STABLE-ISOTOPE LABELS AS A TOOL TO DETERMINE THE IRON-ABSORPTION BY PERUVIAN SCHOOL-CHILDREN FROM A BREAKFAST MEAL

Fractional iron absorption from a breakfast meal was determined in Per uvian children employing stable iron isotopes as labels. Iron isotopic analysis was performed by the recently developed negative thermal ion ization technique for high-precision iron isotope ratio measurements u sing FeF4- ions. By increasing the ascorbic acid content of the standa rd breakfast meal as served within the Peruvian school-breakfast progr am from 27 mg to 70 mg, it was possible to increase the geometric mean fractional iron absorption significantly from 5.1% (range 1.6-13.5%) to 8.2% (range 3.1-25.8%). Fractional iron absorption was calculated a ccording to isotope dilution principles and by considering the non-mon oisotopic character of the used spikes.