Folate and vitamin B12 status: temporal evaluation after mandatory fortification in Brazil

Objectives To perform temporal evaluation of folate and vitamin B12 status and their associated factors in a Brazilian population exposed to mandatory fortification. Methods Data from the cross-sectional population-based studies 2008 and 2015 Health Surveys of São Paulo, including individuals ≥ 20 years, both sexes, N = 549 in 2008 and N = 610 in 2015. Folate and vitamin B12 biomarkers status, B-complex supplements and medications use, and dietary intake were assessed. Results Serum folate concentrations increased in the entire population, adults and older adults in 2015 compared to 2008, while serum vitamin B12 concentration increased only in older adults. B-complex supplement use raised in 2015, reflecting in serum vitamins status. Overall serum vitamin B12 deficiencies (<200 pg/mL) were 23.2% and 21.2%, while serum folate deficiencies (<4 ng/mL) were 4.1% and 1.5% in 2008 and 2015, respectively. The lowest quintile of serum folate (≤8.7 ng/mL) was positively associated with smoking and oral contraceptive use, while the highest quintile (≥17.8 ng/mL) was inversely associated with smoking and positively with B-complex supplement use. The odds of having vitamin B12 deficiency was inversely associated with B-complex supplement use, higher serum folate median, higher dietary vitamin B12 intake and positively associated with using oral contraceptive. Conclusion Overall deficiency of folate has decreased in 2015, being almost non-existent. Low vitamin B12 status presented similar proportions in the overall population comparing both periods, except for older adults. Different predictive variables were identified to better understand vitamins status outcomes in the most recent period of the study.