The thyroid is a butterfly-shaped gland located in the neck that can affect many functions of the body. Its impact on your health starts before you’re even born—the thyroid health of the mom will determine the baby’s brain development and physical size, says Neeti Sharma, MD , internal medicine physician and functional medicine doctor at Parsley Health . In adults, the thyroid affects metabolic activity (or how your body uses energy), your heart, and your bones, but it can really have an influence on every function and organ in the body to some degree, Dr. Sharma says. That means, if something is off, it could have a ripple effect.
The thyroid works in relation to the pituitary gland and the hypothalamus, a region in the brain. The hypothalamus releases thyroid-releasing hormone (TRH) which stimulates the pituitary, another region in the brain to release thyroid-stimulating hormone (TSH). That, in turn, stimulates the thyroid gland to make T3 and T4 thyroid hormones. There is a feedback loop between the thyroid hormones T4 and the brain, so when there is enough hormone in the blood the TRH and TSH stop getting released. This is going on constantly to keep hormones in balance. These thyroid hormones are specifically what can have an influence on most organ functions, Dr. Sharma explains.
The key to understanding your thyroid’s role in your health is knowing that your environment can deeply affect its function and even put it off balance, Dr. Sharma says. “When people think of the thyroid and how it functions, they think it’s a fixed thing and that it doesn’t change, but the opposite is true—how we’re doing in our environment, how we eat, our stress, the pollutants, can all very dynamically and drastically change what our thyroid does and how it responds,” she says. “That’s why it’s important to determine how to change your environment to better suit the thyroid.” In other words, if your thyroid hormones are out of whack, there are changes you can make to improve your thyroid health, which can ultimately be beneficial for your overall health.
Here’s what to know about thyroid conditions, including causes, how to spot symptoms of a thyroid issue, and how to address concerns.
One in eight women will experience thyroid problems in their lifetime, according to the Office of Women’s Health . While the most common causes of low and high thyroid are autoimmune thyroid conditions, Dr. Sharma points out a few other factors that can play a role in thyroid conditions, including:
Because the thyroid can affect so many organs and systems in your body, the range of symptoms of a thyroid problem can be widespread. Dr. Sharma explains what to look out for to determine if you could have a thyroid condition:
Depending on whether the body is making too much of the thyroid hormones T3 and T4 or too little, this could cause you to either lose or gain weight, respectively. This change in weight comes from the thyroid’s role in your metabolism. If you haven’t changed your eating or exercise routine, but still see the scale number increasing or decreasing, it could be time to talk to your doctor.
The thyroid gland affects mitochondrial health, or the power packs of our cells that produce energy. When you have low thyroid hormone, the mitochondria can’t work as efficiently or effectively, so you’ll feel less energized, Dr. Sharma says. This feeling of fatigue could be a sign of a thyroid issue at play.
Irritability and depression can also accompany low thyroid function, while feeling jittery or anxious might signal high thyroid activity. Experts aren’t exactly sure the mechanism that causes the thyroid to affect mood, but Dr. Sharma says animal studies show that the thyroid hormone can influence neurotransmitters that play a role in mood disorders. Because the thyroid targets the brain, it could also result from high or low thyroid hormones stopping brain cells from functioning at their optimal level.
While those with low thyroid function might experience a slow heart rate, those with an overactive thyroid may find they have heart palpitations, or their heart skips a beat. A slow heart rate can make you feel tired or fatigued and that you’re short of breath; if someone has a fast heartbeat, it might feel like a pounding in the chest or you might be able to feel the palpitations. That quick rate might also feel similar to anxiety . These changes to your heart rate are because there is either too much or too little thyroid hormone telling the heart to pump too fast or too slow.
If you find yourself walking a certain distance that used to be no problem, and now you’re short of breath when you do it, that could be a sign of a thyroid issue.
Swelling, particularly non-pitting edema, which can occur on your body or face, especially around the eyes, might also signal low thyroid function.
When the thyroid isn’t functioning properly, your body can’t convert beta carotene into vitamin A. This can leave your skin looking discolored. If you notice any abnormal changes to your skin color, it could be a sign of a thyroid issue and you should talk to your doctor right away.
Your thyroid helps to control your menstrual cycle. If your body isn’t making enough thyroid hormones, you could have heavy or long-lasting periods. On the other hand, if your body is making too much of the thyroid hormones, you might have a light period. So, keep an eye on irregular periods , as they can signal a thyroid problem.
While the connection between the thyroid and muscle weakness isn’t fully understood, it likely has to do with the thyroid’s role in cell metabolism and normal cell function . Low thyroid hormones can negatively affect the breakdown of glycogen into glucose, which your muscles need for energy, and it can also slow down the conversion of ATP, the molecule that breaks down food into energy that your skeletal muscle can use.
Just like thyroid hormones can affect your heart and other organs, it can also cause issues for your gut. Those with low thyroid function might experience constipation, while those with high function might get diarrhea.
Other signs of underactive thyroid: feeling cold, joint or muscle pain, thinning hair, dry skin, a hoarse voice
Other signs of overactive thyroid: feeling hot, increased sweating, bulging eyes
Hypothyroidism means your thyroid is not making enough crucial thyroid hormones. This is more common than hyperthyroidism, though it often goes unnoticed, Dr. Sharma says. Hypothyroidism slows down bodily functions, like your metabolism and heart rate, and can lead to weight gain.
Hyperthyroidism means that the thyroid is making too much of the thyroid hormones. It speeds up body functions, like your metabolism and your heart rate and can lead to weight loss.
An autoimmune disease , Hashimoto’s involves antibodies that attack the thyroid gland, so it can’t function properly. It’s the most common cause of hypothyroidism and affects about five out of every 100 people, according to the National Institute of Diabetes and Digestive and Kidney Diseases . It’s also more common in women than men.
This autoimmune condition involves an overactive thyroid gland. Like Hashimoto’s, the immune system attacks the thyroid gland, but in this case, it causes it to make more of the thyroid hormones than your body really needs. That means you’ll have higher-than-normal levels of T3 and T4 in your body, but lower levels of TSH.
If you find you can check off a few of the signs of thyroid issues listed above, it’s always a good idea to talk to your doctor. They’ll be able to offer a thyroid test via a blood sample. Many doctors look at your levels of TSH, but at Parsley Health, doctors also routinely check Free T4, Total T4, Free T3, Reverse T3, anti-TPO antibodies, and anti-thyroglobulin—these give a bigger picture into what’s going on with your thyroid health. Many doctors will also check iodine levels, as it can increase flares in Hashimoto’s, Dr. Sharma says. While some doctors prescribe medications, it’s important to talk to them and figure out the underlying problems that might be causing the thyroid condition (say, heavy metals, nutrient deficiencies , or high stress levels), she adds.
Research backs up the importance of looking at a person’s environment and how it plays a role in thyroid function. There are many thyroid healing lifestyle changes that can help you address the thyroid conditions in the long-term. Dr. Sharma mentions that tactics like stress management and practices like yoga, Tai Chi, or meditation , are one example of a helpful lifestyle adjustment. But it’s most important to consider the whole picture. You might need to evaluate your diet, gut bacteria, or your sleep schedule, too. A doctor trained in holistic medicine can help you find a diagnosis and a personalized treatment plan.
Mallory, a New York City-based freelance writer, has been covering health, fitness, and nutrition for more than a decade. Her work has appeared in publications like Women's Health, Men's Journal, Self, Runner's World, Health, and Shape, where she previously held a staff role. She also worked as an editor at Daily Burn and Family Circle magazine. Mallory, a certified personal trainer, also works with private fitness clients in Manhattan and at a strength studio in Brooklyn. Originally from Allentown, PA, she graduated from Syracuse University's S.I. Newhouse School of Public Communications.