The hypothesis of this study is that chicken eggs can be enriched in vivo with 14C-B12 and fed to healthy human subjects to determine B12 bioavailability from eggs.

The goal of this research is to enrich eggs in vivo with radioactively labeled vitamin B12 to a level that allows us to feed the enriched eggs to humans and determine how much of the vitamin B12 is digested and absorbed into the body. This will tell us if eggs are a good dietary source of vitamin B12. Importantly, sensitive technology available at the Lawrence Livermore National Laboratories allows us to measure very low amounts of radioactive vitamin B12. This allows us to do this experiment with a level of radioactive B12 that is not harmful to animals or humans. The results of the investigators first experiment indicate that the investigators can inject radioactively labeled vitamin B12 into a laying hen and detect the radioactive vitamin B12 in the eggs at a level sufficient for feeding to humans in a bioavailability study.

Inclusion Criteria:

• normal healthy subjects, adequate B12 status and absorptive capacity and the availability to complete the protocol.

Exclusion Criteria:

• any chronic health disorder, anemia of any kind, renal insufficiency, and pregnancy or lactation.

Healthy adults, 18 y or older