Bioavailability of Vitamin B 12 from Dairy Products Using a Pig Model.

The present study compares the bioavailability of vitamin B ₁₂ (B ₁₂ ) of dairy products or synthetic B ₁₂ , using the pig as an experimental model for humans. Eleven pigs were used in a cross-over design to assess the net portal drained viscera (PDV) flux of blood plasma B ₁₂ after ingestion of tofu (TF; devoid of B ₁₂ ), Swiss cheese (SC), Cheddar cheese (CC), yogurt (YG), and synthetic B ₁₂ (TB ₁₂ ; TF supplemented with cyanocobalamin), providing a total of 25 µg of B ₁₂ each. PDV blood plasma flow for SC and CC were higher than for TF and TB ₁₂ ( p ≤ 0.04) whereas YG was higher than TF ( p = 0.05). Porto-arterial difference of blood plasma B ₁₂ concentrations were higher for CC and TB ₁₂ than for TF and YG ( p ≤ 0.04) but not different from SC ( p ≥ 0.15). Net PDV flux of B ₁₂ was only different from zero for CC. However, the net PDV flux of B ₁₂ for CC was not different from SC or TB ₁₂ . Cumulative net PDV flux of B ₁₂ for SC, TB ₁₂ , and CC were 2.9, 4.4, and 8.3 µg 23 h post-meal, corresponding to a bioavailability of 11.6%, 17.5%, and 33.0%, respectively. In conclusion, CC had the best bioavailability of B ₁₂ among the tested dairy products or compared to synthetic B ₁₂ .