• Log in with Facebook Log in with Twitter Log In with Google      Sign In    
  • Create Account
  LongeCity
              Advocacy & Research for Unlimited Lifespans

Photo
- - - - -

B12 mega doses


  • Please log in to reply
29 replies to this topic

#1 Invariant

  • Guest
  • 176 posts
  • 60
  • Location:-

Posted 20 January 2010 - 08:32 PM


Hi all,

After hearing about some of the benefits of vitamin b12, I started taking 1mg (1000mcg) b12 a couple times a week. Since then, I have developed a rash/redness on my forehead, wrists, elbows and lower back. I have a history of allergies, so that was my initial thought, but I also suspected it has something to do with my supplements.

I just read this on wikipedia

Dermatologic: Itching, rash, transitory exanthema, and urticaria have been reported. Vitamin B12 (20 micrograms/day) and pyridoxine (80 mg/day) has been associated with cases of rosacea fulminans, characterized by intense erythema with nodules, papules, and pustules. Symptoms may persist for up to 4 months after the supplement is stopped, and may require treatment with systemic corticosteroids and topical therapy.


What do the more knowledgeable members of the forum think of this?

Megadosing b12 seems very common on this forum, with some well informed people taking up to 5mg a day. The 1mg I'm taking is already 16,666% of the RDA.. What's the rationale behind this?

#2 kismet

  • Guest
  • 2,984 posts
  • 424
  • Location:Austria, Vienna

Posted 20 January 2010 - 10:58 PM

The 1mg I'm taking is already 16,666% of the RDA.. What's the rationale behind this?

Saturation of active absorption mechanisms. Look it up if you haven't yet, a very important concept when it comes to b12.

The article provides no references, but if I had to guess: for some reason medical texts often mention extremely rare and improbable side-effects of many vitamins (e.g. acne and vitamin D, ironically there's no evidence I could find; only evidence to the contrary). Often based on (antiquated) case-reports, not able to prove causation, or based on weak mechanistical plausibility.

The B vitamins are said to be linked with acne medicamentosa, but is it a side-effect of any relevance? (it isn't if the incidence is low enough) There is no such thing like a safe drug, supplement, nutrient or any substance for that matter; so we have to to live with the risk of some side-effects if the benefits outweigh said risks...

I am more interested in long term safety / toxicity of B12.

Edited by kismet, 20 January 2010 - 10:59 PM.


sponsored ad

  • Advert
Click HERE to rent this advertising spot for SUPPLEMENTS (in thread) to support LongeCity (this will replace the google ad above).

#3 Sillewater

  • Guest
  • 1,076 posts
  • 280
  • Location:Canada
  • NO

Posted 21 January 2010 - 09:50 AM

The 1mg I'm taking is already 16,666% of the RDA.. What's the rationale behind this?

Saturation of active absorption mechanisms. Look it up if you haven't yet, a very important concept when it comes to b12.


So b12 isn't 100% absorbed your saying. What other nutrients are required to take in more than the RDA?

#4 wolfeye

  • Guest
  • 124 posts
  • 7

Posted 22 January 2010 - 02:00 PM

Cancer Incidence and Mortality After Treatment With Folic Acid and Vitamin B12

Conclusion Treatment with folic acid plus vitamin B12 was associated with increased cancer outcomes and all-cause mortality in patients with ischemic heart disease in Norway, where there is no folic acid fortification of foods.



http://jama.ama-assn...ourcetype=HWCIT

#5 Jay

  • Guest
  • 406 posts
  • 22
  • Location:New York

Posted 22 January 2010 - 02:19 PM

Cancer Incidence and Mortality After Treatment With Folic Acid and Vitamin B12

Conclusion Treatment with folic acid plus vitamin B12 was associated with increased cancer outcomes and all-cause mortality in patients with ischemic heart disease in Norway, where there is no folic acid fortification of foods.



http://jama.ama-assn...ourcetype=HWCIT


The result is much more likely attributable to folic acid.

Edited by Jay, 22 January 2010 - 02:19 PM.


#6 kismet

  • Guest
  • 2,984 posts
  • 424
  • Location:Austria, Vienna

Posted 22 January 2010 - 03:36 PM

So b12 isn't 100% absorbed your saying. What other nutrients are required to take in more than the RDA?

Nope, that's not what I am saying at all -- B12 is well absorbed at or around RDA levels, but not at higher intakes. IIRC around ~1% of mega-doses are absorbed via passive diffusion (or something in that ballpark see for instance: http://lpi.oregonsta...ins/vitaminB12/)

Edited by kismet, 22 January 2010 - 03:38 PM.


#7 bocadillodelomo

  • Guest
  • 49 posts
  • -2

Posted 24 January 2010 - 09:00 PM

You have to understand the RDA is generally garbage for vitamins and minerals. It's a good guideline for the absolute minimum. The reason that b12 sublinguals come in such "high doses" is that usually those who are deficient have run out of their stores in their liver and have absorption issues, conversion issues, etc. And like ^ said upabove, it is to saturate your tissues and stores. The RDA of 4-6 mcg or whatever minute amount is not enough for repair of nerve damage or replication of cells, restoring body needs, etc. And i would also be interestedin the long term effects of b12 but as far as toxicity goes, there have been people who dose at 100,000 mcg (yes, thats 100 grams) of b12 daily with no adverse effect.

In fact those who have neuropathy and anemia and all sorts, seem to need more and more of both the dibencozide form (adenosyl) and methyl and have even healed their nerve and bodily functions from mega dosing b12. (assuming b12 was the problem, which there is a very good chance it is considering b12 is so misdiagnosed). 1000 mcg is not even that much actually.


I'm not sure about your rash though, are you allergic to any other ingredients in the pill? Sorbitol, magnesium stearate, etc.?

The wikipedia info doesn't seem very reliable to me but that's just a personal opinion. There have been cases of b12 rashes and hives but those were documented from b12 shots, not sublinguals ..which can be attributed possibly to the other junk that's in the b12 solutions.

#8 Animal

  • Guest
  • 689 posts
  • 158
  • Location:UK

Posted 24 January 2010 - 10:16 PM

there have been people who dose at 100,000 mcg (yes, thats 100 grams) of b12 daily with no adverse effect.


100,000 micrograms is not 100 grams. :p

#9 bocadillodelomo

  • Guest
  • 49 posts
  • -2

Posted 24 January 2010 - 10:26 PM

there have been people who dose at 100,000 mcg (yes, thats 100 grams) of b12 daily with no adverse effect.


100,000 micrograms is not 100 grams. :p


oh shit i meant 10 grams. hahahah def not 100

#10 kismet

  • Guest
  • 2,984 posts
  • 424
  • Location:Austria, Vienna

Posted 24 January 2010 - 11:13 PM

You have to understand the RDA is generally garbage for vitamins and minerals. It's a good guideline for the absolute minimum.

(Un)fortunately that's not true. The RDAs are just fine for most vitamins and minerals. Evidence to the contrary?

#11 bocadillodelomo

  • Guest
  • 49 posts
  • -2

Posted 25 January 2010 - 12:04 AM

You have to understand the RDA is generally garbage for vitamins and minerals. It's a good guideline for the absolute minimum.

(Un)fortunately that's not true. The RDAs are just fine for most vitamins and minerals. Evidence to the contrary?


Well depends on what you mean by "evidence". If you're looking for studies on whether the RDA of 60 mg of vitamin C (as 100%) is sufficient for optimal health, there are too many relatives and subjectives to really provide this kind of evidence. But books like "the magnesium miracle", "the vitamin D cure", "Could it be b12?" outline just how much you have to take of a vitamin or a mineral to really see the benefit in your health. the recommended daily value set by the FDA is just a number, based on nothing other than toxicity and levels that are the absolute minimum for someone. As many people know, even health people benefit from taking 2000 IU of vitamin D which far above the RDA, or B12 would be another because of its highly complicated absorption process. RDA also doesn't take into consideration the bioavailability of vitamins and minerals and their delivery method. An oral tablet of 1000 mcg of methylcobalamin is 1666% of the "RDA", and yet absolutely pales in comparison to a sublingual form of the same dose. Or 1000 mcg of cyanocobalamin is EQUAL to 1000 mcg of methylcobalamin on the measurement scale of the RDA, and yet everyone knows that the bioavailability and absorption is literally a hundred times greater in the methyl form. (This i can find you a study but i have to dig around. :p)
I'm not saying the RDA isn't useful, they're a very very lenient guideline for toxicity and minimum that everyone should have, but doesn't really take into consideration the different forms of vitamins and minerals and absorption factors, or sometimes downright off on the numbers.

It's interesting because i know it's not very popular on this forum, but i'm really a fan of whole food nutrient vitamins like New chapter, etc. and just based on personal experience and the feedback of others that i have recommended them to, the "feeling" of health from whole food nutrients are better than let's say, a well a multivitamin with the same ingredients and the same RDA. And i can swear by the effects of whole food vitamin C like NOW's Acerola which has 270mg of vitamin C for 1 teaspoon, and yet is way more effective in my experience than 2 mg of absorbic acid. But that's another discussion. :p

#12 VespeneGas

  • Guest
  • 600 posts
  • 34
  • Location:Oregon, atm

Posted 25 January 2010 - 03:26 AM

there have been people who dose at 100,000 mcg (yes, thats 100 grams) of b12 daily with no adverse effect.


100,000 micrograms is not 100 grams. :p


oh shit i meant 10 grams. hahahah def not 100


Actually, it's 100 milligrams.

I'd love to see the study that shows that methylcobalamin is 100 times better absorbed than cyanocobalamin (I'd accept 3 times better absorbed).

It appears that sublingual is no better than oral dosing with b12:

The Journal of Alternative and Complementary Medicine A Single-Center, Double-Blinded, Randomized Controlled Study to Evaluate the Relative Efficacy of Sublingual and Oral Vitamin B-Complex Administration in Reducing Total Serum Homocysteine Levels
Yuka YazakiCollege of Naturopathic Medicine, University of Bridgeport, Bridgeport, CT.Gigi ChowCollege of Naturopathic Medicine, University of Bridgeport, Bridgeport, CT.Mark Mattie, M.D., Ph.D.Clinical Research, University of Bridgport, Bridgeport, CT, and Yale University, New Haven, CT. Objective: Reports correlating total homocysteine (tHcy) concentrations with arteriosclerosis have become a matter of interest amongst healthcare professionals and the public. Several commercial preparations of vitamin B complexes have been marketed as supplements intended to reduce elevated levels of tHcy. Among these preparations are those that have been specifically designed for sublingual administration. This study is designed to evaluate the relative efficacy of sublingually versus orally delivered vitamin B complex in reducing serum tHcy levels.

Design: Forty-one (41) subjects, between the ages of 50 and 80 years with total serum tHcy concentrations exceeding 11 µmol/L, were treated with a six-week regimen of vitamin B complex. Each B complex consisted of 1000 µg vitamin B12 (as methylcobalamin), 400 µg folate (as folic acid), and 5 mg vitamin B6 (as pyridoxine HCl). Participants in the study were randomized into two groups designated, retrospectively, as SL and PO. Members of group SL were given a sublingually delivered vitamin B complex and a matching orally delivered placebo. Members of group PO were given an orally delivered vitamin complex and a matching sublingually delivered placebo. A statistically significant reduction in tHcy values was observed in both groups upon completion of the 6-week protocol.

Results: There was no statistically significant difference in serum tHcy concentrations between SL and PO groups either before or after treatment, substantiating the idea that there is no difference in efficacy between the two methods of vitamin complex delivery.

#13 nightlight

  • Guest
  • 374 posts
  • 36
  • Location:Lexington MA

Posted 25 January 2010 - 04:50 AM

Cancer Incidence and Mortality After Treatment With Folic Acid and Vitamin B12

Conclusion Treatment with folic acid plus vitamin B12 was associated with increased cancer outcomes and all-cause mortality in patients with ischemic heart disease in Norway, where there is no folic acid fortification of foods.



http://jama.ama-assn...ourcetype=HWCIT


That trial didn't show that supplementing b12+folic acid causes adverse effects (more cancers) but rather that supplementing for ~39 months plus the abrupt termination of the supplements for ~38 months resulted in the observed effects. The latter sequence is entirely different causal chain being tested.

Consider an analogy -- effects of supplementing person's income on depression, happiness, bankruptcy, financial difficulties, hunger, medical problems,.... Say, you wish to prove that increasing person's income will make it all worse. From common experience we all know that's not true. Yet the sponsor of your research wants you to scientifically prove just that. How do you do it? You select subjects from the middle/low income and those in the test group are given an extra $100,000 every year, for 3 years, while the control group is left alone to live as before. Then you abruptly stop the cash injection to the test group and watch the effects for another 3 years. They will end up worse off on just about every measure. Can you conclude that the extra $100,000 caused those problems? The same goes in any other analogous up-down sequence (e.g. getting promoted then abruptly demoted vs left in the same position, having a girlfriend or wife then losing her vs not having one, having a kid then losing it vs not having kids,...). The negative effects in all such up-down scenarios are entirely due to the abrupt halt of the otherwise beneficial influence.

That's the kind of transparent leap made in the above paper. It is not clear why did they abruptly halt the supplements, then wait for the same period to tally the effects. That needlessly muddies the the water of causes and effects (maybe that's what they intended). It is even less clear why did they misattribute the negative effects to the supplementation rather than to the actual set of the conditions being tested (supplementation+abrupt termination). This kind of sleight of hand is typical for the big pharma/sickness industry sponsored junk science against any inexpensive supplements or remedies.

Edited by nightlight, 25 January 2010 - 04:51 AM.


#14 neogenic

  • Guest
  • 481 posts
  • 6
  • Location:Charlotte, NC

Posted 25 January 2010 - 03:20 PM

No one's stating differences in types of "b12"...cyanocobalamin (cyanide-bound cheap supplemental form in your cheerios), methylcobalamin (co-enzymated/active), adenosylcobalamin (coenzymated/active-krebs), and hydro (food-based form that needs to be converted, but is "natural"). Plus there's intrinsic factor/gastric acid differences. Plus there's differences with injections, sublingual or just PO (by mouth) capsules.

Methylcobalamin, for me, take in large doses is highly noticeable. 1mg is good...but 5mg is much better. I can tell the difference. I do sublingual tabs, like NOW's Brain B-12. NOW has new B-vitamin "shots" (not the IM/IV kind...little liquid shots) that have 10,000mcg (10mg) of cyano...and that's not that noticeable to me...even at that dose.

#15 Clarity

  • Guest
  • 135 posts
  • 13
  • Location:Long Island, NY

Posted 25 January 2010 - 03:34 PM

I don't agree that sublingual isn't better absorbed than oral. I was taking ample B's (tablets, capsules) and I had low B12. I then started taking B12 sublingually and my levels actually got too high, pushing my homocysteine below acceptable levels (I was also taking high dose folic acid too). Incidently, too low homocysteine can cause a pro-oxident state. I no longer have the link, but if you google a little you may be able to find some info on that.

#16 VespeneGas

  • Guest
  • 600 posts
  • 34
  • Location:Oregon, atm

Posted 25 January 2010 - 07:52 PM

No one's stating differences in types of "b12"...cyanocobalamin (cyanide-bound cheap supplemental form in your cheerios), methylcobalamin (co-enzymated/active), adenosylcobalamin (coenzymated/active-krebs), and hydro (food-based form that needs to be converted, but is "natural").


Bocadillodellomo wrote:

Or 1000 mcg of cyanocobalamin is EQUAL to 1000 mcg of methylcobalamin on the measurement scale of the RDA, and yet everyone knows that the bioavailability and absorption is literally a hundred times greater in the methyl form. (This i can find you a study but i have to dig around. ;) )


Are you (neogenic) saying that there ARE differences in absorption between the different forms? The first part of your post seems to suggest no, but the latter part yes. Obviously the methyl group on the methylcobalamin molecule makes it more suited to jump immediately into the methylation cycle, I've just never seen any pharmacodynamic studies showing improved absorption of methyl vs cyano, or of sublingual vs oral.

#17 neogenic

  • Guest
  • 481 posts
  • 6
  • Location:Charlotte, NC

Posted 25 January 2010 - 08:54 PM

No one's stating differences in types of "b12"...cyanocobalamin (cyanide-bound cheap supplemental form in your cheerios), methylcobalamin (co-enzymated/active), adenosylcobalamin (coenzymated/active-krebs), and hydro (food-based form that needs to be converted, but is "natural").


Bocadillodellomo wrote:

Or 1000 mcg of cyanocobalamin is EQUAL to 1000 mcg of methylcobalamin on the measurement scale of the RDA, and yet everyone knows that the bioavailability and absorption is literally a hundred times greater in the methyl form. (This i can find you a study but i have to dig around. ;) )


Are you (neogenic) saying that there ARE differences in absorption between the different forms? The first part of your post seems to suggest no, but the latter part yes. Obviously the methyl group on the methylcobalamin molecule makes it more suited to jump immediately into the methylation cycle, I've just never seen any pharmacodynamic studies showing improved absorption of methyl vs cyano, or of sublingual vs oral.

I was wondering why you and the person above you interpreted my statement that way.

Let me be clear. I am saying...YES...there are massive differences. I was simply saying that no one in this thread is alluding to these differences, of which there are many. Such as the forms, the IF/gastric acid thing, the delivery, etc.

People in the thread kept typing "B12" and maybe mentioning a dose. This is somewhat ridiculous and is what bothered me. Form and delivery are crucial to the discussion and relevance from one statement to the next, whether scientific or anecdotal may be easily questionable with that omission...or overgeneralization as it may be.

Sorry, for the confusion. My stance is clear and what you interpreted at the bottom...is also what I was saying at the top...it may not have read that clearly, my apologies. Cyano has to convert to methyl and is an inefficient process vs. directly using the coenzyme form. There are issues with large doses in the cyano form. I will grab some info to post here.

Edited by neogenic, 25 January 2010 - 08:55 PM.


#18 neogenic

  • Guest
  • 481 posts
  • 6
  • Location:Charlotte, NC

Posted 25 January 2010 - 09:11 PM

This isn't the differences in the forms, but a good overview on absorption.
Human absorption and distribution (from Wikipedia) http://en.wikipedia....iki/Vitamin_B12

The human physiology of vitamin B12 is complex, and therefore is prone to mishaps leading to vitamin B12 deficiency. Unlike most nutrients, absorption of vitamin B12 actually begins in the mouth where small amounts of unbound crystalline B12 can be absorbed through the mucosa membrane.[17] Food protein bound vitamin B12 is digested in the stomach by proteolytic gastric enzymes, which require an acid pH (Even small amounts of B12 taken in supplements bypasses these steps, and thus, any need for gastric acid, which may be blocked by antacid drugs). Once the B12 is freed from the proteins in food, R-proteins, such as haptocorrins and cobalaphilins, are secreted, which bind to free vitamin B12 to form a B12-R complex. Also in the stomach, intrinsic factor (IF), a protein synthesized by gastric parietal cells, is secreted in response to histamine, gastrin and pentagastrin, as well as the presence of food. If this step fails due to gastric parietal cell atrophy (the problem in pernicious anemia), sufficient B12 is not absorbed later on, unless administered orally in relatively massive doses (500 to 1000 µg/day). Due to the complexity of B12 absorption, geriatric patients, many of whom are hypoacidic due to reduced parietal cell function, have an increased risk of B12 deficiency.[21]
In the duodenum, proteases digest R-proteins and release B12, which then binds to IF, to form a B12-IF complex. B12 must be attached to IF for it to be absorbed, as receptors on the enterocytes in the terminal ileum only recognize the B12-IF complex, in addition, intrinsic factor protects the vitamin from catabolism by intestinal bacteria. The conjugated vitamin B12-intrinsic factor complex (IF/B12) is normally absorbed by the terminal ileum of the small bowel. Therefore, absorption of food vitamin B12 requires an intact and functioning stomach, exocrine pancreas, intrinsic factor, and small bowel. Problems with any one of these organs makes a vitamin B12 deficiency possible.
Once the IF/B12 complex is recognized by specialized ileal receptors, it is transported into the portal circulation. The vitamin is then transferred to transcobalamin II (TC-II/B12), which serves as the plasma transporter of the vitamin. Genetic deficiencies of this protein are known, also leading to functional B12 deficiency.
For the vitamin to serve inside cells, the TC-II/B12 complex must bind to a cell receptor, and be endocytosed. The transcobalamin-II is degraded within a lysosome, and free B12 is finally released into the cytoplasm, where it may be transformed into the proper coenzyme, by certain cellular enzymes (see above).
Hereditary defects in production of the transcobalamins and their receptors may produce functional deficiencies in B12 and infantile megaloblastic anemia, and abnormal B12 related biochemistry, even in some cases with normal blood B12 levels.[22]
Individuals who lack intrinsic factor have a decreased ability to absorb B12. This results in 80-100% excretion of oral doses in the feces versus 30-60% excretion in feces as seen in individuals with adequate intrinsic factor.[21]
The total amount of vitamin B12 stored in body is about 2,000-5,000 µg in adults. Around 50% of this is stored in the liver.[17] Approximately 0.1% of this is lost per day by secretions into the gut as not all these secretions are reabsorbed. Bile is the main form of B12 excretion, however, most of the B12 that is secreted in the bile is recycled via enterohepatic circulation.[17] Due to the extremely efficient enterohepatic circulation of B12, the liver can store several years’ worth of vitamin B12; therefore, nutritional deficiency of this vitamin is rare. How fast B12 levels change depends on the balance between how much B12 is obtained from the diet, how much is secreted and how much is absorbed. B12 deficiency may arise in a year if initial stores are low and genetic factors unfavourable or may not appear for decades. In infants, B12 deficiency can appear much more quickly.[23]


Edited by neogenic, 25 January 2010 - 09:16 PM.


#19 neogenic

  • Guest
  • 481 posts
  • 6
  • Location:Charlotte, NC

Posted 25 January 2010 - 09:16 PM

Again from wiki:

Cyanocobalamin is one such "vitamer" in this B complex, because it can be metabolized in the body to an active co-enzyme form. However, the cyanocobalamin form of B12 does not occur in nature normally, but is a byproduct of the fact that other forms of B12 are avid binders of cyanide (-CN) which they pick up in the process of activated charcoal purification of the vitamin after it is made by bacteria in the commercial process. Since the cyanocobalamin form of B12 is easy to crystallize and is not sensitive to air-oxidation, it is typically used as a form of B12 for food additives and in many common multivitamins. However, this form is not perfectly synonymous with B12, inasmuch as a number of substances (vitamers) have B12 vitamin activity and can properly be labeled vitamin B12, and cyanocobalamin is but one of them. (Thus, all cyanocobalamin is vitamin B12, but not all vitamin B12 is cyanocobalamin).[3]


This last statement was my point exactly on this discussion of "B12" and the generalization of the term, when in fact that could mean many, many things...not all comparable.

Now think about this next statement with 10,000mcg per serving of cyanocobalamin in products, or people using 2 or 3 "b12" tabs of cyano-

A common synthetic form of the vitamin, cyanocobalamin, does not occur in nature, but is used in many pharmaceuticals and supplements, and as a food additive, due to its stability and lower cost. In the body it is converted to the physiological forms, methylcobalamin and adenosylcobalamin, leaving behind the cyanide, albeit in minimal concentration. More recently, hydroxocobalamin (a form produced by bacteria), methylcobalamin, and adenosylcobalamin can also be found in more expensive pharmacological products and food supplements. The utility of these is presently debated.



#20 neogenic

  • Guest
  • 481 posts
  • 6
  • Location:Charlotte, NC

Posted 25 January 2010 - 09:29 PM

Proc Natl Acad Sci U S A. 2008 Sep 23;105(38):14551-4. Epub 2008 Sep 8.
Errors, as mentioned in this study, can be avoided when using the coenzyme forms. 5-MTHF is a great example of a large portion of the population not being able to make it to the final, active step in "folic acid" (a different vitamin from this one...of course, but used for illustrative purposes).

Decyanation of vitamin B12 by a trafficking chaperone.
Kim J, Gherasim C, Banerjee R.

Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109-0606, USA.
The mystery of how the cyanide group in vitamin B(12) or cyanocobalamin, discovered 60 years ago, is removed, has been solved by the demonstration that the trafficking chaperone, MMACHC, catalyzes a reductive decyanation reaction. Electrons transferred from NADPH via cytosolic flavoprotein oxidoreductases are used to cleave the cobalt-carbon bond with reductive elimination of the cyanide ligand. The product, cob(II)alamin, is a known substrate for assimilation into the active cofactor forms, methylcobalamin and 5'-deoxyadenosylcobalamin, and is bound in the "base-off" state that is needed by the two B(12)-dependent target enzymes, methionine synthase and methylmalonyl-CoA mutase. Defects in MMACHC represent the most common cause of inborn errors of B(12) metabolism, and our results explain the observation that fibroblasts from these patients are poorly responsive to vitamin B(12) but show some metabolic correction with aquocobalamin, a cofactor form lacking the cyanide ligand, which is mirrored by patients showing poorer clinical responsiveness to cyano- versus aquocobalamin.

#21 meat250

  • Guest
  • 66 posts
  • -1

Posted 26 January 2010 - 03:34 AM

lets not forget intrinsic factor, which more is required if B's to get past it, especially the older you are

wiki:
Intrinsic factor is a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B12 later on in the terminal ileum.

Upon entry into the stomach, vitamin B12 becomes bound to haptocorrin (R factor), a glycoprotein. The resulting complex enters the duodenum, where pancreatic enzymes digest haptocorrin. In the less acidic environment of the small intestine, B12 can then bind to intrinsic factor. This new complex travels to the ileum, where special epithelial cells endocytose them. Inside the cell, B12 dissociate once again and bind to another protein, transcobalamin II. The new complex can exit the epithelial cells to enter the liver.

The intrinsic factor is an enzyme-like unidentified substance secreted by the stomach. It is present in the gastric juice as well as in the gastric mucous membrane. The optimum pH for its action is 7 and it is inactivated at temperatures above 45oC. It does not necessarily run parallel with the amount of HCl or pepsin in the gastric juice. So in some cases, the intrinsic factor may be present even if there is no HCl or Pepsin or vice versa. The site of formation of the intrinsic factor varies in different species. In pigs it is obtained from the pylorus and beginning of the duodenum. In human beings it is present in the fundus and body of the stomach

#22 kismet

  • Guest
  • 2,984 posts
  • 424
  • Location:Austria, Vienna

Posted 26 January 2010 - 05:20 PM

Well depends on what you mean by "evidence". If you're looking for studies on whether the RDA of 60 mg of vitamin C (as 100%) is sufficient for optimal health, there are too many relatives and subjectives to really provide this kind of evidence. But books like "the magnesium miracle", "the vitamin D cure", "Could it be b12?" outline just how much you have to take of a vitamin or a mineral to really see the benefit in your health.

Most people don't even reach the Mg RDA. There is no strong evidence to suggest that more than that is necessary or beneficial. Experimental data largely negative, prospective data confounded.
There is weak evidence to suggest that more vitamin C is beneficial, but the data is severely confounded by fruit and vegetable intake. The Linus pauling institute has a good take on the issue. Yes, the vit C RDA may be too low, but there is not conclusive evidence to suggest this is the case & getting enough C is extremely easy. Hence the issue is irrelevant for many people (and almost all people with a good diet).

the recommended daily value set by the FDA is just a number, based on nothing other than toxicity and levels that are the absolute minimum for someone.

Again, this is wrong.

As many people know, even health people benefit from taking 2000 IU of vitamin D which far above the RDA, or B12 would be another because of its highly complicated absorption process.

There is no such thing like a vitamin D RDA, only an AI. The FDA implicitely acknowledges that their number may suck and could be off by a mile. There is no evidence that healthy people need additional b12 (with rare exceptions -- pharmacologic use!) and the FDA & co acknowledge that elderly people need more B12.

I'm not saying the RDA isn't useful, they're a very very lenient guideline for toxicity and minimum that everyone should have, but doesn't really take into consideration the different forms of vitamins and minerals and absorption factors, or sometimes downright off on the numbers.

No.

Maybe vit D, but the FDA acknowledges the weakness of their recommendation (AI vs RDA). Vitamin C weak and shaky evidence. Vitamin K is also possibly too low by a factor of 10, but again this is supported by weaker and somewhat speculative evidence (a few prospective cohorts, not all of 'em showed benefits; small RCTs). Considering just how untypical those intakes are, long term studies would be needed to confirm safety before you can recommend that 300 million people just decaduple their intakes..

Edited by kismet, 26 January 2010 - 05:24 PM.


#23 neogenic

  • Guest
  • 481 posts
  • 6
  • Location:Charlotte, NC

Posted 26 January 2010 - 05:48 PM

lets not forget intrinsic factor, which more is required if B's to get past it, especially the older you are

wiki:
Intrinsic factor is a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B12 later on in the terminal ileum.

Upon entry into the stomach, vitamin B12 becomes bound to haptocorrin (R factor), a glycoprotein. The resulting complex enters the duodenum, where pancreatic enzymes digest haptocorrin. In the less acidic environment of the small intestine, B12 can then bind to intrinsic factor. This new complex travels to the ileum, where special epithelial cells endocytose them. Inside the cell, B12 dissociate once again and bind to another protein, transcobalamin II. The new complex can exit the epithelial cells to enter the liver.

The intrinsic factor is an enzyme-like unidentified substance secreted by the stomach. It is present in the gastric juice as well as in the gastric mucous membrane. The optimum pH for its action is 7 and it is inactivated at temperatures above 45oC. It does not necessarily run parallel with the amount of HCl or pepsin in the gastric juice. So in some cases, the intrinsic factor may be present even if there is no HCl or Pepsin or vice versa. The site of formation of the intrinsic factor varies in different species. In pigs it is obtained from the pylorus and beginning of the duodenum. In human beings it is present in the fundus and body of the stomach

We didn't. They were in my posts above.

No one's stating differences in types of "b12"...cyanocobalamin (cyanide-bound cheap supplemental form in your cheerios), methylcobalamin (co-enzymated/active), adenosylcobalamin (coenzymated/active-krebs), and hydro (food-based form that needs to be converted, but is "natural"). Plus there's intrinsic factor/gastric acid differences. Plus there's differences with injections, sublingual or just PO (by mouth) capsules.

Methylcobalamin, for me, take in large doses is highly noticeable. 1mg is good...but 5mg is much better. I can tell the difference. I do sublingual tabs, like NOW's Brain B-12. NOW has new B-vitamin "shots" (not the IM/IV kind...little liquid shots) that have 10,000mcg (10mg) of cyano...and that's not that noticeable to me...even at that dose.


Individuals who lack intrinsic factor have a decreased ability to absorb B12. This results in 80-100% excretion of oral doses in the feces versus 30-60% excretion in feces as seen in individuals with adequate intrinsic factor.[21]



#24 nito

  • Guest
  • 996 posts
  • 27

Posted 04 March 2010 - 01:52 AM

is it wise to take 1000 mcg or 5000 mcg of methyl b12, if you allready are taking SAMe which is linked to methyl?

#25 kurdishfella

  • Guest
  • 2,200 posts
  • -62
  • Location:USA
  • NO

Posted 23 November 2019 - 06:54 AM

b12 cream works well bypasses the gi tract https://www.amazon.c...n/dp/B00I2THMAW

 

taken together with dmso now you have something



#26 osris

  • Guest
  • 299 posts
  • 22

Posted 03 February 2022 - 07:05 PM

"Folic Acid Does Not Cause Cancer. So Who Made the Mistake?"

by Andrew W. Saul

"Science is a great servant but a poor master. Not infrequently, it can exemplify what Harvard math professor Tom Lehrer satirized as where "the important thing is to understand what you're doing, rather than to get the right answer." Just because a published study suggests something does not make it true.

I never liked math very much, and I still don't. But I am indebted to dedicated math teachers who taught me in spite of myself. Decades ago, one such teacher gave me wise advice that spans all disciplines: "Look at your answer. Does your answer make sense?"

So when research suggests that the vitamin folic acid somehow causes lung or colon cancer, it is time to hit the books. It may even occasionally be necessary to hit them right out of the way, and use common sense instead.

Folate, once known as vitamin B-9, is named after the dark green leafy vegetables it was first extracted from. "Folium" is Latin for leaf. Leaves and greens are high in folate. Herbivorous animals get plenty of folate because they eat plenty of foliage. Carnivorous animals also get plenty of folate, because they consume herbivorous animals. In the wild, this means the entire animal, including its abdominal organs full of the prey's last meal of partially digested vegetation. Indeed, the viscera are typically the first thing a predator eats.

If folate caused cancer, the whole animal kingdom would have a lot of it. And while wild animals have their own problems, cancer is rarely one of them.

If you look at the research suggesting a human cancer connection (1,2), it does not say that folate in food causes cancer. The research only points to folic acid, as specifically as found in supplements, as the bogey man.

But there is virtually no difference whatsoever between the two forms of this nutrient. Folate and folic acid are different only in whether the carboxylic acid groups have dissociated or not. Folic acid's molecular formula is C19, H19, N7, O6. Folate is C19, H18, N7, O6. The difference? Folate has one less hydrogen cation (H+). A hydrogen cation is a proton. A single proton. I have never seen evidence that protons cause cancer.

If folate/folic acid somehow caused cancer, it would have to be the rest of the molecule that is the problem. But most research shows that folic acid/folate prevents cancer. It is well-known that persons eating plant-based diets have a significantly lower risk of cancer. In addition to providing nutrients, eating more vegetation means more fiber and less constipation, valuable for preventing colon cancer. Herbivorous animals are definitely not constipated. Ask any dairy farmer, and you can start with me: many years ago, I used to milk 120 cows twice daily. When you walk behind Bossy, look out.

As for lung cancer, the research accusing folic acid also happens to show that 94% of the study subjects who developed lung cancer were either current or former smokers. Smoking causes cancer. Animals do not smoke. But they do eat a lot of foliage, either by grazing on greens or gorging on guts.

Both studies claiming that folic acid causes cancer were published in the Journal of the American Medical Association, which also contains a large amount of pharmaceutical advertising. JAMA is among the journals that peer-reviewed research has shown to be biased against vitamins due to vested interests. (3)

What is more likely: that a small group of scientists made an error or two, or that all of Nature did? On this one, I am backing the animals. 1.8 million species can't be all wrong."

(Andrew W. Saul taught biology, nutrition, and health science at the college level. He is the author of Doctor Yourself and Fire Your Doctor! and, with Dr. Abram Hoffer, co-author of Orthomolecular Medicine for Everyone and The Vitamin Cure for Alcoholism. Saul is featured in the documentary film Food Matters. He is on the Editorial Board of the Journal of Orthomolecular Medicine.)"


References:

(1) Folic acid, B12 may increase cancer risk.
http://www.webmd.com...ase-cancer-risk
Original study: http://www.ncbi.nlm....pubmed/19920236

(2) High doses of folic acid may increase colon cancer risk.
http://www.foxnews.c...,278237,00.html
Original study: http://www.ncbi.nlm....pubmed/17551129

(3) Pharmaceutical advertising biases journals against vitamin supplements.
http://orthomolecula...ns/v05n02.shtml
Original study: Kemper KJ, Hood KL. Does pharmaceutical advertising affect journal publication about dietary supplements? BMC Complement Altern Med. 2008 Apr 9;8:11. Full text at http://www.biomedcen.../1472-6882/8/11 or http://www.pubmedcen...bmedid=18400092

http://orthomolecula...ns/v06n17.shtml



#27 osris

  • Guest
  • 299 posts
  • 22

Posted 03 February 2022 - 07:10 PM

In 2017, there was a study claiming that high-dose vitamin B6 and B12 caused lung cancer in men. The following is a segment from a 2020 scientific literature review, debunking the 2017 "scare-mongering" study:
 
 
Update on Safety Profiles of Vitamins B1, B6, and B12: A Narrative Review:
 
"One of the few studies proposing an association between B vitamins and lung cancer risk was published by Brasky et al34 in 2017. The Vitamins and Lifestyle (VITAL) cohort included 77,118 subjects aged 50–76 from the US and examined the association between the long-term use of supplemental B vitamins and lung cancer risk.34 In the 6-year follow-up on average, 808 lung cancer cases occurred. The 10-year average daily doses from individual and multivitamin supplements as well as mixtures were retrospectively documented at baseline by self-assessment questionnaires. When trying to establish associations, the authors found the long-term use of high-dose vitamin B6 (defined as >20 mg/day) or B12 (defined as >55 µg/day) from individual supplement sources, but not multivitamins, to be associated with a 30–40% increase in lung cancer risk among male smokers.34 However, in our opinion, the study does not prove causality between B vitamin intake and lung cancer risk and has significant limitations, as already pointed out by Obeid and Pietrzik.60 When reviewing patient characteristics of the VITAL study, 42% of lung cancer cases were ≥70 years, while only 19% of controls belonged to this age group.34 The percentage of smokers was almost four times higher for cases than controls.34 This imbalance was even more evident for smoking duration: 71% of lung cancer cases had smoked for >35 years vs 16% of controls. Likewise, 70% of cases and only 19% of controls had smoked >25 pack-years of cigarettes.34 Finally, the history of COPD was 5-times more frequent in cases than controls,34 and it is well known that this condition increases the risk of lung cancer – especially squamous cell carcinoma – by the factor five.61,62 Because these determinants of lung cancer, such as advanced age, cigarette smoking, and COPD history, were much more prevalent in cases than controls,34 it is much more likely that the authors estimated the effect of these well-known risk factors instead of the effect of B vitamins on this outcome.34,60
 
Without measuring serum levels over time, Brasky et al34 started from the premise that a self-reported intake above the RDA reflects disturbed vitamin homeostasis, but self-reported intakes should not be taken as surrogate markers for vitamin levels. As mentioned before, age, smoking status, smoking duration, smoking intensity, COPD history, and some genetic variants are well-known lung cancer risk factors.63 The fact that these factors were also associated with vitamin usage raises the suspicion that the association between vitamin intake and cancer was due to confounding, despite the authors’ attempts to compensate for it through adjustment for known or suspected risk factors. Like Obeid and Pietrzik,60 we consider a reverse causality more likely; ie, knowing to have an increased risk (which every smoker does) can trigger healthier behaviors in other areas of life, including taking vitamin supplements. Therefore, we do not believe that the VITAL study uncovered a causal relationship between supplement intake and lung cancer. Apart from our own assumptions, many studies contradict the findings from a scientific point (Table 3). For example, several authors reported inverse relationships between vitamin B6 levels and lung cancer risk,64–66 and Yang et al67 even consider a possible protective effect of vitamin B6 in a systematic review and meta-analysis, including 14 studies and >8,000 patients. This protective effect of vitamin B6 has also been described in gastrointestinal cancer, pancreatic cancer, and breast cancer.68–70
 
Taken together, the current evidence from (almost exclusively epidemiological) studies on a relationship between vitamin B6 and/or B12 intake and lung cancer risk is not conclusive.34,–59,–64–67,80–89 The results of Brasky et al34 regarding vitamins B6 and B12 should be interpreted with caution. The potential role of B vitamins in lung cancer carcinogenesis should be regarded in a bigger context and consider the complex interaction in OCM, folate cycle, etc., which we believe requires further intense research. However, the focus should still be on the actual high-risk factors such as smoking, which increase the risk many times."
 

  • Informative x 1
  • WellResearched x 1

#28 kurdishfella

  • Guest
  • 2,200 posts
  • -62
  • Location:USA
  • NO

Posted 04 March 2022 - 06:36 PM

Just avoid the cyano version it fked with my health gave my headache and chest pains.

 

 

Cyanide prevents the cells of the body from using oxygen. When this happens, the cells die. Cyanide is more harmful to the heart and brain than to other organs because the heart and brain use a lot of oxygen.

 


Edited by kurdishfella, 04 March 2022 - 06:38 PM.


#29 kurdishfella

  • Guest
  • 2,200 posts
  • -62
  • Location:USA
  • NO

Posted 06 April 2022 - 03:00 AM

if you have been deficient for a long time you need methyl b12 activated form of b12 to kickstart back your CNS quicker to health and then after you can maintain with a diff form and lower dose.

sponsored ad

  • Advert
Click HERE to rent this advertising spot for SUPPLEMENTS (in thread) to support LongeCity (this will replace the google ad above).

#30 kurdishfella

  • Guest
  • 2,200 posts
  • -62
  • Location:USA
  • NO

Posted 22 May 2022 - 08:10 AM

No reason mega doses can forcibly activate pathways  and b12 turns darker overtime didn't realize it was a problem until someone said






2 user(s) are reading this topic

0 members, 2 guests, 0 anonymous users