Oh My, There is Cyanide in B12 Supplements. Really.
There are many things in life to worry about but cyanide in vitamin B12 supplements is not one of them. Why do I bring this up? Because of a video that has been circulating about “the toxic ingredient in your child’s vitamins.” In the video, a man drones on about how he finds it “hard to believe that we are allowed to make vitamins out of hydrogen cyanide in this country, but we are.” That man turns out to be Gary Brecka, who labels himself a “human biologist,” whatever that may mean, on the basis of having a BS in Human Biology from National College of Chiropractic. Not exactly Harvard.
Yes, there actually is cyanide in B12 supplements, but the scare about it is total nonsense. Vitamin B12 is synthesized by bacteria that inhabit the gut of animals and is present in animal foods. These bacteria are not found in fruits, grains or vegetables which is why vegetarians and vegans are generally advised to take a supplement. Vitamin B12, which the body needs for various tasks ranging from red blood cell production and DNA synthesis to proper nerve function, is actually not one compound. The term can refer to any one of four very closely related compounds, each of which has vitamin activity. They share the common feature of having an atom of cobalt at the center of the molecule but differ in the substituents attached to that atom. This has no bearing on their biological activity.
None of these “vitamers,” as they are called, can be synthesized from simple molecules in the lab, so supplements have to be produced by fermentation using the same bacteria that make B12 in animals. Fermentation yields adenosylcobalamine and methylcobalamin, but the problem here is that these tend to degrade when formulated into supplements. However, treatment with potassium cyanide, (not hydrogen cyanide as stated in the video,) converts these into cyanocobalamine which is very stable. Once ingested, cyanocobalamine is converted back into the original adenosylcobalamine and methylcobalamine, releasing the cyanide in the process. This is where the scare originates.
Vitamin B12 dosages are measured in micrograms, that is in millionths of a gram. The recommended daily intake is 2-3 micrograms, but supplements can contain up to a couple of thousand because B12 is poorly absorbed from the gut. Even at the highest doses, the amount of cyanide released is about 20-40 micrograms which is far less than the amount of naturally occurring cyanide to which one could be exposed by consuming flax seeds, unpasteurized almond milk, fresh apple juice or apricots.
The oral dose of cyanide below which there is no risk has been determined to be 50 micrograms per kg of body weight. This means that a child weighing 15 kilograms who is given a gigantic daily dose of 1000 micrograms of B12, would still be ingesting less than 3% of this safe amount! There is simply no issue here. How about people who are enticed by smoothies made of raw almonds or flaxseeds, which contain the highest doses of cyanide to which one could reasonably be exposed? A 70 kg adult would have to consume 16 regular-sized smoothies in less than two hours to be poisoned by cyanide! A child would have to drink about three. This of course is totally unrealistic. But how about someone who drinks a smoothie every day that contains as much cyanide as a smoothie can possibly contain, which is around 220 micrograms per serving? Still less than 6% of the maximum safe dose!
Bottom line? There is no reason to worry about cyanide in vitamin B12 supplements, but there is reason to worry about self-styled pseudoexperts with a sketchy understanding of science alarming the public, usually with an eye towards monetary gain in some fashion.
Office for Science and Society
McGill University
801 Sherbrooke Street West
Montreal, Quebec H3A 0B8
