The geometric mean ( range 1 SD ) of heme Fe bioavailability before and after treatment was 16.5 % ( 8.3-32 .8 ) and 26 % ( 15.5-43 .6 ) for the Ca group and 21.8 % ( 13.0-36 .6 ) and 25.1 % ( 16.5-38 .3 ) for the P group .