It’s Thyroid Health Month: What is a “normal” thyroid function?

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By Leigh Lewis ND L.Ac. Naturopathic Doctor

Most patients have had thyroid function testing prior to seeking assistance at ilumina, whether it is for fertility issues, difficulty losing weight, mood and energy issues or simply as part of a general check up.  However, there is much confusion amongst health care providers and patients regarding what constitutes normal function tests. In fact, recent research suggests that patients can be experiencing significant symptoms such as those mentioned above even when the results are normal and may be able to safely take and benefit from thyroid replacement. This is why we often request patients bring in their results or get new testing even if they have been told that all their thyroid testing is within normal range.

The thyroid can be through of as the gas pedal to many bodily functions.  It’s hormones increase heart rate, bone turn-over, basal metabolic rate, cognition, digestion, reproductive function, etc.  When there are not enough thyroid hormones, these processes slow down and when there is too much, they speed up.  The tricky thing is, two individuals can have the same thyroid hormone levels and one feels great and the other feels terrible.  Individual biochemistry dictates these differences and our current lab testing is based on pooled population data, therefore, often missing individual nuances.

A quick explanation on thyroid function testing:

Typically we here at ilumina recommend the following tests:

  • TSH – thyroid stimulating hormone:
    • This is a hormone produced by the brain to stimulate the thyroid to produce its own hormones such that when thyroid hormones levels are low, TSH levels rise and when thyroid hormones levels are high, TSH levels drop.
  • Free T3 and T4 – triiodothyronine and thyroxine
    • These hormones are produced by the thyroid, T4 is viewed as a precursor to T3, which is more biologically active and potent, T4 is converted to T3 via an enzymatic reaction…some people have difficulty making this conversion, necessitating a combination of T3 + T4 for replacement.
  • Thyroid antibodies:
    • These immune cells represent a common cause of thyroid disease; produced by the body, they attack specific mechanisms in the production and function of the thyroid hormones such that activity is either increased (autoimmune hyperthyroidism) or decreased (autoimmune hypothyroidism).  Research suggests that the presence of these antibodies may explain symptoms of thyroid disease despite normal thyroid function tests.

There are several other thyroid tests that may be done other practitioners, but in practice it is our experience these do not lend much more information.

Confused? You should be.

Basically, it is important to remember that, while your thyroid function testing may be within the normal range, it doesn’t mean you would not benefit from a trial of thyroid replacement.  Some patients, like those with mood, weight and energy issues, will be monitoring symptoms to see if the replacement has a positive impact, others, like those with fertility issues, may not notice a day to day improvement in any symptoms, but the hope is that time to conception & risk of miscarriage will decrease.  Replacement can be done safely in those with initially normal labs because repeat labs will  detect over medication or if the dose needs to be increased. If thyroid antibodies are positive, anti-inflammatory supplement and diet measures may be helpful.

Thyroid function affects nearly all of our physical, psychological, and mental processes either directly or indirectly; talk to us today to review yours for a healthier tomorrow.