Calcium absorbability from spinach

R. P. Heaney, C. M. Weaver, Robert R. Recker

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The absorbability of calcium from spinach was compared with the absorbability of Ca from milk in 13 healthy adults in a randomized cross-over design in which the test meal of either milk or spinach had 200 mg of Ca labeled with 45Ca. Absorption was measured by the standard double-isotope method in which both the test food and the miscible Ca pool are labeled with different Ca tracers. Measurement of both Ca and oxalate in our test spinach revealed a very slight stoichiometric excess of oxalate; hence it is likely that all of the spinach Ca was effectively bound. Absorption was higher from milk in every case, with the mean absorption from milk averaging 27.6% and from spinach, 5.1%. The mean within-subject difference between Ca absorption from milk and from spinach was 22.5 ± 9.5% (P <0.0001). These results conclusively establish that spinach Ca is much less readily available than milk Ca.

Original languageEnglish
Pages (from-to)707-709
Number of pages3
JournalAmerican Journal of Clinical Nutrition
Issue number4
Publication statusPublished - 1988


All Science Journal Classification (ASJC) codes

  • Food Science
  • Medicine (miscellaneous)

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