Feeling cold, hair loss and insomnia: The warning signs of thyroid issues

Fatigue, thinning hair, irritability. These are common symptoms that are sometimes the product of lifestyle choices, but can also be signs of underlying health conditions. Many people brush symptoms like moodiness and tiredness under the rug, accepting them as a nonnegotiable of life. 

However, many symptoms that people think are "normal" actually indicate that there's a hormone imbalance at play. One common type of hormone imbalance involves the thyroid gland, an important organ that affects virtually every function of your body. 

What does the thyroid do?

The thyroid is a small butterfly-shaped gland at the front of the neck. "It acts as the body's thermostat, making thyroid hormones and turning metabolism up and down," says Melissa Groves Azzaro, a registered dietitian and author of A Balanced Approach to PCOS. Thyroid hormones are used by every cell in the body, she says, thus they affect nearly every body system.

Thyroid gland health isn't just a matter of producing thyroid hormone, though. This gland works via a complex loop of actions, says Dr. Jessica Wright, owner and medical director at Rejuvenate Austin.

Here's how it works:

• Your pituitary gland (a small gland at the base of your brain) produces thyroid-stimulating hormone, or TSH. 
• But the pituitary gland only secretes TSH when the hypothalamus (a small region of your brain near the pituitary gland) secretes thyrotropin-releasing hormone, or TRH.
• This feedback loop helps balance thyroid hormone levels in the body.
• When things are working in harmony, the thyroid gland produces thyroxine (T4) and triiodothyronine (T3), two thyroid hormones needed for a number of bodily functions.

Signs of thyroid hormone imbalance

Thyroid hormone imbalances can lead to some potently uncomfortable symptoms. They differ depending on whether you have too much or too little thyroid hormone. 

Signs of hyperthyroidism (too much thyroid hormone) include: 

• Weight loss
• Feeling hot
• Irritability
• Rapid heart rate or heart palpitations
• Insomnia
• Anxiety
• Irregular menstrual cycle

Signs of hypothyroidism (too little thyroid hormone) include: 

• Weight gain
• Dry skin
• Brittle nails
• Hair loss
• Feeling cold (especially hands and feet)
• Constipation
• Low energy
• Low body temperature
• Irregular menstrual cycle

What causes thyroid hormone imbalances? 

Most thyroid issues are symptoms of medical conditions, Wright says, but lifestyle factors, such as nutrition and stress, can also contribute.

Autoimmune and medical conditions

Hyperthyroidism is caused by a number of diseases, Wright says, with Grave's disease being the No. 1 cause. In people with Grave's disease, the immune system produces antibodies that bind to thyroid-stimulating hormone receptors and tell your thyroid to produce more thyroid hormone. "There is no off switch to this," Wright says, and it requires medical treatment. 

Other conditions behind hyperthyroidism include:

• Plummer's disease: enlargement of the thyroid gland and overproduction of T4
• Hyperfunctioning thyroid nodules: parts of your thyroid gland produce too much T4
• Thyroiditis: inflammation of the thyroid

The most common cause of hypothyroidism is Hashimoto's thyroiditis, an autoimmune condition that occurs when your immune system produces antibodies that attack your thyroid gland even in the absence of disease. 

Hypothyroidism may also be caused by: 

• Overcorrection of hyperthyroidism
• Removal or radiation of the thyroid
• Cancer treatments
• Medications

Stress

"The thyroid is affected by your adrenal glands at the level of the hypothalamus," Wright explains. "Too much cortisol and you suppress the thyroid by limiting the amount of thyrotropin-releasing hormone, which in turn reduces thyroid-stimulating hormone." 

Low TSH reduces the amount of thyroid hormone secreted, "and you now have a picture that looks like hypothyroidism, when the issue is the adrenals," Wright says. 

Many lifestyle factors can cause this, but the top of the list is physical or mental stress, she says. Excessive exercise and over-dieting can stress the body and produce this effect, as can stressors like work and relationships.

Nutrition

Eating patterns and nutrition status profoundly impact all hormone levels, including thyroid hormones.

"Undereating in general triggers the body to slow metabolism down by lowering production of thyroid hormones," Azzaro says. "Additionally, several key nutrients are needed to make adequate thyroid hormones and convert them to the active usable form. These are iodine, selenium, zinc and iron." Too little of these can negatively affect your thyroid. 

Iodine is of particular importance, Wright says. A diet with insufficient iodine can lead to hypothyroidism because the thyroid needs iodine to produce the hormone. "In this situation, the thyroid becomes enlarged and can form a goiter," she says, which is an abnormal enlargement of the thyroid gland. Too much iodine, however, can stimulate hyperthyroidism.

What happens if you don't treat it?

Mild consequences of hypothyroidism include weight gain and high cholesterol, Azzaro says. Chronically low thyroid hormones can result in much worse effects, including infertility and nerve damage.

Hypothyroidism also involves pregnancy risks and "absolutely has to be corrected during pregnancy for the normal development of the fetus," Wright says. It also increases your risk of heart disease.

Hyperthyroidism often results in emergency medical care due to increased heart rate, abnormal heart rhythms and palpitations, Azzaro says. It can also lead to osteoporosis and eye problems. In many cases, hyperthyroidism requires removal or radiation of the thyroid gland, and the person must take thyroid hormone replacement for the rest of their life.

"Leaving hyperthyroidism unchecked can lead to life threatening heart arrhythmias and damage to the myocardium, or heart muscles," Wright adds.  

How to fix thyroid problems

Azzaro recommends starting by addressing your diet and ensuring your levels of thyroid-supporting nutrients such as iodine, zinc, selenium and iron are within normal range. Then, make sure you're not overexercising or under prolonged stress, she suggests. 

If you make lifestyle changes to no avail, definitely consider seeing a functional medicine doctor or endocrine specialist to assess your thyroid health. An endocrine specialist should run a variety of tests to check for any root causes of thyroid imbalances.

Some cases of hypo- and hyperthyroidism can be sorted out with lifestyle changes under the guidance of a specialist, while others require surgery or treatment of underlying medical conditions.