Vitamin B12 assimilation from chicken meat

Abstract

Chicken meat labeled in vivo with radio-B12 was ingested by normal volunteers. The absorption, measured by the fecal excretion method, was similar to that reported for crystalline radiocyanocobalamin and for mutton, but exceeded that from eggs. Parenteral injection of 1000 microgram of nonlabeled vitamin B12 did not interfere with the absorption of the radio-B12 from the meat. The urinary radioactivities, which were as low as those after oral administration of radioactive hydroxocobalamin and vitamin B12 coenzyme, suggested that the radio-B12 was present in meat in coenzyme form or was converted into the stable hydroxoform during the process of cooking and digestion. Patients with pernicious anemia showed insignificant urinary radioactivities in a standardized urinary excretion test using chicken meat whereas subjects with simple gastric achlorhydria and partial gastrectomy had subnormal values although their absorption of crystalline radiocyanocobalamin was normal. The subnormal serum vitamin B12 concentration seen in these latter subjects may, therefore, be due to impaired assimilation of vitamin B12 from food.

Systematic Review on Daily Vitamin B12 Losses and Bioavailability for Deriving Recommendations on Vitamin B12 Intake with the Factorial Approach

“…Unfortunately, information on age, sex and ethnicity of the study populations was not provided for most of the studies. Serum vitamin B12 concentrations were reported to be normal in all but one study that included subjects with low serum concentrations [23], but only five studies [8,9,10,27,28,36] actually reported concentrations (137-546 pmol/l).…”

“…When no SD was provided, we estimated it based on individual subject data {SD = √[∑(x i - x mean 2 )/(N - 1)]} [8,10,11,16,22,23,30], on the standard error (SE: SD = SE * √n) [25,26,31] or we approximated it by the total range (SD ≈ 0.25 * total range) [11,25,32,33]. …”

“…Currently, the bioavailability of vitamin B12 is generally assumed to be 40 or 50% for healthy adults with normal gastrointestinal functioning [2,4,5,6,7]. This assumption is based on the absorption of labeled vitamin B12 from a few food products, including mutton and chicken meat, rainbow trout, eggs or fortified foods [8,9,10,11,12]. …”

Scientific Opinion on Dietary Reference Values for cobalamin (vitamin B12)

“…By whole body counting, values from 4.5 % (CV = 38 %) at a dose of ~ 38 µg from mutton liver to 83 % (CV = 11 %) at a dose of ~ 3 μg from mutton meat were reported (Heyssel et al, 1966). Two studies observed cobalamin absorption of more than 50 % with cobalamin doses ranging between 0.42 and 5.11 μg (Heyssel et al, 1966;Doscherholmen et al, 1978), while it was lower in the other studies. Overall, the absolute amount of cobalamin absorbed (A i ) increases with increasing doses of cobalamin (D i ), while fractional absorption decreases.…”

Older Men and Women Efficiently Absorb Vitamin B-12 from Milk and Fortified Bread

“…These percentages compare well with the reported absorbability of vitamin B-12 from meat. Using similar whole body counting or stool counting techniques, 65% is absorbed from mutton, 60% is absorbed from chicken, 39% is absorbed from trout and 24 -36% is absorbed from eggs (Doscherholmen et al 1975(Doscherholmen et al , 1978(Doscherholmen et al and 1981. Our results of high body retention of an extrinsic B-12 label from milk and fortified bread are not surprising given the recent report by Tucker et al (2000), which showed stronger associations between serum vitamin B-12 and intake of vitamin B-12 (by quintiles) from milk and fortified cereal than from other food products in the Framingham Offspring Study.…”