I hope you find this information on thyroid function as exciting and useful as I have.
In almost 40 years of clinical practice I can’t count the number of times thyroid problems have been at the core of many health issues and went undiagnosed, untreated or under treated. The confusion wasn’t in observing the obvious, but rather in using certain blood tests to evaluate thyroid function and determine the type and dosage of thyroid medication. Unfortunately the medical community and the alternative health community have accepted falsehoods re/ thyroid diagnosis and treatment. This is not intentional but is based on the false assumption that blood levels of thyroid hormones are an accurate indication of thyroid activity in the cells. The key here is “cellular activity” and whether levels in the blood actually tell us what’s going on inside the cell – intracellular. Keep in mind that all the “work” associated with thyroid function occurs inside the cell, not in the blood. Moreover, the only thyroid hormone that is active in the cell is T3 (Free T3). Keep these basics in mind as we look into this in more detail.
Breakthrough: Thyroid Function Accurs in the Cells, Not the Blood
Dr Kent Holtorf, MD recently published an article entitled Thyroid Hormone Transport into Cellular Tissues in the Journal of Restorative Medicine. Dr Holtorf is a thyroid research expert and has 169 (!!) references to his research. He certainly qualifies as a dedicated thyroid researcher. In this article Dr Holtorf builds a very strong case that blood levels of thyroid hormones are often not an accurate way to determine what’s really going on inside the cells. Historically the theory was that thyroid hormones “diffused” from the blood into cells, but this is now known to be inaccurate. What has been established is that there is an active transport system which uptakes T3 into cells. Therefore in many cases blood levels do not actually represent cellular levels. Again, let’s not lose sight of the fact that ALL the work performed by the thyroid occurs in the cells, not in the blood. This concept alone is a huge breakthrough and illustrates how we need to shift our thinking about thyroid diagnosis and treatment. If you have one or more of the many symptoms associated with hypothyroid activity, the symptoms are more important than the hormone levels in your blood. Currently symptoms are basically ignored if blood levels are normal.
How Does One Accurately Assess Cellular/Tissue Activity?
According to Dr Holtorf’s research there are a number of ways to evaluate cellular thyroid function. One approach is to measure blood levels of SHBG (sex hormone binding globulin). SHBG has a direct relationship with T3 & estrogen levels in the liver. If a woman’s SHBG is below 75 nmol/L, or a man is below 25 nmol/L, the likelihood of low thyroid cellular activity is quite high. Another indicator is the ratio of Free T3 to Reverse T3 (inactive T3) in the blood. If the ratio is below 0.2, it is likely that cellular thyroid levels are low.
Lastly, let’s not forget the outstanding work of Dr Broda Barnes who pioneered thyroid testing via waking basal body temperature. After all, THE primary function of cellular thyroid activity is to generate heat and maintain normal body temperature. The technique is simple: immediately upon arising put a thermometer in armpit for 10 minutes (axillary temperature). If between 97.8 and 98.2 then all is well. If below 97.8, and to the extent temperature is lower, the individual is likely hypothyroid. Countless practitioners for over 60 years have had excellent results using Dr Barnes temperature testing.
Treatment is another matter but the above tests are used to titrate dosages – to provide enough medication, nutrition and herbal support to normalize test results and resolve symptoms. One key consideration re/ treatment in Dr Holtorf’s article is the use of a medication that contains T3, either natural desiccated T3 as found in Naturethroid & Armour Thyroid, or synthetic T3 / Liothyronine / Cytomel. The problem with taking only synthetic T4 (Synthroid, Levoxyl, Levothyroxine, etc.) is that it must be converted into active T3 / Free T3 before it can function in the cells. On it’s own, T4, including Free T4, has no activity. In many individuals the conversion of T4 into T3 is fraught with inefficiency and malfunction, which often produces Reverse T3 (rT3), which is inactive. Sadly, so many people with thyroid problems are only taking synthetic T4 and continue to experience hypothyroid symptoms. Those who take synthetic T4 and efficiently convert it into T3 are fortunate indeed, but in my experience the odds of this occurring are less than 50%.
The TSH Fallacy
Another key consideration addressed in Dr Holtorf’s research is the fallacy of using TSH (thyroid stimulating hormone) as a primary means of determining thyroid function. TSH is a pituitary hormone that has regulatory influence on thyroid function — particularly T4, but not T3. It may be a mistake for doctors to assume that if TSH is in range then thyroid hormones are likewise acceptable. This might make sense for T4, which TSH is supposed to regulate, but not for the active hormone — Free T3. Clinical reality has often proven that TSH is irrelevant to T3 and hypothyroid symptoms. Not only is TSH a poor diagnostic tool, it is even more challenging to try to use it to adjust the dose of thyroid medication. As a result, millions of people suffering from hypothyroidism are not diagnosed and millions more are having their doses reduced based on TSH results. Dr Holtorf goes deeper into the biochemistry of why TSH is a poor thyroid test but rather than paraphrase I think it would be best for the reader to refer to his article.
Summary of Key Points
- Thyroid activity occurs in the cells, not the blood.
- Cellular/tissue activity is often not accurately measured in the blood.
- SHGB and the Free T3 / Reverse T3 ratio is perhaps the best way to measure cellular activity using blood tests
- Waking basal temperatures should always be performed because body temperature is the primary function of cellular thyroid activity.
- TSH is not an accurate test and is flawed in numerous ways, both biochemically and clinically.
I would be happy to discuss this with anyone interested in the subject. There are several other considerations discussed in Dr Holtorf’s research that would best be considered on an individual basis. If you wish to set up a consultation, you can begin the process here: