Inhibitory Effect of Eggs on Vitamin B12 Absorption: Description of a Simple Ovalbumin 57Co‐Vitamin B12 Absorption Test

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Abstract
Ovalbumin and egg yolks, mixed separately in vitro with radiocyanocobalamin (57Co-vitamin B12), were served to normal volunteers in a cooked form. Ovalbumin, and to a lesser degree, egg yolks were observed to inhibit vitamin B12 absorption. This observation explains the rather poor assimilation of vitamin B12 from eggs labeled in vivo with 57Co-vitamin B12. The assimilation of vitamin B12 from the ovalbumin 57Co-vitamin B12 mixture was also measured in patients with structural alterations and functional disorders of the stomach. In contrast to the absorption test using crystalline radio-vitamin B12, this simple food-vitamin B12 absorption test successfully distinguished between the controls and subjects who had simple gastric achlorhydria and patients who had undergone a Billroth I or II operation or a successful vagotomy with pyloroplasty. This ovalbumin 57Co-vitamin B12 test successfully separated patients with pernicious anemia from those with simple gastric achlorhydria. The ovalbumin 57Co-vitamin B12 test, in contrast to that using crystalline 57Co-vitamin B12, showed a positive correlation with the serum vitamin B12 concentration. This ovalbumin 57Co-vitamin B12 test, being more physiologic and informative than the method using crystalline radio-vitamin B12, is the 1st simple model for food-vitamin B12 absorption to be proposed for research and for clinical purposes.