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Lab Lesson: Energy & Metabolism

What is itThe Energy & Metabolism test is a comprehensive assessment of thyroid function.  Not only does it test the Thyroid Stimulating Hormone (TSH), which is the standard test ordered in medical clinics but also Free T4 (actual thyroid hormone produced in the thyroid gland), Free T3 (metabolically active thyroid hormone), Thyroid Peroxidase Antibodies (TPO) which identify an autoimmune response to thyroid function, as well as ferritin (iron storage capability).

What is its function on health? The thyroid gland plays a critical role in metabolism and affects one’s ability to lose weight and fat.  It dictates how each cell in our body converts calories consumed in the diet as well, as those stored in fat cells, into energy.  When the thyroid gland isn’t functioning optimally, energy levels and body weight are affected.  It has been documented that 1 in 10 people have dysfunctional thyroid function [i] with more women than men experiencing this imbalance.  Other potential symptoms of a dysfunctional thyroid include depression, constipation, dry skin and hair, loss of hair, brittle nails, cold hands and feet, and a lower overall body temperature (< 98°).  Decreased iron storage often accompanies suboptimal thyroid function, which impacts the delivery of iron and oxygen to our cells for energy.

Who would benefit from getting it testedAnyone struggling with the above symptoms, significant fatigue, and difficulty losing weight or fat would benefit from testing their thyroid function. 

Reference range on lab report:

Standard Reference Ranges


0.45-4.5 uIU/mL

Free T4

0.82-1.77 ng/dL

Free T3

2.0-4.4 pg/mL


0-34 IU/mL


30-400 ng/mL (male)


13-150 ng/mL (female)



Optimal Reference Ranges


1.3-2.0 uIU/mL

Free T3

3.0-3.26 pg/mL


<20 IU/mL


Impact of being outside the “optimal” rangeWhen lab values are outside of the “optimal” ranges, one feels more tired during the day, has difficulty sleeping at night, and struggles to lose body fat and weight.  If TPO is outside the optimal range, it can reflect thyroid tissue destruction due to an autoimmune response as seen in Hashimotos or Autoimmune Thyroiditis.

“Myths” that surround this lab profile: When thyroid function is tested in a medical clinic, typically only TSH and T4 are checked.  Unfortunately, T3 is not usually tested. T3 is a critical value to know, as it’s the metabolically active hormone that supports energy production. In fact, many health practitioners are finding a surprising number of people have normal TSH and T4  levels but suboptimal T3 levels.[ii]  Another thing to be aware of is what form of T4 and T3 are being tested.  Regular T4 and T3 levels are bound to protein and cannot be converted properly or attach to the cells to produce energy.  Free levels of T4 and T3 need to be tested for a more accurate picture of thyroid hormone production and function.

How diet affects level: Poor digestive health can affect thyroid hormone levels and function.  By consuming a highly processed diet of refined flours, sugars, and pesticides (90% of pesticides are found in our food supply), one can disturb the balance of healthy to unhealthy bacteria or flora in our gut.  This causes inflammation which can make us more allergenic to foods and disturb thyroid function.[iii]  Certain nutrients are required for proper thyroid hormone production – iodine, selenium, and iron.[iv]  Iodine is best acquired from seaweed, kelp, and cod.  Selenium is found in brazil nuts, mushrooms, fish, and liver.  The best absorbable iron is found in animal sources such as liver, grass fed beef, chicken, and turkey.  It’s best to stick with whole, natural foods with ingredients that you can identify and pronounce.  If able, stick with organic options to avoid the hormone, antibiotic, and pesticide/chemical ingredients that disrupt our endocrine balance and function resulting in an inability to lose weight or fat.

How lifestyle affects levelOne of the most common disruptors of optimal thyroid function is stress.  If under chronic stress (whether physical, chemical, nutritional, emotional, environmental), thyroid hormone function can be impacted enough to decrease one’s metabolism by as much as 40%.[v]  This also includes inadequate sleep, which resembles stress in our body’s functioning.  Aim for 7-8 hours of uninterrupted sleep each night and incorporate regular stress management techniques like meditation or yoga.  Environmental toxins also disrupt thyroid function.  Heavy metals, chlorine and fluoride in our water supply and toothpaste, as well as pesticides and chemicals in our food supply, plastics, toiletries, cosmetics, and cleaning supplies all have been found to disrupt metabolism and weight by decreasing our thyroid hormone production and function. [vi]  Opt for organic, fragrance free options of the above items to decrease your exposure to the metabolic-suppressing chemical ingredients.

Supplements to support optimal values

  • AM/PM multivitamin/mineral contains iodine, iron (not in the mens) and selenium for adequate production of thyroid hormones. 
  • ThyroMend ™ provides a great source of iodine (from seaweed) and herbs to help optimize thyroid function.  Safe to use alongside hypothyroid medications.
  • L-Tyrosine is the amino acid that makes up both T4 and T3 and is critical for adequate thyroid hormone production.
  • MultiProbiotic 4000 is a probiotic supplement to enhance the beneficial flora balance in the gut to support optimal thyroid hormone function.

[i] American Thyroid Association. Accessed October 4, 2008.

[ii] Takashima N et al. Characterization of subclinical thyroid dysfunction from cardiovascular and metabolic viewpoints. Circ J. 2007 Feb;71(2):191-5.

[iii] Psaltopoulou T, Ilias I, Toumanidis S, et al. Endogenous subclinical hyperthyroidism: Metabolic and cardiac parameters. Eur J Intern Med. 2007 Sep;18(5):423-9.

[iv] Zaichick VYe, Tsyb AF, Vtyurin BM. Trace elements and thyroid cancer. Analyst. 1995 Mar;120(3):817-21.

[v] Klecha AJ, Barreiro Arcos ML, Frick L, Genaro AM, Cremaschi G. Immune-endocrine interactions in

autoimmune thyroid diseases. Neuroimmunomodulation. 2008;15(1):68-75.

[vi] Pearce EN, Braverman LE. Environmental pollutants and the thyroid. Best Pract Res Clin Endocrinol Metab. 2009 Dec;23(6):801-13. Review.

This article is not intended for the treatment or prevention of disease, nor as a substitute for medical treatment, nor as an alternative to medical advice. Use of recommendations in this and other articles is at the choice and risk of the reader.

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Reader Comments (1)

Nice article!Brilliant post!

December 5, 2011 | Unregistered CommenterNoah Berkowitz

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