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Витамин С: аскорбат и аскорбиновая кислота

Витамин С несчастный треплют лет 100 уже.

Есть теория (или гипотеза), что пить надо строго аскорбат, но не аскорбиновую кислоту. Мол, усваивается организмом только именно аскорбат (https://healthy-back.livejournal.com/412842.html, https://healthy-back.livejournal.com/382831.html#UPD, https://healthy-back.dreamwidth.org/403848.html, https://healthy-back.dreamwidth.org/374962.html#UPD). Попытка найти ссылки на исследования по этому вопросу привела к 2 статьям:

1) на сайте https://alkalineforlife.com/. Это люди, которые борются за правильный уровень кислотности в организме и считают лимон — главным ощелачиваетелем. Статья есть, но нет ссылки НИ НА ОДНО исследование откуда они что взяли. Считают, что картинок молекул достаточно.

Статья содержит прямое враньё по поводу приятного вкуса аскорбата и неприятного вкуса кислоты, а также ограничений потенциальных максимальных доз из-за вкуса. На практике вы не можете выпить много ни того, ни другого из-за поноса, который они вызовут в больших дозах.

2) Статья врача о том, что вся эта волна про преимущество аскорбата пошла из-за того, что для серьёзного лечения нужно внутривенное введение, а при внутривенном введении кислота слишком кислая, её надо бодяжить на месте перед введением — не будет стерильности. И сейчас кислоту для внутривенного введения в США вообще не достать, только аскорбат.

А для орального применения — всё равно что пить, если нет раздражения желудка. Единственно — кислота в таблетках продаётся, там всегда что-то набодяжено для текстуры и цвета, а аскорбат — чистый порошок в банке, можно пить ложками.

Я скопирую обе статьи, они небольшие. Переводить не стану. Кому интересно — Промт https://www.online-translator.com/ стал переводить заметно лучше, чем 20 лет назад. Окончания падежей ещё не согласует, но переводит прямо фразами.

https://alkalineforlife.com/blogs/vitamin-c/ascorbate-vs-ascorbic-acid
VITAMIN C: IS IT ALL THE SAME?

Here at Alkaline for Life® we use and teach about the L-ascorbate form of vitamin C. This is the form of vitamin C that our body uses. Within the human body, 99% of the vitamin C under physiological conditions is in the form of L-ascorbate.

Another term that is often used for vitamin C is “ascorbic acid.” While “ascorbic acid” and “ascorbate” are often used without distinguishing one from the other, there are important differences between these two chemical compounds. Here are a few differences between common vitamin C which is ascorbic acid, and a fully buffered, fully reduced L-ascorbate.

COMMON VITAMIN C VERSUS “L-ASCORBATE”

Today in the US, most people supplementing with vitamin C use the “ascorbic acid” form, not the “ascorbate” form. Ascorbic acid is inexpensive and readily available; however, “ascorbic acid” is a distinct molecule from “ascorbate” as illustrated below.

Ascorbate is the metabolite of vitamin C actually used within the body and thus the preferable form of vitamin C. Ascorbate is the superior form of vitamin C for several reasons:

1) Ascorbate is the physiological form of vitamin C used by the body.

2) Ascorbate is the form of vitamin C that serves as the most powerful water-soluble antioxidant.

Ascorbate can have different qualities. First, it can be “fully reduced," which means its electrons are all in place and ready to be donated for full antioxidant activity. “Fully reduced” means that it is not already oxidized, even partially. To be “fully reduced” the ascorbate must be processed without exposure to oxygen, light or excess heat.

Second, ascorbate can also be “fully buffered.” A “fully buffered” ascorbate is one that has been combined with small amounts of selected minerals (for example, calcium, magnesium, zinc, potassium). “Fully buffered” ascorbate reduces metabolic acidity and contributes to a life-supporting, slightly alkaline tissue pH.

Over decades of clinical practice, I have found that a pure and properly processed, fully buffered and fully reduced ascorbate is a potent antioxidant and the best natural antiviral and repair agent available.

COMPARISON OF COMMON ASCORBIC ACID WITH A FULLY BUFFERED, FULLY REDUCED ASCORBATE

Common Vitamin C (aka Ascorbic Acid):

● Vitamin C is produced by plants and most animals (humans being one of the exceptions).

● Vitamin C/ascorbic acid is acidic.

● The vast majority of the vitamin C found on store shelves today is corn-based and contains corn antigens.

● The vast majority of the vitamin C found on store shelves today is at least one-half synthetic, in the D form, not the natural L form. This synthetic D form of vitamin C is not useful in the body.

● The vast majority of the vitamin C found on store shelves today has a reduced antioxidant potential due to processing. Vitamin C becomes oxidized upon exposure to oxygen, moisture, light, and high temperatures.

● The vast majority of the vitamin C found on store shelves today contains unwanted additives including colorings, flow agents, binders, stabilizers, and the like.

● The vast majority of the vitamin C found on store shelves has an unpleasant acidic taste, which limits higher dose usage.

A Fully Buffered, Fully Reduced Ascorbate (Alkalini-C):

● Ascorbate is a form of vitamin C that is actually used within the body.

● Ascorbate is the biologically active form of vitamin C, which serves as the most abundant and important water-phase antioxidant and a substrate for numerous enzyme reactions.

● Ascorbate is an alkalizing agent capable of donating electrons to energize our cells.

● Ascorbate can be completely buffered with alkalizing minerals to enhance absorption and tissue action.

● Alkalini-C ascorbate is fully reduced and protected from oxidation during manufacture and storage resulting in an extraordinarily high antioxidant capacity.

● Alkalini-C ascorbate is free of stabilizers, flow agents, or other additives.

● Alkalini-C ascorbate has a pleasant taste and is easy on the stomach, making it suitable for high-dose usage.

ASCORBIC ACID (COMMON VITAMIN C) VS. A FULLY BUFFERED, FULLY REDUCED L-ASCORBATE (ALKALINI-C)

Ascorbic Acid/Common Vitamin C L-Ascorbate
Produced in plants Physiologic form of vitamin C used in the human body
Acidic Alkalizing
Product is often oxidized with lowered antioxidant potential Fully reduced and protected from oxidation
Made up of generally one-half of the synthetic D form that is not useful to body Natural L form that is useful to body
Contains additives such as colorings, flow agents, binders, stabilizers, etc. Free of stabilizers, flow agents, or other additives
Unpleasant taste limits high-dose use Pleasant taste suitable for high-dose use


https://www.consultdranderson.com/ascorbic-acid-versus-sodium-ascorbate/
A great deal of information circulates about ascorbic acid and various forms of it which are available. Thoughts as to its chemistry, absorption, and bioavailability and other factors are debated more so in the arena of social media and less so in the scientific community.

In this blog, I will address the difference between ascorbic acid (ASC) and sodium ascorbate (NaASC) to a small degree in their oral use and to a larger degree in their intravenous (IV) use.

Ascorbic acid is an organic acid with a ring structure similar to glucose. It mainly exists in two forms in humans L-ascorbate (reduced form – ASC) and Dehydroascorbate (oxidized form- DHA). (To be complete there is an intermediate molecule the ascorbate radical which has one more electron than DHA, and one less than ASC, but it converts to DHA in milliseconds normally.) As such it absorbs partly via GLUT transporters but also via specific “vitamin c” transporters of the SVCT family. The GLUT family transport DHA via facilitated diffusion into cells (where DHA must be reduced to ASC to be in its antioxidant state) and the SVCT family transport ASC directly into cells via sodium-dependent co-transporters. [PMID: 11396616] In the intestine this difference between DHA being absorbed via facilitated diffusion at the GLUT receptor family and ASC by either GLUT or the sodium-dependent co-transport of SVCT (with a preference for SVCT by ASC). [PMID: 21749321]

Multiple forms of ASC exist for oral use and a few forms for parenteral (usually IV) administration are used. Plain ASC is used as an oral supplement and is acidic but well absorbed. A “fat-soluble” ester form of ASC (ascorbyl palmitate) is used as an oral and topical delivery system for ASC and then “mineral ascorbates” are often promoted as “buffered vitamin c” supplements. (Of note ‘Ester-C’ ™ is actually a mineral and not an ester version of ascorbate).

In oral administration, ASC is well absorbed but some report GI upset and will have fewer GI symptoms with a mineral “buffered” form of ASC. Commonly this is NaASC, Calcium ASC, or mixtures that include one or both of these forms and any number of other mineral ascorbate forms. While there is some idea that ASC versus a mineral ASC have different absorption overall this is likely a minor issue in regard to GI to Plasma uptake overall.

In parenteral use (mainly IV in humans) a misconception exists regarding the use of “Ascorbic Acid versus Sodium Ascorbate” and the superiority of NaASC over ASC in the IV form. In days gone by one could obtain pure ASC and solubilize it and add it to an IV. This led one of my mentors, Dr. Robert Cathcart, to give instructions to physicians regarding how to make a NaASC infusion solution as opposed to a pure (and acidic) ASC IV. This is believed to be (by some) still a necessary distinction to make in modern IV Vitamin C compounding. While it was a consideration years ago for us, in modern IV Vitamin C use in North America the regulations of manufacturing of IV Vitamin C actually render all IV Vitamin C NaASC. Why?

Legally any pharmacy or pharmaceutical manufacturer must follow the guidelines of the United States Pharmacopeia (USP) which allows pH of infusions to be in the range of 4.5 – 8.0 however it is considered the medical standard of care to infuse as close to physiological human pH as possible (with rare exceptions) which is considered in pharmacology literature to be pH 7.4 plus or minus (also expressed as “pH 7 to 8”). [PMID: 12593942] So when considering this and then a pharmacy has a base solution of ASC with a pH PubChem lists it at 2.0 to 3.0 pH range (specifically ASC pH is concentration dependent but 2.0 – 3.0 is the range it falls in) the CANNOT legally make a sterile pure ASC for infusion. They MUST buffer it with sodium bicarbonate and or sodium hydroxide – both of which yield an acceptable pH for USP AND create NaASC. So while the label of IV ASC usually says “Ascorbic Acid for Infusion” or some similar phrase it is actually NaASC. IV ASC in areas controlled by USP rules can only be made and sold as NaASC.

Yes in the early days of Dr. Klenner, Dr. Cathcart, and even me there was an option and distinction between IV ASC and IV NaASC. In modern times you only can infuse NaASC – you cannot purchase it any other way from any US pharmacy. And that has been the case for many years. Those who promote “the only real NaASC for infusion” are generally either selling something, very misinformed about the above or both (I have spoken to many). They even often emphatically invoke Dr. Cathcart’s name as “proof” of their confusion at which point I normally say “I knew Dr. Cathcart did you?” and proceed to tell them the above.

So, for oral use, NaASC as a mineral ascorbate can be great in sensitive stomachs and may have a slight GI absorption advantage over ASC but that absorption claim in and of itself has a number of mitigating factors.

For IV use you can only infuse NaASC.

A resource for extensive scientific updates and data: An extensive publication regarding most aspects of Vitamin C physiology/biology see Padayatty and Levine PMID: 26808119
Tags: Фармакология
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