Mallet's Guide To Thyroid Function

Thyroid Function Explained Part-1

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I"ll break this up into parts...so as not to bore you to death...this is however a must read for those considering supplementing with thyroid meds.

HOW THE THYROID GLAND REGULATES METABOLISM

Whithin the the endocrine system, the thyroid is the biological engine that ultimately directs hormonal function and, therefore, metabolism. The thyroid gland produces the hormones that make the body burn calories. Thyroid hormones are what drive your basal metabolic rate ( the energy required for internal or cellular work when the body is at rest), in other words your metabolism.
The thyroid is a large, butterfly-shaped gland with two lobes connected by a body (or isthmus) over the trachea. Embedded within the thyroid gland are four masses of tissue called the parathyroid glands. The thyroid produces and secretes three major hormones: thyroxine, triiodothyronine, and calcitonin. Thyroid hormones influence almost every cell of the body. The thyroid glans has a crucial role in metabolism, fat burning, and oxygen utilization, as well as in gastrointestinal and neuromuscular function. That's why prolonged symptoms of heartburn or extended muscle aches are a sign of low thyroid function, Are we learning just how important the thyroid is yet?.
Thyroxine and triiodothyronine are produced when iodine combines with the amino acid tyrosine. Thyroxine (t4) is tyrosine bound to four molecules of iodine. Triiodothyronine (t3) is tyrosine bound to three molecules of iodine...understand how they came up with the term t4 and t3!. Iodine and tyrosine must be present in adequate amounts in the diet for the synthesis of t4. When thyroid hormone was first discovered, t4 was given exclusive credit for the metabolic activity at the cellular level, it was later discovered that t3 was four times more active than t4 at the target cells. It is now understood that much of the circulating t4 is actually converted to t3 prior to cellular metabolic activity.
The anterior pituitary gland and the hpta (hypothalamus) regulate thyroid hormone levels. Initially, the hpta responds to a metabolic change such as low body temp, stress, or sleep be releasing thyrotropin releasing factor (TRF), while simultaneously signaling the anterior pituitary gland to release thyroid stimulating hormone (TSH). TSH stimulates the thyroid, which traps iodine, synthesizes T4, and releases the thyroid hormone. See the importants of iodine in your diet yet?. As levels of t4 increase, the activities of the hpta and pituitary are inhibited (that didn't take long did it?).

T4 increases the metabolic rate of almost every tissue in the body. It's effects on metabolism are astonishing. For example, a person whose thyroid gland reduces the production of T4 will experience as much as a 40% drop in metabolism, or basal metabolic rate (the rate at which the bodyspends energy for the maintenance activities of the body). Meanwhile, overproduction of T4 can increase normal metabolic activity by 100%. T4 increases the basal metabolic rate (BMR) by impacting the rate of ATP (energy) production in the mitochondria ( the energy producing component of cells). The thyroid uses much of this energy to convert caloric energy to heat in a process called Thermogenesis. In other words, how your body uses food determines your metabloism.

Thyroid hormone increases the utilization of carbs and fat from food, and the rate of protien synthesis. It stimulates the appetite and the movement of food through the digestive tract...bet you didn't know that?. In the presence of thyroid hormone, muscle catabolism increases, which increases the resting metabolic rate (muscle burns more energy than fat). Thyroid hormone also increases the sensitivity of skeletal muscle to impulses from the spinal cord. ( An excess of thyroid hormone is known to cause tremors, and a deficiency results in sluggish muscle response.) Thyroid hormone increases the uptake of oxygen into the cells, which speeds aerobic respiration. Finally, thyroid hormone actually increases the number of mitochondria whithin the cells.

Stay tuned for PART 2...

Part 2

Well if you made it through the first read...In this chapter I will explain the importance of diet and how it impacts your thyroid.

KEY INFLUENCES ON THYROID FUNCTION

As we have already discussed in PART 1, the endocrine glands are in constant comunication not only with each other, but also with the nervous and immune systems. In conjunction with the pituitary gland, thyroid hormones influence almost every function in the body, as metabolism establishes the official temp at which systems operate. Because the thyroid gland's work involves interaction with many body systems, it is particularly sesitive to influences that can disrupt it's proper functioning ( this is key to those supplementing with thyroid meds, AAS, and GH).

DIET AND THYROID FUNCTION

There is a direct relationship between nutrition status and the impact of hormones. The foods we eat and the vitamins, minerals and nutrients available to the body regulate the synthesis and utilization of thyroid hormones. At the same time, thyroid hormones influence the rate of metabolism of fuel sources from food: fats, protiens, and carbohydrates. Thyroid hormones increase the rate of energy released from carbs, increase the rate of protein synthesis, and stimulate the breakdown of fats. Low thyroid function slows the metabolism of these foods, leading to depleted energy and a slower metabolic rate that leads to weight gain.
In the presence of too much thyroid hormone, food is turned to energy with high speed and efficiency, increasing the basal metabolic rate (BMR) you should be familiar with this term by now!...and leading to exccesive weight loss.

The digestive and endocrine systems are dependent upon each other for the optimal absoption of nutrients from foods and the utilization of nutrients for hormone synthesis. Hypothyroidism results in weight gain, despite a poor appetite, constipation, pernicious anemia, poor utilization of fatty acids, and inadequate conversion of beta carotene to vit A. Hypothyroidism is also associated with insufficient production of hydrochloric acid by the parietal cells of the stomach. For those who don't know what HCA does...It provides the proper PH environment for the digestion of proteins by the enzyme pepsin. Without HCA, the amino acid phenylalinine (from which tyrosine is derived) remeber the importance of tyrosine in PART1...)))cannot be obtained from food, and tyrosine is unavailable in adequate amounts for the production of thyroxine (T4) A cycle of hypothyroidism can be created in this interplay between digestion and thyroid function. Hyperthyroidism can cause diarrhea, weight loss, and deficiencies in fat soluble vitamins and calcium. Hyperthyroidism can increase metabolic rates by as much as 200%, requiring a proportional intake of calories.

NUTRIENTS AND THYROID FUNCTION

Several nutrients are critical for the proper functioning of the thyroid gland. In order for the thyroid gland to produce T4, it needs the trace element iodine, chromium, and selenium, the mineral zinc, and the amino acid tyrosine. Without sufficient supply of these nutrients in the diet, thyroid function is diminished. Several reasons why a person may be lacking these nutrients include dysbiosis ( a disruption in the normal balance of microorganisms in the gastrointestinal mucosa), taking oral contraceptives, which deplete many nutrients, especially selenium and zinc...I thought I'd through that in incase some of our female members are looking into taking thyroid meds. Also consuming a diet high in processed foods lack these nutrients due to the destruction during processing.

ENZYMES

I'm just going to sweep over this because most of us understand the importance of enzymes...but one enzyme in particular must be mentioned as it relates so closely to thyroid function at that is ADENYLATE CYCLASE. This enzyme activates the molecule cyclic adenosine monophosphate or ( cAMP) sometimes reffered to as cyclic AMP. cAMP is the "second messenger" of cells, helping to initiate changes in the cells specific to certain hormones. Hormones whose actions depend on the cAMP mechanism include thyroid-stimulating hormone (TSH) folicle stimulating hormone (FSH), and luteinizing hormone (LH) from the anterior pituitary, antidiuretic hormone (ADH) bet you didn't know you had one of them! from the posterior pituitary, parathyroid hormone (PTH) from the parathyroid , and calcitonin from the thyroid. If Adenylate cyclase and the cAMP mechanism are disrupted, all the metabolic process dependent on them, including thyroid activity, are shut down.
The conversion of t4 to the more active t3 is regulated in part, by the enzyme iodothyronine deiodinase.

Any body suffering from a low body temp reading...I always recomend taking acti-cyclase ( which contains forskolin) to help regulate your thyroid function and have seen great success, and would recommend anybody taking t3 or t4 to take this compound post thyroid!

Last I will discuss briefly the symptoms of thyroid hyperthyroidism and hypothyroidism as well as some natural ways to help treat these problems and get them undere control...stay tuned for PART 3 for those of you who haven't fallen asleep yet.

Part 3

CONDITIONS ASSOCIATED WITH THYROID DYSFUNCTION

The thyroid gland, with the help of the pituitary, is the most important organ in the body for controlling weight and body fat. Thyroid hormones define the rate of cellular metabolism. If the thyroid gland is functioning properly, and enough thyroid hormone is getting to the cells, the energy from food is properly utilized. If there is a problem with the gland itself or if something is interfering with the thyroid hormone's ability to bind to it's target cells, metabolism alters, slowing down or speeding up every process in the body, which in turn can cause many reccuring problems.

FATIGUE AND FREE-RADICAL DAMAGE

Fatigue can be directly related to problems with the thyroid. The process by which energy from food is released and transferred to useable energy by the cells is a complex chain of chemical reactions known as cellular respiration. Some energy is released from food in the absence of oxygen (anaerobic respiration), but most is derived in the mitochondria of the cells in the presence of oxygen (aerobic respiration). In the mitochondria, aerobic respiration produces cellular energy in the form of ATP ( a large energy molecule). T3 and T4 are needed to utilize oxygen during aerobic respiration. If T4 or T3 levels are low, cellular respiration and energy are depleted, excess oxygen builds up in the cells, and oxidative, or free-radical, damage occurs. When these levels are low, the number of mitochondria in our cells actually begins to decrease.

CARDIOVASCULAR DISEASE

The metabolism of fats and absorption of essential fatty acids (EFAs) are important functions of the thyroid. Insufficient T4 to stimulate fat metabolism can lead to Hyperlipidemia, or elevated cholesterol. Whithout the benefit of cardioprotective nutrients from essential fatty acids, you may be at an increased risk of cardiovascular disease. If you have a high cholesterol reading, be sure to have your thyroid function evaluated before beginning medication. T3 is necessary for the utilization of oxygen by the mitochondria during cellular respiration. Inadequate T3 in the cells has a negative effect on oxygen consumption. Excess oxygen results in an increase in the oxidation of lipids (fats) and free radical damage. Increased oxidation of the low-density lipoprotein (LDL) form of cholesterol, often reffered to as "bad" cholesterol, has been identified in hyperthyroidism and hypothyroid states.

INSULIN RESISTANCE

T4 also influences how quickly glucose (sugar) is absorbed from the intestines and then taken up by the cells. T4 stimulates the conversion of proteins and fats to glycogen when blood sugar is high and the transformation of glycogen to glucose when blood sugar is low. The thyroid gland assists the pancreas and liver in maintaining stable blood sugar. In other words, T4 increases insulin response.

STRESS AND THYROID FUNCTION

Chronic stress affects the thyroid and endocrine function in a number of ways. The pituitary gland, the bodies "master gland," stimulates and controls the function of the adrenal cortex by secreting adrenocorticotropic (ACTH). If required to maintain a constant level of the major stress hormone cortisol in response to stress, the pituitary gland may over work. Too much production of ACTH may divert the pituitary from manufacturing other tropic hormones such as TSH, FSH, and LH. Cortisol production requires tyrosine, the same amino acid needed for the synthesis of T4. Excess cortisol production can deplete tyrosine levels, making it unavailable to the thyroid gland to make thyroid hormones. Stress depletes other important nutrients for T4 production, namely chromium and zinc. Excessive cortisol production from chronic stress also inhibits the conversion of T4 to T3 and the secretion of TSH.

HERE ARE SOME SYMPTOMS:

HYPOTHYROIDISM
behavior and mood...depression, fatigue, sleepiness, poor concentration
cardiovascular.........slow pulse rate (<70bpm):
cholesterol..............elevated cholesterol
features..................coarse voice, stunted growth, enlarged thyroid
Gastrointestinal........slowed digestion, bloating, heartburn, poor appetite
metabolism..............decreased basal metabolic rate, weight gain
muscles and reflexes..muscle aches, cramping, numbness in hads and feet
respiratory...............breathing slows, poor ventilation
Tolerance to temp..... intolerance to cold.

HYPERTHYROIDISM

behavior and mood...nervousness, irritability, insomnia, exhaustion
cardiovascular.........heart palpitations, rapid pulse
cholesterol..............decreased cholesterol
features.................bulging eyes, enlarged thyroid
gastrointestinal........diarea, increased appetite
metabolism..............increased basal metabolic rate, weight loss
muscles and reflexes..muscle weakness, tremors
respiratory..............hyperventilation
tolerance to temp.....intolerance to heat.

I know that's alot to stomach, but perhaps people will consider the importance of their thyroid gland before taking thyroid meds out of ignorance or being miss informed...the choice is ultimately yours...compare and save!

If you haven't already, take the BMT test that I have posted and see where your thyroid lies. Be responsible and your body will thank you for it with long life.

GREAT READ BLOWN