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15.7: The Thyroid Gland - Biology

15.7: The Thyroid Gland - Biology



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A butterfly-shaped organ, the thyroid gland is located anterior to the trachea, just inferior to the larynx. Surrounded by a wall of epithelial follicle cells, the colloid is the center of thyroid hormone production, and that production is dependent on the hormones’ essential and unique component: iodine.

Thyroid Gland

The thyroid gland is located in the neck where it wraps around the trachea. (a) Anterior view of the thyroid gland. (b) Posterior view of the thyroid gland. (c) The glandular tissue is composed primarily of thyroid follicles. The larger parafollicular cells often appear within the matrix of follicle cells. LM × 1332. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)


Synthesis and Release of Thyroid Hormones

Hormones are produced in the colloid when atoms of the mineral iodine attach to a glycoprotein, called thyroglobulin, that is secreted into the colloid by the follicle cells. The following steps outline the hormones’ assembly:

  1. Binding of TSH to its receptors in the follicle cells of the thyroid gland causes the cells to actively transport iodide ions (I) across their cell membrane, from the bloodstream into the cytosol. As a result, the concentration of iodide ions “trapped” in the follicular cells is many times higher than the concentration in the bloodstream.
  2. Iodide ions then move to the lumen of the follicle cells that border the colloid. There, the ions undergo oxidation (their negatively charged electrons are removed). The oxidation of two iodide ions (2 I) results in iodine (I2), which passes through the follicle cell membrane into the colloid.
  3. In the colloid, peroxidase enzymes link the iodine to the tyrosine amino acids in thyroglobulin to produce two intermediaries: a tyrosine attached to one iodine and a tyrosine attached to two iodines. When one of each of these intermediaries is linked by covalent bonds, the resulting compound is triiodothyronine (T3), a thyroid hormone with three iodines. Much more commonly, two copies of the second intermediary bond, forming tetraiodothyronine, also known as thyroxine (T4), a thyroid hormone with four iodines.

These hormones remain in the colloid center of the thyroid follicles until TSH stimulates endocytosis of colloid back into the follicle cells. There, lysosomal enzymes break apart the thyroglobulin colloid, releasing free T3 and T4, which diffuse across the follicle cell membrane and enter the bloodstream.

In the bloodstream, less than one percent of the circulating T3 and T4 remains unbound. This free T3 and T4 can cross the lipid bilayer of cell membranes and be taken up by cells. The remaining 99 percent of circulating T3 and T4 is bound to specialized transport proteins called thyroxine-binding globulins (TBGs), to albumin, or to other plasma proteins. This “packaging” prevents their free diffusion into body cells. When blood levels of T3 and T4 begin to decline, bound T3 and T4 are released from these plasma proteins and readily cross the membrane of target cells. T3 is more potent than T4, and many cells convert T4 to T3 through the removal of an iodine atom.

Regulation of TH Synthesis

The release of T3 and T4 from the thyroid gland is regulated by thyroid-stimulating hormone (TSH). Low blood levels of T3 and T4 stimulate the release of thyrotropin-releasing hormone (TRH) from the hypothalamus, which triggers secretion of TSH from the anterior pituitary. In turn, TSH stimulates the thyroid gland to secrete T3 and T4. The levels of TRH, TSH, T3, and T4 are regulated by a negative feedback system in which increasing levels of T3 and T4 decrease the production and secretion of TSH.

Classic Negative Feedback Loop

A classic negative feedback loop controls the regulation of thyroid hormone levels.


Functions of Thyroid Hormones

The thyroid hormones, T3 and T4, are often referred to as metabolic hormones because their levels influence the body’s basal metabolic rate, the amount of energy used by the body at rest. When T3 and T4 bind to intracellular receptors located on the mitochondria, they cause an increase in nutrient breakdown and the use of oxygen to produce ATP. In addition, T3 and T4 initiate the transcription of genes involved in glucose oxidation. Although these mechanisms prompt cells to produce more ATP, the process is inefficient, and an abnormally increased level of heat is released as a byproduct of these reactions. This so-called calorigenic effect (calor- = “heat”) raises body temperature.

Adequate levels of thyroid hormones are also required for protein synthesis and for fetal and childhood tissue development and growth. They are especially critical for normal development of the nervous system both in utero and in early childhood, and they continue to support neurological function in adults. As noted earlier, these thyroid hormones have a complex interrelationship with reproductive hormones, and deficiencies can influence libido, fertility, and other aspects of reproductive function. Finally, thyroid hormones increase the body’s sensitivity to catecholamines (epinephrine and norepinephrine) from the adrenal medulla by upregulation of receptors in the blood vessels. When levels of T3 and T4 hormones are excessive, this effect accelerates the heart rate, strengthens the heartbeat, and increases blood pressure. Because thyroid hormones regulate metabolism, heat production, protein synthesis, and many other body functions, thyroid disorders can have severe and widespread consequences.

Calcitonin

The thyroid gland also secretes a hormone called calcitonin that is produced by the parafollicular cells (also called C cells) that stud the tissue between distinct follicles. Calcitonin is released in response to a rise in blood calcium levels. It appears to have a function in decreasing blood calcium concentrations by:

  • Inhibiting the activity of osteoclasts, bone cells that release calcium into the circulation by degrading bone matrix
  • Increasing osteoblastic activity
  • Decreasing calcium absorption in the intestines
  • Increasing calcium loss in the urine

However, these functions are usually not significant in maintaining calcium homeostasis, so the importance of calcitonin is not entirely understood. Pharmaceutical preparations of calcitonin are sometimes prescribed to reduce osteoclast activity in people with osteoporosis and to reduce the degradation of cartilage in people with osteoarthritis.

Thyroid Hormones
Associated hormonesChemical classEffect
Thyroxine (T4), triiodothyronine (T3)AmineStimulate basal metabolic rate
CalcitoninPeptideReduces blood Ca2+ levels

Of course, calcium is critical for many other biological processes. It is a second messenger in many signaling pathways, and is essential for muscle contraction, nerve impulse transmission, and blood clotting. Given these roles, it is not surprising that blood calcium levels are tightly regulated by the endocrine system. The organs involved in the regulation are the parathyroid glands.


Chemistry and Biology in the Biosynthesis and Action of Thyroid Hormones

Thyroid hormones (THs) are secreted by the thyroid gland. They control lipid, carbohydrate, and protein metabolism, heart rate, neural development, as well as cardiovascular, renal, and brain functions. The thyroid gland mainly produces l-thyroxine (T4) as a prohormone, and 5'-deiodination of T4 by iodothyronine deiodinases generates the nuclear receptor binding hormone T3. In this Review, we discuss the basic aspects of the chemistry and biology as well as recent advances in the biosynthesis of THs in the thyroid gland, plasma transport, and internalization of THs in their target organs, in addition to the deiodination and various other enzyme-mediated metabolic pathways of THs. We also discuss thyroid hormone receptors and their mechanism of action to regulate gene expression, as well as various thyroid-related disorders and the available treatments.

Keywords: deiodinases iodine selenium thyroid hormones thyroxine.


Thyroid Gland: Thyroxine and Triiodothyronine

The thyroid gland weighs about 25-30 gm. and con­sists of closely packed sacs (follicles) filled with proteinaceous colloid. The gland secretes the hor­mones thyroxine and triiodothyronine. Of a total of 50 mg of iodine in the body, about 10-15 mg are in thyroid.

Thyroxine and Triiodothyronine:

1. Iodination of tyrosine’s in thyroglobulin occurs first in position 3 of the aromatic nucleus and then at position 5 forming monoiodotyrosine and diiodotyrosine, re­spectively.

2. Coupling of two molecules of diiodotyrosine (I2 Tyr.) then occurs within the thyroglobulin molecule to form tetraiodothyronine (Thyroxine).

3. Coupling of monoiodotyrosine (I Tys.) with diiodotyrosine (I2 Tyr.) also occurs to form triiodothyronine (T3).

Protein Bound Iodine (PBI) in Blood:

The term PBI in blood represents iodine present in thyroid hormones. The PBI values for normal adults are 3.5-7.5 mg/100 ml of plasma. PBI is a reliable measure of thyroxine content of plasma.

The vlaues for PBI in hypo- and hyperthyroidism are given below:

1. In hypothyroid animals, the tissues show a low rate of oxygen consumption, the patient has a slow pulse, lowered vigour, obesity, blood cholesterol levels are in­creased, lipolysis and fatty acid liberation are decreased. In hyperthyroid states, re­verse occurs.

2. Thyroxine causes increased intestinal glu­cose absorption. It increases glycogenolysis in liver and muscle. It promotes neoglucogenesis.

3. It increases RNA, amino acid transport and protein synthesis.

4. In hypothyroidism, there is marked in­crease in serum cholesterol and triglycer­ide, and phospholipid contents in blood are also increased. In hyperthyroidism, the serum cholesterol level is decreased.

5. In high concentration of thyroid hor­mones, calcium is mobilized from bone, there are losses of potassium and nitrogen in urine, and calcium and phosphorus in­crease in the urine.

6. High concentration of thyroid hormone causes uncoupled oxidative phosphoryla­tion and increased swelling in the mito­chondria. Such action results in the pro­duction of heat rather than storage of en­ergy as ATP.


Hormone imbalances: Overactive and underactive thyroid gland

An overactive thyroid (also known as hyperthyroidism) occurs if the thyroid gland makes too many hormones. An underactive thyroid (hypothyroidism) is where the gland doesn’t make enough hormones. Both of these imbalances can lead to a great number of symptoms.

The thyroid gland may grow in size too. Sometimes the whole thyroid gland becomes enlarged (diffuse goiter), and sometimes individual lumps called nodules grow in the gland (nodular goiter). A special examination, known as thyroid scintigraphy, can be used to see whether these nodules are producing abnormal amounts of hormones. If they make more hormones than the rest of the thyroid tissue, they are called “hot” nodules. If they make less, they are called 𠇌old” nodules.

In most cases, an enlarged thyroid or nodules aren’t caused by anything serious. They are only rarely cancer. But it’s still important to see a doctor if you notice any changes in your thyroid gland.


Physiology of the Thyroid Gland

The thyroid gland, which sits mid-line and anteriorly on the neck, is like the manager of a factory and maintains metabolic rate and serum calcium levels in the body (Cain, Campbell, Minorsky, Reece, Urry, 2017, Chapter 45). The thyroid gland secretes three different types of hormones, thyroxine (T4), triiodothyronine (T3), and calcitonin, all which act like supervisors of the factory.

Figure 1. Thyroid Gland (University of California Los Angeles Health, n.d.)

REGULATION OF T3 AND T4

When there is a decrease in the number of T3 and T4 hormones in the body, the metabolic rate decreases (Cain, Campbell, Minorsky, Reece, Urry, 2017, Chapter 45) similar to how the production of a factory declines from insufficient motivation by the supervisor on workers . The decrease in metabolic rate then causes a stimulus to be sent to the hypothalamus, which is located in the limbic system, from various sensory nerves this would be like a report being sent from the factory to the chief operating officer (COO), the hypothalamus, that more supervisors are needed to increase worker motivation.

After receiving the stimulus from the various sensory neurons, the hypothalamus then releases a hormone called thyrotropin-releasing hormone (TRH) to the anterior pituitary gland (Cain, Campbell, Minorsky, Reece, Urry, 2017, Chapter 45) analogically, the COO is sending an internal company memo, TRH, to the division director, the anterior pituitary gland, regarding the issue.

The anterior pituitary gland would then release thyroid-stimulating hormone (TSH) via blood vessels to stimulate the thyroid gland (Cain, Campbell, Minorsky, Reece, Urry, 2017, Chapter 45) analogically, the division director is sending an intra-company email, TSH, to the manager informing that more supervisors are needed.

The thyroid gland would then release T3 and T4 hormones into the vessels, where then they would reach various organs of the body to stimulate them and cause them to increase their basal metabolic rates, such as increasing heat production and oxygen consumption, stimulation of the respiratory system and the cardiovascular system to increase blood flow and oxygen delivery to the body’s tissues, and to stimulate bone formation with the help of growth hormone (Cain, Campbell, Minorsky, Reece, Urry, 2017, Chapter 45) analogically, the manager puts more supervisors in the factory which then motivate the workers to increase their productivity, and for those supervisors to also work with an engineer, growth hormone, to create steel beams that maintain the skeletal structure of the factory.

As the levels of T3 and T4 hormones return to normal levels, a negative feedback mechanism occurs to decrease the levels of TRH and TSH being released by the hypothalamus and anterior pituitary gland, respectively, so that the body’s metabolic rate remains stable (Cain, Campbell, Minorsky, Reece, Urry, 2017, Chapter 45) analogically, as the number of supervisors goes up and productivity increases, reports are sent to the COO and division director to change company strategy and decrease the number of supervisors needed to motivate the workers, the company strategy will change once again that productivity is down. The cycle repeats itself when the levels of T3 and T4 are insufficient.

Figure 2. Control of Thyroid Hormones (Bowen, n.d.)

REGULATION OF CALCITONIN

Calcitonin is a hormone that helps regulate the level of serum calcium by lowering the amount of it in the bloodstream (Cain, Campbell, Minorsky, Reece, Urry, 2017, Chapter 45). Calcitonin prevents the breakdown of bone and stimulates the kidneys to excrete excess calcium from the bloodstream analogically, the manager is sending a supervisor, calcitonin, to prevent any steel beams from being melted down and recycled inside the factory and to instruct the cleaning crew, the kidneys, to trash any excess steel.

The amount of calcitonin is reduced by a negative-feedback mechanism once the serum calcium reaches normal levels, and the cycle repeats itself once calcium increases again.

Bowen, Richard. (n.d.). Control of thyroid hormone synthesis and secretion [digital image]. Retrieved from http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/thyroid/control.html

Cain, M. L., Campbell, N. A., Minorsky, P. V., Reece, J. B., Urry, L. A. (2017). Campbell biology . New York, NY: Pearson Education, Inc.


MCQs on Thyroid Gland

1. The main hormone secreted by the Thyroid gland
(a) T4
(b) T3
(c) (a) and (b) Both
(d) TSH

2. Iodine deficiency can cause
(a) Goitre
(b) Thyroid cancer
(c) Solitary thyroid nodules
(d) Thyroiditis

3. Grave’s disease or Basedow’s disease is due to
(a) Hyperactivity of adrenal cortex
(b) Hypoactivity of the thyroid gland
(c) Hyperactivity of thyroid gland
(d) Hypoactivity of islets of Langerhans

4. The four small glands in the thyroid gland are known as
(a) Adrenal gland
(b) Pineal gland
(c) Parathyroid gland
(d) Endocrine and exocrine gland

5. Sometimes, the thyroid symptoms are mistaken for which condition?
(a) Menopause
(b) Posttraumatic stress
(c) Pregnancy
(d) Crohn’s disease

6. Medications for hypothyroidism include treatment that:
(a) Replaces insulin
(b) Replaces ADH
(c) Replaces TH
(d) Replaces surfactant

7. Which of these diseases is not related to thyroid glands?
(a) Cretinism
(b) Myxoedema
(c) Goitre
(d) Acromegaly

8. In chronically deficient patients, this abnormality is directly related to the enlargement of the thyroid gland
(a) Impaired conversion of T3 and T4
(b) Reduced activity of thyroperoxidase
(c) Elevated levels of TSH
(d) An antibody that binds to the TSH receptor in the thyroid gland

9. ____________ encloses thyroid, responsible for its movement during swallowing
(a) Prevertebral fascia
(b) Pretracheal fascia
(c) Investing layer of the deep cervical fascia
(d) Superficial fascia

10. This condition of chronic inflammation of the thyroid leading to under-activity is
(a) Thyroiditis
(b) Goitre
(c) Hypothyroidism
(d) Hyperthyroidism


Structure and Function of Thyroid Gland

Thyroid Gland is a two-lobed gland that wraps around the trachea and is located at the base of the neck in vertebrate animals. The thyroid gland secretes two important hormones: thyroxine, which regulates the cell metabolism necessary for normal growth and development, and calcitonin, which stimulates the formation of bone and helps regulate the amount of calcium in the blood.

Hormonal output from the thyroid is regulated by thyroid-stimulating hormone (TSH) secreted from the anterior pituitary gland, which itself is regulated by thyrotropin-releasing hormone (TRH) produced by the hypothalamus.

The thyroid gland or thyroid is a highly vascular, brownish-red gland located anteriorly in the lower neck, extending from the level of the fifth cervical vertebra down to the first thoracic. The gland varies from an H to a U shape and is formed by 2 elongated lateral lobes with superior and inferior poles connected by a median isthmus, with an average height of 12-15 mm, overlying the second to fourth tracheal rings.

Structure of Thyroid Gland

The thyroid is a butterfly-shaped gland that sits low on the front of the neck. The thyroid has two side lobes, connected by a bridge (isthmus) in the middle. When the thyroid is its normal size, we can’t feel it. The thyroid weighs 25 grams in adults, with each lobe being about 5 cm long, 3 cm wide and 2 cm thick, and the isthmus about 1.25 cm in height and width. The gland is usually larger in women, and increases in size in pregnancy.

Principal innervation of the thyroid gland derives from the autonomic nervous system. Parasympathetic fibers come from the vagus nerves, and sympathetic fibers are distributed from the superior, middle, and inferior ganglia of the sympathetic trunk. These small nerves enter the gland along with the blood vessels. Autonomic nervous regulation of the glandular secretion is not clearly understood, but most of the effect is postulated to be on blood vessels, hence the perfusion rates of the glands.

The thyroid sits near the front of the neck, lying against and around the front of the larynx and trachea. The thyroid cartilage and cricoid cartilage lie just above the gland, below the Adam’s apple. The thyroid gland is covered by a thin fibrous capsule, which has an inner and an outer layer. The outer layer is continuous with the pretracheal fascia, attaching the gland to the cricoid and thyroid cartilages, via a thickening of the fascia to form the posterior suspensory ligament of thyroid gland also known as Berry’s ligament. This causes the thyroid to move up and down with swallowing. The inner layer extrudes into the gland and forms the septae that divides the thyroid tissue into microscopic lobules. Typically four parathyroid glands, two on each side, lie on each side between the two layers of the capsule, at the back of the thyroid lobes.

The lobules are composed of follicles, the structural units of the gland, which consist of a layer of simple epithelium enclosing a colloid-filled cavity.

Epithelial cells are of 2 types: principal cells (ie, follicular) and parafollicular cells (ie, C, clear, light cells). Principal cells are responsible for formation of the colloid (iodothyroglobulin), whereas parafollicular cells produce the hormone calcitonin, a protein central to calcium homeostasis. Parafollicular cells lie adjacent to the follicles within the basal lamina.

The thyroid is supplied with arterial blood from the superior thyroid artery, a branch of the external carotid artery, and the inferior thyroid artery, a branch of the thyrocervical trunk, and sometimes by an anatomical variant the thyroid ima artery, which has a variable origin.

Functions of Thyroid Gland

The primary function of the thyroid gland or thyroid is the production of the iodine-containing thyroid hormones, triiodothyronine (T3) and thyroxine (T4) and the peptide hormone calcitonin. T3 is so named because it contains three atoms of iodine per molecule and T4 contains four atoms of iodine per molecule. The thyroid hormones have a wide range of effects on the human body. The thyroid’s hormones regulate vital body functions, including:

  • Breathing
  • Heart rate
  • Central and peripheral nervous systems
  • Body weight
  • Muscle strength
  • Menstrual cycles
  • Body temperature
  • Cholesterol levels

The thyroid has two sides called lobes that lie on either side of your windpipe, and is usually connected by a strip of thyroid tissue known as an isthmus. Some people do not have an isthmus, and instead have two separate thyroid lobes.

The thyroid is part of the endocrine system, which is made up of glands that produce, store, and release hormones into the bloodstream so the hormones can reach the body’s cells. The thyroid gland uses iodine from the foods you eat to make two main hormones: Triiodothyronine (T3), Thyroxine (T4).

It is important that T3 and T4 levels are neither too high nor too low. Two glands in the brain—the hypothalamus and the pituitary communicate to maintain T3 and T4 balance.


1. The main hormone secreted by the Thyroid gland
(a) T4
(b) T3
(c) (a) and (b) Both
(d) TSH

2. Iodine deficiency can cause
(a) Goitre
(b) Thyroid cancer
(c) Solitary thyroid nodules
(d) Thyroiditis

3. Grave’s disease or Basedow’s disease is due to
(a) Hyperactivity of adrenal cortex
(b) Hypoactivity of the thyroid gland
(c) Hyperactivity of thyroid gland
(d) Hypoactivity of islets of Langerhans

4. The four small glands in the thyroid gland are known as
(a) Adrenal gland
(b) Pineal gland
(c) Parathyroid gland
(d) Endocrine and exocrine gland

5. Sometimes, the thyroid symptoms are mistaken for which condition?
(a) Menopause
(b) Posttraumatic stress
(c) Pregnancy
(d) Crohn’s disease

6. Medications for hypothyroidism include treatment that:
(a) Replaces insulin
(b) Replaces ADH
(c) Replaces TH
(d) Replaces surfactant

7. Which of these diseases is not related to thyroid glands?
(a) Cretinism
(b) Myxoedema
(c) Goitre
(d) Acromegaly

8. In chronically deficient patients, this abnormality is directly related to the enlargement of the thyroid gland
(a) Impaired conversion of T3 and T4
(b) Reduced activity of thyroperoxidase
(c) Elevated levels of TSH
(d) An antibody that binds to the TSH receptor in the thyroid gland

9. ____________ encloses thyroid, responsible for its movement during swallowing
(a) Prevertebral fascia
(b) Pretracheal fascia
(c) Investing layer of the deep cervical fascia
(d) Superficial fascia

10. This condition of chronic inflammation of the thyroid leading to under-activity is
(a) Thyroiditis
(b) Goitre
(c) Hypothyroidism
(d) Hyperthyroidism


The Link Between Your Thyroid And Adrenal Glands

Thyroid problems are one of the most common conditions we treat at our clinics. They are especially common in women. They are a big cause of fatigue and inability to lose weight.

Thyroid problems can develop at any age, but they are especially common in women who have recently given birth and women who have recently gone through menopause. The hormonal shifts at this time are a trigger for abnormal thyroid function.

Hashimoto’s thyroiditis is the most common cause of an under active thyroid gland. The usual treatment is prescription thyroid hormone – either synthetic hormones known as levothyroxine (eg. Synthroid), or natural porcine thyroid hormones (commonly referred to as Armor).

The problem is, many people with a thyroid condition are already taking one of these medications but they continue to suffer with symptoms of an under active thyroid gland. That is, they are still tired, depressed, suffer with fluid retention and can’t lose weight. What causes these ongoing symptoms? Sometimes the answer is adrenal gland dysfunction. Fixing the adrenal glands is sometimes the key to overcoming thyroid symptoms.

Your thyroid gland is a butterfly shaped organ at the front of your neck. It performs many essential functions related to growth, metabolism, body temperature, hormonal control (including menstrual cycle regulation), and mood. Your adrenal glands are two tiny triangular glands sitting on top of your kidneys. They control your stress response, immune function, blood pressure, blood sugar and your reproductive hormones.

If you experience prolonged chronic stress, your adrenal glands tell your body to conserve energy. Your metabolism slows down, you feel tired and want to sleep more and may experience more food cravings. Your thyroid gland function slows down, too. It’s like a warning system that tries to force your body to get more rest and sleep. Chronically over worked adrenal glands have a major negative impact on your immunity – over time this increases your risk of developing chronic inflammation and autoimmunity. These factors can lead to an eventual development of Hashimoto’s thyroiditis, which causes autoimmune hypothyroidism and is responsible for around 90 percent of all thyroid dysfunction in the USA.

When you are experiencing chronic stress, your immune cells release chemicals called inflammatory cytokines. Some examples include IL-1 beta, IL-6 and TNF-alpha. These chemicals have the unfortunate side effect of down regulating the production of the thyroid hormones TSH, T3, and T4. They make your thyroid less sensitive to TSH and decrease the conversion of the inactive form of the thyroid hormone T4 to the active form, T3. Chronic inflammation can make the thyroid hormone receptors on your cells less sensitive to active thyroid hormones. This means your thyroid hormones can’t do their job properly. This is called thyroid hormone resistance.

Reducing stress and improving the health of your adrenal glands can help improve thyroid health

Here are my tips

  • Try to get adequate sleep. People with adrenal fatigue often have poor quality sleep, but your adrenal glands will greatly benefit if you can be in bed before 10:30pm. The hours before midnight are much more restorative to your body. Magnesium is a great tool to promote a deeper and more restful sleep.
  • If you have low levels of cortisol (typical with adrenal gland exhaustion, and can be measured in a blood test), you may benefit from taking Adrenal Natural glandular capsules. They contain natural glandular material derived from government-inspected, range-fed animals, raised in New Zealand and Australia. This provides your body with natural adrenal gland hormones that help to relieve the symptoms of exhaustion and low stamina. It is important to take this in the morning.
  • Try to reduce the stress in your life or find more effective ways of dealing with it. Massage, meditation, yoga, dancing classes, facials, counseling, reading or going for a bike ride can all be healthy ways to unwind.
  • Many people with a thyroid condition are low in the nutrients required for the production of thyroid hormones. Being low in these nutrients can result in fatigue, low mood and impaired concentration. These nutrients are found in Thyroid Health capsules.
  • Make sure you eat enough protein and healthy fats. These two nutrients will help to keep your blood sugar stable throughout the day, thereby reducing energy slumps caused by a blood sugar crash.
  • You may benefit from a tyrosine supplement. Tyrosine is an amino acid that your body uses to manufacture adrenalin and noradrenalin. It helps you to emotionally cope with stress more effectively and even helps mood and concentration.
  • Most of the vitamin C in your body is stored in your adrenal glands. Most people do not consume enough fresh vegetables and fruit to get sufficient vitamin C in their diet. Your adrenal glands will struggle to function unless you consume enough vitamin C. If you have adrenal exhaustion you will need at least 1000mg of vitamin C daily.

The above statements have not been evaluated by the FDA and are not intended to diagnose, treat or cure any disease.


4. Conclusions

The maintenance of a physiological concentration of selenium (selenostasis) through a balanced diet or, alternatively, via supplementation is a prerequisite not only to prevent thyroid disease but also to maintain overall health. Selenium has a U-shaped relationship with disease, and either the deficiency or the excess of this micronutrient may be associated with adverse outcomes. In fact, there is a selenium concentration range in the body in which selenium benefits seem to be maximized.

Selenium supplementation in patients with Hashimoto's thyroiditis and reduced intake of this micronutrient may be useful, even for those who are already being treated with levothyroxine, although further studies are needed to confirm this benefit.

In patients with mild to moderate Graves' orbitopathy, selenium supplementation seems to be beneficial and the organic formula (selenomethionine) seems to be more advantageous than the inorganic formula.