Away from extremes vitamin A has positive functions ^ :The present findings expand our understanding of the action of retinoids by elucidating the events in which retinoid signaling up-regulates steroid biosynthesis in gonadal, adrenocortical, glial and epidermal cells, namely by increasing StAR expression, and that retinoids can reverse the decline in steroid biosynthesis in aged epidermal keratinocytes through this same mechanism.
Cholesterol, longevity, intelligence, and health (Ray peat, as in ray peat forum if you focus your eyes on the website name, pretty cool guy!)
Thyroid hormone and vitamin A are used in the process of converting cholesterol into pregnenolone, the immediate precursor of progesterone and DHEA. Anything that interfered with these processes would be disastrous for the organism. The supply of cholesterol, thyroid and vitamin A must always be adequate for the production of steroid hormones and bile salts. When stress suppresses thyroid activity, increased cholesterol probably compensates to some extent by permitting more progesterone to be synthesized. https://raypeat.com/articles/articles/cholesterol-longevity.shtml
retinoic acid treated adipose tissue= higher metabolic rate / more oxygen consumption (woah!)
Retinoic acid induces white adipose tissue browning by increasing adipose vascularity and inducing beige adipogenesis of PDGFRα+ adipose progenitors - Cell Discovery
& https://www.sciencedirect.com/science/article/pii/S0022227520317223
+ has a role in thyroid t3 receptor expression, (huh?)
[T3 receptor mRNA % went from 7.96 -> 5.55 in vit A deficient group]
thyroid & vit a RAR receptor have a connection. t3 hormone increases RAR expression.]
+ vitamin A is also 1 key part of immunity -> Retinol Depletion in Severe COVID-19, ( hmmmmmm )
Retinol Depletion in Severe COVID-19
+ Low vitamin A levels in autism, autism symptoms improve when vit A is added
BUT , at the other extreme vs depletion vitamin A overload is not good either.
there it inhibits thyroid action instead, has been used to treat hyperthyroidism. and can also throw off vit D balance too shown in bone studies when ratio is off,
e.g
USE OF MASSIVE DOSES OF VITAMIN A IN THE TREATMENT OF HYPERTHYROIDISM & feeding high amounts to rats reduces metabolic rate -20%.
- some studies show high intakes ~12,000iu human equivalent daily lowered total t3, but fT3 increased as a percentage to adjust
So, there's a middle balance outside of a mindset of extremes either end
((forum collapses))
see ya!
View: https://www.youtube.com/watch?v=Z6dqIYKIBSU
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