New Insights on Thyroid Function and Human Intelligence

A new study indicates that the cerebellum region of your brain¹ plays a far more important role in preventing cognitive decline than previously thought.  In my effort to connect the dots for everyone, this means that proper signaling for the production of thyroid hormone now plays an essential role in preserving your mind.

We generally think of our higher-level intelligence being based on the function of the cortex regions of our brains, which are obviously quite important. However, in a new brain imaging study of 228 Scottish people ages 63-65, the researchers found that the size of the cerebellum predicted general intelligence. This is quite interesting, as you can consider the cerebellum to be a key part of the foundation for cortex functioning.

“General intelligence is correlated with many basic aspects of information processing efficiency, which I believe depend upon the functioning of the cerebellum, including the speed and consistency of our perceptions and decisions, and the speed with which we learn new skills,” notes Dr. Michael Hogan, first author of the study. “This is exciting research, as it suggests that there may be a backdoor route into maintaining higher cortical functions in old age, through the sustained activation of cerebellar networks via novel sensory-motor and cognitive activities, all of which I believe the cerebellum seeks to regulate and automate, working in concert with the cortex.”

When your brain decides to make thyroid hormone, it first produces a message in your hypothalamus gland called TRH (thyroid releasing hormone) which then travels to your pituitary gland to activate the production of TSH (thyroid stimulating hormone as measured on lab tests).  THS travels through the blood to the thyroid gland, which is why it can be measured on a lab test. TRH is not easily measured and so not available on common blood work.

It is important because we know that TRH is doing many other things at the same time it is stimulating TSH production.  For one thing, it is vital to the function of the cerebellum, where it activates multiple genes. Thus, it is now recognized that clumsiness, which is a cerebellum problem, is a symptom of poor thyroid function via the lack of TRH activation.

We also know that TRH signaling goes on all over the brain, turning on multiple aspects of metabolism that have nothing to do with the TSH, T3, T4 levels, and have everything to do with properly activating multiple energetic pathways in the brain, which are then signaled into the body. That gives a person better energy and a lack of what has become known as hypothyroid symptoms.

TRH can be disrupted by many factors ranging from stress to toxins. Importantly, TRH is suppressed by taking thyroid hormone. That is because the brain senses higher circulating levels of thyroid hormone and so decides not to make any by not making TRH and thus not making TSH.  This problem will show up as low scores of TSH or low normal scores of TSH, which means TRH has been turned down significantly. This will have adverse effects on brain function, coordination, and metabolism.

I make this point in part because many alternative doctors think it is OK to give anyone thyroid hormone to the point their body temperature rises. Invariably TSH is suppressed, which they don’t seem to care about. The new science says this approach to helping thyroid problems is foolhardy.  Anyone taking thyroid hormone should not have a TSH score below the middle of the normal range (work with your doctor, I’m giving you info, not medical advice).  Figure out a different way to fix your metabolism if you still have symptoms and low body temperature. Your future brain health depends on it.