Vitamin B12 is one of the very most important nutrients we get from animal foods. Vitamin B12 is a compound that is red in color because of the presence of cobalt. Absorption of Vitamin B12 is a complex process which can be problematic for many. For it to be absorbed effectively, B12 attaches to a protein known as intrinsic factor which is secreted in the stomach. Vitamin B12 binds with intrinsic factor and travels through to the small intestines. Once in the bloodstream, B12 binds to transport proteins. Enzymes release B12 from the protein complex and convert it to two forms- methylcobalamin and adenosylcobalamin. Deficiency in the enzymes can stop this conversion. Because there are so many potential blocks in the absorption process many people develop Vitamin B12 deficiencies even though they get plenty of Vitamin B12 in their diet.