9 things you need to know about your thyroid

Got weight gain or unexplained fatigue? That butterfly-shaped gland in your neck may be to blame. Here's what it controls, how to tell if it's healthy – and how to keep it that way.

Your thyroid

Your thyroid – a small gland in your neck – has a huge impact on your body. It produces thyroid hormone (TH), which is responsible for keeping your metabolism, heartbeat, temperature, mood, and more, in check. An underactive thyroid doesn’t produce enough TH, and that can cause a host of health problems.

How your thyroid works

Your thyroid pumps out the key hormones triiodothyronine (T3) and thyroxine (T4), which are partially composed of iodine. Here's how the gland affect your well-being, head to toe.

Your heart: Thyroid hormones influence your heart rate and help control blood flow by relaxing the muscles in the walls of your blood vessels.

Your fertility: Thyroid hormones influence your menstrual cycle. When they're out of whack, you might have irregular ovulation and periods.

Your bones: The rate at which old bone is broken down is driven by thyroid hormones; when that process speeds up, bone is destroyed faster than it can be replaced – which can lead to osteoporosis.

Your weight: Because the thyroid regulates your metabolism (how quickly your body burns through fuel), an overactive thyroid – or hyperthyroidism – is linked to weight loss, while hypothyroidism is linked to weight gain.

Your brain: Low thyroid levels can bring on forgetfulness, difficulty concentrating, and depression. Luckily, these symptoms tend to reverse with synthetic hormone treatment.

Your skin: When your thyroid is underactive, your body stops making and shedding skin cells at its normal pace. Cells build up, causing dry, dull-looking skin. (Hair and nail growth slow down as well.)

Thyroid issues are more common in women

We are five to eight times as likely to have thyroid problems as men. But why that's the case remains a mystery. The key suspect is estrogen. Thyroid cells have a large concentration of estrogen receptors which means they're extra sensitive to the effects of the female hormone. Another possible reason: Many causes of hypo- and hyperthyroidism are related to autoimmune diseases, and women are generally more prone to those disorders. The most common cause of hypothyroidism, for example, is Hashimoto's disease (which is about seven times as prevalent in women), and the most common cause of hyperthyroidism is Graves' disease (which is up to 10 times as prevalent in women).

Know your symptoms

Both hypothyroidism and hyperthyroidism can be challenging to detect because the symptoms tend to be vague and common to other ailments. But if you notice more than two of the signs below, talk to your doctor about having your thyroid tested.

Hypothyroidism: Dry skin and hair, forgetfulness, constipation, a rundown feeling, muscle cramps, unexplained weight gain, heavier/irregular menstrual flow, swelling in the face, heightened sensitivity to cold.

Hyperthyroidism: Irritability, increased perspiration, racing heartbeat, difficulty sleeping, frequent BMs, unexplained weight loss, less frequent and lighter periods, bulging eyes, shaky hands.

You may or may not need treatment

About 30 per cent of people taking thyroid medications for hypothyroidism may not need them. Many of these folks have what's dubbed "subclinical hypothyroidism." It means that their levels of TSH are mildly elevated, but their levels of T3 and T4 are normal, and they have few, if any, symptoms. If your TSH test reveals a level of 10 mIU/L or higher, most experts recommend treatment. But if your level is in the range of roughly 4 to 10mIU/L, consider your symptoms. If you're not having symptoms, thyroid medication won't help, and it could result in overtreatment and increase your risk of heart palpitations and other symptoms of hyperthyroidism. If you are treated, your doctor should monitor you with blood tests after six to 12 weeks to make sure the meds don't cause hyperthyroidism.

Know how to check your neck

Try this simple test from the American Association of Clinical Endocrinologists to see if you have a telltale sign of thyroid disease.

1. Use a handheld mirror to look at the lower front area of your neck, above your collarbones and below your voice box.

2. Tip your head back, take a sip of water, and watch for protrusions in that area.

3. If you notice a bulge, call your doc. You may have a thyroid nodule or enlarged thyroid (an indication of hypo- or hyperthyroidism).

Keep your thyroid happy

Thyroid problems can be helped by what you eat.

Seaweed: It’s rich in iodine, which your thyroid needs to work properly. Don’t overdo it – one seaweed salad a week is plenty.

Eggs: They’ve got iodine and selenium, another nutrient that helps regulate thyroid hormones.

Yogurt: Dairy is also a good source of iodine.

Chicken or beef: Meats are a good source of zinc, another key thyroid nutrient.

Berries: Their antioxidants protect against damaging free radicals, which are high in people with thyroid problems.