title: Vitamin B-12 and homocysteine status in a folate-replete population: results from the Canadian Health Measures Survey.
abstract: 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.
  
  
  METHODS
  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.
authors: Nutrition Research Division, Health Canada, Ottawa, Canada. amanda.macfarlane@hc-sc.gc.ca
authors: Amanda J
authors: AJ
authors: MacFarlane
authors: Linda S
authors: LS
authors: Greene-Finestone
authors: Yipu
authors: Y
authors: Shi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002170:Canada / Q000453:epidemiology; D002648:Child; D003430:Cross-Sectional Studies; D004912:Erythrocytes; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood; D005494:Folic Acid Deficiency / Q000453:epidemiology / Q000517:prevention & control; D005527:Food, Fortified / Q000032:analysis; D006306:Health Surveys; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007881:Legislation, Food; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D009765:Obesity / Q000150:complications; D015995:Prevalence; D012720:Severity of Illness Index; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12