pregnancy.

Hypothyroid symptoms usually start off mild and then worsen with time as thyroid function decreases. If your thyroid function test results show TSH levels are high but thyroid hormone levels remain normal, this indicates that your thyroid is in the early stages of hypothyroidism and treatment is required before it progresses.

Hyperthyroidism

Hyperthyroidism is a condition where the thyroid gland becomes overactive and makes and releases more thyroid hormones than the body requires. In Australia around three in 1000 people suffer from hyperthyroidism. Both men and women can develop hyperthyroidism; however, it is more commonly seen in women aged 20 to 40.

Common causes of hyperthyroidism

One cause of hyperthyroidism is a condition called Graves’ disease. This is an autoimmune condition where the immune system produces antibodies that stimulate the thyroid gland to overproduce thyroid hormones. Leaky gut syndrome is associated with the development of autoimmune disorders like Graves’ disease.

Thyroid nodules and thyroiditis are other causes of hyperthyroidism. Thyroiditis is where the thyroid gland becomes inflamed as a result of a viral infection or issue with the immune system. This can also happen after childbirth, called post-partum thyroiditis.

Having excessive amounts of iodine in the diet from supplementation or from prescription medications can also result in hyperthyroidism.

Common symptoms of hyperthyroidism

Some of the most common symptoms of hyperthyroidism include an irregular and rapid heartbeat, sensitivity to heat, unintentional weight loss, fatigue, muscle weakness, tremors, increased appetite, anxiety, irritability and issues with sleep. Changes in menstrual patterns, more frequent bowel movements and hair loss are also seen in people with hyperthyroidism.

A goitre is another symptom of hyperthyroidism. An enlarged thyroid gland can cause feelings of tightness in the throat and can make it difficult to breathe or swallow.

Hyperthyroidism is also associated with an increased risk of osteoporosis as hyperthyroidism causes bone mineral density loss.

Sometimes people with Graves’ disease can have a condition called Graves’ ophthalmopathy, where their eyeballs protrude due to swelling of the tissues and muscles behind the eyes. This can also cause dryness, redness, light sensitivity and blurry double vision.

Diagnosing thyroid conditions

Unfortunately thyroid issues often go undetected, especially when people present with subclinical hypothyroidism or hyperthyroidism. These thyroid conditions also have symptoms that are common to a lot of other health conditions, so it makes it difficult sometimes for doctors to diagnose. If you suspect you have issues with your thyroid it is important that you visit your doctor. They will perform a physical examination to check for any thyroid swelling or goitre, as well as any changes to your skin or eyes. They will check your pulse to see if it is too low or high, and they will do a thyroid function blood test which tests TSH, T3 and T4 levels, as well as tests for thyroid antibodies which can indicate thyroid autoimmune disease. Your doctor may also order a thyroid scan or ultrasound if they suspect any thyroid nodules.

Conventional treatment

Conventional treatment options for hyperthyroidism include antithyroid drugs (methimazole and propylthiouracil), which block the thyroid from making thyroid hormones; radioactive iodine, which works by damaging thyroid cells so that the thyroid shrinks and reduces the production of thyroid hormones; beta blockers that block the action of thyroid hormones to help control symptoms like nervousness, shakiness and rapid heartbeat; and surgery where the thyroid gland is removed.

Unfortunately, these conventional treatments come with side effects. Antithyroid drugs carry the risk of causing damage to the liver. Researchers from the National Cancer Institute have recently found an association between radioactive iodine treatment for hyperthyroidism and the long-term risk of cancer, including breast cancer. The removal of the thyroid gland results in hypothyroidism and the need to take thyroid medication for life to maintain normal thyroid hormone levels.

Hypothyroidism is usually treated with a thyroid medication called levothyroxine, which increases the amount of thyroxine in the body to help normalise your thyroid hormone levels. This medication is usually taken for life but the dosage may be altered at different times, which needs to be monitored by your doctor.

Natural ways to heal your thyroid

Fortunately, there is a variety of beneficial dietary and lifestyle changes and effective herbal medicines that can help optimise thyroid function and balance thyroid hormone production, and reduce the risk of autoimmune thyroid disease.

Selenium. 

The trace mineral selenium is vital for making thyroid hormones and for healthy thyroid function. If your diet is lacking in selenium you will increase your risk of hypothyroidism.

The thyroid gland has the highest selenium content of any organ in the body. A deficiency in selenium increases the risk of thyroiditis, which is inflammation of the thyroid that can cause over- or under-functioning of the thyroid gland. You need selenium to make the antioxidant glutathione, which helps protect cells in the body, including thyroid cells, from damaging free radicals and inflammation. Selenium also helps protect the thyroid gland from excessive iodine exposure, and it’s needed for converting T4 into T3.

The best food source of selenium is Brazil nuts — you only need two a day to get your daily dose of selenium. Other good sources include cod, tuna, salmon, chicken, lamb, eggs and shiitake mushrooms.

Studies have shown that selenium supplementation is beneficial for people with Hashimoto’s disease as it can decrease antithyroid antibody levels. Selenium supplementation in pregnancy has also been shown to be helpful as it can significantly decrease the risk of women developing post-partum thyroiditis and hypothyroidism. The recommended dosage for selenium is 200μg daily.

Iodine.

Iodine is another important trace mineral that is essential for making thyroid hormones. If your diet is low in iodine you will be at risk of developing hypothyroidism. Supplementing with iodine is recommended if your iodine levels are low. Kelp is an excellent source of iodine, which is often recommended for the treatment of hypothyroidism. You should always take selenium when you supplement with iodine as excessive amounts of iodine without selenium can worsen autoimmune diseases. Iodine supplements and seaweed products should be taken under the supervision of a naturopath, herbalist or nutritionist. The recommended iodine dosage is 150–300μg daily, with 200μg of selenium a day. Always start off with a lower dose of iodine and then gradually increase the dose. Anyone with hyperthyroidism should not take iodine supplements as it can worsen their condition. The best way to get iodine in the diet is by eating seaweed (such as kelp, kombu, wakame, nori or dulse), fish and eggs. Iodised salt is also a source of iodine.

Gut health.

The health of your gut influences your thyroid function. Your intestinal microbiome affects the production of hormones including thyroid hormones. If your gut microbiome is out of balance or if your intestinal lining becomes compromised, inflamed and permeable (leaky gut), this will compromise your thyroid function and can increase the risk of autoimmune diseases such as Hashimoto’s and Graves’ disease. Leaky gut is a condition where the intestinal lining becomes inflamed and gaps form which allow larger protein molecules to travel into the bloodstream. The immune system is triggered and mounts an attack, which can result in the development of autoimmune diseases. Gut microbiomes also have the role of converting T4 into the active form of thyroid hormone T3. Around 20 per cent of T4 is converted to T3 in the gut. People will poor gut health have issues with this conversion.

When treating thyroid conditions it is important to look at the health of the gut and remove any food allergies or sensitivities that may be irritating the intestinal lining. Gluten and dairy are two common offenders that can trigger inflammation. Chronic stress, unbalanced gut microbiome (dysbiosis), antibiotic use and certain medications such as non-steroidal anti-inflammatories can all affect gut health and cause inflammation and damage to the intestinal lining. Chronic gut inflammation also triggers the release of cortisol which reduces active T3 levels.

Probiotic-rich foods.

Including fermented foods in your daily diet is an important way to boost your gut health. Fermented foods are considered probiotic foods as they contain live bacteria that help improve the levels of beneficial microbiome components in the gut. It’s important that you have a good balance of these beneficial gut microbiota for a strong functioning immune system. When your gut microbiome is out of balance certain harmful bacteria can activate immune cells to produce inflammation that can damage the intestinal lining. Probiotics are found in fermented foods such as yoghurt, kefir, miso, kvass, kimchi, kombucha, sauerkraut and other fermented veggies.

Taking a probiotic supplement daily with around 50 billion CFU (colony forming units) is recommended to help promote a healthy balance of gut microbiome, to heal the gut and reduce inflammation and to support healthy immune function.

Soothing herbs.

Sipping on gut-soothing anti-inflammatory herbal teas like camomile, ginger, turmeric, cinnamon and liquorice can help ease inflammation of the gut and promote healing. Slippery elm, aloe vera and marshmallow are also lovely soothing herbs that are used to heal the intestinal lining.

Collagen.

Bone broths are another way to help heal an inflamed and leaky gut. Bone broths made from chicken, beef, lamb or fish bones contain collagen that help soothe, nourish and repair the gut lining. Collagen is a type of protein that is abundant throughout the body including the digestive tract. Taking a collagen supplement is also beneficial for healing the gut.

Glutamine.

Glutamine is an amino acid that is the primary fuel source for the cells that line the gut. It helps repair and strengthen the gut lining by tightening up the openings in the gut wall, which prevents large undigested food particles and toxins from entering the blood stream. Glutamine also helps soothe the gut by suppressing inflammation. Glutamine supplementation is recommended for anyone with a leaky gut or any type of inflammatory bowel condition.

Issues with gluten and dairy.

People with hypothyroidism or hyperthyroidism often have a sensitivity to gluten or have coeliac disease, which is an autoimmune disease that causes damage to the gut lining from the consumption of gluten. Gliadin, a type of protein found in gluten, has a very similar molecular structure to your thyroid gland. When gliadin passes through a leaky gut into the bloodstream the immune system can confuse it with thyroid tissue. Antibodies to gliadin can start attacking the thyroid. Research shows that a gluten-free diet can be beneficial for people with autoimmune thyroid disease. Foods that commonly contain gluten include breads, pasta, crackers, breakfast cereals and a lot of processed foods like soups, sauces and dressings that are thickened with flour.

Dairy may also be an issue for people with an autoimmune thyroid disease. Casein, the protein found in dairy, has a very similar structure to gliadin. Because of this similarity, people who react to gluten often react to dairy. The immune system may set off a similar immune response to casein as it does for gliadin. Switching to plant-based milks and yoghurt is recommended for anyone with autoimmune thyroid disease, such as almond, coconut, hazelnut or hemp. Avoid plant-based milks with carrageenan, which is an additive used as a thickener and emulsifier, as it has been linked to increased gut inflammation.

Dietary fibre and water.

It is important to include adequate fibre in the diet to prevent constipation and improve digestive function. Around 30g of fibre is recommended daily for adults, by consuming foods such as wholegrains, nuts and seeds (such as chia, flax or hemp), legumes, fruits and vegetables. It is also important to drink plenty of water daily, especially when you are increasing your fibre intake. Aim for at least three litres of purified water daily. Studies have found that drinking fluorinated water can effect TSH and T3 hormones, and can inhibit iodine absorption, so people with hypothyroidism should use a water purifier.

Stress management.

Healthy thyroid function also depends on healthy functioning adrenals. Chronic physical or emotional stress can suppress thyroid function. Inflammatory cytokines are released when we are stressed. These pro-inflammatory compounds reduce hypothalamic and pituitary function, which both control thyroid hormone production. These inflammatory cytokines also inhibit the conversion of T4 to T3. Chronic stress also affects the health of the gut by disrupting intestinal microbiome balance and the integrity of the gut lining. Stress weakens the immune system and increases the risk of autoimmune thyroid diseases.

Making certain lifestyle changes and incorporating stress-relieving techniques into your daily life can do wonders for supporting your adrenals throughout ongoing stress. Daily exercise, yoga, meditation, breathing techniques and getting adequate sleep and eating
a wholesome well-balanced diet are all key ways to help manage stress.

Herbal medicine and the use of adaptogenic herbs is one of the most effective ways to support the body during times of stress. Some of the best adaptogenic herbs include Panax ginseng, Siberian ginseng, holy basil, ashwagandha, Bacopa, Rhodiola, maca and medicinal mushrooms such as cordyceps, lion’s mane, turkey tail, reishi, chaga and shiitake. Supplementing with B vitamins and magnesium are also beneficial ways to support energy production and improve fatigue, relieve anxiety and aid sleep.

B vitamins are also essential for producing our “feel-good” neurotransmitters serotonin and dopamine, which are important for our emotional health and wellbeing.

Anti-inflammatory and antioxidant-rich foods

Inflammation and oxidative stress caused by free radicals can cause damage to thyroid cells and affect thyroid function. Both inflammation and oxidative stress are associated with hypo- and hyperthyroidism and autoimmune diseases such as Hashimoto’s and Grave’s disease.
A wholesome diet made up of unprocessed and predominantly plant-based foods will provide plenty of protective antioxidants, phytochemicals and other important nutrients that will nourish the thyroid gland and support thyroid hormone production. Eating these nutrient-rich foods will also help improve gut health and immune function, reduce inflammation and neutralise damaging free radicals.

Stock your kitchen full with fresh fruits, vegetables, legumes, avocados, raw nuts and seeds (such as chia, flax, hemp and quinoa), nut butters and tahini, gluten-free wholegrains (such as brown rice, amaranth and buckwheat), oily wild fish and healthy oils like cold-pressed olive, avocado, flaxseed and macadamia. Coconut oil and olive oil are healthy options to cook with. Olive oil can be used for low-to-medium heat cooking and coconut in moderation for higher heat cooking. Coconut oil contains medium-chain triglycerides (MCT), which support healthy metabolism and help boost energy levels.

Fruits and vegetables are abundant in flavonoids, carotenoids and vitamin C, which have powerful antioxidant and anti-inflammatory properties. Berries such as blueberries, raspberries, açaí, strawberries and blackberries, dark green leafy vegetables, beetroot, cherries, pomegranates, oranges, tomatoes, lemons, carrots, kiwi, papaya, broccoli, avocado and mangoes are all loaded with these important protective compounds.

Oily fish are rich in beneficial omega-3 fats which have potent anti-inflammatory properties. They’re also essential for a healthy functioning immune system, hormone balance and thyroid function, and can help to heal and repair an inflamed leaky gut. Wild oily fish like Alaskan salmon, trout, cod, mackerel and sardines are all great choices. Chia, flax and hemp seeds, walnuts, seaweed and algae are also good sources of alpha-linolenic acid (ALA), which is a type of plant-based omega-3 fatty acid. Omega-3 fatty acids also help balance omega-6s in the diet. Taking a good-quality fish oil or a plant-based algae supplement is also a great way to increase omega-3 fats in your diet. The recommended dosage of omega-3 fats is 1–2g daily.

Processed foods should be avoided as they contain highly inflammatory ingredients like refined vegetable oils and sugars that can produce inflammatory cytokines in the body. Vegetable oils including corn, safflower, sunflower, soy and peanut oils oxidise quickly when heated and form trans-fats and aldehydes which are highly inflammatory. These oils are also high in omega-6 fats which are important in moderation but inflammatory when eaten in excess.

Reduce goitrogen-rich foods

People with an under-functioning thyroid should reduce their intake of raw brassica vegetables, which include Brussels sprouts, kale, cauliflower, broccoli and cabbage. Although extremely healthy vegetables, brassicas contain compounds called goitrogens that can disrupt thyroid function by inhibiting the uptake of iodine into the thyroid gland. Soy is also a goitrogen-rich food. People with hypothyroidism should reduce raw brassica vegetables and soy products in their diet. Fermenting and cooking brassica vegetables and soy beans, however, reduces their goitrogens. Some fermented vegetables like sauerkraut and organic tempeh can make a healthy addition to the diet.

Tyrosine

Tyrosine is an amino acid that is essential for healthy thyroid function. Tyrosine with iodine is a building block for thyroid hormones and adrenal hormones. Tyrosine is made in the body from another amino acid called phenylalanine; however, supplementation is recommended for anyone with hypothyroidism or poor adrenal function. L-tyrosine can help improve the production of adrenal hormones dopamine and norepinephrine, which will help boost mood, alertness and brain function and reduce stress and fatigue. It can also help improve sleep as it plays a role in melatonin production. People with hyperthyroidism or Graves’ disease should avoid tyrosine supplementation as it can increase thyroxine levels and worsen their condition. You will find tyrosine in chicken, fish, almonds, avocado, bananas, pumpkin seeds and sesame seeds or tahini. The recommended dosage of tyrosine is 500mg twice a day.

Bugleweed and lemon balm

Studies have shown that the herbs bugleweed and lemon balm have anti-thyroidal effects, which make them beneficial for the treatment of hyperthyroidism and Graves’ disease. Extracts of these herbs inhibit the stimulation of thyroid hormone production and can help regulate an overactive thyroid.

Bugleweed (Lycopus virginicus) isa member of the mint family and is native to North America. This herb is commonly used by herbalists and naturopaths to treat hyperthyroidism. Bugleweed can suppress thyroid function and lower high levels of thyroid hormones, which makes it useful in the treatment of overactive thyroids. Bugleweed has also been used historically to help ease anxiety, palpitation, tachycardia and insomnia, which are all common symptoms of hyperthyroidism.

Lemon balm (Melissa officinalis) is also a member of the mint family. The Arabs in the 11th century used lemon balm as a remedy for depression and anxiety. Today lemon balm is popular among herbalists for treating insomnia and anxiety-related conditions, as it has a sedative and calming effect on the nervous system. Lemon balm and bugleweed can be taken as liquid extracts or as teas. These herbs should not be taken by anyone with hypothyroidism or Hashimoto’s disease.

The treatment of thyroid conditions is complex, so it is important to always consult with your doctor and naturopath or herbalist before starting any herbal medicines or nutritional supplements. Natural medicines can be taken in conjunction with conventional medicinal treatments; however, they must be overseen by a trained healthcare professional. Diagnosing and treating thyroid disorders early with natural medicines and diet is important to prevent the progression of thyroid dysfunction and the development of associated health conditions.

Lisa Guy is a respected Australian naturopath with over 20 years clinical experience. She runs a Sydney based naturopathic clinic Art of Healing and is the founder of Bodhi Organic Tea, an award-winning premium organic wellness tea company. artofhealing.com.au.

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