Thyroid Health 101: Function, Conditions, and Diagnosis

Medically reviewed by Dr. Stacy Hengisman MD and Felice Ramallo MSRD.

Many of us have heard in passing about the importance of our thyroids, and we may even know what hormones it helps control and regulate in the body – but where it is, the signs of a thyroid disorder, and how to care for our thyroid are questions not many people know the answers to. That’s why in this article we’ll be discussing the many functions of the thyroid (spoiler: it’s critically important!), the most common thyroid conditions and their origins, how to go about getting a diagnosis if you suspect a problem with your thyroid, and how to better support thyroid health through lifestyle choices. Let’s get into it!

What Is the Thyroid?

Let’s start with the basics: your thyroid is both a gland and an organ, and it’s located in the front of your neck. It’s wrapped around the windpipe, and is said to be shaped like a butterfly, with a smaller middle and wider ‘wings’ that extend on either side of your throat.

It produces two hormones, triiodothyronine (T3) and thyroxine (T4). These hormones play a key role in regulating blood pressure, body temperature, heart rate, and metabolism. The thyroid is also in charge of producing calcitonin, which helps bone cells use calcium to build and strengthen bones.

What Does the Thyroid Do?

To understand what is going on when our thyroid starts acting up, let’s talk about the hormones that the thyroid is in charge of.

T3 and T4 are made in the follicular epithelial cells of the thyroid, and iodine is an essential “building block” of both hormones. Since our bodies can’t produce this iodine on their own, we rely on getting enough of this element through our food, which is then absorbed into our bloodstream from our bowel. This is the reason table salt has added iodine in the US, just look for “iodized salt.” From there, it is transported to the thyroid gland, where it’s converted (along with other things) into thyroid hormones.

T4 is responsible for your metabolism, mood, and body temperature, while T3 is massively important to your digestive and metabolic function, as well as overall bone health. In the case of T3 or T4 being too low, the pituitary gland will try to compensate by releasing more TSH (while the opposite is true if T3 and T4 levels are too high).

Types of Thyroid Conditions

Most of the time, the thyroid is acting as it should, and our hormones are in balance (as well as the rest of our body). Unfortunately, there are several disorders associated with the thyroid, and all of these require collaboration with a physician to manage symptoms. Let’s walk through the most common ones.

Hyperthyroidism

Hyperthyroidism is the term to describe an overactive thyroid. This means the thyroid gland is making too many hormones. It currently impacts between 1 and 3% of the US population.

Causes of hyperthyroidism can include:

• Graves disease
• Approximately 70% of people with an overactive thyroid have this autoimmune condition. Most common in women over the age of 20, it can affect individuals of all ages and genders.
• Too much iodine intake
• Taking too much thyroid medication
• Overactive thyroid nodules
• Otherwise referred to as goiter, its most common cause is an iodine deficiency.
• Non-cancerous pituitary gland tumor

The most common symptoms of hyperthyroidism include restlessness, nervousness, increased sweating, anxiety, brittle hair and nails, weight loss, increased appetite, difficulty sleeping, racing heart rate, thin skin, muscle weakness, bulging eyes, and frequent bowel movements.

Hypothyroidism

Hypothyroidism is essentially the opposite of hyperthyroidism: it means your thyroid isn’t producing as many hormones as it needs. It affects around 4% of the US population.

Common causes of hypothyroidism include:

• Thyroiditis
• This a term used to describe a group of conditions that trigger inflammation in your thyroid gland
• Congenital hypothyroidism
• This means you were born with the condition
• Iodine deficiency
• A problem with your pituitary gland or hypothalamus
• Certain medications (such as those for bipolar disorder or cancer)

The most common symptoms of hypothyroidism include: fatigue, feeling cold a lot of the time, dry skin, memory problems, depression, slow heart rate, weight gain, fertility problems, heavy or irregular menstruation, feeling weak, muscle or joint pain, hair loss, and constipation.

Hashimoto’s disease

This is an autoimmune disease that is closely associated with hypothyroidism (though in rare cases it can cause hyperthyroidism). We’re calling it out in a separate category because of the way it prompts a thyroid disorder. In people with Hashimoto’s disease, the immune system produces antibodies that attack the thyroid gland; these large numbers of white blood cells build up in the thyroid and the thyroid’s hormone-producing cells become damaged and can’t make enough hormones. Interestingly, Hashimoto’s is about 4 to 10x more prevalent in women than men, though men can also be diagnosed with Hashimoto’s, and it often develops in women aged between 30 and 50.

The risk factors for this autoimmune disorder are the following:

• Having a family member with the condition
• Radiation exposure
• Iodine excess
• Pregnancy
• Having other autoimmune diseases

Graves’ disease

While Hashimoto’s is strongly associated with hypothyroidism, Graves is associated with its counterpart, hyperthyroidism. For unknown reasons, Graves’ triggers the body to attack its own thyroid gland tissue, and once again it is more prevalent in women than men.

The risk factors for Graves’ disease include:

• A family history of this condition
• Stress
• Being under 40
• Having other autoimmune disorders (such as rheumatoid arthritis, Chrohn’s disease, or type 1 diabetes)

Graves’ disease is thought to be responsible for approximately 70% of hyperthyroidism cases (although, like we mentioned earlier, thyroid diseases are relatively rare in the general population, accounting for approximately 5% of Americans combined).

Goiter

Goiter refers to the irregular growth of the thyroid gland and is often associated with hyperthyroidism and Graves’ disease.

Usually, goiters involve the overall enlargement of the thyroid, or the irregular growth of cells (forming nodules) in the thyroid. Sometimes a goiter may not be a cause for concern: it doesn’t necessarily have to impact thyroid function, and it may not impact the production of thyroid hormones in ideal cases. For instance, small goiters that don’t trigger any symptoms are generally left alone but monitored. Occasionally, though, goiters that cause problems will be treated as part of a larger treatment plan that addresses other coordinating conditions (such as Graves’ and hyperthyroidism).

Goiters that grow large enough to cause problems may trigger the following symptoms:

• Visible swelling on throat/neck
• Difficulty swallowing
• Difficulty breathing with ease
• Cough
• Hoarseness
• Snoring

Thyroid nodules

Finally, we reach the last most common thyroid condition: the presence of nodules on the thyroid. Most nodules (over 90%) are benign and do not cause any symptoms, in which case they go undiagnosed or untreated. According to one study conducted in the past decade, approximately 1% of men and 5% of women living in countries with iodine sufficiency have thyroid nodules that are able to be felt in a physical exam. That being said, like with other thyroid conditions we’ve discussed in this section, the rate of nodules in women is 4x that of men, while the rate of thyroid cancer in men is double that of women. In other words, women are more likely to have nodules than their male counterparts, but men with nodules on their thyroid are at higher risk for these nodules to not be characterized as benign. In either case, if you suspect you have nodules on your thyroid, it’s important you speak with your primary care physician to make sure they are nothing to worry about.

It’s worth noting that thyroid nodules not associated with Hashimoto’s, and those that do not impact thyroid function, are often not accompanied by any symptoms.

Diagnosing a Thyroid Disorder

Okay, so let’s say hypothetically you go to a doctor about some troubling symptoms that seem like hyperthyroidism, hypothyroidism, or even a potential goiter on the neck: what will the doctor do?

If you do see a doctor about potential thyroid issues, how will they find out if your thyroid is acting normally or not? There are three primary means your doctor may use to determine whether you have a thyroid disorder: blood tests, imaging tests, and a physical exam. Let’s walk through each in turn.

1. Blood Tests

Thyroid stimulating hormone (TSH)

Most of the time, thyroid hormone deficiency (ie hypothyroidism) is associated with an elevated TSH level, while thyroid hormone excess (ie hyperthyroidism) is associated with a low TSH level. Makes sense, right? Your pituitary gland will signal to your thyroid to make more or less T3 and T4, depending on how much it has been monitored in the bloodstream, and it communicates these messages via TSH.

T4 and Free T4

Your primary care physician can also understand if you have an over or underactive thyroid from looking directly at your T4 levels to see if they fall within a ‘normal’ range. Different from measuring T4, free T4 eliminates the effect of proteins that naturally bind T4 and may prevent an accurate measurement.

T3 and Free T3

Low T3 can signal hypothyroidism, but it is often more useful in diagnosing hyperthyroidism, in which T3 levels are usually elevated. Like with free T4, free T3 allows doctors to eliminate any influence of proteins naturally binding to T3 that can affect getting an accurate measurement.

2. Imaging Tests

Blood tests are extremely helpful in understanding how your thyroid is functioning, and whether it is outputting an excess of hormones, or not enough. At the same time, a thyroid scan can lend insight into any irregularities or changes to the size and shape of your thyroid, in addition to any nodules or growths on it.

An ultrasound is conducted by an ultrasound technician, who will use a device that transmits high-frequency waves through body tissue, and echoes are recorded and translated into video footage or a picture. In many cases, ultrasounds are preferable because they do not use radiation. They last about half an hour.

3. Physical Exam

Finally, we have the classic exam your physician might conduct on the same day you explain your symptoms. A physical exam is useful for determining any irregularities in the size and shape of the thyroid, as well as any potential growths. This exam is quick – typically just a couple of minutes in length – and painless.

How to Support Thyroid Health in your Lifestyle

There is limited research dedicated to understanding the role of diet and thyroid function, but what we know so far is that dietary stress in the body can be triggered by inflammation, a sensitivity, or an allergic response, as well as spikes in blood sugar, while high amounts of unhealthy fats and certain toxins or chemicals can cause immune responses.

So what are some concrete steps you can take to support your body, and by extension, help support thyroid function?

Consider eating more:

• Anti-inflammatory or Mediterranean diet foods, like fruits, vegetables, whole grains, legumes/beans, and dairy products
• Foods with very little nutritional value don’t work to support your body’s health (though they can be great as an occasional treat); try to avoid highly processed foods, instead swapping them out for nutrient-dense, high-fiber foods that help alleviate symptoms of thyroid disorder, such as fatigue and constipation.
• Olive oil, avocado oil, and healthy nuts
• These all have anti-inflammatory properties!

Consider limiting:

• Sweets and candy
• A thyroid disorder puts you at increased risk of type 2 diabetes, so try to reduce your intake of soda, candy, and artificial sweeteners. Instead try to incorporate these treats into your diet in moderation and with extra protein, fat, or fiber (for instance, by swapping half of your sweet intake to your favorite fruit, and adding nuts or full-fat dairy).
• Triggering foods
• Foods that you are sensitive or allergic to are best avoided, and if you need help identifying those, it is always a good idea to speak with a Registered Dietitian. For instance, Celiac disease is 3-fold as common in those with autoimmune conditions such as Hashimoto’s and Graves’ than in the general population, and the body’s reaction to gluten in those suffering from Celiac’s can mean iodine and selenium (important for thyroid health) are not absorbed properly.

Allara Health provides personalized treatment for hormonal, metabolic & gynecological conditions that utilizes a holistic plan that merges nutrition, lifestyle, medication and supplementation, and ongoing, expert support to heal your body.