Bioavailability of Vitamin C

[OxC]

...our crude measurements have shown that these very high blood concentrations are only visible from minutes 5 to 25 after oral ingestion, and only with ascorbic acid (not sodium ascorbate).
...One benefit of our crude measurements was showing the difference between AA (ultrafine powder) and Sodium Ascorbate. Sodium ascorbate was either delayed or not absorbed (as we didn't measure longer than one hour)
...But the AA was noticed by our meter at minute five and if memory serves, peaked around minutes 20 to 25. So any test that is not measuring this soon and this often is going to MISS a lot of vitamin C (as ascorbic acid) entering the blood stream

These findings (and conclusions) are wildly different than a whole body of scientific studies have previously demonstrated. I believe you should very seriously consider the possibility that your "crude measurements" are invalid and misleading before trying to find physiological explanations for those measurements. I'll say it again: You cannot get reliable plasma ascorbate measurements using a glucose meter.

[OxC]

For AA to reach the blood this quickly (5 minutes!) something like this MUST be happening, and as I mentioned, we did not observe the same thing measuring sodium ascorbate.

Absolutely. Whenever I get sneezes from my hay-fever and take a glass of water with 2 tea-spoons of vitamin C, within 3 minutes it eases it already.

Two teaspoons of AA is about 10 grams, and a glass of water is typically about 12 ounces. The concentration of the solution you are swallowing is about 2.8%, or, in the same units as we have been talking about in blood, 158,000 uM. So, you see, swallowing this solution exposes the back of the throat and the back of the sinus cavity to a solution containing vitamin C somewhere in the neighborhood of 2000 times more concentrated than is found normally in blood.

I do not doubt that you experience relief in just minutes from hay fever sneezing after drinking this. I experience the same rapid relief of nasal congestion when I gargle a far less concentrated DHAA solution.

But the question here is how that vitamin C is getting to the cells that line your sinuses. One possible way is that exposure of the opening of the sinus cavity where it enters the throat to a solution containing an extremely high (158,000 uM) concentration of vitamin C allows small amounts to migrate into the sinuses, in much the same way as, say, eating a hot pepper or horseradish sauce allows sufficient of their constituents to enter the sinuses and cause the effects we've all experienced (i.e. runny nose).

Another possible way is that within only 3 minutes, sufficient vitamin C is absorbed into your bloodstream from the stomach to increase the blood concentration enough to deliver significantly larger quantities throughout the body, including to the sinuses.

Many, many studies on the absorption of AA do not support the second possibility. In fact, Owen's experience, derived from his blood glucose meter, is the only suggestion of such rapid blood absorption of AA that I have ever seen.

[Johnwen]

There's some misgivings being brought up in this discussion like ascorbic acid being absorbed by the stomach!
Fact is only a few lipid containing items can be absorbed in the stomach and everyone's favorite Ethanol! The stomach is a digestive bag it's job is to breakdown food etc. with acids. It's normal PH is in the 1.4 to 2.0 ranges.

Ascorbic acid is just that an acid yielding a PH between 1.2 to 2.3 depending on the mix and the stomach will not absorb acid if it did we would all be in trouble.
It must move into the duodenum where it's Ph will be raised to be absorbed into the blood. This is done by digestive secretions into the duodenum, primarily bicarbonate from the pancreas and over dose's of ascorbic acid will slow it's absorption here and delay release to further down in the intestines where other secretions will further neutralize it and absorb it. A little fact here the pancreas uses 99% of it's volume to the production of bicarbonate and 1 % for exocrine production.
Yes in can pump out some serious volume's of bicarbonate! Eating a normal meal will yield about a liter of bicarbonate!
If any AA remains when it hit's the colon it will be excreted in the feces. If a high amount of this acid hit's the colon the Low PH it will bring in water through osmosis and flush it out (Bowel tolerance). This is done because the acids will disrupt the normal flora in the colon and the normal nutrients absorbed there will cease so the body reacts by a flushing the problem out!

The process of neutralizing AA converts it to it's reduced form of DHA which is then absorbed thru the capillaries of the intestines and into the hepatic portal veins where it is taken to the liver and stored and converted either back to a majority of AA or to a minor amount of 2,5 diketogulonic acid which is the useless and spend form of AA!
The AA that's converted back will be released in a controlled manner to maintain the PH balance of the blood. The 2,5 diketogulonic acid component is released at the same time but when it comes in contact with the water component of the blood will be converted to Oxalic Acid and L-threonic acid and be taken up and excreted by the kidneys. The CO2 component produced in the acid/bicarbonate reaction will be also taken into the blood and helps protect the veins from damage by the acids being moved through the hepatic system and into the right chambers of the heart and is exhaled in the lungs.

All three of the AA components are readable as ascorbic acid on AA blood tests. They don't differentiate what form they are reading!
Now if you were able to consume DHA with water which is possible if you have access to lab materials and machinery you probably won't even then get in excess of 5% concentration!
This mix would mostly be hydrated to 2,5 diketogulonic acid which cannot be converted back to AA and when it reaches the digestive stage would be further degraded and when absorbed into the hepatic system it would be released in larger quantities so it can be disposed of from the body and the larger quantities of Oxalic Acid and L-threonic acid would burden the kidney's even further.

Another possibility for home made dehydroascorbic acid is to obtain the compound from a chemical supply house in its pure, powdered form. The best price I've seen is about $40 per gram. Most chemical suppliers won't sell directly to the public, but you might have a contact in a laboratory or at a university that can help. Dry dehydroascorbic acid powder doesn't dissolve well, and so it requires heating the water to about 60 degrees C (140 F) with constant stirring to dissolve. It is difficult to get more than about 5% concentration. Heat destroys the compound, so it is important to not overheat the solution, and to cool it immediately after it dissolves. Water solutions are extremely unstable, especially if the pH isn't acidic. The best way to acidify it is to add about an equal amount of ascorbic acid right after the dehydroascorbic acid dissolves. Then mix the water solution with equal parts glycerin and store refrigerated. This process is not recommended for those who don't have laboratory experience and basic tools like heating stir plates, magnetic stir bars, small beakers and flasks, and a thermometer.

OK! Why not tick off everybody off, but hay facts are facts!
Try this! Did you know drinking Fruit Juices causes Kidney Stones???
Ask your self this! Why haven't I heard about this?? Maybe it's $$$$
How about Just blaming the V-C component? Yea! They ain't got NO $$$$

Well Here it is simple chemistry!!
5 C7H8O7 + 7 H2O = 3 H2C2O4 + 6 C4H8O5

So my advice here if your interested in how AA makes it into system is to educate yourself on how the digestive system works first. When you understand how secritin is produced and used and HCL is produced and why it don't destroy the stomach your on your way! However you have about another 5 meters to concern yourself with! To give you an idea the digestive system is the most tested subject in med school! Good luck

[ofonorow]

Lot to digest.
The point of our crude measurements are that if any study waits more than 30 minutes to do the measurement - it is probably invalid. They missed all the action!

And our "crude" experiments are entirely repeatable.

Of course there are always alternate explanations of what may be going on, and I am all ears.

#1: Why the vastly different readings after taking the same amount of ascorbic acid (ultra fine) powder and sodium ascorbate?

#2: The sinus membrane hypothesis. Oxc this seems reasonable, except for the fact that when I first noticed this, it was with my father during his last days at the hospital. He took a 500 mg pill. A tablet, so little opportunity to for any ascorbate to escape the pill as he swallowed. (He was having difficulty breathing, and the sinuses cleared within minutes of swallowing.. Leading me too)

Hickey/Roberts Ridiculous Dietary Allowance (Bioavailability. Pg 65)

Bioavailability measures absorption from the gut. The RDA committee suggest that this absorption occurs in the intestines by means of active transport. This may not be the only route, or even the dominant one. Vitamin C is a weak, organic acid, and such acids are normally absorbed rapidly through the stomach

Looking for the reference in pubmed - and will edit.

[OxC]

[b]The point of our crude measurements are that if any study waits more than 30 minutes to do the measurement - it is probably invalid. They missed all the action!
[/i].

Here is a study in which plasma was collected at 15 minutes and 30 minutes after oral doses of ascorbic acid. Refer to Figure 3. You will see that there is no "action" to miss at these times, that it is usually about one hour before significant increases in plasma ascorbate concentrations can be seen, and that peak values occur at around 2 hours. http://www.pnas.org/content/93/8/3704.full.pdf In this study, plasma ascorbate was measured using a reliable HPLC method. In study after study, whenever reliable analytical methods are used, the absorption profile of ascorbic acid is always like this. There is never a peak in 5 or 10 minutes followed by a drop to baseline in 30 minutes as the blood glucose levels you have previously reported show. I think the most reasonable explanation of your results is that the blood glucose meter measured exactly what it was designed to measure...your blood glucose levels.

[Johnwen]

Vitamin C is a weak, organic acid, and such acids are normally absorbed rapidly through the stomach

Says who?? Perhaps they think because acetylsalicylic acid can be absorbed in small quantities from the stomach as while some NSAID's Which are weak acid's with ph's of 3-5. Vitamin C is not a weak acid with a ph of 1.4 in it's non mixed state and does not get ionized in the stomach like aspirin and NSAID's do. If it did, it would have the same ulcer causing properties as aspirin and NSAID's.
If what they say was true those of us who take larger doses of VC daily would be spending more time in the hospital instead of avoiding them
(unless you work there! Which is a better reason to avoid them!) getting bleeding of the stomach stopped!

Here's some reading for understanding!

Note; on this link he says 'SMALL amounts of certain lipid-soluble compounds.'

http://www.madsci.org/posts/archives/20 ... .An.r.html

How about Lipid-soluble Vitamins. Maybe a small amount make it through the stomach???

http://chemwiki.ucdavis.edu/Organic_Che ... e_Vitamins

Nope! V-C don't make the list!!! It's water soluble.

How about Ascorbyl Palmitate??

https://en.wikipedia.org/wiki/Ascorbyl_palmitate

Nope! It separates in the digestive system!!!

How about liposome V-C??
Nope! The purpose of the encapsulation is to make it through the digestive system intact!

http://orthomolecular.org/resources/omns/v05n10.shtml


So pray tell!! How can one say that V-C is absorbed in the stomach when it don't even meet the properties needed to even be absorbed in SMALL quantities????

How about this when a person consumes V-C which is an acid it adds to the acid levels in the stomach and the stomach normally rapidly releases it into duodenum to equalize the stomach's acid balance. Then it get's neutralized by the pancreatic juices which primarily are bicarbonate. The duodenum also releases transport elements for V-C and gets absorbed into the capillaries and then to the portal vein and into the blood system!
In some people the excess acids will not be released into the duodenum rapidly and this additional acid will cause a back up causing, from discomfort to heart burn to GERD.

[ofonorow]

Here is a study in which plasma was collected at 15 minutes and 30 minutes after oral doses of ascorbic acid. Refer to Figure 3. You will see that there is no "action" to miss at these times, that it is usually about one hour before significant increases in plasma ascorbate concentrations can be seen, and that peak values occur at around 2 hours. http://www.pnas.org/content/93/8/3704.full.pdf In this study, plasma ascorbate was measured using a reliable HPLC method. In study after study, whenever reliable analytical methods are used, the absorption profile of ascorbic acid is always like this. There is never a peak in 5 or 10 minutes followed by a drop to baseline in 30 minutes as the blood glucose levels you have previously reported show. I think the most reasonable explanation of your results is that the blood glucose meter measured exactly what it was designed to measure...your blood glucose levels.

First, to review our procedure - we also tested the FreeStyle lite device against vitamin C in water, and it was able to measure vitamin C in water at the same concentration as in the blood. (Furthermore, people from the Riordan clinic, who routinely measure vitamin C after IV/C - and if blood levels are zero, continue the IV, put out a paper showing how certain glucose meters provide a cheap and reliable substitute.)

When I look at the graphs of this paper you cite OxC - they look just like our sodium ascorbate measurements. So I looked to confirm that they really gave ascorbic acid (can you help with this? The type of vitamin C given makes all the difference in the world).

There is a section where they describe what looks to be the Vitamin C used for IV - but if given orally too, it was at least partially sodium ascorbate.

Vitamin C powder USP-FCC was a gift from Takeda USA Inc. Vitamin C was batch-prepared for clinical use by the NIH Clinical Center Pharmacy as a sterile solution of 50 mg/ml in water adjusted to pH 6.5 with NaOH.

I'll get to johnwens post after reviewing the links. The Hickey/Roberts reference is to a primer on Drugs (a book) but they expand on the fact that the lower the pH, the stronger the stomach acid, the stronger the effect moving "organic" acids through the stomach wall..

[ofonorow]

Here is a study in which plasma was collected at 15 minutes and 30 minutes after oral doses of ascorbic acid. Refer to Figure 3. You will see that there is no "action" to miss at these times, that it is usually about one hour before significant increases in plasma ascorbate concentrations can be seen, and that peak values occur at around 2 hours. http://www.pnas.org/content/93/8/3704.full.pdf In this study, plasma ascorbate was measured using a reliable HPLC method. In study after study, whenever reliable analytical methods are used, the absorption profile of ascorbic acid is always like this. There is never a peak in 5 or 10 minutes followed by a drop to baseline in 30 minutes as the blood glucose levels you have previously reported show. I think the most reasonable explanation of your results is that the blood glucose meter measured exactly what it was designed to measure...your blood glucose levels.

First, to review our procedure - we also tested the FreeStyle lite device against vitamin C in water, and it was able to measure vitamin C in water at the same concentration as in the blood. (Furthermore, people from the Riordan clinic, who routinely measure vitamin C after IV/C - and if blood levels are zero, continue the IV, put out a paper showing how certain glucose meters provide a cheap and reliable substitute.)

When I look at the graphs of this paper you cite OxC - they look just like our sodium ascorbate measurements. So I looked to confirm that they really gave ascorbic acid (can you help with this? The type of vitamin C given makes all the difference in the world).

There is a section where they describe what looks to be the Vitamin C used for IV - but if given orally too, it was at least partially sodium ascorbate.

Vitamin C powder USP-FCC was a gift from Takeda USA Inc. Vitamin C was batch-prepared for clinical use by the NIH Clinical Center Pharmacy as a sterile solution of 50 mg/ml in water adjusted to pH 6.5 with NaOH.

I'll get to johnwens post after reviewing the links. The Hickey/Roberts reference is to a primer on Drugs (a book) but they expand on the fact that the lower the pH, the stronger the stomach acid, the stronger the effect moving "organic" acids through the stomach wall..

[ofonorow]

Vitamin C: Its Functions and Biochemistry in Animals and Plants

https://books.google.com/books?hl=en&lr ... &q&f=false

Page 100 starts with information oxc should appreciate,

Vitamin C Transport in Animals and Plants ' Chapter 6

Page 100

Utilization of ASC (Ascorbate Ion) as an antioxidant and enzyme cofactor causes its oxidation to DHA in extra cellular fluid and cells. DHA has been demonstrated to play important roles in animal and plant cells because it can be used to regenerate ASC and, directly or indirectly, change the redox state of many other molecules.

For instance in humans, who cannot synthesize vitamin C and depend on dietary sources, ingesting either ASC or DHA rases serum ASC concentrations to similar extents. Thus DHA can seve as a dietary source of vitamin C. Indeed, there is a widely held understanding that dietary ASC or DHA possess roughly equivalent bioavailability (the faction of the ingested amount has the potential to meet the function requirements of tissues for vitamin C.) Evidently cellular mechanisms of transport and metabolism convert DHA to ASC at appropriate locations and rates to fulfill the human requirement for vitamin C. It is because both molecules are commonly thought to be bioavailable that the vitamin C content of foods is commonly reported as the sum of ASC and DHA contents.


Page 100

The human small intestine absorbs both reduced and oxidized vitamin C. DHA can be degraded by bicarbonate at alkaline pH but is unlikely to meet these destabilizing conditions in the lumen of the small intestine, where the alkaline secretions from the pancreas and duodenal glands mix with the acidic gastric juice to form a slightly acidic fluid.

Page 101

DHA competes with glucose for uptake through the mammalian facilitative glucose transports GLUT1, GLUT3 and Glut4. GLUT proteins do not transport ASC (ascorbate ion) or AA (ascorbic acid)

This answers the question from the earlier topic, How Is Vitamin C Absorbed.

Page 102

An excess of glucose, such as occurs during the hyperglycemia of uncontrolled diabetes or sepsis, may competitively block most DHA uptake through facilitative glucose transporters and this impair the clearance of DHA by some cell types.

Page 104

DHA is lethal to neurons in the absence of astrocytes (Song 2001)

Found this online book via google/scholar looking for the assimilation/diffusion through the stomach wall reference.

[Johnwen]

JOHNWEN Wrote:
The duodenum also releases transport elements for V-C and gets absorbed into the capillaries and then to the portal vein and into the blood system!

SVCT's are made where? GLUT's Where?

Not in the stomach that's for sure!

As this article you posted says INTESTINES!!!!! NOT THE STOMACH!!!!

[ofonorow]

Right, and no doubt some/most of the job of transporting vitamin C to the blood stream happens in the intestines.

The question is how taking a vitamin C pill can clear the sinus in 5 minutes?

Or how and why our readings from minutes 10 to 35 (w/glucose meter) after the ingestion of 4 to 5 grams of ascorbic acid rise markedly (and don't with the same amount of sodium ascorbate)

And while liposomal takes 2 to 3 hours to get the vitamin C in the blood (peak), it too can eliminate sinus drip in minutes after taking by mouth (this affect I assumed was because the liposomes enter the mucous membranes in the mouth)

Vitamin C (as ascorbic acid) can apparently reach the blood stream quicker than seems possible -- passing through the stomach and into the intestines (even with the small aperture/opportunity.) Still looking for the detailed Hickey/Roberts treatment of the "weak organic acid" effect they mention.. And there were reports that Nexium interferes with vitamin C absorption..

[Johnwen]

GLUT proteins do not transport ASC (ascorbate ion) or AA (ascorbic acid)

NOT CORRECT!

I'll cover this misgiving first!

SVCT1 is expressed predominantly in epithelial tissues such as intestine where it contributes to the supply and maintenance of whole-body ascorbic acid levels.

The expression of SVCT2 is relatively widespread, where it serves to either deliver ascorbic acid to tissues with high demand of the vitamin for enzymatic reactions or to protect metabolically highly active cells or specialized tissues from oxidative stress.

http://www.ncbi.nlm.nih.gov/pubmed/23506882

DHA, the oxidized form of ascorbic acid is taken up and distributed in the body by facilitated transport via members of the SLC2/GLUT family (GLUT1, GLUT3, and GLUT4).

http://www.ncbi.nlm.nih.gov/pubmed/23177992

GLUT1 is also a major receptor for uptake of Vitamin C as well as glucose, especially in non vitamin C producing mammals as part of an adaptation to compensate by participating in a Vitamin C recycling process. In mammals that do produce Vitamin C, GLUT4 is often expressed instead of GLUT1

https://en.wikipedia.org/wiki/GLUT1

The reduced vitamin C, DHA, can be indirectly imported by a three-step mechanism involving: 1) extracellular oxidization of ascorbate to DHA; 2) transport of DHA by the GLUT transporter; and 3) intracellular reduction of DHA to ascorbate.

http://jn.nutrition.org/content/137/10/2171.long


What glut transports are used the most by V-C

http://www.researchgate.net/publication ... _and_GLUT8

How does it get in the cells?

http://www.fasebj.org/content/19/12/1657.full





Want MORE???

[Johnwen]

This question dissected!

And while liposomal takes 2 to 3 hours to get the vitamin C in the blood (peak), it too can eliminate sinus drip in minutes after taking by mouth (this affect I assumed was because the liposomes enter the mucous membranes in the mouth)

These are excerpts from Dr. Levy's comment to you at this post

http://www.vitamincfoundation.org/forum ... =3&t=11942

However, emulsification is no more the same as liposome encapsulation than an apple is an orange.
a properly liposome-encapsulated preparation of vitamin C, which I have found to be substantially better than any other delivery form of vitamin C. A good liposome preparation of vitamin C can give the clinical benefits of IV vitamin C orally. Emulsification with just improved absorption into the blood will never do this.
Thanks,

Dr. Levy

Thank you! Dr. Levy.

This goes back to our discussion on liposome's

http://www.vitamincfoundation.org/forum ... 10&t=11219


I'll keep it simple!
When producing Lipo-C your going to have a residual amount of V-C still in the mix that didn't make it into the Liposphere's ( didn't get encapsulated). However this residual V-C may have attached themselves to the outer layer's of the spheres forming an emulsion. This emulsion will act and be processed just like V-C and have a rapid action just as a dose of V-C will.

Just like other V-C doses you will see the benefits of this rapidly absorbed emulsion as in this case clearing of the sinuses!

The encapsulated portion will be taken into the blood and there will be no rise in serum V-C levels because it's encapsulated. Those lipids that where not used by the cells will be broken down by the bodies immune system. Primarily macrophages which will break the sphere by consumption and release the V-C molecules into the blood if enough have been broken you will see a rise in blood levels. However without the appropriate amount of transporters they will be sent either to the liver or kidney's where they will either be recycled or disposed of in the same manner as other free V-C molecules would be.

The rise of blood levels at 2-3 hours is a product of cells not consuming the lipids and being broken down by the body.
To get an accurate picture of the actual amount of lipid absorption. The blood levels of the lipids would need to be measured to assure that the lipids were absorbed into the blood and not remaining in the digestive tract where they would be broken down and the V-C would be released into the blood from the digestive tract. Which would void the effectiveness of a liposome delivery into the cells.

So just measuring blood levels of V-C are not a accurate indicator of the efficacy of the product.

So the question is? Did the lipids actually make it into the blood or did they get broken down in the gut???

QUALITY!!!

[ofonorow]

johnwen, I hope you are planning on writing a book! (If so, I look forward to it.)

GLUT proteins do not transport ASC (ascorbate ion) or AA (ascorbic acid)

NOT CORRECT!

Your argument then is with the authors of that book! (That GLUT does not transfer reduced ascorbate makes perfect sense to me.)

And yes, we have discussed many of the liposomal issues before. Even the notion that some vitamin C remains outside the liposomes (as an emulsion argument) but this does not appear to explain a) why taking a True-liposomal by mouth clears sinuses as rapidly as a 500 mg ascorbic acid tablet, but the professional measurements show that vitamin C levels in the blood don't peak for 2 to 3 hours. (Or the claim that Eme Blair's True-Liposomes are 98% encapsulated . The simplest explanation is that some of this nano sized spheres can make it through mucous tissue in the mouth to the sinuses.)

I still would like an answer to the question how a 500 mg ascorbic acid tablet, which must take some time to dissolve in the stomach can clear mucous from the sinuses in as little as five minutes. I don't think its possible that it reaches the small intestines in that short interval.

Now back to read your links..

Added - so your last link (vitamin C update in the mitochondria) says the following.

We found that the oxidized form of vitamin C, dehydroascorbic acid (DHA), enters mitochondria via facilitative glucose transporter 1 (Glut1) and accumulates mitochondrially as ascorbic acid (mtAA).

So which link again, claims that reduced vitamin C is taken up by GLUT???

[Johnwen]

Actually all of them do! However if you want to get down to the nitty gritty this one goes into a lot of detail!

http://www.researchgate.net/publication ... _and_GLUT8

Did you miss the via in your quote???

enters mitochondria via facilitative glucose transporter 1 (Glut1)

VIA; Preposition! By way of!!!!