This paper was published in Nutrition Reviews 2013 Feb;71(2):110-7
Study title and authors:
How prevalent is vitamin B(12) deficiency among vegetarians?
Pawlak R, Parrott SJ, Raj S, Cullum-Dugan D, Lucus D.
Department of Nutrition Science, East Carolina University, Greenville, NC 27858, USA. firstname.lastname@example.org
This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/23356638
The aim of this paper, headed by Dr Roman Pawlak from the Department of Nutrition Science at East Carolina University, was to review the scientific literature to assess the rate of vitamin B12 deficiency among vegetarians and vegans. The review found 18 studies that assessed vitamin B12 deficiency rates.
The review found:
(a) 62% of vegetarian pregnant women were vitamin B12 deficient.
(b) Between 25-86% of vegetarian children were vitamin B12 deficient.
(c) Between 21-41% of vegetarian adolescents were vitamin B12 deficient.
(d) Between 11-90% of elderly vegetarians were vitamin B12 deficient.
(e) Higher rates of deficiency were reported among vegans compared with vegetarians.
(f) Higher rates of deficiency were reported among individuals who had adhered to a vegetarian diet since birth compared with those who had adopted such a diet later in life.
Dr Pawlak concluded: "The main finding of this review is that vegetarians develop B12 depletion or deficiency regardless of demographic characteristics, place of residency, age, or type of vegetarian diet".