• cobalamin deficiency;
  • oral;
  • sublingual

Aims  To compare the efficacy of sublingual and oral administration of 500 µg of cobalamin in subjects with cobalamin deficiency.

Materials and results  Thirty subjects with low serum concentrations of cobalamin participated in the study. Subjects were randomly allocated to receive one tablet daily of 500 µg cobalamin sublingually or orally, or two tablets daily of a vitamin B complex. Serum cobalamin concentrations before treatment were 94 ± 30 pmol l−1,  108 ± 17 pmol l−1  and  98 ± 14 pmol l−1  in  the  sublingual  B12,  oral  B12  and oral B-complex groups, respectively. After 4 weeks, concentrations rose to 288 ± 74 pmol l−1, 286 ± 87 pmol l−1 and 293 ± 78 pmol l−1, respectively. The increase in each group across time was statistically significant (P = 0.0001, differences [95% confidence intervals] 194.2 (114.5, 273.9), 178.3 (104.2, 252.4), and 195.1 (135.0, 255.2) pmol l−1, respectively). There was no significant difference in concentrations between the treatment groups.

Conclusion  A dose of 500 µg of cobalamin given either sublingually or orally is effective in correcting cobalamin deficiency.