title: Older men and women efficiently absorb vitamin B-12 from milk and fortified bread.
abstract: Nothing is directly known about the bioavailability of vitamin B-12 from dairy products or fortified grain products. We directly studied vitamin B-12 absorption from water, milk and fortified bread in adult subjects using (58)Co-labeled vitamin B-12 and a whole body gamma-ray counter/spectrophotometer. Sixteen healthy men and women over the age of 60 y with normal serum levels of vitamin B-12 and normal basal gastric acid secretion were studied. (58)Co vitamin B-12 (0.25 microg) was administered in water, milk or fortified bread to each subject along with 185 kBq (5.0 microCi) (51)Cr as a stool marker. Whole body counting was performed 30 min after ingestion of the radioactive dose and at 7 and 14 d after dosing. Mean absorptions from water, milk and fortified bread were 55, 65 and 55%, respectively, and did not differ. The high body retention of the extrinsic vitamin B-12 label from milk and bread may warrant a greater use of such fortified products in the elderly to ensure vitamin B-12 adequacy.
authors.affiliation: Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts 02111, USA. russell@hnrc.tufts.edu
authors.forename: R M
authors.initials: RM
authors.lastname: Russell
authors.forename: H
authors.initials: H
authors.lastname: Baik
authors.forename: J J
authors.initials: JJ
authors.lastname: Kehayias
mesh_terms: D000368:Aged; D000375:Aging / Q000378:metabolism*; D000818:Animals; D001682:Biological Availability; D001939:Bread; D003036:Cobalt Isotopes; D005243:Feces / Q000737:chemistry; D005260:Female; D005527:Food, Fortified; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D008875:Middle Aged; D008892:Milk; D013051:Spectrometry, Gamma; D014805:Vitamin B 12 / Q000008:administration & dosage / Q000493:pharmacokinetics*; D014806:Vitamin B 12 Deficiency / Q000517:prevention & control; D014867:Water
chemical_list: D003036:Cobalt Isotopes; D014867:Water; D014805:Vitamin B 12