Inhibition by Raw Eggs of Vitamin B12 Absorption

Abstract

To the Editor.— Radiocyanocobalamin ( 57 Co-B 12 ), mixed separately in vitro with ovalbumin and egg yolks, cooked and served to normal volunteers, was poorly absorbed as compared with a dose of crystalline 57 Co-B 12 . 1 This finding led to the conclusion that ovalbumin and egg yolk inhibit the gastrointestinal assimilation of vitamin B12. The validity of this conclusion may be open to question, since it was based on a comparison between the absorption of cooked radioactive vitamin B12 in the eggs and noncooked crystalline radiocyanocobalamin. The present study eliminated this inconsistency of design by comparing the gastrointestinal absorption of noncooked radioactive vitamin B12 administered in a watery solution with that of a similar dose incorporated into raw egg yolks and ovalbumin (Table). Crystalline 57 Co-B 12 mixed with the raw yolks of two eggs was ingested by a normal volunteer. The test was repeated two weeks later with