Safety of Cyanide in Cyanocobalamin
Due to some articles going around the Internet, many people have written me asking whether vitamin B12 supplements in the form of cyanocobalamin are safe due to the cyanide content. Because so many people have asked, I have updated the page Side Effects of B12 Supplements of Vitamin B12: Are You Getting It? with the following information:
The safety of cyanocobalamin has raised concerns due to the fact that cyanide is a component of cyanocobalamin, and the cyanide molecule is removed from cyanocobalamin when used by the body’s cells. Cyanide is also found in many fruits and vegetables and so humans are always ingesting small amounts of cyanide, and like in most fruits and vegetables, the amount of cyanide in cyanocobalamin is considered to be physiologically insignificant.
According to the European Food Safety Authority, “Data of from a Norwegian dietary survey show that the average and high (97.5th percentile) daily intake of [cyanide] among consumers amounts to respectively 95 and 372 micrograms/person or 1.4 and 5.4 micrograms/kg bw/day (7).” The amount of cyanide in a 1,000 microgram cyanocobalamin is 20 micrograms.
Table 1 contains some additional numbers regarding cyanide amounts in cyanocobalamin for comparison purposes.
| Table 1. Cyanide Content of Cyanocobalamin | |
|---|---|
| molecular weight of vitamin B12 | 1,355 g/mol |
| molecular weight of cyanide | 27 g/mol |
| Percentage of cyanide in vitamin B12 by weight | 2.0% |
| Amount of cyanide in 1,000 micrograms of cyanocobalamin | 20 micrograms |
| Minimal Risk Level for oral cyanide4, a | 0.05 mg/kg of body weight per day |
| Minimal Risk Level for oral cyanide for 140 lb person | 3,175 micrograms/day |
| Percentage of Minimal Risk Level in 1,000 micrograms of cyanocobalamin | 0.6% |
| Lethal dose of cyanide5 | 0.5 to 3.0 mg/kg of body weight |
| Lower end of lethal dose of cyanide for 140 lb person | 31,750 micrograms |
| Percentage of lethal dose in 1,000 micrograms of cyanocobalamin | 0.06% |
| aMinimal Risk Level do not assess cancer risk (6). | |
In summary, the amount of cyanide in 1,000 micrograms of cyanocobalamin is about .6% of the amount that is thought to be the lower level that causes harm.
References
See Side Effects of B12 Supplements.
Thank you, Ginny, for sending some of the research!
February 9th, 2012 at 2:51 am
Not to mention that DEVA and others have started to provide B12 supplements based on methylcobalamin instead of cyanycobalamin.
Great article. Cheers
February 9th, 2012 at 6:54 am
Given this info, doesn’t it seem reasonable to recommend an upper daily limit of cyanocobalamin in qualifying the “no upper limit” for B12?
February 9th, 2012 at 9:18 am
Rick,
I never recommend more than 2,000 micrograms of cyanocobalamin per day which would be well short of any theoretical upper limit due to cyanide poisoning, I would think. I try not to be in the business of setting upper limits.
February 9th, 2012 at 9:21 am
Bruce,
Cyanocobalamin has an advantage over methyl- in that it is more stable and it’s generally thought that it requires much more methyl- from supplements to equal the same amount of cyanocobalamin. One person wrote me saying:
“I’d been taking 500 mcg of methylcobalamin for years, not knowing that the B12 dosages so often cited (daily 25 – 100 mcg) are just for cyanocobalamin. So, about a week ago I started taking 1000-2000 mcg of methylcobalamin instead of just 500 mcg, and I feel a difference!”
Of course, it could be a placebo. More info can be found here: http://veganhealth.org/b12/noncyanob12
February 9th, 2012 at 1:40 pm
Thank you. The new page will be very useful to link to when the topic comes up in online discussions.
February 9th, 2012 at 4:50 pm
From a reader:
Thanks for your excellent post on this topic. I’d add that the cyanide is not a problem as long as kidney function is adequate to handle excretion appropriately. I understand as renal function declines, this may become an issue.
February 10th, 2012 at 1:34 pm
What do you mean when you said that the fellow whom you quoted above could be experiencing a benefit from the placebo effect. I mean, really. To follow this logically, all supplements and drugs, too, should be fake, consisting of inexpensive, neutral substances: with sufficient faith, induced in us by advertising, we will experience relief from our symptoms.
It looks to me as if cyano VS methyl is 6 of one and 1/2 a dozen of the other.
February 10th, 2012 at 3:35 pm
Betty,
The placebo effect can be very powerful. That doesn’t mean that it can overcome any ailment or that drugs and supplements never work. I don’t know if, in this case, it was or it wasn’t.
February 12th, 2012 at 10:43 pm
Awhile ago, I compared the amount of cyanide from 25µg of cyanocobalamin to 2tbspoons of flax seeds based on data taken from this paper:
http://www.sciencedirect.com/science/article/pii/S0308814601003132
140ppm (µg/g) x 20g Flaxseed = 2800µg in 2Tbsp Flax Seed
In 25µg Cyanocobalamin 25µg x 27g/mol/1355g/mol = 0.5µg
So the amount in 2tablespoons of flax seed is over 5600x the amount in 25µg of cyanocobalamin. Funny, the same people who fear cyanocobalamin (raw foodists in particular) are the same people who make an effort to eat lots of flax seeds.
Even at 1000µg dose, the cyanide in cyanocobalamin is 140x less than 2 tablespoons of flax seeds.
February 12th, 2012 at 11:11 pm
The various forms of B12 vitamers are really more or less a marketing ploy (IMO) as the non cyano B12′s sold in the US (methyl and dibencozide) are marketed as “superior” because they are the co-enzyme forms used in the body/
They break down in the presence of water and/light light to produce hydroxocobalamin which is still bioactive, and is used in some USP injectable solutions, but is not a co-enzyme form, so doesn’t have the same marketing appeal. In the EU, you can find the hydoxocobalamin form for OTC use.
I’m surprised some US companies haven’t started to sell the hydroxo form as an cyanide poisoning antidote as the cyano group has a very strong affinity for the corrin ring, which explains it’s stability. We used to boil it out of food matrices without any loss.
February 13th, 2012 at 1:52 am
Hi Jack,
A story about B12 supplementation on ABC Radio National today.
I thought you might find this of use. Here is the link;
http://www.abc.net.au/radionational/programs/healthreport/vitamin-b12-supplementation/3823160
February 19th, 2012 at 9:25 am
What is the role that intestinal bacteria play in providing vitamin B12 to their host?
What factors might be causing symptoms of vitamin B12 deficiency in people who regularly consume animal products?
February 19th, 2012 at 12:41 pm
Eselpee,
> What is the role that intestinal bacteria play in providing vitamin B12 to their host?
For humans, not much. Here is info on other animals: http://veganhealth.org/b12/animal
> What factors might be causing symptoms of vitamin B12 deficiency in people who regularly consume animal products?
A rare genetic inability to efficiently absorb or metabolize vitamin B12, and the inability to cleave vitamin B12 from proteins in animal foods as people age.
March 12th, 2012 at 3:47 pm
The word Cyano does not mean Cyanide; the word Cyano means: Blue Green Algae or Blue Green Bacteria; Vitamin B12 is found in Blue Green Algae; Cyanide is found in Blue Green Algae; Kyanos is Greek for Blue Green in color…
So Cyanide is a Cyano
but NOT all Cyanos are Cyanide;
so Cyano Cobalamin is not about Cyanide; Cyano Cobalamin is about Vitamin B12 which is derived from HydroxlyCobalamin
the only reason Cyano Cobalamin MIGHT have trace Cyanide is because the activated charcoal they use to purify Hydroxyl cobalamin might have trace cyanide…not harmful in Vit. B12;
Summary: Cyano means Cyano Blue Green Bacteria or Algae
Cyano does not mean cyanide; Cyano means “Blue Green
so the fear of cyandie in CyanoCobalamin if highly unfounded !
March 12th, 2012 at 5:01 pm
Anne,
I appreciate you setting the record straight regarding the prefix “cyano”. But, all cyanocobalamin does include a cyanide component (or “ligand” as it’s technically called). As I mention in this post, it is only 2% of the cyanocobalamin by weight and except for in people who have cyanide metabolism issues, is toxicologically insignificant.
March 15th, 2012 at 5:23 am
I’m surprised some US companies haven’t started to sell the hydroxo form as an cyanide poisoning antidote as the cyano group has a very strong affinity for the corrin ring, which explains it’s stability. We used to boil it out of food matrices without any loss.
Anne’s comment: FDA approved Cyano-Kit 2007 is HydroxylCobalamin @ 5 mgs. given by a “professional only; this is used mostly for “smoke inhalation which has Cyanide”; this is why tobacco smokers are sometimes deficient in B12 because Tobacco Smoke creates Cyanide in the system…ar
March 15th, 2012 at 5:27 am
But, all cyanocobalamin does include a cyanide component (or “ligand” as it’s technically called)…
comment : I thought all cyanocobalamin contained a “Cyano” Ligand which is a Blue Green Bacteria Ligand which is derived when the Hydroxyl is pushed thru the Charcoal column
questions: Does Cobalt contain natural cyanide ?
does blue green alage (CYANO IS KYANOS FOR BLUE GREEN IN GREEK); Where does the Vitamin B12 get the Cyanide:
a. from the hydroxyl B12? b. or from the Activated charcoal ?
I know Cobalamin searches for and seeks out “cyanide…thnx!
March 15th, 2012 at 5:30 am
summary: the prefix “Cyano” before another word does not mean Cyanide; Cyano is NOT an abbreviation or slang for Cyanide; CYANO means “The Nitrile Group; as “green plants; and my concern is: if people think Cyano cobalmin means cyanide cobalmin then people will not use the purifed form of vitmain B12 which is CYANO (Blue Green Bacteria) not cyanide; and then the anti nuttient people will have won because a Deficiency of Vitmain B12 can be a chronic prob.
March 15th, 2012 at 5:33 am
PS from what I have read (I have been an OLV for 45 years !)
Cyano (blue green bacteria) Cobalamin is almost identical in molecular structure to “Purifed Liver estracts (where Vitmain B122 was discvored in 1947); yet Cyano Cobalamin is Vegan!
I recommend the Sublingual Vitmain B12; better uptake…imo !
March 15th, 2012 at 9:06 am
Anne,
> Does Cobalt contain natural cyanide ?
Cobalt is a mineral and thus it does not contain anything more than protons, neutrons, and electrons.
I do not know how the cyanide in cyanocobalamin is added to the cobalamin, but by all accounts that I can find, it is indeed cyanide. If you have proof to the contrary, feel free to post it. Otherwise, I don’t think I’m going to post any further comments about it.
April 3rd, 2012 at 4:47 pm
I bought a bottle of B12 (Methylcobalamin) would your recommendations change vs cyanycobalamin?
April 3rd, 2012 at 8:38 pm
> I bought a bottle of B12 (Methylcobalamin) would your recommendations change vs cyanocobalamin?
Yes, methylcobalamin should be taken at 1,000 micrograms per day. 1,000 micrograms = 1 mg.
April 9th, 2012 at 12:35 pm
Jack,
I been following Dr. Mcdougall recommendations in regards to B12. Dr. Mcdougall recommendations are a 1 weekly dose of 500mcg per week of B12 of methylcobalamin because it has better absorption. When i came across your site your recommendations are totally different so i began to research and realize every doctor and dietitian has a different recommendation.
Here are some of the recommendations i came across:
1 dose of 500mcg per week
1 dose of 500mcg per day
1dose of 1000mcg per week
1dose of 1000mcg twice a week
1dose of 1000mcg per day
1 dose of 60mcg per day that is included in a multivitamin(Dr. fuhrman gentle care
I been feeling a bit disappointed and confuse. Why is it that most doctors and dietitians don’t agree in just one universal dose for B12?
Thanks for your help.
April 9th, 2012 at 4:25 pm
Sharon,
Some people are recommending doses to prevent overt B12 deficiency and others are recommending higher doses to minimize homocysteine and methylmalonic acid levels. I’m in the latter group. Here is a letter written to the vegan community that was signed by numerous dietitians, doctors, and organizations. If you want a suggestion that comes from a wide range, you might want to go with theirs:
http://veganhealth.org/articles/everyvegan
This article also appears on the UK Vegan Society website:
http://www.vegansociety.com/lifestyle/nutrition/b12.aspx
May 31st, 2012 at 6:39 pm
In (bio) Chemistry the cyano prefix is used to name the CN- functional group, just as acetyl and formyl are used to identify the CH3(C=O)O- and H(C=O)O- functional groups respectively.
Even though they too are derived from other words (Latin Aceto =Vinegar and formica = ant) t’s just a name for a particular functional group.
In the case of cyanocobalamin, the CN ligand is bound to the Cobalt atom in the corrin ring. The only difference, structurally between the various vitamers is the ligand bound to the central Cobalt atom.
When Cyanocobalamin is converted to methylcobalamin and cobamide in the body, the CN group gets knocked out, but most likely it will find an iron atom to cling to somewhere and at such low exposure limits won’t have any negative affects on the body.
May 31st, 2012 at 6:49 pm
btw, The Cyanide is added to the broth at the end fermentation to convert all the various vitamers into the most stable vitamer, cyanocobalamin. This makes it easier to extract,
This is done strictly for stability purposes. Like I said previously, we used to boil it out of food matrices.
August 28th, 2012 at 7:51 pm
I was sure I read somewhere on your site about extremely different doses for b12 depending if one is taking methylcobalamin vs cyanocobalamin. I would think this would be an important thing to note, but I’m having a very difficult information finding it anywhere on the web.
August 28th, 2012 at 9:32 pm
Tracie,
I don’t have official recommendations for methylcobalamin, only cyanocobalamin, but there is more info on other forms here:
http://veganhealth.org/b12/noncyanob12
And I just updated my recommendations to indicate that I’m only referring to cyanocobalamin:
http://veganhealth.org/articles/dailyrecs
August 29th, 2012 at 4:16 am
hello again
I understand the Cynadie is formed when the basic Vitamin B12 (grown in a lab with special bacteria) is “pushed throught the charcoal column” to Purify the Vitamin B12″ somehow the charcoal creates Cyandie reside; the cynadie is not “added !
the Cynadie is a natural process of manufacturaing Vit. B12…!
ps did you know some people consider “cyanide” to be “a nutrients or a medicine” if used in proper amounts; this is because Cyandie has been shown to destory some germs…
there are many types of cyandie; the cyandie found in peach ptis; flax seeds is not the type of Cyanide which is dangerrous!
]summary if you do not take some type of Vitamin B12; you can come down with “pseudo alzhmers and SCD (sub acute degenration of the spinal cord
so i would rish a little cyanide to prevent aformention diseases!
so I would risk a little cyandie to prevent SCD (sub acute degenration of the spinal cord ) because SDC is terrible AND VITAMIN B12 IS THE ONLY KNOWN CURE FOR SCD…thnx!
August 29th, 2012 at 5:38 pm
Thanks!
I finally found the page I was thinking of @ http://www.theveganrd.com/2010/11/recommended-supplements-for-vegans.html. She has your site listed on her blogroll. Quite a search to refind it tho. Sorry about my bad editing in my above post but looks like you sorted that out.
September 1st, 2012 at 9:27 am
Anne, I believe you are confusing the steps in the process. Cyanide, albeit in very minute quantities, is added to the broth and THEN the broth is filtered. The charcoal is a standard method of purification similar to a britta filter to remove particulates(most likely the biomass itself). Charcoal is relatively inert and would require extreme conditions to produce cyanide, which is a reductive product and not something that readily forms in an oxygen rich environment under typical temperatures & pressures (thankfully)
Wikipedia has a good description of the process:
http://en.wikipedia.org/wiki/Cyanocobalamin#Production
“Fermentation by a variety of microorganisms gives a mixture of methyl-, hydroxo-, and adenosylcobalamin. These compounds are converted to cyanocobalamin by addition of potassium cyanide in the presence of sodium nitrite and heat.”
September 1st, 2012 at 9:58 am
Cyanide has been shown to kill some germs for the same reason it kills humans:
It binds to Iron containing enzymes in a cell, specifically Cytochrome-C Oxidase
http://en.wikipedia.org/wiki/Cytochrome_c_oxidase.
This does not make it a medicine and was a dangerous form of quackery in the 70s & 80s that resulted in several deaths.
http://ajcn.nutrition.org/content/32/5/1121.full.pdf
http://www.cancer.org/Treatment/TreatmentsandSideEffects/ComplementaryandAlternativeMedicine/PharmacologicalandBiologicalTreatment/laetrile
Cyanide is cyanide. When it is a free ion it behaves the same irrespective of its source and in sufficient quantities can kill. There are several deaths each year (mostly children) from accidental cyanide poisoning from eating enough uncooked foods that contain cyanogenic glycosides. For example:
http://www.chinadaily.com.cn/english/doc/2005-03/10/content_423641.htm
Cyanogenic glycocides are thought to be a protective mechanism of a plant against animals eating its seeds. The cyanide is only released when the seed is crushed and the two parts (enzyme + glycoside), which are normally separated in the cell, are brought together. Cooking destroys the enzyme.
In some foods, there are some metal ions (especially iron) around that the free cyanide will bind to before it gets to cells in the body, which can deactivate some of it. Once it is deactivated it is far less toxic, but also relatively inert and offers no medical benefit:
http://en.wikipedia.org/wiki/Prussian_blue#Safety
Most of the make believe around “natural” is from people who don’t want to believe nature is indifferent to the human life and kills as much as it sustains.
September 2nd, 2012 at 6:11 am
So cyanide is added to (a) kill bacteria, and (b) stabilize the b12 molecule. Is this correct? The stabilization is important to help extract the b12 in the production process.
Does this stabilization also serve to increase the shelf life? In other words, does cyanocobalamin have a longer shelf life than methylcobalamin?
Is that why recommendations for methylcobalamin are sometimes higher than for cyanocobalamin, to factor in that the users will be administering a significantly lower dose of the methylcobalamin by the time that they consume it than when it was manufactured, whereas the cyanocobalamin dose will be relatively higher upon administration?
September 2nd, 2012 at 4:55 pm
Rick,
> In other words, does cyanocobalamin have a longer shelf life than methylcobalamin?
That’s my understanding.
> Is that why recommendations for methylcobalamin are sometimes higher than for cyanocobalamin,
Yes.
November 27th, 2012 at 10:13 am
NORI SEAWEED: The purple laver contained five types of biologically active vitamin B12 compounds (cyano-, hydroxo-, sulfito-, adenosyl- and methylcobalamin), in which the vitamin B12 coezymes (adenosyl- and methylcobalamin) comprised about 60 % of the total vitamin B12. http://www.nih.com
So this proves Cyano Cobalamin (Vitamin B12) is in nature…”
ps I think you misunderstood me Jack: i said there is no Cyanide in CyanoCobalamin because Cyano = Nitriles which are plants usually blue green algae or bacteria; I did not advocate natrual cyanide synthetic cyanide or any other type !!
November 27th, 2012 at 10:20 am
Anne,
Your link doesn’t go to anything about nori. It is possible that cyanocobalamin is in nature, but it does have a cyanide molecule attached – it doesn’t matter what the term “cyano” means. Also, I’m not putting through most of your comments as they are simply restatements of the same thing over and over again.
Here is a diagram of cyanocobalamin: http://en.wikipedia.org/wiki/Cyanocobalamin The cyanide molecule is the CN attached to the cobalt atom in between the 4 nitrogens towards the top, middle of the diagram. And here you can see that CN is cyanide: http://en.wikipedia.org/wiki/Cyanide
I’m not going to put through any further comments arguing that cyanocobalamin doesn’t contain cyanide.
November 27th, 2012 at 10:40 am
For anyone who might be interested, Anne sent me this link off list showing that the purple laver had cyanocobalamin: http://www.ncbi.nlm.nih.gov/pubmed/11430774
November 27th, 2012 at 1:23 pm
http://www.theveganrd.com/2010/11/recommended-supplements-for-vegans.html. thanks Tracie !!!
November 29th, 2012 at 7:02 am
everything originates with Green Blue algae; this i why Clams have high Vitamin B12; they thrive on Sea Algae!
clams have the most B12 ! (USDA Clams Nutrient Database
November 29th, 2012 at 11:11 am
Most likely it’s b/c clams sit at the bottom where poop and other animals solids end up. If you want “natural b12″ you can make poop extracts. I’d rather take a 2cent vitamin supplement.
December 11th, 2012 at 3:14 pm
can anyone tell me? If I put potassium cyanide 800 mg. to the vitamin B12 ( in the energy drink ) who is win ?
December 11th, 2012 at 4:23 pm
noname,
No idea what you mean.
February 17th, 2013 at 8:53 am
“1.4 and 5.4 micrograms/kg bw/day”
Does this information also apply for infants?
Is there any evidence infants should rather take methylcobalamin instead of cyano?
February 17th, 2013 at 10:24 am
Livia,
Infants should be getting their B12 through breast milk or formula, especially the first 6 months. Here are my recommendations for older than 6 months:
http://veganhealth.org/articles/dailyrecs
> Is there any evidence infants should rather take methylcobalamin instead of cyano?
I’ve never seen any.
February 18th, 2013 at 10:27 am
From the info I get in this article cyanide is cyanide (shrinks ur brain)why does the stuff have to be present in B12. Have U folks heard of methylcobalamin. Not mentioned above.
February 18th, 2013 at 2:00 pm
jriley,
We discuss methylcobalamin on this site *all the time*! Example: http://jacknorrisrd.com/?p=3383
BTW, did you mean to make your email address public? If not, let me know and I’ll remove this comment.
April 2nd, 2013 at 6:58 pm
Costco now sells economical Kirkland brand B-12: cherry flavored sublingual tablets (300 per bottle), Methylcobalamin form, 5000 mcg.
On the bottle it says, “Suggested Use: Dissolve one tablet daily, under tongue for 30 seconds, then swallow.”
Could taking that much lead to any problems?
April 2nd, 2013 at 7:08 pm
The label on the bottle of Kirkland brand B-12 does include the following warning:
“WARNING: Pregnant or nursing women, individuals taking medication(s), or persons who have a health condition should consult their physician before using this product. KEEP OUT OF REACH OF CHILDREN. Store at 15 to 30 C (59 to 86 F).”
April 2nd, 2013 at 8:03 pm
vsheline,
I am not aware of 5,000 micrograms a day of methylcobalamin causing problems. Perhaps you should start out breaking the tablet in half. That way, if you have a rare reaction, it will be to less of a dose.