by Bryan Timmins

A recent study indicated that nearly 13 million Americans may be undiagnosed for low thyroid function. This is in addition to the approximately 20 million individuals who are receiving thyroid replacement treatment for hypothyroidism. Why the large discrepancy in diagnosis? One reason may be inadequate testing for thyroid hormone levels, and the sole reliance by medical practitioners on these lab tests despite the individuals specific health complaints.

This article will help to explain the short-comings of traditional medicines view towards thyroid function, and low thyroid diagnosis, while exploring the vast array of nutritional and biochemical influences on thyroid function. However, before we can begin an explanation of normal thyroid physiology is warranted.

Thyroid Physiology

The thyroid is a small "butterfly-winged" shaped gland at the base of the neck. It forms a core link of (hormone) glands in the body with a specific function to help regulate cellular metabolism and energy production.

The thyroid receives information from the pituitary gland in the form of TSH (thyrotrophin stimulating hormone). This pituitary hormone under direct control from the hypothalamus directs the thyroid to produce thyroid hormone from iodine, protein, and amino acid tyrosine. Thyroxine (T4), which is relatively inert and tri-iodothyronine (T3), the biologically active hormone are made in an approxiately 90/10 ratio respectively in the thyroid gland. This preserves a steady pool of T4 for eventual conversion to T3 in the bloodstream which is needed for cellular energy activation. The conversion of inactive T4 to active T3 is crucial in the stepward progression of thyroid physiology.

Once T4 to T3 conversion takes place cellular membranes are activated to assist transfer of thyroid hormone into the interior of our cells. Once inside it activate various enzyme pathways to increase energy production and metabolism, protein synthesis and breakdown of fat and carbohydrates, increased tissue oxygenation, mineral exchange within cells, and insulin production. In fact, thyroid hormone activates over 100 enzymes to produce a multitude of bodily functions. This is the main reason that altered thyroid production and/or function has such a broad range of negative effects on people's behavior, moods/emotions, energy level, and physical well-being. In fact, the brain, heart, lungs, intestines, sex glands, muscles, adrenal glands owe much of their function to normal thyroid physiology.

Finally, through blood level sensoring the hypothalamus and pituitary help regulate thyroid hormone production by either increasing or decreasing signal input to the thyroid gland based on the overall needs of the body. In the case of low thyroid the hypothalamus will stimulate the pituitary to secrete TSH, which in turn stimulates the thyroid gland to produce and release thyroid hormones, T4 and T3.

"Reverse" T3 phenomenon

As a normal byproduct of T4 to T3 conversion a chemical called reverse T3 is produced. This hormone, which is an inactive form of T3 has no appreciable biological effects on cellular metabolism. Instead, it should be re-absorbed by the body without causing untold problems. Unfortunately, in excessive amounts this inactive hormone can have a negative feedback effect on the pituitary and hypothalamus leading to reduced production of thyroid hormone. This is important in the context of low thyroid because many abnormal physical stressors can lead to this abnormal production or reverse T3. Increased cortisol, heavy metal and chemical pollutants, nutrient deficiencies such as selenium, and certain drugs such as steroids, and asthma inhalers are all contributors.

Are You Hypothyroid? - Signs and Symptoms

The symptoms of low thyroid are extensive and touch on many aspects of our physical and mental/emotional well-being. It is important to realize that thyroid hormones regulate energy production. Therefore, hormone production and balance, immune function, digestion, biochemical regulation, thought and mood production can all be effected:

• Depression and Anxiety
• Insomnia and Restlessness
• Fatigue and Weakness
• Heart Problems
• Decreased Libido and Sex Hormone Issues
• Weight Problems
• Blood Sugar Imbalances
• Cold Sensitivity, Dry Skin and Brittle Nails
• Infertility and Miscarriages
• Retarded Growth in Children
• Cholesterol Problems
• Immune Dysfunction
• Osteoporosis

Thyroid Testing - The Area of 'Repeated' Misdiagnosis

Before the advent of laboratory testing most doctors used clinical judgement based on the patients history of complaints and physical examination indicators to diagnosis hypothyroidism. Unfortunately, this skill has become all but lost, unless an individual presents with end-stage signs and symptoms of 'classic' hypothyroidism. Even with this many people go undiagnosed. One reason for this is the long held belief that certain laboratory markers are absolutely specific for the evaluation of thyroid function. The main culprit is the TSH (thyrotropin stimulating hormone).

TSH - The normal reference range for TSH is 0.35 to 5.50. Strict adherence to this broad range is used as sole evidence for the existence of normal thyroid function by many health care practitioners despite an individual's physical signs and symptoms. Therefore, a TSH above 5.50 would be indicative of low thyroid function. This rigid interpretation is leading to many undiagnosed cases of thyroid function!

A recent report in the Journal of the American Academy of Endocrinology revealed that the range for TSH may be to broad. That is, numbers approaching the upper range of normal, ie. 4.25 to 5.0 may in fact be developing hypothyroidism. This is a major shift in the field of traditional endocrinology which for years has steered away from non-diagnositic absolutes, specifically with relationship to thyroid disease. Our experience is that TSH numbers above 2.0 (sometimes 1.5) indicate a potential underactivity of thyroid function.

Total T4 and T3 - Often a doctor will obtain a total thyroid (T4 and/or T3) level in addition to a TSH. These tests reveal the total amount of T4 and T3 thyroid hormone in your blood. What is confusing about this measurement is that it does not indicate the actual amount of active thyroid that is needed at the cellular level. This active component is called free T3 and free T4.

After T4 (and some T3) is produced in the thyroid gland it is excreted into the bloodstream attached to a protein molecule. This protein acts as a transport module for the thyroid as it courses through our bodies. Once in the liver and kidneys T4 can be converted to T3. Much of this conversion unlocks the thyroid hormone from the protein carrier and 'frees' it into bloodstream. This unbound hormone is then free to perform its necessary metabolic activity. Total thyroid hormone measurements are important, but unfortunately are often misleading in the diagnosis of hypothyroidism. This is evidenced by a common scenario in which the total T4 and/or T3 is normal, but the free fraction is low.

T3 Uptake and Free Thyroxine Index (FTI) - These are common tests still performed by many laboratories. Our experience is that they are outdated and unreliable gauges of thyroid function, and therefore should be abandoned.

Free T4 and Free T3

These two measurements, along with a highly sensitive TSH are necessary to adequately evaluate thyroid hormone production. Anything less is inadequate. Because of the high reliability of the FT4 and FT3, many alternative-minded clinicians are performing them. However, it is still important to look at these numbers in the context of the patient's history. Many other factors such as elevated cortisol levels, increased melatonin, and environmental factors can impact on thyroid function.

The normal range for FT4 is .70 - 1.53 and FT3 is 2.3 - 4.2. Our experience is that most people should maintain levels in the upper 2/3 of normal. This can be acheived with a variety of thyroid medications, diet, and/or nutritional supplementation.

Thyroid Treatment - The 'Synthroid' Dilemma

For many years pharmaceutical companies have cornered the market in relation to thyroid treatment. The most successful campaign has been that of Knoll pharmaceuticals, the producers of Synthroid. This particular medication has been the mainstay in the treatment of hypothyroidism, with very few other options ever presented by physicians to their patients. People are told that they will have to be on Synthroid for life, and that this is the best treatment for them. Albeit, Synthroid is an easy medication to regulate in its dosage and frequency, but for many people it is not ultimately effective.

One problem with Synthroid, and other similar drugs is that they are synthetic derivatives of T4 only. Usually, T3 is not given to hypothyroid people because of fear of potential side effects such as osteoporosis, irritability, hormone irregularities, etc. The major error in the prescribing of T4 only medications is that the active component of T3 is forgotten. Most doctors assume that the body will make the necessary conversion of T4 to T3 with resulting correction of the hypothyroid state. This is a big mistake!

T4 to T3 - Factors Controlling Conversion

The conversion of T4 to T3 is a crucial step in the process of thyroid function. If this step is deficient or altered in any way the individual will suffer with symptoms of low thyroid. Many factors are involved in this important step in thyroid physiology, and get completely overlooked by narrowed-minded prescribing of T4 only drugs. 80% of T3 is produced outside the thyroid gland. Therefore, what appears clinically to be low thyroid function could actually be occurring for reasons that have nothing to do with the thyroid gland. What is the primary player in this process? The enzyme T4-5 deiodinase. This enzyme cleaves off one iodine molecule from T4 to make T3. Many factors have an effect on this enzyme:

• Certain pharmaceutical drugs such as propylthiouracil, amiodarone, and propanolol all decrease the activity of T4-5 deiodinnase.
  
• Starvation, diabetes, uremia, and other chronic debilitating conditions and diseases.
  
• Nutrient deficiencies, most notably selenium. Also, zinc, glutathione, cobalt, vitamin D and riboflavin deficiencies have been implicated.
  
• High Carbohydrate diets
  
• Stress and the increased cortisol response.
  
• Caloric Restriction

Other Factors of Thyroid Inhibition

Besides the effects on T4 to T3, there are many other factors that inhibit thyroid function:

• Chemical exposure from PCB's, PVC's, DNP's, Red Dye #3, cigarette smoke, and halogenated organic compounds chlorine and flouride.
  
• Heavy Metal exposure such as mercury from fish, water, vaccines, and dental filling contamination.
  
• Certain flavonoids in foods such brussel sprouts, rutabaga, turnips, kahlrabi, cabbage, radishes, cauliflower, kale, and soy products. Miilet has the highest content of antithyroid flavonoids.
  
• Radiation exposure
  
• Neck Trauma/Whiplas
  
• More pharmaceutical drugs such as Lithium, Dilatin, Tegretol, Dopamine, and excess Iodine.

Treatment Options - The Natural and Nutritional Approach

There are many options for the treatment of thyroid problems. Not everyone needs to take the synthetic hormones such as Synthroid and Levoxyl, instead replacement with the natural hormone compound Armour Thyroid can be advantageous.

Armour Thyroid, a compound of porcine thyroid, utilizes both T4 and T3. It is not limited to just replacing the T4 component of thyroid hormone like Synthroid, but helps augment entire thyroid function. At times an individual may develop sensitivities to the porcine compounds, or have a thyroid condition that is too unstable to benefit entirely from amour thyroid. In these cases use of synthetic T4 and T3 may be warranted. However, other nutritional interventions can be employed to assist in proper thyroid function:

• L-Tyrosine - This amino acid is a precursor to thyroid hormone. 500 mg twice daily on empty stomach. Avoid use with milk. B6 and Vitamin C can help absorption.
  
• Iodine - Take in the form of kelp at 2,000 - 3,000 mg daily. Caution: Some people with autoimmune thyroid disease can develop aggravations from taking iodine.
  
• B-Complex Vitamins including B2 and B12. Approximately, 100 mg three times daily is good. Brewer's yeast is an excellent source of natural B-Complex vitamins.
  
• Essential Fatty Acids such as Flax Seed Oil and Cod Liver Oil are essential for thyroid function. One tablespoon per day of each is recommended.
  Increase consumption of molasses, egg yolks, fish, parsley, apricots, dates, and prunes.
  
• Avoid processed and refined foods, including white flour and sugar.
  
• Avoid alcohol, soda and diet drinks.
  
• Increase consumption of fresh, organic produce with a wide variety of fruits, vegetables, vegetable juices and meats if desired.

Herbal Uses:

• Black Cohosh Root - Glandular tonic
  
• Triphala - Ayurvedic herbal glandular tonic
  
• Saw Palmetto - tonic
  
• Siberian Ginseng - Tonic for adrenal and glandular system
  
• Astragalus - Immune support
  
• Fo-ti Root (Ho Shou Wu) - Similar to Siberian ginseng, but slower and broader action.

Basal Body Temperatures (BBT) - Factors Beyond The Thyroid

In the early 1980's Broda Barnes, M.D. wrote a book titled "Hypothyroidism: The Unsuspected Illness." Dr. Barnes attempted to make the public more aware of the use of axillary (armpit) basal body temperature as a sign and symptom of hypothyroidism. It is still in use today by many alternative and complimentary health care practitioners. The premise is simple: If your average axillary basal body temperature is below 97.6 then you are suffering with low thyroid function. The temperature readings need to be average over a 5 day period first thing in the morning before arising. Although the basal body temperature reading is a good way to assess low functioning metabolism, it does not allows indicate a primary thyroid problem. Other factors can impact body temperature leading to false diagnosis of hypothyroidism.

Cortisol, Melatonin, Neurotensin, and The BBT Riddle

Cortisol is an adrenal gland hormone that has many important functions within our bodies. Apart form its role in glucose (blood sugar) control, anti-imflammatory properties, and immune system function, it has an impact on thyroid function, energy production, a body temperature set point. One of the major functions of cortisol is during a stressful event. When our bodies are confronted with stress, the adrenal glands are stimulated to secrete cortisol which is necessary to meet the demands for increase fuel and energy by our muscles and brain cells. In a normal situation, the cortisol levels should drop again after the stressful event to prevent overstimulation of our energy production systems. Unfortunately, this is rarely the case in our modern culture as people are pushed beyond their normal coping mechanisms to deal with stress. For many people elevated cortisol levels become the norm leading to a multitude of problems including depressed immune function, sugar control issues, low thyroid function, and ultimately overtime adrenal fatigue and chronic illness.

Elevated cortisol leads to an inhibition of TSH. This causes reduced signal to the thyroid gland and decreased production of thyroid hormone. It also disrupts the production of Free T3 and increases Revere T3 leading to reduced thyroid function at the cellular level. In relationship to body temperature cortisol is a key factor in setting the core temperature set point. With chronically elevated cortisol levels, especially in the morning the basal body temperature will be low.

Melatonin - This hormone produces from the pineal gland within our brains is intimately involved in sleep and nervous system recovery. Along with cortisol, it is also involved in the core body temperature set point. Melatonin tends to reduce this set point by 50 - 60%. When melatonin is at its peak the core body temperature can drop by one degree. This is especially problematic if too much melatonin is being produced in the morning when basal body temperatures are being taken.

Neurotensin - This chemical is not widely known. It is thought to be a neurotransmitter in the brain that is released when people are under stress. One of its functions is to suppress thyroid at the cellular level. In experimental animals an injection of neurotensin can mimic hypothyroidism.

It is important to realize that basal body temperatures are good way to assess problems with the metabolic state of the body including thyroid function, but can give a false analysis of primary low thyroid function leading to unnecessary thyroid treatment.

Key Points - What You Can Do If You Suspect Hypothyroidism

1. Obtain a thyroid panel that includes a high-sensitive TSH, Free T4 and Free T3.
   
2. If your TSH number is above 1.5 then low thyroid may be an issue. The higher your TSH numbers are to 5.5 the greater the chance your thyroid is underfunctioning.
   
3. Make sure your free T4 and free T3 numbers are in the upper 2/3 of normal range. Always obtain copies of your laboratory results for analysis. If you suffer with chronic debilitating illness such as heart failure or other cardiovascular ailments where elevated thyroid levels may be contraindicated then lower levels may be necessary.
   
4. If you are currently on synthetic T4 (Synthroid or Levoxyl) consider switching to a combination formula (Armour Thyroid) to better supply T4 and T3.
   
5. Increase consumption of thyroid enhancing nutrients (see above)
   
6. Obtain an Adrenal Stress Profile to assess cortisol levels.
   
7. Avoid or reduce consumption of Goitrogenic foods (see above list)
   
8. Work to reduce stress in your life by getting adequate rest, sleep, exercise, and avoiding stimulants such as cigarettes, caffeine, and diet pills.
   

If attempting to change your medication, or you suffer with chronic debilitating illness, always work in conjunction with a friendly, support and open-minded physician to better handle your health care needs.