Vitamin B-12 is almost exclusively present in animal and animal product and is only found in traces in fruit and vegetables. there is one algae called chlorella which could be source of a genuine vegan Vit B-12.
B12 analogues of algae are molecules which are similar to real B12 that they bond to the same transport molecule. In contrast, however, they have no vitamin effect on the body whatsoever. This is detrimental to health, as only real B12 that is bound to this specific transport molecule can be used by the body.
When B12 analogues bind to this transport molecule, even when there is a very good dietary supply of the vitamin, B12 deficiency can occur, as the real vitamin simply cannot be transported and utilised.
It is also not recommended to take spirulina alongside B12 supplements, as the analogues in the spirulina can hinder B12 absorption.
Algae chlorella and nori can be considered B-12 sources. However, their B-12 content is not produced by the algae itself, but rather by microorganisms which live on the plant or in the soil. So naturally produced Chlorella has positive effect on B12 status.
