Adenosylcobalamin is a cofactor in the conversion of methylmalonyl-CoA (MMA) into succinyl-CoA, an important enzyme used in the citric acid cycle to create energy.
Methylcobalamin is used to convert homocysteine into methionine. High homocysteine levels are associated with an increased risk in developing heart disease.
Cyanocobalamin, the most common form used in supplements, is not a natural form of cobalomin. It is manufactured in labs through bacterial fermentation. It must be converted to methylcobalamin or adenosylcobalamin to be used.
Hydroxycobalamin is found naturally in foods. The body naturally converts it into methylcobalamin or adenosylcobalamin.
A U.S. based company that commercially grows water lentils has confirmed through six independent tests the presence of both adenosylcobalamin and methylcobalamin (the best ones!) inside the water lentil plant.
Nori has been widely debated as a source of Vitamin B12. However, recent studies have shown that although raw nori contains the real Vitamin B12, dried nori contains a large amount of pseudovitamin B12 (an analog that mimics Vitamin B12).
Studies have analyzed various chlorella supplements to find that they range from <0.1 mcg to 415 mcg per 100 grams. This wide range can be due to the different conditions that chlorella is grown under., making it an unreliable source.
Due to old testing methods, spirulina was once believed to contain Vitamin B12. However, new tests have shown that spirulina contains a pseudovitamin B12 (an analog that mimic Vitamin B12 without the physiological action of the vitamin).