Vitamin B-12 and homocysteine status in a folate-replete population: results from the Canadian Health Measures Survey

Am J Clin Nutr. 2011 Oct;94(4):1079-87. doi: 10.3945/ajcn.111.020230. Epub 2011 Sep 7.


Background: Vitamin B-12 is an important cofactor required for nucleotide and amino acid metabolism. Vitamin B-12 deficiency causes anemia and neurologic abnormalities-a cause for concern for the elderly, who are at increased risk of vitamin B-12 malabsorption. Vitamin B-12 deficiency is also associated with an increased risk of neural tube defects and hyperhomocysteinemia. The metabolism of vitamin B-12 and folate is interdependent, which makes it of public health interest to monitor biomarkers of vitamin B-12, folate, and homocysteine in a folic acid-fortified population.

Objective: The objective was to determine the vitamin B-12, folate, and homocysteine status of the Canadian population in the period after folic acid fortification was initiated.

Design: Blood was collected from a nationally representative sample of ∼5600 participants aged 6-79 y in the Canadian Health Measures Survey during 2007-2009 and was analyzed for serum vitamin B-12, red blood cell folate, and plasma total homocysteine (tHcy).

Results: A total of 4.6% of Canadians were vitamin B-12 deficient (<148 pmol/L). Folate deficiency (<320 nmol/L) was essentially nonexistent. Obese individuals were less likely to be vitamin B-12 adequate than were individuals with a normal BMI. A total of 94.9% of Canadians had a normal tHcy status (≤13 μmol/L), and individuals with normal tHcy were more likely to be vitamin B-12 adequate and to have high folate status (>1090 nmol/L).

Conclusions: Approximately 5% of Canadians are vitamin B-12 deficient. One percent of adult Canadians have metabolic vitamin B-12 deficiency, as evidenced by combined vitamin B-12 deficiency and high tHcy status. In a folate-replete population, vitamin B-12 is a major determinant of tHcy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Biomarkers / blood
  • Canada / epidemiology
  • Child
  • Cross-Sectional Studies
  • Erythrocytes
  • Female
  • Folic Acid / administration & dosage*
  • Folic Acid / blood
  • Folic Acid Deficiency / epidemiology
  • Folic Acid Deficiency / prevention & control
  • Food, Fortified* / analysis
  • Health Surveys
  • Homocysteine / blood*
  • Humans
  • Legislation, Food
  • Male
  • Middle Aged
  • Nutritional Status*
  • Obesity / complications
  • Prevalence
  • Severity of Illness Index
  • Vitamin B 12 / blood*
  • Vitamin B 12 Deficiency / blood
  • Vitamin B 12 Deficiency / complications
  • Vitamin B 12 Deficiency / epidemiology*
  • Young Adult


  • Biomarkers
  • Homocysteine
  • Folic Acid
  • Vitamin B 12