Abstract
Background: Metformin use may be associated with vitamin B12 deficiency especially in vegetarians.
Objectives: To determine the prevalence of holotranscobalamin deficiency among vegetarian and nonvegetarian patients with type 2 DM using metformin. To study the relation of dose and duration of metformin use on holotranscobalamin levels.
Results: Total of 65 patients were included. 22 were vegetarians. In the whole population, 7.7% had vitamin B12 deficiency (holotranscobalamin <25 pmol/L), 36.9% had equivocal (25-50 pmol/L) and 55.4% had normal levels (>50 pmol/L). Significantly higher proportion of vegetarians (77.3%) had deficient or equivocal holotranscobalamin compared to only 27.9% in non-vegetarians (p<0.0001). In the entire population, there was a negative but non significant correlation between duration, mean daily dose, and cumulative dose of metformin and serum holotranscobalamin. When stratified by diet status, significant negative correlation was noted between serum holotranscobalamin and duration (r=-0.48), mean daily dose (r=-0.48) and cumulative dose of metformin (r=-0.53) only in vegetarian population (p<0.05).
Conclusion: Higher daily dose, duration and cumulative dose of metformin significantly reduced serum holotranscobalamin levels in vegetarians. Empirical supplementation with B12 may be considered in vegetarians on metformin.