Low Toxin Diet Essentiality of Vitamin A

[GorillaHead]

You have posted a summary of the mainstream position on "Vitamin A".

Genereux has refuted this by living without vitamin A for almost 10 years now and not losing his eyesight. If there's only one black swan, the claim that "All swans are white" is debunked. If there's only one person who can go without vitamin A, the claim that vitamin A is essential for humans is debunked.

The argument that sometimes comes up - he still eats miniscule amounts of retinol and therefore that small amount goes to the eyes to save him - is ridiculous. That would mean that something like 10mcg of retinol per day would be enough, which is basically the same as saying it's not essential.

Whether few molecules of retinol are actually essential is a matter that is independent from the toxicity epidemic. Lowering retinol as much as possible is still the answer for most people, even if extremely small amounts are necessary. The liver stores need to be emptied.

Something that is as toxic as retinol is likely not essential, it's just a toxin, no matter the dose.



Carnivores have a higher ratio of hepatic stellate cells to hepatocytes. The stellate cells store retinol. the hepatocytes are the normal liver cells that are responsible for the usual processes in the liver. That doesn't mean they thrive on retinol, it just means they can get away with eating other animals.

Carnivores are also able to excrete retinyl esters through the urine, something humans can't do. This means that carnivores detoxify the dangerous unbound form of retinol conveniently via urine, while in humans elevated free retinyl esters are very dangerous and can build up easily.

These differences between carnivores and humans is the primary reason lions can get away with eating liver. This also shows that humans were never designed to eat high A foods like liver, otherwise we would be able to excrete retinol via urine.

He could have stores in his liver tho for that entire time. How do we know genereux is actually retinol deficient?

 

[Peater]

Carnivores have a higher ratio of hepatic stellate cells to hepatocytes. The stellate cells store retinol. the hepatocytes are the normal liver cells that are responsible for the usual processes in the liver. That doesn't mean they thrive on retinol, it just means they can get away with eating other animals.

Carnivores are also able to excrete retinyl esters through the urine, something humans can't do. This means that carnivores detoxify the dangerous unbound form of retinol conveniently via urine, while in humans elevated free retinyl esters are very dangerous and can build up easily.

This should have been one of those forum header banner things. That's a very simple and plausible hypothesis.

 

[GorillaHead]

 

[mosaic01]

This should have been one of those forum header banner things. That's a very simple and plausible hypothesis.

Here is one of the sources talking about it:

"It is of note that, in addition to potential biliary excretion, carnivores such as dogs and cats have a unique ability to eliminate excess vitamin A from their bodies through urine, specifically in the form of protein-bound vitamin A and retinyl esters [67]."

Pet Wellness and Vitamin A: A Narrative Overview

The health of companion animals, particularly dogs and cats, is significantly influenced by nutrition, with vitamins playing a crucial role. Vitamin A, in particular, is indispensable, with diverse roles ranging from vision to immune modulation and reproduction. Despite its importance, the...

www.mdpi.com

 

[Jabuger]

Here is one of the sources talking about it:

"It is of note that, in addition to potential biliary excretion, carnivores such as dogs and cats have a unique ability to eliminate excess vitamin A from their bodies through urine, specifically in the form of protein-bound vitamin A and retinyl esters [67]."

Pet Wellness and Vitamin A: A Narrative Overview

The health of companion animals, particularly dogs and cats, is significantly influenced by nutrition, with vitamins playing a crucial role. Vitamin A, in particular, is indispensable, with diverse roles ranging from vision to immune modulation and reproduction. Despite its importance, the...

www.mdpi.com

Seems we would too if it weren’t for TTR

Retinol Binding Protein and Its Interaction with Transthyretin - Madame Curie Bioscience Database - NCBI Bookshelf

“Whether vitamin A is to be ultimately utilized as retinoic acid, 11-cis-retinal or another retinoid, RBP delivers only all-trans-retinol, and only retinol can trigger secretion of RBP.4 In the plasma, RBP binds to the larger protein, transthyretin (TTR, previously referred to as thyroxine binding prealbumin). The binding of RBP to TTR was suggested to prevent extensive loss of the low molecular weight RBP through glomerular filtration .3 This hypothesis was supported by the much later experiments of Blaner and colleagues with TTR “knockout” mice that demonstrate that RBP is rapidly clearly from the plasma in TTR deficient mice.11 In vitro one tetramer of TTR can bind two molecules of retinol binding protein. However, the concentration of RBP in the plasma is limiting and as a consequence the complex isolated from serum is composed of TTR and RBP in a one to one stoichiometry with a resultant molecular mass of about 80000 Da.”

 

[mosaic01]

“Whether vitamin A is to be ultimately utilized as retinoic acid, 11-cis-retinal or another retinoid, RBP delivers only all-trans-retinol, and only retinol can trigger secretion of RBP.4 In the plasma, RBP binds to the larger protein, transthyretin (TTR, previously referred to as thyroxine binding prealbumin). The binding of RBP to TTR was suggested to prevent extensive loss of the low molecular weight RBP through glomerular filtration .3 This hypothesis was supported by the much later experiments of Blaner and colleagues with TTR “knockout” mice that demonstrate that RBP is rapidly clearly from the plasma in TTR deficient mice.11 In vitro one tetramer of TTR can bind two molecules of retinol binding protein. However, the concentration of RBP in the plasma is limiting and as a consequence the complex isolated from serum is composed of TTR and RBP in a one to one stoichiometry with a resultant molecular mass of about 80000 Da.”

Looking further into this, it seems in carnivores, retinol is not primarily bound to RBP.

"The retinol–RBP complex is secreted into circulation bound to transthyretin for delivery to peripheral tissues (3). However, dogs and other carnivores do transport VA in blood plasma not only as retinol bound to RBP but predominantly as retinyl stearate (RS) and retinyl palmitate (RP) associated with all lipoprotein fractions (4., 5., 6.). In mammals other than carnivores the occurrence of lipoprotein-bound retinyl esters is observed only under conditions of acute or chronic vitamin A intoxication (7). The physiological factors and processes responsible for a lower susceptibility of carnivores to high dietary VA intake are not entirely understood. One factor protecting dogs from a VA intoxication may be the excretion of retinol and retinyl esters in the urine in association with Tamm–Horsfall protein (THP) (8,9). We therefore examined the effect of a large single oral dose of VA on the retinol and retinyl ester response in plasma and on the excretion of retinol, retinyl esters and THP with the urine."

"Based on Western blot analysis, RBP can be excluded as a carrier for VA in urine. Therefore, it is unlikely that the loss of VA in urine of dogs is a consequence of merely glomerular filtration and decreased tubular RBP reabsorption."

https://www.sciencedirect.com/science/article/pii/S0022316622151837

 

[DanDare]

@mosaic01

Gives the answer to the question of essentialness in the first response to the op and is all that is necessary.

The empirical evidence says it is not essential for Man or Gerbil, unless only needed in tiny amounts. Child or woman, we do not know, or elephant or cow, we do not know, without further experiment, though one might expect the same. Regardless the essential vitamin a theory deeply wrong.

 

[Dr. B]

@mosaic01

Gives the answer to the question of essentialness in the first response to the op and is all that is necessary.

The empirical evidence says it is not essential for Man or Gerbil, unless only needed in tiny amounts. Child or woman, we do not know, or elephant or cow, we do not know, without further experiment, though one might expect the same. Regardless the essential vitamin a theory deeply wrong.

Someone mentioned, vitamines were changed to vitamins because vitamin A wasnt an amine?

 

[DanDare]

Someone mentioned, vitamines were changed to vitamins because vitamin A wasnt an amine?

Originally yes but I think the current definition is fairly consistently : essential compound for normal growth, cannot be synthesised.

 

[DanDare]

Grant on his vision changes.

I believe some have also noted changes in eye colour ( note that is merely iris muscle colour not the retina )

 

[Dr. B]

View attachment 62176

Grant on his vision changes.

I believe some have also noted changes in eye colour ( note that is merely iris muscle colour not the retina )

What kind of eye color changes? Lightening of the eyes?

 

[DanDare]

What kind of eye color changes? Lightening of the eyes?

Lighter and/or towards blue was how the person described it but I cannot find the source

 

[Dr. B]

Lighter and/or towards blue was how the person described it but I cannot find the source

Wow thats crazy! It was all from just that one change of no vitamin A? Do you think vitamin A causes some sort of inflammation to the eye, so as the inflammation heals the iris gets lighter?

 

[DanDare]

Wow thats crazy! It was all from just that one change of no vitamin A? Do you think vitamin A causes some sort of inflammation to the eye, so as the inflammation heals the iris gets lighter?

Blue eyes are not actually blue due to pigment, its the way the structure interacts with light, whereas brown are brown due to melanin pigment. So if you subtract either melanin or vit a / carotenes, perhaps they look less brown (or green/grey) and more blue. Or indeed as you say it could be a change in structure due to proper protein folding (or whatever other theory about how vit a interferes with proteins) . Indeed people's eyes tend to get lighter with age, so one might see one's eyes get darker but less yellow if one gets healthier. It is wide open to speculation I think.

 

[Blossom]

this is peoples lives we are playing with

I see this a bit differently. Our lives have already been played with from the womb and continue to be impacted negatively in numerous ways and from multiple angles. This information just gives people a chance to start chipping away those burdens if they choose to do so.

 

[Highserotonin90]

@DanDare So retinaldehyde has nothing to do with the retina of the eye?

 

[DanDare]

@DanDare So retinaldehyde has nothing to do with the retina of the eye?

The short answer is I don't know

 

[proteome]

Soon enough there will be hundreds to thousands of blind or NOT low vA enthusiasts. Then the model will be proven or refuted.

Based

 

[proteome]

So it seems you want to know whether technically vA is needed for vision, independent of any practical considerations at all, since no one can reduce their vA intake to zero. And you want someone to specifically look at the biochemical process that is described in textbooks and in your post and take it apart based on biochemical pathways and interactions.

I would welcome this, too.

Many dermatologists have shown positive effects of retinoids like tretinoin on scalp hair growth and skin health. These effects are repeatably testable.

 

[DanDare]

I would welcome this, too.

Many dermatologists have shown positive effects of retinoids like tretinoin on scalp hair growth and skin health. These effects are repeatably testable.

Theres enough concern over retinol creams that their use in skin creams is now limited to a much smaller amount in Europe starting this year with a grace period for manufacturers to reformulate. I have a thread on it linking to the scientific evaluation that lead to it.