If for any reason you choose not to use fortified foods or supplements you should recognize that you are carrying out a dangerous experiment – one that many have tried before with consistently low levels of success. If you are an adult who is neither breast-feeding an infant, pregnant nor seeking to become pregnant, and wish to test a potential B12 source that has not already been shown to be inadequate, then this can be a reasonable course of action with appropriate precautions. For your own protection, you should arrange to have your B12 status checked annually. If homocysteine or MMA is even modestly elevated then you are endangering your health if you persist.
If you are breast feeding an infant, pregnant or seeking to become pregnant or are an adult contemplating carrying out such an experiment on a child, then don?t take the risk. It is simply unjustifiable.
Claimed sources of B12 that have been shown through direct studies of vegans to be inadequate include human gut bacteria, spirulina, dried nori, barley grass and most other seaweeds. Several studies of raw food vegans have shown that raw food offers no special protection.
Reports that B12 has been measured in a food are not enough to qualify that food as a reliable B12 source. It is difficult to distinguish true B12 from analogues that can disrupt B12 metabolism. Even if true B12 is present in a food, it may be rendered ineffective if analogues are present in comparable amounts to the true B12. There is only one reliable test for a B12 source ? does it consistently prevent and correct deficiency? Anyone proposing a particular food as a B12 source should be challenged to present such evidence.