Reading: Weight Gain. Hair Loss. Sweating. You Might Have Thyroid Disease

I have to admit: Like most people, I don’t give my thyroid gland much thought.

What Your Thyroid Does

Though this small, butterfly-shaped organ in the neck is intricately involved in just about all of our bodily functions, the thyroid is a behind-the-scenes kind of player — one that quietly orchestrates the body’s metabolism without much fanfare.

But when thyroid function goes awry, it can trigger an avalanche of seemingly unrelated symptoms that are as likely to affect the digestive system as the brain, not to mention the eyes, hair, skin, and heart.

Twenty million Americans suffer from some form of thyroid disease; in fact, one in eight women will develop a thyroid disorder during her lifetime. Yet, despite the wide-ranging symptoms, half of them won’t even know they have a problem.

Symptoms of an under- or over-reactive thyroid can range from thinning hair to depression to weight gain. “Because the symptoms of thyroid disease are common, and can be caused by other conditions, life stressors, lifestyle, or normal aging, they may be disregarded by the person experiencing them,” says Dr. Jacqueline Jonklaas, professor of medicine at Georgetown University School of Medicine.

When untreated, however, thyroid disorders can lead to serious medical issues, including cholesterol problems, heart disease, infertility, and osteoporosis. So it’s crucial that women get acquainted with this humble organ — and learn how to recognize when it’s not doing its job.

How Thyroid Disorders Mess With Your Hormones

The thyroid produces thyroid hormone, which regulates metabolism in all the body’s organ systems. “There are thyroid hormone receptors all over the body — in the kidneys, the digestive organs, the brain, the skin,” says Angela M. Leung, MD, an endocrinologist and assistant professor of medicine at the UCLA David Geffen School of Medicine. “So thyroid dysfunction can affect everything.”

Symptoms of hyperthyroidism — or overactive thyroid — can include weight loss, anxiety, insomnia, vision changes, and heart palpitations. Signs of hypothyroidism, a condition in which the gland produces insufficient thyroid hormone, can include hair loss, unexplained weight gain, constipation, slowed thinking, and depression. While too little thyroid hormone can skew the body temperature cold, too much can cause a person to feel hot. “Among older individuals, there are so many overlapping symptoms with menopause and aging that these patients might not come to the attention of the medical community,” says Dr. Leung.

Even when they do, their symptoms are often attributed to other conditions.

The prevalence of hypothyroidism is much higher than that of hyperthyroidism, occurring in as much as 10 percent of the population, according to Dr. Leung. The risk of hypothyroidism increases with age, affecting up to 20 percent of women over 75, and sometimes causing memory loss and confusion that can be mistaken for dementia.

In comparison, hyperthyroidism affects about 1 to 2 percent of adults, she says. Both are significantly more common in women.

The Causes of Thyroid Disease

In the US, the most likely cause of hypothyroidism is Hashimoto’s Disease, an autoimmune disorder in which the body’s antibodies attack the thyroid, mistaking it for an intruder.

(Globally, iodine deficiency is more often to blame for an underactive thyroid — as iodine is needed to produce thyroid hormone — but here in the US where table salt is iodized and bread and dairy products are often fortified with the mineral, iodine deficiency is uncommon.)

When the body doesn’t produce enough thyroid hormone, the metabolism becomes sluggish, explaining symptoms like low energy, unexplained weight gain, constipation, and coldness in the extremities. Because thyroid hormone is involved in brain signaling, too little can impact the ability to concentrate and affect your mood.

The Depression Connection

Depression, in fact, is a common symptom.

A recent Malaysian study of over 12,000 individuals revealed that even patients with mild hypothyroidism exhibited higher levels of depression.

Dr. Kelly Brogan, author of A Mind of Your Own: The Truth About Depression and How Women can Heal Their Bodies to Reclaim their Lives, claims in her blog that the vast majority of psychiatric symptoms are driven by thyroid dysfunction, calling thyroid disease a “psychiatric pretender.”

Too little thyroid hormone also means that cholesterol cannot be metabolized properly. If left untreated, hypothyroidism could lead to a dangerous build-up of cholesterol in the bloodstream.

Hyperthyroidism, on the other hand, is most often caused by Grave’s Disease, another autoimmune condition in which the body’s antibodies attack receptors on the thyroid, leading to over-production of thyroid hormone, and often characterized by bulging eyes and swelling in the neck. Benign thyroid nodules can also be to blame.

Excess thyroid hormone speeds up metabolism, leading to symptoms like heart palpitations, anxiety, weight loss, insomnia, and atrial fibrillation, a type of arrhythmia that is a risk factor for stroke. Because hyperthyroidism also causes the bones to turn over faster than normal, it can lead to bone loss or osteoporosis.

Should You Get Tested?

Experts agree that thyroid testing (via a blood test) should be considered in individuals experiencing symptoms, in those with a family history of autoimmune diseases, and in women considering pregnancy or experiencing fertility problems. (Thyroid hormone is integral during pregnancy — having an underactive thyroid can lead to miscarriage, preterm delivery, and neurocognitive defects in offspring.) But guidelines to screen those in the general —and otherwise healthy — population vary.

“Who should get tested depends on who you ask,” says Dr. Leung. “The American Academy of Family Physicians says screen everyone — men and women — beginning at the age of 60. The American College of Physicians says only screen symptomatic women beginning at age 50. The American Thyroid Association recommends testing both men and women every five years after age 35, and the US Preventive Services Task Force says there is insufficient evidence for or against screening.”

To test thyroid function, doctors begin by measuring levels of TSH, or thyroid-stimulating hormone. This hormone produced by the brain’s pituitary gland stimulates the thyroid to produce T4, the inactive form of thyroid hormone, which is then converted to T3, the active form. “TSH will be high when a person is underactive, and low if a person has high thyroid hormone production,” explains Dr. Leung. “Even small changes in T3 and T4 will lead to large changes in TSH.”

Still, if TSH is abnormal, complete testing then includes measuring for T3 and T4 as well.

Some doctors also recommend testing for the presence of certain thyroid antibodies, like TPO (thyroid peroxidase antibody), since so many cases of thyroid dysfunction are linked to autoimmune diseases.

How to Keep Your Thyroid Happy

For women with hypothyroidism, a daily dose of synthetic thyroid hormone can significantly improve quality of life. Those with hyperthyroidism can either be treated with a medication that slows the production of thyroid hormone or with radioactive iodine therapy or surgery to destroy or remove thyroid cells — after which, they, too, may require thyroid replacement.

Consuming adequate iodine is vital to thyroid health: iodized salt, fish, shellfish, seaweed, eggs, and other dairy products all contain this mineral. Selenium — found in meats, poultry, fish, shellfish, eggs, and Brazil nuts — is also necessary for proper thyroid function. Though a well-balance diet typically contains sufficient selenium, supplemental selenium may improve eye symptoms in patients with Grave’s Disease, according to Dr. Leung.

While cruciferous vegetables like broccoli, cauliflower, bok choy, and kale have many health benefits and should be included in a healthy diet, notes Dr. Leung, limited data suggest that overconsumption of these vegetables can interfere with the thyroid’s ability to use iodine, so it’s important to eat a mix of vegetables.

Soy also contains natural substances that may interfere with our body’s ability to make thyroid hormone, she adds, though moderate soy consumption is unlikely to affect the thyroid.

While experts aren’t clear on what causes thyroid disease, they suspect that radiation to the neck area — given to treat cancers like Hodgkin’s lymphoma — can lead to hypothyroidism or thyroid nodules. (Routine dental x-rays haven’t been linked to thyroid disease, but leaded thyroid shields should be used for extra caution, experts say.)

Research has also suggested that pesticides and other chemicals in the environment — such as PCBs — may be associated with thyroid disorders, though more studies are needed, Dr. Jonklaas says.

Because studies suggest that even women with “subclinical” hypothyroidism are at increased risk of cholesterol problems and that even those with mild hyperthyroidism are at heightened risk for hip fractures and heart problems, it is imperative that women pay attention to symptoms that might be associated with thyroid function, rather than brushing them off as side effects of menopause or aging.

Particularly if you have multiple thyroid-related symptoms, says Dr. Jonklaas, and symptoms seem to be worsening, you should ask your doctor about thyroid testing.