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What is the Thyroid and what does it do?
The thyroid, a butterfly-shaped endocrine gland, might be small but it is so important for many essential functions of the body. In order for this organ to function properly, the consumption of iodine is essential.
The job of the thyroid is to regulate our metabolism; therefore, controlling our heart rate, digestive function, brain development, bone maintenance and muscle function, it can slow them down or speed them up. This organ also affects our energy levels, the way we regulate our body temperature, and our mood.
Two hormones are secreted, one is the inactive Thyroxine or T4 and the active Triiodothyronine or T3, these are secreted in varying proportions. Most of the cells in our body convert T4 to T3 according to what is needed; thus, it is not surprising that when things go wrong and there is too little or too much of these hormones, multiple systems in the body are affected, triggering a myriad of symptoms.
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Prevalence
Over 3 million people in the UK live with thyroid disorders, with hypothyroidism being the most common affecting 2% of the population. Thyroid disorders can affect people of all races, ages, and genders, but women are at a higher risk of developing thyroid disorders than men.
When things go wrong
Thyroid diseases can be congenital, autoimmune as in the case of Graves’ and Hashimoto’s, caused by iodine deficiency or excess, triggered by stress (environmental or physical), viral infections or cancer.
They are usually classified as hypothyroidism and hyperthyroidism based on the thyroid hormone levels. When there are too many hormones, known as hyperthyroidism, it can cause our metabolism to go faster than normal. The opposite happens when there are too little hormones, known as hypothyroidism, our metabolism slows down. If left untreated it can have serious long term health consequences.
Unfortunately, because many of the symptoms are common in other diseases and can develop slowly, it can take years to get a diagnosis and even the right treatment, which can be frustrating.
Let’s not forget that when things go wrong with our thyroid, the way our body utilises carbohydrates, lipids and proteins is also compromised, which can lead to heart problems, insulin resistance, and low energy levels.
Thyroid diseases are chronic, but thankfully there are treatments available.
Fun fact, it is thought that the Mona Lisa suffered from severe hypothyroidism, can you spot the physical symptoms in her portrait?
Thyroid nutrition and diet
Contrary to many claims online about the best diet for thyroid health and to ‘reset’ your thyroid, truth is that there is not one single perfect diet or specific food for this, unless the problem you have is due to iodine deficiency then adequate iodine intake will help.
Iodine
Nutritionally speaking there are three key nutrients for a healthy thyroid, the most important being iodine, which is a vital component to produce thyroid hormones, too little or too much can have dire consequences for the health of our thyroid. Iodine levels vary and it depends on the soil and the seasons. In the UK iodine intake is mainly from dairy products, interestingly when cow's milk is produced during the winter season it usually contains higher levels of iodine.
If you don’t consume dairy, fish, or follow a plant-based diet, then look for iodine fortified non-dairy milks, there are a few in the market such as: M&S, Gro, Oatly original, Mighty Pea, and Alpro growing up, and iodised salt, in the UK we have the brand Cerebos.
Seaweeds in general are not a reliable source of iodine, they usually contain far too much iodine which can also be dangerous, except for nori and dulse which have low levels, so they are fine. Regarding supplementation, avoid kelp supplements, they are not highly regulated and can contain way more iodine than what the label states.
Selenium
The Thyroid is characterised for having a high concentration of selenium, which is an essential trace mineral, key for a healthy immune system and critical for the activation of Thyroid hormones. A deficiency of this mineral has been independently associated with the swelling of the eyes in Graves’ disease, which is a rare autoimmune condition also known as thyroid eye disease (TED).
Hence, it is important to make sure that we are consuming enough selenium, but it is equally important to not overdo it, as it can easily cause toxicity. Brazil nuts is one of the foods with the highest amount of selenium, although this can vary with location because selenium levels in food depend very much on the soil where they are grown. Unfortunately, selenium levels in the UK soil are quite low; therefore, it is not recommended to rely solely in one source of selenium.
Iron
Iron is not just essential for blood health but also plays an important role in the production of thyroid hormones by activating the thyroid peroxidase enzyme.
T3 is also important to stimulate the production of precursors of red blood cells. Thus, iron and thyroid hormones depend on each other.
Low levels of iron – not necessarily anaemia – can lead to decreased levels of T4 and T3, it is recommended to check your iron levels and stores (ferritin levels) to make sure they are within the normal range.
Brassicas and Soya
Brassicas are foods like cabbage, kale, broccoli, brussels sprouts, cauliflower, and turnips, they have compounds that compete with iodine absorption and may cause swelling of the thyroid. However, most of these compounds are destroyed during cooking.
Isoflavones in soya are thought to affect thyroid function, however, recent studies do not support this, and the European Food Safety Authority has classified them as safe. Even though some studies showed that it can decrease iodine absorption, the effect is minimal as to affect the thyroid.
In a nutshell, brassicas and soya foods are safe to eat, as long as you don’t eat bucketloads of them, and preferably cooked. If you live with hypothyroidism and take levothyroxine, then is better to eat these foods at least 1-2 hours after taking the medication.
Vitamin D
Due to its role in the immune system, some studies suggest there is a link between vitamin D deficiency and development of autoimmune thyroid diseases, especially Graves'. Although not 100% conclusive and the research is still ongoing, vitamin D supplementation is highly recommended for the general population particularly during the winter months.
Gluten
Autoimmune diseases go hand-in-hand with each other, thus Coeliac disease is highly associated with Graves’ and Hashimoto’s, the therefore screening in this population is recommended.
Some studies suggest an improvement of thyroid symptoms when these patients follow a gluten-free diet but is not conclusive and more research is needed in this area.
Medication
There are no contraindications for those taking carbimazole (anti-thyroid) which is the treatment for hyperthyroidism, but those who are on Levothyroxine (T4) tablets must take extra care.
Levothyroxine is absorbed in the small intestine and its absorption is influenced by an acidic environment. It must be taken on an empty stomach, either morning or evening, at least one hour before foods and ideally with a vitamin C or citrusy drinks.
Certain nutrients like iron, calcium, soya proteins, caffeine and fibre can inhibit the absorption of levothyroxine, that’s why it is important to take it on an empty stomach. Medication that decreases the stomach acid i.e., antacids and proton pump inhibitors, bile acid sequestrants and orlistat (for treating obesity) can also inhibit the absorption of levothyroxine, so it best to have them at least 4 hours before Levothyroxine. There is also a liquid form of levothyroxine that is absorbed faster than the tablets.
Health Quality of Life
Torquil Watt, a researcher and endocrinologist from the University Hospital of Copenhagen in Denmark has developed the ‘ThyPro-39’ a validated patient-report outcome measures that detects relevant clinical changes to treatment of thyroid diseases, this tool is currently used worldwide.
Even though adequate treatment helps patients to get their thyroid levels back to within normal range, it is highly documented that many symptoms persist, and quality of life is not restored in all patients, especially in those with autoimmune thyroid conditions.
Thyroid cancer is one of the cancers that are successfully treated and cured, but the quality of life of thyroid cancer survivors is the same as those who had cancers with worse survival rates.
Persistent symptoms are a big part of thyroid disease, so much that in the UK, the NICE guidelines have recently changed their guidelines and now recommend healthcare professionals to ‘'Consider titrating levothyroxine dose until symptoms are resolved’.
Patient support
Patient led organisation like The Thyroid Trust offer support to patients, they actively work on making Liothyronine (T3) available for patients with hypothyroidism. Together with the British Thyroid Foundation, they provide information for patients and professionals, and hold events to spread awareness on the significance of thyroid diseases.