Wednesday, 19 November 2014

T4 with four Iodine molecules (I) attached, Remove Top Right to convert to T3

The Science of Thyroid Function - Reverse T3 And All That Jazz

Despite being hypothyroid for 20 years and having a body that makes too little thyroxine, I had never really appreciated exactly how thyroxine works in the body. The thyroid gland makes T4 and T3. T4 has four iodine molecules attached, and is stored in the body ready to be converted to T3 by removing one of those iodine molecules. It is only T3 that works in the cells of the body to produce energy. I did not appreciate that every cell in my body needs thyroxine, more specifically needs T3. I had this general idea that the symptoms I had had 20 years ago which led to me being diagnosed as hypothyroid were produced because my body was having to work harder to make T4 and T3. I did not realise that in fact it is the reduced amount of T3 in the cells that leads to those cells not functioning properly.

This means in effect that if you have a severe shortage of T3 in your cells every part of your body can be affected, that means from your heart, to your liver, your brain, all your organs will struggle to function effectively without the thyroxine they need. It can also affect how your whole adrenal system works, if you don't have enough T3 your adrenal system will also struggle to function effectively, and if your adrenal system is struggling this can also affect how your body is able to use the thyroxine, how your body is able to take up T3 in the cells. When I realised just how fundamental the need for thyroxine and specifically T3 is in the body I began to see how a chronic lack of it would, if nothing else, have a massive impact on my M.E, even raising the possibility that perhaps some problem with my thyroid was at the root of all of my symptoms. Because if all my organs were in some way compromised by lack of T3 then all those organs would struggle to function. Perhaps this is why my heartbeats so slowly and blood has a tendency to pool in my feet, perhaps this is why my adrenals aren't functioning properly and I have a body that can not respond effectively to the slightest stress, perhaps this is why my liver is not processing sugars properly or my insulin is not working consistently, resulting in reactive hypoglycaemia and symptom of sugar crashing Perhaps this would explain why I could only go so far in gradually increasing my exercise before I would reach my limit and my recovery would progress no further.

But how could this be true? How could it be that my body had suddenly stopped being okay on the dose of thyroxine I was on and how could it be that my blood results did not indicate a lack of thyroxine?

Let's deal with the blood results first. When you have your blood tested to see how your thyroid is functioning you have to realise that the reference ranges used by the laboratory to indicate normal, are actually an average or median of all the results that that laboratory gets from the people it tests. Then you have to ask yourself what kind of people have thyroid function tests, perfectly healthy ones, or people who are tired, ill, or have chronic fatigue? Of course the proportion of people who have this test are ill in some way that is why they are being tested. My local laboratory sets its TSH range – TSH is a measure of how hard your body is working to produce thyroxine – at somewhere between 2 and 4, below 2 hyperthyroidism is a possibility and above 4 hypothyroidism is a possibility. However, there is a piece of research which actively recruited healthy individuals, with no known family histories of thyroid problems and tested their TSH levels. Guess what? The average for this group of people was not between 2 and 4 it was just under 1, demonstrating that in fact the optimal level for a healthy individual is to have a TSH level of around 1. If you are on thyroxine and your level comes in at just under 1 it is probable that your doctor would reduce your thyroxine in the belief that you are on so much it is suppressing your thyroid function.

The other part of the equation is how much free T4 and free T3 is in your blood, rarely do doctors test for this as a matter of course, but one can also assume that the levels being seen as normal as set by the laboratory for T4 and T3 are as distorted as the levels set by the laboratory for TSH. By this you can see that you could potentially get thyroid function results which are not optimal but which are considered within the normal range by a doctor. In addition to this, I was on a combination of T4 and T3, taking synthetic T3 is known to suppress your TSH levels, so my levels when tested were always around 0.01, which in itself could have masked what was going on in my body.

The second part of the equation is something called Reverse T3. (RT3) If you imagine four iodine atoms in each corner of the molecule of a molecule of T4, and that in order to convert this to T3 the body takes away one the top right hand side iodine atom, reverse T3 is where the body has taken away, for example, a iodine atom on the bottom right hand side, rendering the molecule unable to be used by the cells of the body to make energy. There is not a great deal of information and research on RT3, the body naturally makes a certain level of T4 into RT3, it is perhaps a checking system whereby the body can ensure that there is not too much active T3. But it is also known that the body produces more RT3 when it is stressed, physically or emotionally or starved, because at these times it is likely that it needs to preserve energy and function in a minimal way. It is possible to have your RT3 measured privately and there are people who have enormous levels of it in their bloodstream and one can only assume that this hinders the body in accessing the active T3. I can only consider that it is possible that the stress to my body caused by three major abdominal operations, not to mention a long history of eating disorders, has produced too much RT3 and thereby blocked my body's access to T3. It is also possible that with a suppressed TSH perhaps my body sensing enough T3 converted the T4 I was taking into reverse T3 in a disproportionate way. There is also the possibility that as a result of the stress to my body that my body no longer converts T4 as well as it used to, or other possibilities are that my body for some reason, again perhaps the stress, no longer finds synthetic T4 agrees with me, my body does not work well with it any more.

This is all very scientific, and admittedly a lot of hypothesis on my part, not to mention that not many endocrinologists let alone GPs have the faintest idea about RT3, and if they do, do not accept that there may be times when the body no longer works the way they understand it does. Because as with M.E there is very little research in the UK taking place in order to further understanding of these issues. However I have come across many, many people who were diagnosed with M.E only to find that when they took thyroxine, or changed to natural desiccated thyroxine (NDT), or even in extreme cases have taken only T3 in large enough amounts, that they have made a full recovery from their diagnosis of M.E.

It seems to me logical to deduct that if people have experienced a dramatic improvement in their health as a result of changing their thyroid medication that something complicated and little understood is going on with these people's thyroid function. However, a well-known endocrinologist has stated that his research shows there is no improvement in people's symptoms if they take NDT for example, and therefore if people do improve on NDT it is evidence that their condition is psychosomatic. It seems to me an outrageous manipulation of science to draw such a conclusion without any actual psychological or physiological evidence to back it up. To my mind the natural conclusion is not that the people who get better must to all intents and purposes be mad, but that there is something unknown, undiscovered and misunderstood about these people's health conditions.

I have tried to explain to you why you can have a so called normal thyroid function test and yet have a thyroid system that is not functioning normally, and also how reverse T3 may be an invisible influence on a persons thyroid function, but I am not claiming that all M.E, or even my M.E, is caused by abnormal thyroid function. In my next post I will tell you how I have been trying to address the possibility that my thyroid is at the root of my condition.

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