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Dr. Renata Trister DO

The thyroid gland is a butterfly-shaped endocrine gland that is located in the lower front of the neck. The thyroid gland is an important organ of the endocrine system. The thyroid’s job is to make thyroid hormones, which are secreted into the blood and then carried to every tissue in the body. Thyroid hormone helps the body use energy, stay warm and keep the brain, heart, muscles, and other organs working properly. The thyroid makes hormones that control the way every cell in the body uses energy. This process is called metabolism.

Hypothyroidism (underactive thyroid) is a condition in which your thyroid gland doesn’t produce enough of certain important hormones. An underactive thyroid is most common in women and patients over 50.


The major thyroid hormone secreted by the thyroid gland is thyroxine, also called T4 because it contains four iodine atoms. T4 is converted to triiodothyronine (T3) by the removal of an iodine atom. T3 is the active form of thyroid hormone. This occurs mainly in the liver and in the brain. The amount of T4 produced by the thyroid gland is controlled by another hormone, which is made in the pituitary gland located at the base of the brain, called thyroid-stimulating hormone (abbreviated TSH). The amount of TSH that the pituitary sends into the blood stream depends on the amount of T4 that the pituitary sees. If the pituitary sees very little T4, then it produces more TSH to tell the thyroid gland to produce more T4. Once the T4 in the blood stream goes above a certain level, the pituitary’s production of TSH is shut off. In fact, the thyroid and pituitary act in many ways like a heater and a thermostat. When the heater is off and it becomes cold, the thermostat reads the temperature and turns on the heater. When the heat rises to an appropriate level, the thermostat senses this and turns off the heater.

TSH and T4:

The best way to initially test thyroid function is to measure the TSH level in a blood sample. A high TSH level indicates that the thyroid gland is failing because of a problem that is directly affecting the thyroid (primary hypothyroidism). (Low TSH levels usually indicate that the person has an overactive thyroid that is producing too much thyroid hormone.) Occasionally, a low TSH may result from an abnormality in the pituitary gland, which prevents it from making enough TSH to stimulate the thyroid (secondary hypothyroidism).

T4 circulates in the blood in two forms: 1) T4 bound to proteins that prevent the T4 from entering the various tissues that need thyroid hormone and 2) free T4, which does enter the various target tissues to exert its effects. The free T4 fraction is the most important to determine how the thyroid is functioning, and tests to measure this are called the Free T4 (FT4) and the Free T4 Index (FT4I or FTI). Individuals who have hyperthyroidism will have an elevated FT4 or FTI, whereas patients with hypothyroidism will have a low level of FT4 or FTI. Combining the TSH test with the FT4 or FTI accurately determines how the thyroid gland is functioning. The finding of an elevated TSH and low FT4 or FTI indicates primary hypothyroidism due to disease in the thyroid gland. A low TSH and low FT4 or FTI indicates hypothyroidism due to a problem involving the pituitary gland. A low TSH with an elevated FT4 or FTI is found in individuals who have hyperthyroidism.

The most common cause of hypothyroidism is thyroiditis. Swelling and inflammation damage the thyroid gland’s cells.

Thyroiditis is caused by:

The immune system attacking the thyroid gland

Viral infections (common cold) or other respiratory infections

Pregnancy (often called postpartum thyroiditis)

Other causes of hypothyroidism include:

Certain medicines, such as lithium and amiodarone

Congenital (birth) defects

Radiation treatments to the neck or brain to treat different cancers

Radioactive iodine used to treat an overactive thyroid gland

Surgical removal of part or all of the thyroid gland



Increased sensitivity to cold temperature

Fatigue or feeling slowed down

Heavier and irregular menstrual periods

Joint or muscle pain

Paleness or dry skin

Sadness or depression

Thin, brittle hair or fingernails


Weight gain

If untreated:

Decreased taste and smell


Puffy face, hands, and feet

Slow speech

Thickening of the skin

Thinning of eyebrows


Treatment is aimed at replacing the thyroid hormone that you are lacking.

Levothyroxine (also called Synthroid) is the most commonly used medication:

You will be prescribed the lowest dose possible that relieves your symptoms and brings your blood hormone levels back to normal.

Most people with an underactive thyroid will need to take this medicine for life.

When starting your medicine, your dosage may need adjustment and your hormone levels may need to be monitored for 2 to 3 months. Once your hormone levels stabilize, your thyroid hormone levels will be monitored at least once every year.

When you are taking thyroid medicine, be aware of the following:

Do not stop taking the medicine when you feel better. Continue taking it exactly as your doctor prescribed.

If you change brands of thyroid medicine, let your doctor know. Your levels may need to be checked.

Thyroid medicine works best on an empty stomach and when taken 1 hour before any other medications.

Wait at least 4 hours after taking thyroid hormone before you take fiber supplements, calcium, iron, multivitamins, aluminum hydroxide antacids, colestipol, or medicines that bind bile acids.

While you are taking thyroid replacement therapy, tell your doctor if you have any symptoms that suggest your dose is too high, such as:


Rapid weight loss

Restlessness or shakiness



Making dietary changes can be very helpful to your overall health and in addressing hypothyroidism. Many people with hypothyroidism experience crippling fatigue and brain fog, which prompts reaching for non-nutritional forms of energy like sugar and caffeine.

1. Decrease Sugars: Greatly reduce or eliminate caffeine and sugar, including refined carbohydrates like flour, which the body treats like sugar. Reduce grain-based carbohydrates and focus on eating non-starchy vegetables.

2. Add Healthy Proteins: Proteins include nuts and nut butters; quinoa; hormone- and antibiotic-free animal products (organic, grass-fed meats, eggs, and sustainably-farmed fish); and legumes.

3. Good fats: Fat is your friend and cholesterol is the precursor to hormonal pathways; if you’re getting insufficient fat and cholesterol, you could be exacerbating hormonal imbalance, which includes thyroid hormones. Natural, healthful fats include olive oil; ghee; avocados; flax seeds; fish; nuts and nut butters; hormone- and antibiotic-free full fat cheese, yogurt, and cottage cheese (yes, full fat, not skim); and coconut milk products.

3. Nutrients: While nutritional deficiencies may not be the cause of hypothyroidism, not having enough of these micronutrients and minerals can aggravate symptoms: vitamin D, iron, omega-3 fatty acids, selenium, zinc, copper, vitamin A, the B vitamins, and iodine.

It’s commonly believed that hypothyroidism is due to insufficient iodine, but this is not always true true.  Rather than supplements, primary sources of iodine include sea vegetables and seafood. Secondary sources: eggs, asparagus, lima beans, mushrooms, spinach, sesame seeds, summer squash, Swiss chard, and garlic.

Omega-3s, found in fish, grass-fed animal products, flaxseeds, and walnuts, are the building blocks for hormones that control immune function and cell growth, are critical to thyroid function, and improve the ability to respond to thyroid hormones.

4. Address underlying food sensitivities. Just like the body’s attack on the thyroid in the presence of Hashimoto’s thyroditis, the body will also see offending or inflammatory foods as an invader and can induce or exacerbate the autoimmune response. There is much association with gluten sensitivity and various autoimmune disorders. Eating gluten can increase the autoimmune attack on your thyroid. Trying a gluten free diet may be helpful.

5. Do a gut check. A whopping 20 percent of thyroid function depends on a sufficient supply of healthy gut bacteria, so it’s best to supplement with probiotics (friendly intestinal bacteria).

6. Address silent inflammation with whole foods nutrition. Systemic inflammation and autoimmunity often go hand-in-hand.

7. Look at your stressors and practice relaxation. The thyroid is a very sensitive gland and is exceptionally reactive to the stress response.


In most cases, thyroid hormone levels  and symptoms will return to normal with proper treatment. You will likely take a thyroid hormone medicine for the rest of your life.