Evaluation of iron and zinc bioavailability from fortified rice using coating, hot and cold extrusion: human stable isotope studies

Abstract Number Theme Presentation Type Cover Approved
0187 Iron, zinc, vitamin A, iodine, vitamin B12, folate, vitamin D, multiple micronutrients Oral Not Approved


Abstract Content


Rice fortification technologies may affect mineral bioavailability from fortified rice.We measured fractional iron (FAFe, Studies 1 & 2) and zinc (FAZn, Study 2) absorption from ferric-pyrophosphate (FePP) and zinc-oxide (ZnO) fortified rice produced with coating, hot or cold extrusion.


Healthy women were fed rice-meals (both studies: 4 mg iron/meal): Study 1 compared FAFe from hot (HE) versus cold (CE) extruded FePP-fortified rice (n=19); Study 2 compared FAFe and FAZn from hot extruded (HOR) versus coated (COR) FePP-fortified rice, and FAFe versus non-fortified extruded rice with FeSO4 (reference) added after cooking (n=22). Study 1 used citric-acid (CA) as chelating-agent for iron, Study 2 used CA and trisodium-citrate (TSC). FAFe was measured as erythrocyte-incorporation of stable iron isotopes 14 days after meal-administration and corrected to a serum ferritin level of 40 µg/l (FAFecorr). FAZn was assessed via double-isotope urinary-monitoring.


FAFecorr (-SD, +SD) was higher from CE: 1.8% (1.0, 3.4%) than from HE: 1.1% (1.0, 3.0%; P=.029); there was no significant difference in FAFe between HOR: 3.6% (1.5, 9.0%) and COR: 2.8% (1.4, 5.8), however, COR had a lower FAFecorr than the reference meal: 4.6%, (2.4, 8.9%) (P=.001). FAZn (-SD, +SD) did not differ between HOR: 9.9% (6.3, 15.7) and COR 10.0% (7.7, 12.3; n.s.).


Iron absorption from FePP-fortified rice is affected both by iron chelators and fortification technology. We found no difference for FAFecorr and FAZn between hot extruded and coated rice when CA/TSC was present. Cold extruded rice containing CA only, showed increased FAFecorr compared to hot extruded rice.

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