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Low T3 syndrome caused by energy restriction

pattismith

Senior Member
Messages
3,932
Energy Restriction and Starvation

Early reports that serum concentrations of T3 are reduced in states of low caloric intake (47, 49) gave rise to the concept of what we now call the Low-T3 syndrome.

Reduced T3 concentrations have been described in various conditions associated with energy deprivation, including anorexia nervosa (183185), calorie-free diet in obesity (47), military combat training with caloric restrictions (186, 187) and other energy-deficient situations (188).
Even moderate weight loss may result in hypodeiodination with consecutive decreased T3 concentrations (189). Today, at least three mechanisms explaining this finding are known (Figure 6) (23).

In the fed state, peripheral step-up deiodination is stimulated by insulin (119) and bile acids (190192).

In addition, increased leptin concentrations facilitate release of TRH and TSH via the hypothalamic melanocortin pathway (23, 83, 146, 193).

Together, these different mechanisms enhance conversion of T4 to T3, thus mediating postprandial thermogenesis.

Conversely, in fasting conditions concentrations of insulin, bile acids, and leptin are low, which results in decreased step-up deiodination and thyrotropic adaptation, and eventually in low-T3 syndrome.

Additional mechanisms leading to impaired TSH release include increased expression of neuromedin B, a bombesin-related peptide, which is an inhibitor of TSH secretion, and upregulation of hypothalamic D2 expression during fasting (23), resulting in low TRH expression in the PVN (25, 95, 98, 194).

https://www.frontiersin.org/articles/10.3389/fendo.2017.00163/full#F5
 

pattismith

Senior Member
Messages
3,932
Here a table of what happens:

Needless to say that polymorphism in DIO1 will worsen these phenomenons, and that any drugs (ATBX) or toxic exposure (organochlorides and organophosphates for exemple) that affect deiodinases in this way will worsen or even cause this syndrome



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Messages
366
This series on the thyroid you are posting is really interesting!:thumbsup::lol:

I get very few symptoms of high lactate, but I have some signs of thyroid dysfunction in my tests and inactive hashimoto.
I really think thyroid dysfunction is a main issue that reduces my energy production.
Or as it seems that is reduced by my low energy levels, also. I was always wondering what could cause the thyroid dysfunction.
Since TRH production is stimulated by the hypothalamus, adrenal problems might also connect with this issue (?).

I think I have pretty bad fatty acid oxidation, I read that the thyroid supports carnitine and fatty acid breakdown.
Also, the thyroid activates vitamin B2 and I had a big effect from vitamin B2 supplements.
 

pattismith

Senior Member
Messages
3,932
This series on the thyroid you are posting is really interesting!:thumbsup::lol:

I get very few symptoms of high lactate, but I have some signs of thyroid dysfunction in my tests and inactive hashimoto.
I really think thyroid dysfunction is a main issue that reduces my energy production.
Or as it seems that is reduced by my low energy levels, also. I was always wondering what could cause the thyroid dysfunction.
Since TRH production is stimulated by the hypothalamus, adrenal problems might also connect with this issue (?).

I think I have pretty bad fatty acid oxidation, I read that the thyroid supports carnitine and fatty acid breakdown.
Also, the thyroid activates vitamin B2 and I had a big effect from vitamin B2 supplements.

Thank you pinkpanda, I am currently reading a lot on thyroid (as you noticed:lol:), and I am convinced I need to share informations with PR members as Thyroid is really important for ME patients (Adrenal as well of course, but I would put thyroid first).

A subset of ME patients may have primary undiagnosed thyroid dysfunction,
but problems in the metabolism of the thyroid hormons may exist for the other as well...

If B2 gives you a big effect, it means to me that your thyroid hormons are not so bad,
I couldn't see any effect from taking B2 myself!
 

Sundancer

Senior Member
Messages
569
Location
Holland
Thanks a lot @pattismith , I will for sure look into this ( but not today) this is just the information I need.

next week I'll get a nurse here to take some blood to look for antibodies thyroid ( TSI) I sure hope that's not the case but very happy with my new GP who believes I'm ill and does some testing. ( and sends nurses over zo that I do not need to leave my house, grateful!! no PEM for getting a test)

Your posts give some Ideas about what else can have gone awry in the last years ( and maybe how to help the body get out of it)

@PinkPanda, what effect did B2 have on you?
I need to change my Bcomplex because my B6 is way to high, so decided to take the several B's apart ( even more caps to take...) but gives me good possibility to vary with amount of the different B's.
 
Messages
366
@Sundancer
B2 helped me with histamine symptoms, fatigue after meals and general mood. Also had an overall good effect on my body, like relaxing muscles. I always had problems with the muscles in the back of my neck and B2 really helped relax them.

I have the experience that it can induce anxiety though. It is a cofactor for breaking down serotonin and converting choline to betaine, maybe that's why anxiety can worsen. I tolerate low-dose riboflavin best (5-10mg)
 

sb4

Senior Member
Messages
1,654
Location
United Kingdom
I too am recently getting interested in the thyroid. I recently had a vitamin B2 test (glutathione reductase activity) which came up as deficient in B2. I have yet to add B2 as I am consuming nutritional yeast.

So if I understand this correct, I could have low B2 because thyroid is needed to "activate" it and so my thyroid being low could be a route cause?
 

pattismith

Senior Member
Messages
3,932
I too am recently getting interested in the thyroid. I recently had a vitamin B2 test (glutathione reductase activity) which came up as deficient in B2. I have yet to add B2 as I am consuming nutritional yeast.

So if I understand this correct, I could have low B2 because thyroid is needed to "activate" it and so my thyroid being low could be a route cause?

If your Glutathione reductase activity is reduced, it means that either you have a true Riboflavine deficiency, or the second possibility is that you have enough Riboflavine, but it's conversion to FMN and FAD is weak because of a lack of Thyroid hormons.

https://www.ncbi.nlm.nih.gov/pubmed/3809170