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).