Vitamin B12 is essential for red blood cell formation, proper neurological function and making our DNA. We can absorb B12 from foods like meats, poultry, eggs, seafood and dairy products. Unfortunately, mushrooms, algae and fermented foods have yet to show consistent results in providing an absorbable active form of B12. This leaves vegans in a place where supplementation is required.
There are four types of B12 supplementation:
Methylcobalamin – Easiest absorb. Most active in our body. Natural and active form of B12.
Cyanocobalamin – Lab based synthetic. Most affordable form used to fortify foods (cereals, breads, etc).
Hydroxocobalamin – Form of B12 found in most foods. It converts to the easily absorbed methylcobalamin. This version less common and what you would get from a B12 shot.
Adenosylcobalamin – The least stable of the four. This is a natural and active form of B12. This is the second most absorbable form of B12. Vegansafe is a popular product which uses 20% (Adenosylcobalamin) and 80% (Methylcobalamin).
A Study of Vitamin B12 Deficiency in Different Diseases
VeganHealth.org – Clear summary of research papers testing for B12 from vegan food stuffs