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.
|Number of pages||3|
|Journal||American Journal of Clinical Nutrition|
|Publication status||Published - 1988|
All Science Journal Classification (ASJC) codes
- Food Science
- Medicine (miscellaneous)