When the wheels start falling off the bus -- weight gain, low energy, depression -- practitioners check the thyroid first, and for good reason. The thyroid is the ring leader of the endocrine system!
Functions of thyroid hormone:
- Regulate metabolic rate
- Controls rate of protein metabolism
- Controls glucose absorption
- Controls absorption of nutrients in the intestinal tract
- Controls rate of heat and energy production
- Regulate other hormones and hormone production
While it's functions are undoubtedly important, the reasons why the thyroid is thrown out of whack vary from high estrogen to vitamin deficiencies, making it difficult to pinpoint the exact cause of a dysregulated thyroid.
Thyroid function can vary from overstimulated to understimulated. For the purposes of this post, let's talk specifically about an under stimulated thyroid (hypothyroid).
Causes of hypothyroid:
- High Estrogen
- High Cortisol
- Birth Control Pills
- Deficiencies: iodine, tyrosine, zinc, copper, selenium, iron and Vitamin A, B.
- Celiac Disease
- High amounts of raw goitrogenic foods (Brussel sprouts ,broccoli, kale, cabbage) - blocks iodine uptake
- Having an autoimmune disease
Thyroid Function 101
The thyroid is a butterfly-shaped endocrine gland attached to the front of the trachea. The thyroid secretes hormones that regulate the activities of nearly every cell in our body. These hormones regulate metabolic rate, the rate of protein metabolism, glucose absorption, absorption of nutrients in the intestinal tract, rate of heat and energy production and other hormones and hormone production.
Located in the brain, the hypothalamus senses if the body needs additional thyroid hormone. If the body does need additional thyroid hormone, it produces and releases TRH (Thyroid Releasing Hormone) to the pituitary gland. The pituitary gland is also located in the brain and produces TSH (Thyroid Stimulating Hormone) into the blood to signal thyroid hormone production.
The thyroid is located in the front of neck, just below the Adams apple, wherein it stores the protein thyroglobulin. The amino acid tyrosine (from thyroglobulin) combines with iodine to form T1 and T2, then combines with additional iodine to form active thyroid hormone T3 and T4. Thyroid peroxidase (TPO) enzyme binds iodine to the tyrosine and forms T4 and T3.
T3 is just 7% of thyroid hormone production, however is 10x more bioavailable than T4. 60% of T4 is converted to T3 in the liver. On the other hand, T4 is approximately 93% of hormone production and can store for several weeks in the thyroid gland, bound in thyroglobulin
Hypothyroid is the condition where the thyroid does not produce a sufficient supply of T3 and T4, yet the brain continues to produce TSH – because it’s not detecting enough thyroid hormone in the body.
So, we know how the thyroid functions, why it's important, and what can throw it off --here's are 5 key nutrients and foods to support a low functioning thyroid.
5 key nutrients to support a hypothyroid:
Selenium is important to the enzymes that protect the thyroid from damage by free radicals. Selenium is also shown to reduce overactive immune activity. Additionally, selenium helps with the conversion of T4 to T3, and the enzymes responsible for removing 1 iodine atom from the T4 to turn it into T3 are selenium-dependent.
Excellent sources of selenium include tuna, halibut, salmon, shrimp, chicken, eggs, shiitake mushrooms, lamb, turkey, brazil nuts, and crimini mushrooms.
Zinc is important in the conversion of T4 to T3, and to decrease reverse T3 and lower TSH. Zinc is also necessary to stimulate the pituitary gland and make the proper amount of TSH. Copper and zinc work synergistically, thus a balance must be struck between the two minerals.
Excellent sources of zinc include oysters, red meat, pumpkin seeds, sesame seeds, lima beans, almonds and walnuts.
Copper works synergistically with zinc to protect the thyroid and avoid hypothyroid. Copper and zinc work synergistically, thus a balance must be struck between the two minerals.
Excellent sources of copper include liver, oysters, sunflower seeds, walnuts, sesame seeds and shiitake mushrooms.
Obtaining copper through proper nutrition is best.
4. VITAMIN A
Vitamin A combats free radical damages and inflammation, and the thyroid depends on sufficient quantities of Vitamin A, especially for those suffering with the autoimmune condition of low thyroid, Hashimoto’s. The retinol version (animal source) of Vitamin A is preferred due to lower conversion from carotenoids (plant-based source).
Vitamin A retinol foods include liver, cod liver oil, dairy, and eggs. Vitamin A carotenoid foods include spinach, collard greens, swiss chard, carrots and red bell peppers.
Iron increases the enzyme thyroid peroxidase (TPO), which is iron dependent. TPO binds the iodine and the amino acid tyrosine to form T4 and T3. Iron deficiency may also reduce the conversion of T4 to T3.
Iron rich foods include liver, clams, beef, tuna and chicken. Iron is best absorbed through proper nutrition. Serum levels of ferritin can test to see if one is obtaining and absorbing proper doses of iron.
A varied diet plentiful in organic fruits and vegetables and grass-fed meat and eggs is a great place to start in improving thyroid health!
Blach, Phyllis A. Prescription for Nutritional Healing. New York, NY: Avery, 2010.
Gottfried MD, Sara. The Hormone Cure. New York, NY: Scribner, 2013.