Hypothyroidism is one of the most common diseases worldwide. In the United States, 20 million people have some form of thyroid condition, and 60% of people with thyroid disease are unaware of it.
Women are five to eight times more likely than men to have thyroid problems, with one in eight women developing a thyroid disorder during her lifetime. Often, hypothyroidism goes undiagnosed for a significant amount of time, which can put patients at risk for other medical complications.
In this article, we will address how functional medicine approaches hypothyroidism to restore balance.
What is Hypothyroidism
The thyroid is the butterfly-shaped gland at the base of your neck that produces hormones essential for regulating metabolism, body temperature, energy, heart rate, menstrual cycle, mood, and hair and nail growth.
Hypothyroidism is a chronic disease associated with a deficiency in the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Since these hormones influence every cell in the body, hypothyroidism can have wide-reaching impacts, including slowing metabolic processes. This can result in fatigue, weight gain, decreased body temperature, hair thinning, constipation, brain fog, and fluid retention.
Untreated or inadequately treated hypothyroidism can lead to more serious medical conditions such as cardiovascular disease and neurological and musculoskeletal symptoms.
How The Thyroid Works
The thyroid functions within the complex interplay of signals coordinated by the brain, interacting with several nutrients and other hormones. The hypothalamus in the brain is responsible for managing hunger, thirst, sleep, hormones, and body temperature and monitors the level of thyroid hormone in the blood. When it detects the need for increasing metabolism and energy, it releases Thyroid Releasing Hormone (TRH) to signal the pituitary gland at the base of your brain to release Thyroid Stimulating Hormone (TSH).
TSH acts directly on the thyroid, stimulating it to produce and release thyroid hormones. To do this, the thyroid uses the amino acid tyrosine and iodine to manufacture and convert thyroid hormones T4 and T3.
- T4: a storage form of thyroid hormone that circulates throughout the blood and is stored in tissues for when it is needed
- T3: the active form of thyroid hormone
When different parts of the body need active T3, they convert the storage T4 to active T3 using an enzyme called deiodinase. T3 can then act on cells to stimulate energy production and regulate metabolism.
Hypothyroidism Signs & Symptoms
When the thyroid does not produce enough hormones or the hormones it produces can not act effectively, this impacts cells throughout the body, causing symptoms such as:
- Weight gain
- Headaches and migraines
- Thinning or dry hair, nails, and skin
- Brittle nails
- Feeling cold all the time and decreased body temperature
- Irregular periods
- Puffiness or fluid retention
- Slowed heart rate
- Fertility problems
- Low libido
- Slow digestion and constipation
- Brain fog
- Aching muscles and joints
- Loss of muscle strength and tone
Especially early on in the disease process, these symptoms may be vague and seem common in our busy society, delaying diagnosis.
Over time, untreated hypothyroidism can lead to additional complications, including:
- Elevated cholesterol
- Heart disease and heart failure
- High blood pressure
- Problems during pregnancy
- Myxedema a rare, life-threatening condition where the body's functions slow down significantly
Common Reasons For Hypothyroidism
Hypothyroidism can result when the thyroid gland is underactive and not producing enough thyroid hormones, or the thyroid hormones cannot work properly in the peripheral tissues. This can happen for several reasons.
- The pituitary gland malfunctions and does not send enough Thyroid Stimulating Hormone (TSH) to the thyroid.
- TSH levels are normal, yet the thyroid does not produce enough T4 and T3 to adequately stimulate cells due to nutritional deficiencies, malfunction, or other factors.
- The peripheral receptors do not respond appropriately to thyroid hormones.
In iodine-sufficient countries like the United States, Hashimoto's, an autoimmune thyroid disorder, is the most common cause of hypothyroidism, impacting 1-4% of Americans, primarily women. This is an autoimmune condition where the body produces antibodies that attack and damage the thyroid gland, impairing the thyroid's ability to produce thyroid hormone over time.
Globally, low iodine in the diet is the leading cause of an under-functioning thyroid gland. Iodine is a trace mineral found in seafood, seaweed, plants grown in iodine-rich soil, and iodized salt and is needed for the production of thyroid hormones. Too little iodine can lead to hypothyroidism since the gland cannot adequately produce T3 and T4.
*It's important to note that too much iodine can also worsen hypothyroidism in people who already have the condition, so it's vital to work with your provider before supplementing iodine.
Environmental factors such as heavy metals and endocrine-disrupting chemicals (EDCs), often found in foods, food packaging, water, and personal care products, can interfere with thyroid gland functioning and thyroid hormone transport through multiple mechanisms.
Past or ongoing exposures to heavy metals, mercury, arsenic, cadmium, solvents, plastics, and pesticides contribute to an imbalance of gut bacteria (dysbiosis), inflammation, and autoimmunity by harming the body's detoxification, digestive, nervous, and endocrine systems.
Postpartum thyroiditis happens when a woman's thyroid gland becomes inflamed after having a baby. Postpartum thyroiditis may first make your thyroid overactive (hyperthyroidism), but over time the condition leads to an underactive thyroid (hypothyroidism). Postpartum thyroiditis affects 5-10% of women in the first year after giving birth. The condition is typically temporary, but it's essential to screen thyroid function in women during and after pregnancy.
Chronic Dieting (particularly when paired with excessive exercise)
Extended periods of low-calorie diets are associated with increased stress hormones and decreased thyroid hormone, resulting in less-than-optimal thyroid function and its symptoms. While exercise is essential to a healthy lifestyle, the "dose" matters, and it's vital to fuel the body appropriately.
Radioactive iodine or anti-thyroid medications are often used to treat hyperthyroidism when too much thyroid hormone is produced. If hyperthyroidism is over-corrected, it can lower thyroid hormone production too much, resulting in permanent hypothyroidism.
Drug-induced hypothyroidism is when a medication you're taking causes your thyroid gland to be less active, producing less thyroid hormone. It's imperative to find a balance where your levels aren't too high or too low and discuss with your doctor if you start noticing hypothyroid symptoms after starting a new medication.
Thyroid Surgery or Radiation
Removing all or a large portion of the thyroid gland via surgery or damaging it via radiation treatments can lead to hypothyroidism.
A failure of the pituitary gland to produce enough thyroid-stimulating hormone (TSH) results in the thyroid gland failing to produce enough thyroid hormones. This usually occurs due to a benign pituitary gland tumor, inflammation of the pituitary gland, or elevated pressure in the brain that compresses and dysregulates the pituitary gland.
What is Borderline Hypothyroidism?
Sometimes the terms "borderline hypothyroidism" or "subclinical hypothyroidism" are used when blood tests show that the level of TSH is somewhat elevated above normal, but T3 and T4 levels are within the conventional normal laboratory range. For most conventional laboratories, a "normal" serum TSH level is somewhere between around 0.4 to 4.0 mIU/L.
There is growing consensus that a narrower TSH range of 0.5 to 2.5 mlU/L may be more appropriate for most healthy adults. The National Academy of Clinical Biochemistry released data indicating that more than 95% of normal individuals have a TSH level below 2.5 ml/L.
Many Functional Medicine practitioners target an optimal TSH of 0.5-2.5 in most adult clients. Anything above 2.5 mlU/L is commonly treated as borderline hypothyroidism.
The approach to borderline (subclinical hypothyroidism) depends on symptoms and any complicating additional medical conditions. This condition is monitored with repeat follow–up laboratory testing of TSH, T3, and T4 to see if the results change after several months of dietary, supplements, and lifestyle changes.
About 30 percent with borderline hypothyroidism will have their TSH levels return to normal within one year.
Functional Medicine Labs to Test for Root Cause of Hypothyroidism
Functional medicine testing can diagnose hypothyroidism and help to identify the underlying causes. This includes assessing the functioning of the thyroid, measuring thyroid-supporting nutrients, and evaluating factors that play a role in immune system function to uncover the causes of the autoimmunity leading to Hashimoto's disease when that is the cause.
Thyroid function and Autoantibodies
To assess the state of thyroid function, a Complete Thyroid Panel including thyroid-stimulating hormone (TSH), T3 (free and total), T4 (free and total), reverse T3, and thyroid peroxidase (TPO) and anti-thyroglobulin (TG) and antibodies should be assessed using functional medicine ranges.
Compared to conventional lab ranges, which are based on results from the overall population, functional medicine thyroid lab ranges are tailored to detect thyroid issues prior to the onset of more advanced thyroid disease.
- TSH measures how the pituitary gland in the brain is communicating with the thyroid and is indicative of hypothyroidism when elevated. A normal TSH does not rule out thyroid issues on its own since it is an indirect but specific measure of thyroid function.
- Free T4 measures the bioavailable or unbound thyroid hormone and is a marker of low thyroid function when decreased.
- In the peripheral tissues, T4 is converted to T3. A low level of T3 can indicate low thyroid function or a problem with conversion, which often occurs with chronic stress, inflammation, or a high toxic burden.
- Some T4 is also converted to reverse T3, which serves as a "brake" since it competes with free T3 for cell receptor sites. High levels of reverse T3 can cause hypothyroidism and usually reflects a systemic issue like chronic inflammation.
- In addition, thyroid antibody testing for thyroid peroxidase (TPO), anti-thyroglobulin (TG), and antibodies are key for diagnosing Hashimoto's disease.
- In addition to elevated TPO antibodies, typically found in Hashimoto's disease, thyroglobulin antibodies may also be high, although commonly, these antibodies are associated with Grave's disease or autoimmune hyperthyroidism.
Micronutrient testing analyzes vitamins, minerals, and other nutrients required for proper immune function and thyroid health. Nutrients including iodine, iron, tyrosine, zinc, selenium, magnesium, and vitamins E, B2, B3, B6, C, and D all contribute to the proper production of thyroid hormones, and some of these, including zinc and selenium, are also important for supporting the conversion of T4 to T3. Other nutrients like vitamin A improve cellular sensitivity to thyroid hormones.
*Iodine can also be assessed in the urine.
Since dysbiosis and leaky gut are critical factors in developing autoimmune diseases like Hashimoto's and overall inflammation that can impact the thyroid, assessing gut health can help provide targeted interventions.
A Comprehensive Stool Test measures amounts of healthy and unbalanced gut bacteria (dysbiosis), inflammatory markers, leaky gut, parasites, and yeast to assess the state of the gut and guide treatment aimed at restoring balance.
Factors that Influence Detoxification
An individual's ability to detoxify and effectively clear toxins from the body can majorly impact thyroid function.
Methylation, detoxification capacity, and glutathione production can be assessed with specialized labs to understand an individual's genetic susceptibilities and current detoxification capacity. This can help to pinpoint areas that can be supported to bring the body and metabolism back into balance.
Functional Medicine Treatment for Hypothyroidism
While conventional treatment of hypothyroidism usually relies on thyroid medication, it alone does not treat the disease but rather the symptoms resulting from low thyroid hormones.
A functional medicine approach to treating hypothyroidism aims to rebalance and regulate the immune system and not simply only replace thyroid hormone. This approach can help prevent borderline hypothyroidism's progression into more severe disease and even rebalance hypothyroidism once it has fully manifested.
An individualized treatment approach guided by clinical symptoms and functional laboratory testing can tailor a dietary and lifestyle approach that works for each person.
An Individualized Anti-Inflammatory Diet
An essential step in dealing with thyroid imbalances is eliminating contributing factors to the dysfunction. Inflammation increases the autoimmune reaction, so a nutrient-rich, anti-inflammatory diet tailored to an individual's sensitivities while removing trigger foods such as gluten, dairy, and processed sugars, can help balance inflammation and tame autoimmunity.
Restore Thyroid-Supporting Nutrients
Balancing the intake of micronutrients like vitamin A, zinc, vitamin D, omega-3 fatty acids, and selenium can help to reduce inflammation and prevent hypothyroidism due to nutrient deficiencies. While iodine is a mineral that the thyroid uses to make thyroid hormones, too high iodine intake, which can come from too much salt in the form of processed, packaged foods, or excessive consumption of seaweeds, can negatively affect thyroid functioning. Functional laboratory testing can help guide individualized intake.
Rebalance the Gut Microbiome
Since the gut microbiome has such a significant impact on the immune system, maintaining diverse and balanced bacteria in the gut can help tame autoimmunity.
Restoring equilibrium in the gut microbiota by eating a variety of whole foods and incorporating probiotic-rich foods like kimchi and sauerkraut that contain naturally-occurring probiotics and prebiotic-rich foods like artichokes, garlic, and beans that nourish healthy bacteria is critical for repairing the mucosal barrier and halting excess inflammation and autoimmunity that can harm thyroid function.
Adequate Sleep and Stress Management
High levels of chronic stress contribute to hypothyroidism and inflammation and have been associated with autoimmunity. Finding balance via lifestyle practices like adequate quality sleep, stress management practices, and balanced movement can improve thyroid and overall health.
Therapeutic exercises such as yoga, walking, and Qi gong are generally more helpful for balancing inflammation than overly intense exercise. Spending quiet time in nature can also reduce inflammation by providing exposure to natural sunlight to optimize vitamin D and direct contact with the earth.
Additionally, supplementation with the adaptogen ashwagandha has been used to help address thyroid dysfunctions. Eight weeks of supplementation has been shown to improve serum TSH and T4 with few mild and temporary adverse effects.
Addressing Environmental Factors
Chemicals in plastics, pesticides, heavy metals, and other pollutants can disrupt thyroid function. You can reduce exposure to these chemicals by using high-quality water and air filters, choosing organic produce, and assessing other exposures, such as metal dental amalgams.
EWG.Org is a great starting point for education on our exposures to endocrine-disrupting chemicals.
Hypothyroidism occurs when the thyroid is underactive and does not produce enough thyroid hormones. This leads to a cascade of symptoms throughout the body, like fatigue, weight gain or difficulty losing weight, increased sensitivity to cold, constipation, and hair loss. Borderline or subclinical hypothyroidism can also occur in the early stages before conventional laboratory testing may show abnormalities in thyroid hormone levels T3 and T4.
The most common cause of hypothyroidism is the autoimmune disease Hashimoto's.
In addition to TSH, the conventional screening test for thyroid function, testing the blood for the presence of TPO antibodies against the thyroid gland is crucial for diagnosing Hashimoto's and customizing treatment to prevent further damage to the thyroid. A comprehensive thyroid panel including TSH, free T4, free T3, reverse T3, and thyroglobulin antibodies can provide a better picture of overall thyroid function.
A functional medicine approach can also look at other markers of autoimmunity and systemic inflammation by assessing supportive thyroid nutrients, markers of gut health and food sensitivities, and detoxification capacity.
Identifying and treating the root cause of hypothyroidism can allow the body the opportunity to heal.