In adults typical deficiency symptoms include loss of
energy, tingling, numbness, reduced sensitivity to pain or pressure, blurred vision, abnormal gait, sore
tongue, poor memory, confusion, hallucinations and personality changes. Often these symptoms develop
gradually over several months to a year before being recognised as being due to B12 deficiency and they are
usually reversible on administration of B12. There is however no entirely consistent and reliable set of
symptoms and there are cases of permanent damage in adults from B12 deficiency. If you suspect a problem
then get a skilled diagnosis from a medical practitioner as each of these symptoms can also be caused by
problems other than B12 deficiency.
Infants typically show more rapid onset of symptoms
than adults. B12 deficiency may lead to loss of energy and appetite and failure to thrive. If not promptly
corrected this can progress to coma or death. Again there is no entirely consistent pattern of symptoms.
Infants are more vulnerable to permanent damage than adults. Some make a full recovery, but others show
The risk to these groups alone is reason enough to
call on all vegans to give a consistent message as to the importance of B12 and to set a positive example.
Every case of B12 deficiency in a vegan infant or an ill informed adult is a tragedy and brings veganism
The homocysteine connection
This is not however the end of the story. Most vegans
show adequate B12 levels to make clinical deficiency unlikely but nonetheless show restricted activity of
B12 related enzymes, leading to elevated homocysteine levels. Strong evidence has been gathered over the
past decade that even slightly elevated homocysteine levels increase risk of heart disease and stroke and
pregnancy complications. Homocysteine levels are also affected by other nutrients, most notably folate.
General recommendations for increased intakes of folate are aimed at reducing levels of homocysteine and
avoiding these risks. Vegan intakes of folate are generally good, particularly if plenty of green
vegetables are eaten. However, repeated observations of elevated homocysteine in vegans, and to a lesser
extent in other vegetarians, show conclusively that B12 intake needs to be adequate as well to avoid