Bioavailability in humans of zinc from beef: Intrinsic vs extrinsic labels

D. D. Gallaher, P. E. Johnson, J. R. Hunt, G. I. Lykken, M. J. Marchello

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


Beef is a concentrated source of zinc. However, the bioavailability of Zn from beef has not been clearly established. It is also unclear whether there is a difference in absorption between intrinsic and extrinsic Zn. To address these questions, a calf was labeled with 65ZnCl2 and the meat was used as a source of intrinsically labeled beef. Twelve subjects were given a meal containing 100 g beef labeled either intrinsically or extrinsically with 65ZnCl2. Gamma-ray emissions, as determined by whole-body counting, were used to calculate Zn absorption. Absorption values were 20.9 ± 5.5% from the extrinsic meal and 26.4 ± 10.6% from the intrinsic meal, a difference that was not statistically significant (p > 0.05). Zn absorption was thus much less than the 40% assumed in establishing the 1980 Recommended Dietary Allowance for Zn. These results also indicate that extrinsic labels of Zn are valid markers of zinc absorption in beef.

Original languageEnglish (US)
Pages (from-to)350-354
Number of pages5
JournalAmerican Journal of Clinical Nutrition
Issue number2
StatePublished - 1988
Externally publishedYes


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