ecstatichamster
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Is dehydro- form not bioavailable?
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Just means that it is oxidized, no longer of use as an antioxidant...Is dehydro- form not bioavailable?
Nice find.You're very welcome! Thanks to @yerrag too for bringing this up. I certainly won't use tap water ever again!
I found the study and basically, huge oxidation in tapwater (93% after 3 hours at room temperature), none in bottled water:
Oxidative decomposition of vitamin C in drinking water. - PubMed - NCBI
Oxidative decomposition of vitamin C in drinking water.
Jansson PJ, et al. Free Radic Res. 2004.
Authors
Jansson PJ1, Jung HR, Lindqvist C, Nordström T.
Author information
1
Department of Biochemistry and Pharmacy, Abo Akademi University, BioCity, 20521 Turku, Finland.
Citation
Free Radic Res. 2004 Aug;38(8):855-60.
Abstract
We have previously shown that vitamin C (ascorbic acid) can initiate hydroxyl radical formation in copper contaminated household drinking water. In the present study, we have examined the stability of vitamin C in copper and bicarbonate containing household drinking water. In drinking water samples, contaminated with copper from the pipes and buffered with bicarbonate, 35% of the added vitamin C was oxidized to dehydroascorbic acid within 15 min. After 3h incubation at room temperature, 93% of the added (2 mM) ascorbic acid had been oxidized. The dehydroascorbic acid formed was further decomposed to oxalic acid and threonic acid by the hydrogen peroxide generated from the copper (I) autooxidation in the presence of oxygen. A very modest oxidation of vitamin C occurred in Milli-Q water and in household water samples not contaminated by copper ions. Moreover, addition of vitamin C to commercially sold domestic bottled water samples did not result in vitamin C oxidation. Our results demonstrate that ascorbic acid is rapidly oxidized to dehydroascorbic acid and further decomposed to oxalic- and threonic acid in copper contaminated household tap water that is buffered with bicarbonate. The impact of consuming ascorbic acid together with copper and bicarbonate containing drinking water on human health is discussed.
PMID
15493459 [Indexed for MEDLINE]
Thanks.Nice find.
The only problem that I can spot is that it's a capture of the top of a rollercoaster and we don't know for sure what happens over the times. Here it is in perspective:
View attachment 12022 vs View attachment 12023
Solid circle: ultra-purified wasser
Hollow square: tap wasser with less impurity
Solid triangle: tap wasser with more impurity
Hollow circle: ultra-purified wasser with added cupric chlorid and bicarbonate of soda
Whenever possible, it's preferable to do it the most guaranteed way.
Thanks Amazoniac, very good point. We don't know the drop off after the 3 hours. But at least we can avoid the 93% drop off of tap water. I use a filtration system called Berkey Travel I'm very happy with and recommend!Nice find.
The only problem that I can spot is that it's a capture of the top of a rollercoaster and we don't know for sure what happens over the times. Here it is in perspective:
View attachment 12022 vs View attachment 12023
Solid circle: ultra-purified wasser
Hollow square: tap wasser with less impurity
Solid triangle: tap wasser with more impurity
Hollow circle: ultra-purified wasser with added cupric chlorid and bicarbonate of soda
Whenever possible, it's preferable to do it the most guaranteed way.
Just means that it is oxidized, no longer of use as an antioxidant...
Yes, I shouldn't have been so categoric. The body can recharge the oxidized ascorbic acid, but you do lose that first round of 2 donor electrons per ascorbic acid molecule. I don't know what are the rates of recharge or exactly how much of a difference that makes in the absolute, but it seems a shame to waste the initial antioxidant effect you would get from non oxidized ascorbic acid.Nobody ever said that our only source is DH ascorbic acid. But I think we have established that there is a good chance the DH version is quite useful in the human body and is not wasted. So if we use vitamin C that partially turns in the DH ascorbic acid, we are still helping ourselves.
If you look at the study, what is being compared is the tissue accumulation of vitamin C in guinea pigs, between the intake of vitamin C and DHA. Is tissue accumulation of vitamin C a good basis for comparison in comparing the relative efficacy of vitamin C intake vs. DHA intake? Can DHA in its form act as an antioxidant? No. It has to be reduced by glutathione to become the reduced form Vitamin C. So while the body may convert DHA to vitamin C, it comes at the expense of glutathione. It's a zero sum game still. You're robbing Peter to pay Paul. What about vitamin C's role in reducing oxidized vitamin E in the membrance interface interaction between the intracellular vitamin and the extracellular vitamin E? If you start out with vitamin C, you can come out blazing with vitamin C ready to do its job of renewing the vitamin E that has been oxidized inside the cell. There is no free lunch. You can't equate the efficacy of vitamin C to DHA, its oxidized version.Nobody ever said that our only source is DH ascorbic acid. But I think we have established that there is a good chance the DH version is quite useful in the human body and is not wasted. So if we use vitamin C that partially turns in the DH ascorbic acid, we are still helping ourselves.
If you look at the study, what is being compared is the tissue accumulation of vitamin C in guinea pigs, between the intake of vitamin C and DHA. Is tissue accumulation of vitamin C a good basis for comparison in comparing the relative efficacy of vitamin C intake vs. DHA intake? Can DHA in its form act as an antioxidant? No. It has to be reduced by glutathione to become the reduced form Vitamin C. So while the body may convert DHA to vitamin C, it comes at the expense of glutathione. It's a zero sum game still. You're robbing Peter to pay Paul. What about vitamin C's role in reducing oxidized vitamin E in the membrance interface interaction between the intracellular vitamin and the extracellular vitamin E? If you start out with vitamin C, you can come out blazing with vitamin C ready to do its job of renewing the vitamin E that has been oxidized inside the cell. There is no free lunch. You can't equate the efficacy of vitamin C to DHA, its oxidized version.
If the goal of vitamin C intake is to augment the total antioxidant stores in the body, it doesn't make sense to me that one would consciously take DHA over vitamin C.They both are useful. I’m not sure the transient lowering of GTH is an issue.
If the goal of vitamin C intake is to augment the total antioxidant stores in the body, it doesn't make sense to me that one would consciously take DHA over vitamin C.
It's true that it plays a role also as a pro-oxidant, but it's the body's role to decide what it makes of vitamin C, and I don't know when it's needed to morph vitamin C into a pro-oxidant.I agree. But if we consume some it’s fine and still helpful. I think C is much more than an antioxidant.
Dr Cathcart wrote a paper detailing the 3 major functions of vitamin C:I agree. But if we consume some it’s fine and still helpful. I think C is much more than an antioxidant.
Dr Cathcart wrote a paper detailing the 3 major functions of vitamin C:
http://orthomolecular.org/library/jom/1992/pdf/1992-v07n04-p197.pdf
The highlights:
The Three Faces Vitamin C probably always functions by being an electron donor. At the lowest dose level (the first face), it is necessary as a vitamin to prevent scurvy. It is essential for certain metabolic functions which are well described and mostly non-controversial.
At a second level (the second face) vitamin C is still used as a vitamin but larger doses are necessary to maintain its basic vitamin C functions because the vitamin is destroyed rapidly in diseased or injured tissues where there is an overabundance of free radicals.
The third level of doses (the third face) is virtually undiscussed in the literature but is the most interesting. These doses range usually from 30 to 200 grams or more per 24 hours. The most important concept to understand is that while incidentally at these dose levels the vitamin C performs all the functions of levels one and two, it is mostly thrown away for the reducing equivalents it carries.
With these doses it is possible to saturate the body with reducing equivalents, neutralize the excessive free radicals, and drive a reducing redox potential into involved tissues. Inflammations mediated by free radicals can be eliminated or markedly reduced. In many instances patients with allergies or autoimmune diseases have their humoral immunity controlled while their cellular immunity is augmented.
To the extent that free radicals are either essential to the perpetuation of a disease or just part of the cause of symptoms, the disease will be cured or just ameliorated. The list of diseases involving free radicals continues to grow. Infections, cardiovascular diseases, cancer, trauma, burns both thermal and radiation, surgeries, allergies, autoimmune diseases and aging are now included. It is more difficult to think of a disease that does not involve free radicals.
Like Ray Peat?Seems like people had some negative side effects to Vitamin C they didn't want to have to explain, so they just assumed it was due to impurities - and not some other phenomena... Then they repeated to everyone that Vitamin C is so impure :P
Waynish, let's say that you're a loyal customer of a brothel, not because of lack of options, but because you consider it a fair transaction and enjoy the convenience of it. Helvetica is your favorite, you always return for more. But one day the pimp informs you that she was fired and Destiny along with her friends are now the new team; this is a result of some modifications in the house, the only comforting aspect is that the price was lowered. You decide to go for it but end up with a worrying itch around the janitors. What to suspect in this case? You don't know where to find Helvetica but it seems that it's going to be difficult to find prostitutes of her caliber. The reputation of the brothel is now questionable. Would you insist or move on to unpaid options?Seems like people had some negative side effects to Vitamin C they didn't want to have to explain, so they just assumed it was due to impurities - and not some other phenomena... Then they repeated to everyone that Vitamin C is so impure :P