Very Low Oral Doses of Vitamin B-12 Increase Serum Concentrations in Elderly Subjects with Food-Bound Vitamin B-12 Malabsorption1

• Published in: The Journal of nutrition Vol. 137; no. 2; pp. 373 - 378
• Main Authors: Blacher, Jacques, Czernichow, Sébastien, Raphaël, Mathilde, Roussel, Christophe, Chadefaux-Vekemans, Bernadette, Morineau, Gilles, Giraudier, Stéphane, Tibi, Annick, Henry, Olivier, Vayssière, Michel, Oudjhani, Moussa, Nadaï, Sophie, Vincent, Jean-Pierre, Bodak, Alexandre, Di Menza, Claude, Ménard, Joël, Zittoun, Jacqueline, Ducimetière, Pierre
• Format: Journal Article
• Language: English
• Published: Bethesda Elsevier Inc 01.02.2007; American Institute of Nutrition
• Subjects: Biomedical research; Cystic fibrosis; Diet; Folic acid; Gastrointestinal diseases; Hospitalization; Hospitals; Nutrition; Older people; Patients; Public health; Vitamin B
• ISSN: 0022-3166; 1541-6100
• DOI: 10.1093/jn/137.2.373

The BOSSANOVA study, a randomized double-blind trial, was designed to test the ability of very low oral doses of vitamin B-12 to increase the serum vitamin B-12 concentration in elderly subjects with food-bound vitamin B-12 malabsorption, and to determine whether there was a dose response. We also aimed to quantitatively assess the most efficient dose to be added to flour in addition to folic acid (flour cofortification with vitamin B-12 and folic acid). Sixty-seven patients were randomly assigned to 1 of 6 groups receiving various daily oral doses of vitamin B-12 (i.e., 2.5, 5, 10, 20, 40, or 80 μg/d) for 30 d. The dose-response was tested for different biological variables using a mixed model, taking into account the variable’s initial value (between-subject effect), a linear log-dose effect, and a linear log (dose × time) interaction, where time was d 15 or d 30. We planned to determine the amount of oral vitamin B-12 that would increase the serum vitamin B-12 concentration by 37 pmol/L (50 ng/L). Significant between-subject effects were found for serum vitamin B-12, plasma homocysteine, and methylmalonic acid concentrations, but a log-dose effect was found only for vitamin B-12 (P < 0.001). The slope of the line tended to be higher (P = 0.07) at d 30 than at d 15. For a mean serum vitamin B-12 increase of 37 pmol/L, a dose of 5.9 (95% CI, 0.9–12.1) μg/d was needed. We concluded that very low oral doses of vitamin B-12 increased serum vitamin B-12 concentrations in elderly subjects with subclinical vitamin B-12 deficiency, following a log-dose pattern. Our results could be beneficial in the design of a public health program for safe flour cofortification with folic acid.