Excess Vitamin A Tanks Thyroid Function

[youngsinatra]

There are very interesting studies on the relationship between vitamin A and thyroid function.

This study fascinates me the most:

https://link.springer.com/content/pdf/10.1007/s00394-022-02945-5.pdf

I plan on posting more studies on vitamin A & thyroid function here.

(I know the HED is very high tho on the highest dose, but even at the lowest dose, there is significant alterations to TSH, T3)

 

[gabys225]

I think this explains why some of us feel nothing from thyroid supps, even pure T3.

 

[AinmAnseo]

Sinatra,
What is "the lowest dose"?
I can't tell that from the chart, or the study itself.

 

[youngsinatra]

Sinatra,
What is "the lowest dose"?
I can't tell that from the chart, or the study itself.

0.7mg/kg was the lowest dose. The chart tells it.

HED 0.05 mg/kg of retinol.

1mg = 3333 IU retinol (if I remember correctly)

 

[Ras]

Rats.

 

[AinmAnseo]

0.7mg/kg was the lowest dose. The chart tells it.

HED 0.05 mg/kg of retinol.

1mg = 3333 IU retinol (if I remember correctly)

So, for a 200 lbs man, that translates into about 5 mg of retinol, or 3333 IU x 5, daily?

Do I have that right?

 

[lamassu]

This is a good evidence based post

 

[FitnessMike]

ray peat right again?

 

[youngsinatra]

Effects of a large dose of retinol or retinoic acid on the thyroid hormones in the rat - PubMed

The daily food intake of a large dose of retinol (as palmitate) or retinoic acid (as all-trans retinoic acid) modifies numerous parameters of the thyroidal status in the rat. There were decreases of the serum total thyroxine (TT4) and triiodothyronine (TT3), and of the biological half-life of...

pubmed.ncbi.nlm.nih.gov

 

[youngsinatra]

„Thyroid gland is unique among vertebrate endocrine glands is that it stores its secretory products i.e. thyroid hormone. The thyroid influence reproduction, growth and differentiation. Retinol Palmitate (RP) is known for its effects on differentiation and morphogenesis during vertebrate development, as it is important for reproduction development and growth, hyper and hypo-vitaminosis- A both provoke epithelial pathologies in animal and human being. So a critical value of RP is required in vivo for the maintenance of normal architecture and function of many body tissues Thyroid gland is unique among vertebrate endocrine glands is that it stores its secretory products i.e. thyroid hormone. The thyroid influence reproduction, growth and differentiation. The group of adult mouse was treated 4 IU/ day concentration of RP by intubations for 7 days. This constituted the treated group. A similar number of mice were considered as controlled group, and were not given any RP treatment. The animal were observed for their growth, behaviour and weight, during the period of treatment 1.On 8th day of the serum thyroxin level analysis was done to both treated as well as controlled mice. In treated case hypothyroidism was seen. 2.The studies concluded that RP (retinyl palmitate) treatment results in a reduced activity of thyroid follicles i.e. reduced synthesis of thyroxin.“

View of Hypervitaminosis-A, Causes Hypothyroidism in Mouse

www.internationaljournalcorner.com

 

[youngsinatra]

Hypervitaminosis A; report of a case in an adult - PubMed

Hypervitaminosis A; report of a case in an adult

pubmed.ncbi.nlm.nih.gov

 

[charlie]

The is relevant:

Low Toxin Studies - "Many claim that natural & "synthetic" forms of vitamin A (vA) are different...They are quite wrong"

View: https://x.com/NutriDetect/status/1518648405748326400?s=20

raypeatforum.com

 

[peter88]

What happens when you don’t take thyroid for a couple days? Cold hands?

 

[youngsinatra]

What happens when you don’t take thyroid for a couple days? Cold hands?

Yes, hypo symptoms quickly come back.