Am J Clin Nutr. 1988 Sep; 48(3 Suppl): 852-8.
Vitamin B-12: plant sources, requirements, and assay.
Mt Sinai School of Medicine, New York, New York.
Vitamin B-12 is of singular interest in any discussion of vegetarian diets because this vitamin is not found in plant foods as are other vitamins. Many of the papers in the literature give values of vitamin B-12 in food that are false because as much as 80% of the activity by this method is due to inactive analogues of vitamin B-12.