A Functional Approach to Thyroid Health

Updated: Oct 9, 2018



Thyroid problems are becoming too common in modern society, and yet sadly many people take thyroid health for granted. Our thyroid is the primary gland responsible for controlling metabolic rate and basic physiological function, and thyroid hormones impact all major systems, in fact every single cell has a receptor for thyroid hormone.

Thyroid hormone directly acts on multiple body systems like the brain, gut, the cardiovascular system, liver, gallbladder, and influences the metabolism of steroid hormones, glucose and protein metabolism, body temperature regulation, lipid and cholesterol metabolism and more. When thyroid function is compromised, symptoms can manifest throughout the body.

The below stats speak for themselves. It’s estimated that women are 5-8 times more likely than men to have thyroid problems, with one in eight women being likely to will develop a thyroid disorder during her lifetime.


*Stats Image from Kresser Institute ADAPT Framework

Thyroid Problems Affect The Whole Body

The thyroid gland is like the motor of the body, hyperthyroidism causes it to run faster, whereas hypothyroidism causes it to slow down. Symptoms of thyroid malfunction can vary depending on whether the thyroid is over or under active, and whether there is an autoimmune response involved with conditions like Hashimotos or Graves Disease. Hyperthyroidism is less common than hypothyroidism, and is often a more serious condition, because of the increased the risk of heart attack, stroke, and death. Undiagnosed or poorly managed thyroid issues are hazardous for health given the multiple body systems that rely on thyroid hormone, and in the scientific literature thyroid issues are associates with infertility and poor labour outcomes, osteoporosis, cardiovascular disease and more.


The Incomplete Conventional Approach to Thyroid Treatment

The conventional medical model rarely runs a comprehensive thyroid panel, and often relies on simply measuring Thyroid Stimulating Hormone (TSH) as a sole indicator of thyroid function. But this is a flawed approach for multiple reasons, and fails to address the complexity of thyroid issues. While TSH may be the most sensitive marker for thyroid function, TSH tells the thyroid gland to produce thyroxine (T4) and triiodothyronine (T3) which are the primary circulating thyroid hormones. T4 is produced in significantly greater quantities to T3, but T3 is approximately five times more biologically active than T4.

Measuring only a few markers, or only measuring TSH for thyroid function, fails to appreciate the multiple connected systems that influence the thyroid, thyroid conversion, thyroid binding globulin issues, or receptor issues, as well as any immune response. For example:

  • If TSH is in the range, patients will often be misdiagnosed as fine, and sent on their way without further investigation of other thyroid markers, or why the patient is unwell. In the traditional medical model, sub clinical lab values are often neglected, meaning a client will often miss early detection, and can only be treated once they have overt thyroid problems.

  • In cases of where TSH is high, and free thyroid hormones T3/T4 are low, the patient is often given exogenous hormone prescription, and again sent on their way without identifying the underlying cause of why the thyroid hormone was low.

  • And in cases where TSH is low and thyroid hormones are high, the conventional model seeks to suppress thyroid production with drugs, radiation or surgical removal of the thyroid gland, often permanently destroying its ability to produce thyroid hormone.

A common problem a patient with hypothyroidism on prescription T4 hormone may experience is facetious hyperthyroidism, which occurs from excess hormone replacement. This often occurs when there has been no investigation into the underlying cause of low thyroid, and over time the patients symptoms get worse, and so the dose is simply increased. Eventually the dosage of thyroid is so high that the patients own production of thyroid hormone is suppressed, but their T3 production is so high they experience hyperthyroid symptoms like anxiety, weight loss, palpitations, and increased risk for the dangerous conditions associated with hyperthyroidism.

Thyroid Replacement Therapy Rarely Works Alone

Many patients who just take thyroid hormone don’t get better and/or they need higher and higher doses over time. Monotherapy with T4 hormone or levothyroxine, it is the standard of care to replace low thyroid levels. But T4 is the precursor or the storage hormone, and needs to be converted into T3 (the active hormone) to have an effect.

The concept of T4 therapy is that it is safest to allow the body to make the conversion to T3 as required. But this approach is problematic for many reasons, because there are many factors that reduce T4-to-T3 conversion, like inflammation, HPA axis dysregulation, gut dysfunction, aging, iron excess or deficiency, fasting, nutrient deficiency, low testosterone, and genetics.

‘90% of patients with hypothyroidism have Hashimoto’s, which is an autoimmune inflammatory condition, and inflammation inhibits the conversion of T4 to T3!’

– Chris Kresser ADAPT framework

Many patients who take thyroid medication will be on it for life, but addressing the root cause for thyroid disease, can reduce, or even potentially eliminate the need for a lifelong thyroid prescription. The best option for many patients (aside from addressing the underlying causes of thyroid issues) is often natural desiccated thyroid (NDT) which provides a T4-T3 combination. Desiccated thyroid gives you similar doses and ratios of hormones to your own thyroid, rather than just synthetic T4. It's readily available with prescription and over the counter options.

A Functional Perspective


Thyroid dysfunction is often a symptom of a deeper underlying problem. Merely replacing thyroid hormone, or suppressing it, won’t provide the best outcome. The functional medicine model seeks to identify and address underlying causes of thyroid dysfunction, or thyroid associated auto-immune response. In some cases, directly treating the thyroid may be necessary too.

Because of the bidirectional relationship between the thyroid gland and the rest of the body, multiple systems can influence the thyroid, and are worth investigating for a more complete solution. As you can see from the picture, Thyroid function is impacted by toxins, blood sugar, infections, gut health, Hypothalamic Pituitary Adrenal Axis Function, reduced oxygen delivery, nutrient imbalance, and immune reactions.

Image from Kresser Institute ADAPT Framework

A Full Thyroid Panel

Many doctors are reluctant to order a full thyroid panel, but it’s imperative if you suspect a thyroid problem! If you go to a general practitioner and ask for a thyroid screen, you will be lucky to get more than just a TSH measurement. Total T4 and T3 are valuable for seeing available hormone levels and conversions, and Free T3, and T4 are important indicators of what’s happening at the cellular level. Antibodies to the thyroid are important for detecting immune dysregulation, and antibody production can precede the development of clinical thyroid disease by many years, so is important to pay attention to in order to prevent future issues.

Other thyroid markers like T3 uptake, Free thyroxine index (often out of range in hypo or hyperthyroid) or reverse T3 can be helpful. For example reverse T3 (RT3) is the inactive form of T3, and the body may convert excess T4, for RT3 as a protective mechanism against high levels emotional, psychological, or physiological stress. Prescription thyroid replacement in such a case may be harmful as it may upregulate a system that is trying to downregulate and heal.

Low T4 to T3 conversion, high RT3, or a high RT3 and T3 ratio, is often a sign of inflammation, HPA axis dysfunction, or nutrient imbalance, and more so addressing these root causes is a comprehensive and safer solution than thyroid replacement.

In functional medicine, we endeavor to treat the client, and not just the test results. This means looking for patterns between markers, and correlation between clients symptoms for a complete interpretation and solution. Other helpful testis include ALT, Alkaline phosphatase, urine or hair iodine, selenium, thyroid ultrasound, nutrient deficiency testing, and HPA-Axis urine testing, to determine the impact of the Hypothalamic Pituitary Adrenal Thyroid Axis.

The Functional Lab Range For TSH

The conventional reference range of TSH 0.5-4.5 is too broad, and is based on a 2002 NHANES III study which monitored people without evidence of thyroid dysfunction or antibodies production to determine what optimal function would be. However some patients with thyroid disease do not produce thyroid antibodies ever, so they would never test positive, and hence influence the study's results and subsequent recommended reference ranges.

TSH can also vary with age, ethnicity and individual variability, based on our own unique physiology, genetics, and negative feedback loop. The Whickham Survey illustrated that the likelihood of developing clinical hypothyroidism is increased when TSH rises above 2.0. As a result the Kresser Institute has recommended a functional reference range for TSH of 0.5 to 2.0.

Results outside of this range don’t necessarily result in treatment, but should serve as a warning to look more carefully at thyroid function. The broader reference range can neglect to detect subclinical cases of thyroid illness, so a tighter range sooner alerts practitioners to potential issues.

Classic hypothyroidism is high TSH, low T4 and T3. When TSH hormone levels are normal, it is elevated but thyroid’s called subclinical hypothyroidism which again, is why it’s crucial to test more than TSH. Many studies have found that subjects with subclinical hypothyroidism have increased risk of cardiovascular disease, higher total cholesterol, LDL, and C-reactive protein than healthy subjects.

Addressing The Root Causes of Thyroid Problems

The 2 major causes of thyroid problems include nutrient deficiency, and autoimmunity. The thyroid glands needs several nutrients to function properly: iron, zinc, iodine, selenium, B12, B2, vitamins A, C, D, and magnesium so eating a nutrient dense, anti inflammatory diet is crucial for healthy function. The thyroid gland is compromised in cases of excess vitamin D, iron or iodine, so finding the right balance is important, and regular tracking of these nutrients should be part of any thyroid protocol.

Iodine is a particularly tricky nutrient to balance when it comes to thyroid issues because individual response varies markedly, some patients thrive, and in other cases people can feel worse for increasing iodine. Iodine's only known role is the production of thyroid hormone, and many populations are at risk for iodine deficiency: women of child bearing age, children and populations who don't eat iodized salt, conventional bread or dairy products, sea vegetables or fish heads. If you have a thyroid condition, cautiously tracking iodine levels is a must. Studies illustrate that in some populations iodine can provoke an immune response, whereas others feel a marked health improvement. Rather than supplementing with iodine, eating a nutrient dense diet is a better, and often safer option if you are unsure.

Autoimmunity is the other main cause of thyroid disease, so tracking for antibodies is important. When thyroid antibodies are being produced (in either hyper or hypothyroidism) it means the body is erroneously attacking it's own thyroid tissue. This can happen for many reasons, so a full investigation is ideal to reduce the immune response. An active immune response may come from pathogenic bacteria or parasites in the gut, food intolerances, particularly foods like gluten which break down the gut lining.

The prevalence of conditions like Small Intestinal Bacterial Overgrowth (SIBO) and celiac disease or non celiac gluten sensitivity in patients with autoimmune thyroid conditions is high. It's been shown that patients with autoimmune thyroid disease have an extremely high incidence of antigliadin (gluten) antibodies, and researchers suggest patients with autoimmune thyroid disease should be be screened for celiac disease and non-celiac gluten sensitivity.

Comprehensive Thyroid Treatment

Successful treatment, is based on successful diagnosis, so it’s important to get a full thyroid panel and other nutrient markers discussed above, and not just a TSH test. In future posts we will cover more specific approaches to hypo and hyperthyroidism, the below are points that anyone with thyroid issues should consider.

Investigate potential causes of immune response

Test gut health and look at colon, small intestine, stomach function, and screen for parasites, pathogenic bacteria or yeast, small intestinal dysbiosis, and food intolerances. If these factors are present, an active thyroid immune response may never be quelled. Gut health is crucial for thyroid function given that 80% of the immune system is located along the gut lining, and it's our first barrier of defense. It's now known that there are 3 priming factors that create auto-immune response:

  1. Genetic susceptibility. The individual genetics will determine what type of autoimmune problem occurs if certain genes are activated. Genes load the gun, but the environment pulls the trigger, so it's important to optimise epigenetics by living a healthy lifestyle.

  2. Intestinal Permeability (leaky gut) allows the gut lining to be breached and ignite systemic inflammation and immune response.

  3. Environmental trigger or insult: This may be a stressful event, a food intolerance, a gut pathogen etc.The onset of Hashimotos commonly occurs post childbirth!

Calm The Immune Response

This is best done of course by addressing the cause of the immune response, but there are a variety of helpful compounds which can quell the immune response. Glutathione, Curcumin, EPA & DHA fish oils, probiotics, and prebiotic fiber are well studied and effective in reducing the inflammatory cascade.

Nutritional Strategies

An anti inflammatory diet is essential. This means a diet that is nutrient dense in foods like organ meats, seafood, vegetables, healthy fats and proteins, and free from inflammatory foods like sugar, industrial nut and seed oils, and refined grain products. Many people with autoimmune thyroid conditions do particularly well on an Autoimmune Paleo diet, which omits many of the common substances that aggravate autoimmune conditions. It's worth trying for 60 days strictly, before reintroducing suspect foods.

A successful nutritional strategy should aim for stable blood sugar, as blood sugar dysregulation is at the root of many disease processes, is highly stressful for the body, and may exacerbate immune responses. Another point to consider, particularly with paleo style or low carbohydrate approaches, is eating enough carbohydrates, as low carbohydrate diets can reduce the conversion of T4 to T3. Aim to increase intake of iodine (sea vegetables, fish heads, iodized salt, full fat dairy products) and selenium rich foods (ocean fish, Brazil nuts, ham), and other foods rich iron, zinc, B12, B2, vitamins A, C, D, and magnesium.

Reducing foods high in goitrogens is another consideration, as goitrogens increase the thyroid's need for iodine and can cause goiters. A diet too high in goitrogens can inhibit the assimilation of iodine into the thyroid gland, meaning that the thyroid cannot successfully use the available iodine, and no amount of iodine supplementation can offset this. Many forms of cooking reduce goitrogens (fermentation increases goitrogens) but do not eliminate it. Avoiding goitrogen foods completely is unnecessary (and difficult given how many foods contain it) given that these foods often have other health promoting benefits. It is a good idea to avoid eating high amounts of goitrogenic foods, avoid eating them raw, and use cooking methods to reduce goitrogen content.

Lifestyle Interventions

This is the part that is often overlooked, but can be the most powerful part of a health protocol. Managing stress, sleep quality, light exposure, connecting to the earth and nature, physical activity and exercise, social connection and healthy relationships, and avoiding toxin exposure, should be key considerations.

As you can see thyroid health has a complex relationship with a variety of factors, so it's a good idea to treat it with comprehensive approach, and always seek to address the underlying cause! And if you need a hand, reach out as we are happy to assist your thyroid investigation!

#functionalmedicine #wellness #thyroid

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