The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: a review of literature

Abstract

Individuals following vegetarian diets are at risk for developing vitamin B12 deficiency owing to suboptimal intake. As vitamin B12 is essential for the synthesis of nucleic acids, erythrocytes and in the maintenance of myelin, deficiency may result in a variety of symptoms. Some of these symptoms may be severe while others may be irreversible. The objective of this review was to assess vitamin B12 deficiency, based on reported serum vitamin B12, among individuals adhering to different types of vegetarian diets. A systematic literature search was carried out using multiple search engines including PubMed, Medline, CINAHL plus, ERIC, Nursing and Allied Health Collection and Nursing/Academic Edition. The inclusion criteria consisted of original studies that assessed serum vitamin B12, studies written in English, non-case studies and studies that reported actual percentages of vitamin B12 deficiency. Forty research studies were included. The deficiency prevalence among infants reached 45%. The deficiency among the children and adolescents ranged from 0 to 33.3%. Deficiency among pregnant women ranged from 17 to 39%, dependent on the trimester. Adults and elderly individuals had a deficiency range of 0-86.5%. Higher deficiency prevalence was reported in vegans than in other vegetarians. Thus, with few exceptions, the reviewed studies documented relatively high deficiency prevalence among vegetarians. Vegans who do not ingest vitamin B12 supplements were found to be at especially high risk. Vegetarians, especially vegans, should give strong consideration to the use of vitamin B12 supplements to ensure adequate vitamin B12 intake. Vegetarians, regardless of the type of vegetarian diet they adhere to, should be screened for vitamin B12 deficiency.

The long-term health of vegetarians and vegans

“…Overall, these have shown that a wellplanned vegetarian or vegan diet can supply all the nutrients required for good health (6) . However, some concern remains over the possibility of low intakes of some nutrients such as vitamin B 12 , vitamin D, calcium and n-3 fatty acids in poorly selected and/or unfortified vegetarian or vegan diets (7,8) ; in particular, vitamin B 12 status has been widely observed to be relatively low in vegetarians and especially in vegans, and this is associated with relatively high plasma homocysteine (9) . Many studies have assessed health-related factors such as BMI, plasma cholesterol concentrations and blood pressure in vegetarians, but relatively few studies have been of sufficient magnitude and duration to examine the long-term health of vegetarians and vegans.…”

Can vitamin B12 deficiency manifest with acute posterolateral or posterior cord syndrome?

“…Prevalence of Vitamin B12 deficiency among vegetarians is high with vegans more deficient compared to other vegetarians. 10 So it is important that the pure vegetarians should have a diet rich in vitamin B12, like legumes and milk.…”

Urinary levels of early kidney injury molecules in children with vitamin B12 deficiency

“…Cobalamin deficiency may result in a variety of symptoms, since vitamin B12 is essential for nucleic acid synthesis, erythrocytes and for the maintenance of myelin. 2 Neurological symptoms such as hypotonia, seizures and developmental delay can be seen in infants, while in older children megaloblastic hematological changings, extrapyramidal signs and delirium or psychosis can be observed. 3 Selective vitamin B12 malabsorption or Gräsbeck-Imerslund syndrome has been reported together with proteinuria 4 .…”

“…3 Selective vitamin B12 malabsorption or Gräsbeck-Imerslund syndrome has been reported together with proteinuria 4 . In addition, if CD advances, it will cause anemia, 2 which may lead to chronic hypoxia as one of the causes of kidney injury. 5 Although hematological and neurological aspects of CD have been investigated extensively, there is no study on renal effects of CD in the literature search.…”