Health, Thyroid and TSH. Assessing and treating the thyroid.
What is the impact of thyroid hormone on health?Increasingly health is defined by a bunch of arbitrary numbers. High cholesterol? That’s not normal take a pill. Low iron? Here take this iron supplement. In Ivan Illich’s book, Limits to Medicine- Medical Nemesis, Illich makes the reader fully aware of his disdain of medical check ups - " The medicalisation of prevention thus becomes another major symptom of social iatrogenesis. It tends to transform personal responsibility for my future into my management by some agency."
Instead of heavily reliant systems on numbers and markers. Should we not look to improve qualitative and quantitative pairings to get a better picture of health and improve outcomes? The last ten weeks of my life have been wrapped up in a post graduate diploma in endocrinology. Getting a better picture of how clinicians tackle complex areas has been a rewarding but at the same time frustrating area of study.
Sometimes the questioning has been a down the lines of - This patient has this endocrine feature, what are the medication used, which medications interfere, what surgical options can be pursued and what is the follow up? What is frustrating for me is there is little effort to understand why? Why? Why Donald why? Diet, stress and environmental aspects of hormonal health are often forgotten about, because the goal of getting that client back into the window of numerical health takes priority. But what if we took a better look at the why? Might it not yield better long-term outcomes for the patient?
I have a special interest in thyroid function, motivated by the writings of Ray Peat, Broda Barnes, Mark Starr and others. There’s a significant amount of work discrediting the role of combined T4/T3 therapy and in particular natural desiccated thyroid (NDT). In many endocrine textbooks the elevation of the active form of thyroid hormone, T3 was elevated significantly post NDT treatment.
A confounding factor in this assumption was based upon a previously incorrect conversion which can still be found in endocrine textbooks stating that 1mg of NDT was equivalent to 1ug of LT-4. There is recent evidence available showing a patient preference for NDT, which showed improved outcomes to weight loss, energy, happiness, sleep and memory (Hoang, Olsen, Mai, Clyde, & Shakir, 2013).
A reliance on TSH, T3 and T4 levels alone may be ineffective at analysing the effectiveness of combination therapy in comparison to synthetic monotherapy treatment of hypothyroidism. Additionally this study highlights the inaccuracy of the assumed conversion of 1mg: 1ug. Using more accurate 3rd generation TSH assays yields a suggested ratio of 1.47 mg’s to 1ug. This may explain the lack of effectiveness in previously conducted trials and the conclusion that increased transient T3 levels were decided as unacceptable. NDT in many cases may offer a better solution than synthetic thyroid hormone after all
Potential mechanisms of improvement may also lie in the actions of T1 and T2 and assumptions based solely on TSH, T3 and T4 may not explain the benefits recorded in this and other studies.
Another pitfall of number reliance is well known in the reference of thyroid stimulating hormone (TSH). TSH is considered the gold standard for hypothyroid diagnosis but its limitations have become increasingly prevalent due to its production via the stimulating centers from TRH (thyroid releasing hormone) from the hypothalamus and then TSH from the pituitary, if a problem exists at the periphery the likelihood of getting an accurate assessment is diminished. A normal TSH reading is defined as 0.4-4.5 mU/L but generally many Doctors do not consider someone hypothyroid unless they present with a TSH over 4 mU/L.
Increasingly some Doctors are becoming aware of the reduction of hypothyroid symptoms when TSH is kept below 1mU/L and some evidence suggests that even at 0.5 mU/L (lowered but suppressed) is ideal to ensure that hypothyroid symptoms are decreased (Pantalone & Nasr, 2010).
Me? I am going to go back and contradict myself and say that numbers are useful. The basal temperature test with a cheap thermometer, as championed by Broda Barnes still suggests a good window of function of the thyroid test. 36.5 to 37 degrees is considered normal and reflects a well functioning metabolism. Couple that with a pulse rate test and you can also get a good indication of cortisol. So I am not against the numbers. I just think we need to ask better questions before we accept them as absolutes.
References:
Hoang, T. D., Olsen, C. H., Mai, V. Q., Clyde, P. W., & Shakir, M. K. M. (2013). Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: A randomized, double-blind, crossover study. Journal of Clinical Endocrinology and Metabolism, 98(5), 1982–1990. http://doi.org/10.1210/jc.2012-4107
Illich, I. Limits to Medicine - Medical Nemesis. Marion Boyars. 1976.
Pantalone, K. M., & Nasr, C. (2010). Approach to a low tsh level: Patience is a virtue. Cleveland Clinic Journal of Medicine. http://doi.org/10.3949/ccjm.77a.10056