Snow1 presents an extremely thorough and thoughtful approach to the workup of patients with vitamin B12 and folate deficiency. Folate deficiency may be found in a variety of disorders; however, its prevalence has decreased dramatically resulting from folate supplementation in the United States and Canada. The US government mandated the addition of folate to cereal grain products on January 1, 1998.2 Although supplementation is optional in Canada, there is widespread folate fortification of flours, pastas, cereals, and breads.
Cembrowski GS, Zhang MM, Prosser CI, Higgins T. Folate Is Not What It Is Cracked Up to Be. Arch Intern Med. 1999;159(22):2745. doi: