FOLATE AND SYNTHETIC FOLIC ACID INTAKE, SERUM B VITAMIN AND HOMOCYSTEINE CONCENTRATIONS, AND COGNITIVE IMPAIRMENT IN ELDERLY BRAZILIANS

Abstract

Background: An increased risk of cognitive decline in the elderly with B12 deficiency has been associated with excessive synthetic folic acid in food fortification and supplements. Objectives: To assess the dietary folate and folic acid intake from food fortification, as well as serum vitamin B12, folate, iron, and homocysteine concentrations among the elderly and their relationships with cognitive changes. Design: Cross-sectional, observational study. Setting and Participants: Community-dwelling elderly (N = 40), predominantly female (90%), with an average age of 69 years. Measurements: Dietary intake information was collected using four 24-hour dietary recalls, adjusted for iron and folic acid in fortified flour and supplements. Serum vitamin B12, B6, folate, iron, and homocysteine concentrations were determined. Cognitive function was assessed using the Mini-Mental State Examination, adjusted for educational level. Results: Possible serum vitamin B12 deficiency (<258 pmol/L) was present in 5% of the elderly participants, while 27.5% had possible functional deficiency (<400 pmol/L). No serum folate deficiency (<6.8 nmol/L) was observed; however, 15% had possible deficiency (<13.6 nmol/L), and 7.5% had supraphysiological levels. Hyperhomocysteinemia (≥15 µmol/L) was present in 65% of the sample. Almost half of the participants (47.5%) showed cognitive impairment. There were no significant relationships between the Mini-Mental State Examination results and the B12, folate, iron, and homocysteine concentrations. However, the participants with serum vitamin B12 levels <400 pmol/L tended to have poorer Mini-Mental State Examination scores, which were related to older age (P = 0.045) and changes in the oral cavity (P = 0.034). In addition, folic acid consumption was inversely related with serum vitamin B12 levels (P = 0.030). Macrocytosis was not observed. Conclusions: Although Mini-Mental State Examination-assessed cognitive impairment was not related with the investigated biochemical variables, increased folic acid consumption seems to have a negative impact on vitamin B12 metabolism; therefore, fortification may be contributing to functional disability and masking hematological signs in the elderly.