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Exhausted and Gaining Weight? It Could Be Your Thyroid

Here's how to sort it out.

Photo credit: Getty Images

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Walk into any health food shop or browse the wellness section of your favorite bookseller and you'll quickly notice how many products there are targeting people with thyroid disorders—or, more accurately, people who think they have thyroid disorders. While many people actually have a problem with their thyroid, plenty of others just assume that they do.

"You cannot diagnose yourself," says Shuchie Jaggi, DO, endocrinologist at Northwell Health and assistant professor at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell. "If you have a concern, come see an endocrinologist."

Why do many people suspect their thyroid is off? It likely comes down to one word: metabolism.

The thyroid, a butterfly-shaped organ in your neck, is indeed the master controller of your body's metabolism. It produces hormones (T3 and T4) that regulate how quickly energy is used up in cells throughout your entire body. If you don't make enough of these hormones, everything slows down, including your heart rate, respiration rate, and the rate at which food moves through your GI tract (which translates to constipation). You might feel cold, tired and depressed. Puffy eyes and legs thanks to fluid retention, increased hair loss, and abnormal periods are also possible signs of an underactive thyroid. And yes, you may gain weight—but perhaps not as much as you might think.

"You can't blame your thyroid for a large weight gain," says Dr. Jaggi. She explains that an underactive thyroid, also called hypothyroidism, usually causes a patient to put on less than 5 percent of their starting body weight. If you're carrying around an extra 20, 30, or 50-plus pounds, it's probably not your thyroid—or not only your thyroid, anyway.

Just the facts

So who actually has hypothyroidism and why? This condition impacts an estimated 4.6 percent of adults in the U.S., most of them over age 50. Anyone can develop it, but it's most prevalent in women, probably because women are more prone to autoimmune disorders and most cases are caused by an autoimmune condition called Hashimoto's disease.

Family history also predisposes you to Hashimoto’s, so if someone in your family has any type of autoimmune issue (not just one that impacts the thyroid) your risk is higher for developing Hashimoto’s disease, says Dr. Jaggi.

If you suspect you might have hypothyroidism, you'll need to discuss your symptoms with your doctor and get a blood test. Most physicians will start by checking your levels of TSH, a hormone made by the pituitary gland. TSH stands for thyroid stimulating hormone, and it's exactly what it sounds like: It tells your thyroid to make thyroid hormones. If your TSH level is higher than normal, then you probably have hypothyroidism, but your doctor should then check your levels of "free T4," which is a type of thyroid hormone that's circulating freely in your bloodstream.

High TSH and low free T4 mean you have hypothyroidism, because it proves that there's an abundance of chemical signals telling the thyroid to produce thyroid hormones yet the organ is not complying. If it turns out that you do have hypothyroidism, your doctor will most likely prescribe medication containing synthetic thyroid hormone (levothyroxine or Synthroid). It works well, but you'll need blood tests every six months to make sure you're getting the right dose, Dr. Jaggi says.

Dr. Jaggi isn't convinced that dietary changes can help with hypothyroidism, with the exception of getting enough iodine (not really an issue in the U.S. since it's found in iodized salt). Still, if you'd like to try a new diet or other "natural" approaches, be sure to run them by your doctor first. That's especially important when it comes to iodine supplements and anything labeled "thyroid care." The reason: "These supplements are not regulated and should be avoided, because they can be dangerous," she explains.

The other side of the coin

While an underactive thyroid can cause a slew of problems, so can the opposite issue. Your thyroid can be too active, a condition known as hyperthyroidism. When your thyroid is overactive, everything speeds up: Your heart beats faster, you sweat more, and you may lose weight for no apparent reason. You might also feel nervous or irritable.

About 1.2 percent of the U.S. population has hyperthyroidism, most often due to Graves' disease. Another autoimmune disorder, Graves' causes your immune system to mistakenly attack the thyroid and prompt it to make too much thyroid hormone. Other causes include an inflammation of the thyroid or the presence of a thyroid nodule (a small and usually benign bump).

It's also possible for someone who started out with an underactive thyroid to end up with an overactive one if they take too much synthetic thyroid hormone. That kind of flip can be corrected by adjusting your dose, assuming you're not deliberately overdoing it in an effort to lose weight (not a smart idea).

If you or your doctor think you might have hyperthyroidism, you'll need blood tests. You'll be diagnosed with this issue if your TSH is low yet your free T4 is high.

Most people with hyperthyroidism are initially treated with a medication like methimazole or PTU. These drugs interfere with the production of thyroid hormone so you start making less, but you can only take them for a maximum of 18 months, says Dr. Jaggi."They can cause liver injury and make you more prone to infection," she explains.

Some people go into remission within that time period, but if you still need treatment then the next step is to swallow a radioactive iodine pill. "The thyroid is the only place in the body with receptors for iodine, so it ablates any thyroid cells," says Dr. Jaggi. Most patients then become hypothyroid within the next six months, and when that happens you'll need to start on synthetic thyroid hormone.

In rare cases—like when someone is having very severe symptoms and can't wait half a year for the radioactive iodine to kick in—doctors will perform surgery to remove the entire thyroid.

Whatever treatment you end up requiring, a knowledgeable endocrinologist should be able to help you get your hormone levels balanced so that you can feel your best.

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Published September 4th, 2018

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