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Caring for kids new to Canada

A guide for health professionals working with immigrant and refugee children and youth

Vitamin B12 Deficiency

Key points

  • Vitamin B12 deficiency is more likely to occur in people whose diets are low in animal, dairy or egg products. This may include newcomers to Canada who have lived in refugee camps or experienced extreme poverty, or people adhering to restrictive vegetarian diets.
  • Dietary insufficiency, malabsorption or impaired absorption can cause vitamin B12 deficiency.
  • Clinicians should suspect vitamin B12 deficiency in immigrant or refugee children with megaloblastic anemia on complete blood count (CBC) testing.
  • Consequences of vitamin B12 deficiency can include fatigue and weakness, as well as hematological, neurological, psychiatric and cardiovascular symptoms.


Since vitamin B12 is primarily found in animal, dairy and egg products, there is an increased incidence of deficiency among people with restrictive vegetarian diets or in places where access to protein sources is low, including refugee camps or regions of severe poverty.

Rates of vitamin B12 deficiency may be high among refugees. For example, two-thirds of refugees from Bhutan were found to be vitamin B12 deficient.1


Vitamin B12 deficiency can result from decreased dietary intake, impaired absorption (e.g., intrinsic factor deficiency) and malabsorption (e.g., due to chronic gastritis or bacterial overgrowth). Breastfed infants of vegan mothers are also at risk.


Vitamin B12 deficiency can have a range of clinical manifestations:2

  • General symptoms (e.g., fatigue, weakness, stomatitis, diarrhea, constipation, loss of appetite, weight loss),
  • Hematological symptoms (e.g., megaloblastic anemia, pancytopenia),
  • Neurological complications (e.g., paresthesia, peripheral neuropathy, spinal cord degeneration),
  • Psychiatric symptoms (irritability, personality change, depression),
  • Cardiovascular problems (e.g., myocardial infarction and stroke).


Vitamin B12 deficiency should be suspected in refugee children with megaloblastic anemia on CBC. Diagnosis is generally based on the occurrence of risk factors, symptoms and a blood test detecting deficiency in serum vitamin B12 level. Other biochemical markers can be used to help confirm this diagnosis, such as urinary methylmalonic acid (MMA) excretion and total homocysteine.


Treatment may consist of supplementation with vitamin B12, either orally or by injections, as well as dietary modifications: adding foods that are high in vitamin B12, such as fish and shellfish, meat (especially liver), poultry, eggs or dairy.

The recommended daily intake of vitamin B12 for all age groups, including infants, children and adolescents, is available from Health Canada. 

Selected resources


  1. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases. Guidelines for evaluation of the nutritional status and growth in refugee children during the domestic medical screening process. Bethesda, MD: CDC, April 2012.
  2. Benson J, Maldari T, Turnbull T. Vitamin B12 deficiency—why refugee patients are at high risk. Aust Fam Physician 2010;39(4):215-7.


  • Anna Banerji, MD
  • Andrea Hunter, MD

Last updated: April, 2013