Vitamin B12 status of people living in Canada: Results from the Canadian Health Measures Survey 2012-2019.

BACKGROUND: B12 is an essential vitamin found in foods of animal origin, fortified foods, and supplements. Surveillance of B12 status in Canada is prioritized to support evaluation and monitoring of public policy, but national biomonitoring results have not been published since 2007-2009. OBJECTIVE: To describe the B12 status of people in Canada using serum B12 (status indicator) and plasma homocysteine (functional indicator), individually and combined as a two-component cB12 (2cB12) indicator. METHODS: We combined data for non-pregnant participants (n=21,760) from cycles 3-6 of the Canadian Health Measures Survey (2012-2019), a nationally representative survey of the household population aged 3-79. Serum B12 was measured in cycles 3-6 while plasma homocysteine was available in cycles 5-6 only. We used population-weighted data to calculate geometric means and proportions within adequacy thresholds for these indicators stratified by age and sex. We examined associations between sociodemographic and dietary factors with serum B12 status among adults and children using logistic regression. RESULTS: Compared to adults, lower proportions of children had serum B12 in the deficient (<148 pmol/L; children - 0.6% [95% CI 0.4, 0.9]E, adults - 3.5% [2.8, 4.2]) and marginal range (148-220 pmol/L; children - 6.6% [5.4, 7.8], adults- 17.8% [16.0, 19.6]). Homocysteine was high (≥15 μmol/L) in 6.0% (4.8-7.3) of the population and increased with age. The prevalence of adequacy was higher using the 2cB12 indicator than serum B12. Most sociodemographic variables were not associated with B12 adequacy in models adjusting for other factors, whereas diet was strongly associated, specifically supplement use and consumption of red meat, milk or fortified plant-based beverages, eggs, and yogurt (children). CONCLUSIONS: Most people living in Canada have adequate B12 status. Strong dietary associations reinforce the importance of supporting adequate intake through dietary guidance and policies on fortified foods and supplements.