This is kind of an addition to the previously posted question "Is lowered T3 resulting from a low carb diet problematic?" http://paleohacks.com/questions/78343/is-lowered-t3-resulting-from-a-low-carb-diet-problematic
first up, i am not an expert in any of this & do not have an answer myself.
The question below is probably aimed more at the people who's view is NO to the "Is lowered T3 resulting from a low carb diet problematic?". Because i am presuming that following on from that premise they are best positioned to answer my question. But answers (& comments) from everyone welcome of course.
My question relates to "Syndromes" which exhibit (or may exhibit), normal lab ranges for: TSH, T3 (&/or fT3), T4 (&/or fT4) and Thyroid antibodies, But an above lab range level for: Reverse T3 (rT3).
My Assumption (please correct or clarify this assumption if needed in your answers) is that there are two such syndromes;
1. 'Euthyroid Sick Syndrome' (ESS) &
2. 'Wilson's ??????? Syndrome'. With Wilson's Syndrome, i am not sure if there is one or more of these as i have seen multiple names, ie. where ??????? = 'Thyroid' or 'Temperature' or 'Reverse T3 Dominance'.
So let me see if i can word this correctly, my question;
Is having a high rT3 & potentially being labelled with one of these Syndromes anything to worry about when on a low carb diet ie. are you really "ill" or "sick", should you be concerned & attempt to lower the rT3 down to normal lab ranges?
& Another assumption for this is that the HPT axis is disease free ie. no radiation poisoning/exposure, no cancers, no tumours etc.
Edit: for those interested, i just posted some related info here; http://paleohacks.com/questions/74704/reverse-t3-ratio-and-half-life/81363#81363
on the half life of rT3 & also the diurnal rhythm of thyroid hormones
asked bydaz (4493)
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on December 05, 2011
at 03:26 AM
I found this comment by Dr. John C. Lowe on rT3 and related 'syndromes' in an interview with Dr. John C. Lowe here; http://toopoopedtoparticipate.com/blog/dr-john-c-lowe-speaks/
In my opinion, the reverse T3 has served us best in diagnosing a condition that has a variety of names: ???euthyroid sick syndrome,??? ???low T3 syndrome,??? and ???non-thyroidal illness syndrome.??? The word ???euthyroid,??? of course, means that the person has in-range TSH, T4, and T3 levels. In this condition, the hypothalamus secretes less TRH, the pituitary secretes less TSH, and less thyroid hormone is transported into cells. Also, the enzyme called ???5-prime deiodinase,??? which converts T4 to T3, becomes far less active. Another enzyme, ???5 deiodinase??? (no ???prime??? as a modifier) becomes more active and converts more T4 to reverse T3.
The words ???sick syndrome??? is somewhat misleading. That term is used presumably because the condition was first identified in sick people, such as anorexics and hospitalized patients in critical condition. Studies showed that the patients had steeply raised cortisol levels. It???s their high cortisol levels that inhibit the enzyme (5-prime deiodinase) that converts T4 to T3.
I???ve found no evidence that this condition becomes chronic, as Dr. Dennis Wilson proposed. Instead, the research literature shows that within a week or two, TSH secretion increases and 5-prime deiodinase escapes the inhibition by cortisol. This happens even though the person???s cortisol levels remain high. For example, if the person undergoes prolonged treatment with prednisone, within a week or two, the TSH level returns to its previous level and 5-prime deiodinase becomes normally active again.
Old studies show that on average, most people convert more than 50% of their T4 to reverse T3; correspondingly, they convert less than 50% of T4 to the metabolically active hormone T3. And the levels of reverse T3 fluctuate up and down through the day. Because of this, I???m never confident of coming to a conclusion that someone has a problem with high reverse T3, not unless the person has had multiple measures of the reverse T3 over a 24-hour period. Like the TSH, free T4, free T3, reverse T3 levels vary dramatically every 30 minutes or so. Depending on when a person???s blood is drawn or saliva taken. Sometimes the levels will vary enough so that a clinician will give the patient a different diagnosis from the one that he or she would have given 30-minutes before or after the blood or saliva sample was taken.
So blood levels vary rapidly. Because of this, I don???t believe the reverse T3 or the other lab tests in general are very useful. However, I do believe the reverse T3 is useful under one circumstance: when we have enough measures to get averages over time, and when the levels are regularly way out of range. So, in my view, the reverse T3 can be useful, but I think its usefulness is limited, which is true of the TSH and other thyroid hormone levels.hormone levels.
on November 28, 2011
at 08:35 PM
Are you having any adverse symptoms? How do you feel?
Once I had lost about all the weight I was going to lose on a VLC diet, I began having symptoms such as cold extremities and sluggishness. I attributed this to inappropriately low thyroid function (once I didn't have much fat left to burn, my body decided to slow down its engines rather than consume muscle tissue). The unwelcome symptoms went away surpisingly quickly once I added in about 50g of starches a day. I didn't get tested, but I bet I had higher rT3 during this period. (BTW, this n=1 experience inclines me to the Jaminet camp in the current Jaminet/Rosedale debate.)
If you feel good on your current diet, I wouldn't worry about it, especially since the other indicators you cite are all normal (including free T3). If you're feeling off, try upping the carbs a little bit.
on August 28, 2012
at 03:37 PM
My experience was similar, 5'9" and went from 180 lbs to 145 lbs (partly to see how far I could push it) on LC to VLC. Had some hypothyroid symptoms (cold sensitivity, hard stools) but never made the connection that they only emerged after all the weight was off.
I only knew I didn't want to get tested for thyroid function, figured if I ate my way in, I could eat my way out (no history of thyroid problems).
Have been loose lately, back up to 165 lbs with some poor eating. Still trying to find the right balance between training/calories to perform well at "true weight" which I suspect is somewhere between 155 - 160.