I needed to disable self sign-ups because I’ve been getting too many spam-type accounts. Thanks.
Why I don’t think that this is a legit theory anymore
@wavygravygadzooks My opinion on VA is not held on religious grounds, and I'm also incredibly wary of scientific theories that are unfalsifiable. So it is indeed possible to change my opinion on this matter. In my understanding of the scientific method, a single carefully designed & executed experiment is worth a lot more more than the opinion of a thousand "experts". Therefore, it would be sufficient if the deficiency was demonstrated under the following conditions:
- The mammals participating in the experiment should be very young. To avoid arguments about VA stores already present in the liver.
- Large numbers of animals aren't necessary, but the deficiency must occur in all of the animals. B vitamin deficiency was demonstrated reliably in all test subjects, the same standard should apply here.
- The VA deficient diet should be simple and easy to verify as being truly VA free. Pork and dairy products are automatically excluded because of the controversy surrounding their VA status and processing. Preferably, the experiment should be redone with different formulations of a VA free diet and observe the same results.
- The experiment may not use fish oil, butter, or any other pixie dust colloquially known to be high VA to address the deficiency. Please use plain old retinol palmitate or acetate. Bonus points if the deficiency is fixed with tret or another synthetic retinoid.
Yes, I understand that yellowish fat is sign of BC, but I think you're overblowing the problem. The vast majority of beef on the market in NA today is white, and therefore mostly free of BC. I've encountered a lot of beef, lamb, pork, and chicken and I can only recall some chicken skin as having a tinge of yellow. But I think you highlight an important problem here, it's actually incredibly hard to have a VA free diet. It's yet another reason why I'm so skeptical of all those early studies. In the study mentioned by Tim, they fed the participants lard on a VA free diet, and yet there's papers out there claiming that "lard factor" is VA. Who are we to believe then?
The increase in plant consumption, especially plants that haven't been prepared through traditional cooking methods, has increased far more dramatically in recent decades than consumption of animal sources of Vitamin A. Way more likely that a diversity of plant compounds are responsible for an uptick in immune problems and skin conditions than just Vitamin A, although I'm sure the extra beta-carotene is not benefiting hardly anyone.
I don't disagree with anything here. The over consumption of animal sourced VA is not a general phenomenon and is mostly limited to the followers of fringe nutrition "gurus". The general public acquires excess VA from plants, dairy, and sometimes fish in the majority of all cases. Of course, the general public is also deficient in all the ingredients required to safely handle, store, and eliminate VA. I believe this is just as important.
You're welcome. Xeropthalmia is a specific VAD condition. Some here have said it just means dry eyes and while that is its literal translation that's not what it means. It is the degenerative process starting with night blindness progressing to permanent retina damage and blindness. Those who take Accutane or have Hypervitaminosis A never develop xeropthalmia. They may suffer from the beginning stages due to retinoic acid interfering with enzymatic production of retinaldehyde but it never progresses to end stage xeropthalmia.
Btw, @tim-2, do you find anything in common with VB6 here? There are a lot of this, common.
"Isotretinoin (13-cis retinoic acid) slows rhodopsin regeneration and chromophore recycling by inhibition of the retinoid isomerase and 11-cis retinol dehydrogenase enzymes that are necessary for the synthesis of 11-cis retinal."
From my research above.
Quote from tim on October 29, 2021, 6:29 pmYou're welcome. Xeropthalmia is a specific VAD condition. Some here have said it just means dry eyes and while that is its literal translation that's not what it means. It is the degenerative process starting with night blindness progressing to permanent retina damage and blindness. Those who take Accutane or have Hypervitaminosis A never develop xeropthalmia. They may suffer from the beginning stages due to retinoic acid interfering with enzymatic production of retinaldehyde but it never progresses to end stage xeropthalmia.
I have already said that I think that xerophthalmia is more than a toxicity of VA. More precisely, a deficiency of something else(not VA)
I was responding to your statement of your belief about 13-cis-retinoic acid causing eye damage. Accutane can definitely affect the eyes but I was pointing out that it doesn't cause end stage xeropthalmia like VAD does.
Xeropthalmia is caused by VAD however it's very difficult to develop it if one is fully nourished in other respects. It normally occurs in conjunction with other deficiencies such as riboflavin and protein deficiency.
Quote from tim on October 29, 2021, 6:56 pmI was responding to your statement of your belief about 13-cis-retinoic acid causing eye damage. Accutane can definitely affect the eyes but it doesn't cause end stage xeropthalmia like VAD does.
Xeropthalmia is caused by VAD however it's very difficult to develop it if one is fully nourished in other respects. It normally occurs in conjunction with other deficiencies such as riboflavin and protein deficiency.
I understand your point of view. But I have one trump card up my sleeve. I would like to recall something else, namely the "lard factor". So, there is something in lard, egg whites and butter that treats VAD "better than VA supplements". Don't you find logic here?
Yes, people do not develop xerophthalmia from accutane, because they continue to consume/have a supply of "lard factor" to survive it.
Add: Moreover, it is not entirely clear why 13cis-RA inhibits the synthesis of 11cis-retinal. Imho, the only intuitive explanation for this is that one toxin prevents the output of another toxin.
But I have one trump card up my sleeve.
LOL
An Unknown Factor with Vitamin a Activity Distilled from Lard: Two Figures
Summary
The nutritional effects on rats of the distillate and residue fractions of molecularly distilled lard were studied. When vitamin A-free diets containing the residue fraction as the fat source were supplemented by distillate, or when this material was injected, the animals could be protected against the signs of vitamin A deficiency. The protection given by 2% distillate in the diet seemed nearly complete and was much better than that provided by weekly injections of 7.5 units of vitamin A palmitate.
These results could be explained neither by the presence of vitamin A in the distillate nor by a nonspecific anti-oxidant action of the distillate. It was therefore concluded that lard contains a factor with vitamin A-like activity but which is chemically different from the known forms of vitamin A.
The significance of this factor with respect to specific epithelial lesions in animals on vitamin A-low rations, to vitamin A bioassays, and to a “fat minimum” in the diet has been discussed.
So they found that a distillate of lard, not lard protected against VAD. Lard contains a small amount of vitamin A and the distillate obviously contained concentrated amounts of it. A few years later it was found that the "lard factor" was actually vitamin A:
Identification of the So-Called ``Lard Factor'' as Vitamin A
Quote from tim on October 29, 2021, 7:45 pmBut I have one trump card up my sleeve.
LOL
An Unknown Factor with Vitamin a Activity Distilled from Lard: Two Figures
Summary
The nutritional effects on rats of the distillate and residue fractions of molecularly distilled lard were studied. When vitamin A-free diets containing the residue fraction as the fat source were supplemented by distillate, or when this material was injected, the animals could be protected against the signs of vitamin A deficiency. The protection given by 2% distillate in the diet seemed nearly complete and was much better than that provided by weekly injections of 7.5 units of vitamin A palmitate.These results could be explained neither by the presence of vitamin A in the distillate nor by a nonspecific anti-oxidant action of the distillate. It was therefore concluded that lard contains a factor with vitamin A-like activity but which is chemically different from the known forms of vitamin A.
The significance of this factor with respect to specific epithelial lesions in animals on vitamin A-low rations, to vitamin A bioassays, and to a “fat minimum” in the diet has been discussed.
So they found that a distillate of lard, not lard protected against VAD. Lard contains a small amount of vitamin A and the distillate obviously contained concentrated amounts of it. A few years later it was found that the "lard factor" was actually vitamin A:
Identification of the So-Called ``Lard Factor'' as Vitamin A
I should note that 0.3 UI is clearly less than required, but okay, let's say it contained 10UI and the rats were really cured by vitamin A in lard. Then how do you explain that some people do not suffer from xerophthalmia? How many more years does Grant need to stick to a diet to go blind?
In addition, according to their calculations, the lard will contain 100 IU of vitamin A per 100g, which is much more than the databases show.
@wavygravygadzooks that caffeine absorbed by the gut is stimulating liver that's for sure.. It works differently than drinking the coffee..
WEEKLY injections of 7.5IU of vitamin A. When they mentioned 10IU that was 10IU per GRAM.
Grant has experienced some level of night blindness and dry eyes multiple times. He must be one of the most vitamin A depleted humans on the planet. You're going to claim his symptoms are due to detoxification of tiny amounts of vitamin A?
As I said, xeropthalmia is very difficult to develop if one is well nourished in other respects. It normally occurs in conjunction with other deficiencies such as riboflavin and protein deficiency. A well nourished adult that starts with a liver full of vitamin A is going to take many years to develop undeniable xeropthalmia.