Vitamin B12 to Counteract Cyanide Toxicity
Cyanide exposure not occurs not only from intentional poisoning. Cyanide (hydrogen cyanide) and cyanide-containing chemicals are used in mining, in acrylic nail removal and sometimes in fumigation. Most people have heard that apple pits contain cyanide. This is true, although the amount is very small. The cyanide is bound to a sugar called amygdalin. The apple pit has to be broken or crushed to release the amygdalin into the body.
You’d have to eat hundreds of apple pits in a sitting to experience ill effects from cyanide poisoning. The kernels of peach and apricot pits have the same chemical, but if you swallowed a whole peach pit, it would just pass through you intact. Cassava (Manihot esculenta), a root eaten as a staple food in many African, Asian and Caribbean countries has some varieties that contain relatively large amounts of cyanide, bound to another glycoside called linamarin. The cyanide is released from the linamarin during the preparation of the roots. Usually washing and sieving the grated roots several times and exposing them to the air allows the hydrogen cyanide gas to be washed away with the water and to evaporate. Nevertheless, low-grade cyanide poisoning from cassava is relatively common in countries where it is a staple food, causing tingling of the mouth, headaches and goiters. More severe cases include disorientation, paralysis and even death.
The greatest risk for cyanide poisoning in the United States comes from smoke inhalation. Many common household materials like wool, paper and plastics produce hydrogen cyanide when burned under low-oxygen conditions. Smoke inhalation thus presents a greater threat than actual burning in a fire, and hydrogen cyanide toxicity through smoke inhalation is a common occupational hazard for firefighters.
How does vitamin B12 (cobalamin) help remove the hydrogen cyanide from the body? Chemically, cobalamin is attracted to cyanide. Vitamin B12 in the form of hydroxycobalamin is administered through injection to get it into the body as fast as possible. In the body the cyanide ion is exchanged with the hydroxyl group of hydroxycobalamin, producing cyanocobalamin. The cyanocobalamin can now be safely flushed from the body. Many commercial vitamin B12 supplements actually contain cyanocobalamin. This raises the question of the toxicity of cyanocobalamin. In the quantities taken for regular supplementation is it usually not toxic. Exceptions are heavy smokers who already have chronic cyanide toxicity from cigarette smoke, and sufferers of Leber’s hereditary optical neuropathy. If you want to completely avoid any amounts of cyanide, use supplements containing hydroxycobalamin or methylcobalamin. Vitamin B12 is very nontoxic. The hydroxycobalamin dose administered at the scene to smoke inhalation victims is 5 grams for an adult. That is about 2 million times the daily dose needed for an adult (2.4 micrograms).
Of course, this is emergency medicine, you would not take these huge amounts at home. A typical vitamin B12 supplement taken for vitamin B12 deficiency contains from 1000-5000 micrograms, in the range of one thousandth of the detoxification dose for smoke inhalation. Rather than through injections, these supplements for at-home use are usually in oral capsule, liquid or sublingual form. The same chemical principles should also work to flush out lower concentrations of cyanide, such as those accumulated by chronic exposure to cigarette smoke, the consumption of traces of cyanide with cassava, or even by life in industrialized countries.
