More on Cyanocobalamin Safety/Toxicity

 

Cobalamin (vitamin B-12) is synthesized only by certain microbes (bacteria and archaeon), and five forms of vitamin B-12 have been found in foods, according to the British Journal of Nutrition: adenosylcobalamin and hydroxocobalamin are the predominant forms, and other forms found include methylcobalamin, cyanocobalamin, and sulphitocobalamin. Most of these forms are considered synthetic substances, with additional compounds subsequently bonded to the already-synthesized cobalamin.

Methylcobalamin is produced commercially from cyanocobalamin, which is initially produced by fermentation and conversion processes. Adenosylcobalamin is directly produced by bacteria, while methylcobalamin requires an additional process of stripping off the cyanide group (CN, a carbon and a nitrogen atom with a triple bond) and adding a methyl group (CH3). Fermentations producing cyanocobalamin, methylcobalamin, and adenosylcobalamin do not utilize genetically engineered bacteria. The cyanocobalamin form is safe, stable, and bioavailable, and has been used for the vast majority of public health studies over the past century.

The amount of cyanide in cyanocobalamin is trivial, less than in an almond or apple; cyanide tends to be ubiquitous in the food supply in extremely tiny amounts. Cyanide is also produced by our own cellular processes (no great surprise since it's simply a single carbon and nitrogen molecule bonded together), but is quickly absorbed into the bloodstream, converted into thiocyanate (a less toxic form), and excreted in the urine or converted to carbon dioxide and exhaled. 

In fact, the Institute of Medicine has not set an Upper Limit for vitamin B-12 because “no adverse effects have been associated with excess vitamin B-12 intake from food and supplements in healthy individuals” (and both supplementation and food fortification primarily use cyanocobalamin). That same IOM report features this quote: “the amount of cyanide in cyanocobalamin is considered to be physiologically insignificant.” It would take about 2,500 doses of 1,000 microgram cyanocobalamin tabs to approach a dangerous amount of cyanide.

The adenosylcobalamin form is predominant in foods as well as in the human body, whereas methylcobalamin is typically in the body at only half the amount of the adenosyl form. Both are coenzyme forms with separate enzyme systems, and both are needed by the body. Cyanocobalamin feeds both pathways and is an inexpensive, stable, safe, and effective form of vitamin B-12 that does not require genetically engineered bacteria to produce.

Is citric acid made from black mold?

Yes, but so what? That organism - Aspergillus niger - has been used to safely manufacture citric acid for about 100 years. It's also used to make most of the 'fungal enzymes' that are vegetarian-friendly. People consuming citric acid are not eating black mold; just as you're not eating bees when consuming honey. 

People worried about the fermentation process have failed to distinguish between the mold and its purified byproducts that have a long history of safe use.  https://link.springer.com/article/10.1007/s00253-002-1032-6  

The fungus produces materials outside of its body that can be easily isolated and purified, so people are not inhaling or consuming mold when they use a material produced by fermentation. In fact, companies using citric acid perform their normal microbiological screening to assure that there are not concerning levels of mold in that material..

The mold itself would release spores that would be toxic to inhale if it were growing in your house. It may be mildly allergenic if you were eating the actual mold. But that's not what we are exposed to or are consuming when we eat citric acid, which is widely distributed in the processed food chain and has an important role in acidifying and preserving many foods and beverages. Look at your labels!

Isolated Aspergillus-derived products, including citric acid, have been sold for about a century and are considered safe. These also include common plant-derived enzymes such as protease, amylase, and lipase that are not pancreas-derived.  https://fungalbiolbiotech.biomedcentral.com/articles/10.1186/s40694-018-0054-5 

"Microbial citric acid has high economic importance and widely used in beverage, food, detergents, cosmetics and pharmaceutical industries. The filamentous fungus Aspergillus niger is a work horse and important cell factory in industry for the production of citric acid."   https://pubmed.ncbi.nlm.nih.gov/33044884/

"Aspergillus niger has a long tradition of safe use in the production of enzymes and organic acids (Soares de Castro et al., 2015)."  https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/aspergillus-niger#:~:text=The%20Aspergillus%20produces%20different%20types,et%20al.%2C%202015).