Egg. Vitamin B12 content in the whole egg is about
0.9–1.4 lg/100 g (18, 30), and most of the vitamin B12 is
found in the egg yolk (31). Vitamin B12 intakes from the
egg are generally large, because it is a popular food item (7).
Bioavailability of vitamin B12 from scrambled egg yolks,
scrambled whole eggs, boiled eggs, and fried eggs (1.1–1.4
lg vitamin B12 per 100 g) averaged 8.2%, 3.7%, 8.9%, and
9.2%, respectively (30). Vitamin B12 in eggs is generally
poorly absorbed relative to other animal food products (32).
Vitamin B12 Sources and Bioavailability
FUMIO WATANABE 2007