The Link Between Thyroid Disorders and Mental Health
The thyroid is a butterfly-shaped gland that sits in the neck area just below the Adam’s apple and is responsible for the production of two hormones; T3, a molecule that contains three atoms of iodine, and T4, which contains four atoms of iodine. Whilst they both play an important role in the body, T3 is actually the one that is ‘biologically active’, having a key influence on all the cells, tissues and organs in the body. On the other hand, T4 acts as the precursor hormone, which eventually gets converted into T3 in the peripheral cells of the body.
What Role Does T3 Play in the Body?
Thyroid hormone T3 governs the speed at which the mitochondria work - tiny organelles in every single cell in our body that are like the batteries of our cells. They are responsible for taking in nutrients and turning them into energy, or in other words - adenosine triphosphate (ATP) - the energy currency of our body. The mitochondria are also responsible for a cellular process called apoptosis, a term to describe cell death - incredibly important for the recycling and removal of dysfunctional cells that are no longer required. It is believed that this process plays a role in preventing cancer.
Considering how thyroid activity influences the mitochondria - which play a fundamental role in the energy production of each and every cell in our body - it’s no wonder that when it is either over or under-working, people can experience a wide variety of symptoms that can closely relate to mental health conditions. For example, an overactive thyroid can cause symptoms such as restlessness, anxiety, irritability and heart palpitations. Whereas an underactive thyroid can cause symptoms at the other end of the spectrum, such as fatigue, depression, muscle aches, brain fog and sleep issues. These symptoms are commonly coupled with digestive complaints, low or high body temperature and rapid weight gain or weight loss.
It is for this reason that conditions such as subclinical hypothyroid (underactive thyroid) and autoimmune thyroiditis (an autoimmune thyroid condition whereby the immune system produces antibodies against thyroid tissue) can often be either misdiagnosed as mental health conditions such as depression, bipolar disorder and generalised anxiety disorder, or simply missed as part of the missing puzzle piece when identifying underlying drivers to poor mental health.
How common is it for those suffering with mental health symptoms to also have thyroid dysfunction?
Well it appears to be very common - a number of studies have shown a significant association between levels of antibodies and the occurrence of depression.
Other key factors such as low levels of circulating T3 and poor conversion of T4 to T3 have also been identified in cases of depression. Where tricyclic antidepressants have been ineffective, there has been extensive research that demonstrates how using thyroid medication to augment the success of psychiatric medication, has proven to ease symptoms.
The Difficulties of Diagnosing Thyroid Conditions
In the UK, when suspecting a thyroid issue, GP’s will most commonly test for TSH (Thyroid Stimulating Hormone) - a hormone produced by the pituitary gland to prompt the thyroid to produce the two main hormones, Free T3 and Free T4, which are also tested. The UK charity, Thyroid UK, encourage people to never accept seemingly ‘normal’ thyroid results and to always request the actual figures. This is because different parts of the UK have varying reference ranges - in one area the test ranges for TSH may be 0.5-5.0 but in another part of the country it may be 0.4-4.0, meaning that you could be considered ‘borderline’ but not be aware of this.
In addition, a patient’s results may be in the normal range but they may still suffering with symptoms related to thyroid dysfunction, and often no further investigation is done. However, there are other markers that can indicate further issues related to the thyroid gland such as the autoimmune conditions - Hashimoto’s and Grave’s disease. These markers include three types of antibodies - Antithyroid Peroxidase Antibody, Antithyroglobulin Antibody, Antithyroglobulin Antibody - all of which, if high, would indicate that the immune system is mounting an attack on thyroid tissue and if left untreated, over time the thyroid will eventually malfunction and stop producing adequate amounts of hormones.
Lastly, many are unaware of another thyroid hormone that can explain symptoms related to poor mental health, in particular depression, fatigue and poor sleep. This hormone is called rT3 (reverse T3), which has been labelled the ‘hibernation hormone’ by some health practitioners due to the belief of its impact on metabolism - essentially slowing it down. Research shows how in patients undergoing chronic stress, extreme carbohydrate restriction and those in high inflammatory states due to severe illness, rT3, which is an inactive form of T3, is commonly high pushing the body into a ‘hibernating’ state to conserve energy reserves. Although it is still poorly understood and its clinical validity is yet to be confirmed, rT3 can give an indication of how well thyroid hormone is being metabolised in the cells of the body.
Those with mental health conditions such as depression and generalised anxiety disorder, are often chronically stressed, and not to mention in highly inflammatory states. The hormone, rT3, could therefore be an important marker to take into consideration in the management of both mental health and thyroid conditions.
What Other Factors Play a Role in Preventing Optimal Thyroid Function and Mental Health?
Levels of the hormone cortisol, as well as blood sugar management and food intolerances are two important factors that can play a role in thyroid function and mental health, which can be managed through nutrition and lifestyle changes.
High Cortisol Levels:
Cortisol is a hormone produced in the adrenals - two small glands that sit atop the kidneys - and is responsible for our response to stress, as well as helping us to get out of bed in the morning. Whilst it is incredibly important for our health, in those who are chronically stressed or who have experienced a significant period of trauma in their lives, continuously high levels of this hormone has been shown to inhibit neurotransmitter activity in the brain, which can be disastrous for mental health.
The thyroid plays an important role in metabolising excess cortisol. Research shows how an increase thyroid hormone enhances the metabolic clearance of cortisol, and how at normalising cortisol levels depression is improved. So essentially, in those with an underactive thyroid, high cortisol and the negative impact that this has on your brain and body long term can be exacerbated as there is less circulating thyroid hormone to help clear excess cortisol.
How to Regulate Cortisol Levels:
There are lifestyle and dietary changes that can have a significant impact in helping to regulate cortisol levels.
Reduce exposure to electronic screens and bright lights 2 hours before bed and try to get significant light exposure in the morning.
The light emitted by electronic screens such as mobile phones, TVs and laptops mimic sunlight and trigger a hormonal reaction in the brain, preventing the optimum release of melatonin - our sleep hormone. Melatonin is supposed to gradually increase from early evening throughout the night as cortisol tapers off. However, if we are significantly exposed to lights that do not encourage melatonin production, we are favouring cortisol and disrupt the intelligent circadian rhythm that these two hormones are attuned to. Similarly, it is important to get significant light exposure in the morning to encourage optimal cortisol levels when they should be peaking. There are studiesthat show how electronic light boxes have proven to be effective for helping improve symptoms of depression and SAD (seasonal affective disorder), perhaps due to its ability to support a healthy circadian rhythm.
Reduce Caffeine Intake
Although caffeine has many health benefits, namely supporting the cardiovascular system. It is a stimulant and does trigger the adrenals to produce cortisol and adrenaline, which is what causes the quick surge of energy we get after drinking coffee. Studies in humans have shown that caffeine increases cortisol and epinephrine at rest, and that levels of cortisol after caffeine consumption are similar to those experienced during an acute stress. So if ongoing anxiety and mood swings are a key symptom, reducing caffeine exposure may be helpful.
Gluten’s Role in Thyroid Dysfunction
Evidence to show the link between gluten intolerance/allergies and autoimmune thyroid conditions such as Hashimoto’s and Grave’s disease has been well documented. Studies show how gluten can be a driving factor for these conditions due to a process called ‘molecular mimicry’, whereby the molecular structure of gliadin (the protein component of gluten) appears very similar to thyroid tissue. In cases of compromised gut health, gliadin can pass through the protective barrier of the digestive tract and into blood circulation, which consequently triggers an immune response. The immune system identifies gliadin protein and mounts an attack on it, without realising that it is also in fact attacking the thyroid gland.
In cases of autoimmunity, impact on thyroid hormones are almost always affected - either reducing the output or increasing the output of T3 and T4, consequently leading to changes in neurotransmitter balance.
Try an Elimination Diet:
Reactions to foods that aren’t immediate are normally mediated by the IgG antibody rather than the IgE antibody, which governs the allergy response - an immediate and sometimes life threatening reaction to an allergen such as a food or medication. Food intolerances are, in turn, mediated by IgG and can, on the other hand, often trigger very non-specific symptoms that may take up to 3 days to manifest. In addition to symptoms related to digestive problems such as bloating, cramping and diarrhoea, mood related symptoms such as anxiety, panic attacks, depression, severe fatigue and brain fog, are also common. An elimination diet involves avoiding a food for a period of 3 weeks and then reintroducing it for one day and taking note of symptoms for next 3 days after consuming the food. This can be an effective way of identifying whether gluten is an issue.
Blood Sugar Imbalances:
Studies show that those with diabetes are up to three times more likely to develop a thyroid condition. When blood sugar levels are constantly fluctuating, the body perceives this as stress, which consequently taxes the adrenal glands that in response to stress produce cortisol and epinephrine. An excess of cortisol consequently leads to an increase in inflammatory molecules, which further propel a heightened immune response, damaging the thyroid. In particular, an increase in hypothyroidism can be seen in those with conditions such as diabetes and metabolic syndrome.
How to Regulate Blood Sugar Levels:
Eat Protein and Fat with Every Meal
Both the macronutrients, protein and fat, take longer to digest than carbohydrates, meaning that the food is broken down more gradually and sugar is released slowly into blood circulation. This helps to keep blood sugar levels stable throughout the day and prevents fluctuations that can stress the adrenal glands. Including foods in the diet such as nuts and seeds, eggs, avocado, fish, meat, poultry and legumes can help to prevent the blood sugar rollercoaster and therefore support thyroid health.
Avoid Refined Flours and Sugars
Eating foods such as white bread, pastries, biscuits, cakes, fizzy drinks and any food with added sugar, can over time lead to something called insulin resistance. This means that we no longer respond efficiently to insulin, the hormone that helps clear sugar from our blood stream into our cells for storage. This means that the sugar stays in our blood circulation and we eventually become vulnerable to problems such as diabetes, metabolic syndrome, cardiovascular conditions as well as thyroid dysfunction.
Final Word:
These are just a few key factors in helping to prevent thyroid dysfunction, however, there are many more drivers that could be playing a role such as exposure to toxins like heavy metals and environmental pollution. The important point to take away is that if symptoms of poor mental health are being experienced, it is crucial not to rule out the thyroid when investigating underlying drivers to conditions such as depression and anxiety. If you’re test results have come back as seemingly normal or borderline from the GP, yet you continue to experience symptoms, it won’t hurt to investigate further and have private testing, which is widely available.
