The objective of this study is to compare the quantity of Zn absorbed from an accurately weighed quantity (\~100 g) of minimally milled control maize (\~15 µg Zn/g maize), from biofortified maize (\~30 µg Zn/g) and from the same control maize that has been fortified (total level of \~60 µg Zn/g) when fed to young children age 24-36 months whose major habitual food staple is maize.
Participating children were randomized to receive an accurately weighed quantity of \~100g/day of either the control, fortified or biofortified study maize for 1 day. On day 1, mothers brought their child to the health center before breakfast. All meals were extrinsically labeled with a zinc stable isotope (70Zn). Meals on this day were consumed in the presence of the research staff. The quantities of nshima or porridge prepared and eaten were accurately weighed and duplicate meals were collected for subsequent mineral analyses. Between lunch and dinner on day 1 at the Health Center, a blood sample was collected for Hb and plasma Zn analyses and, immediately after and through the same needle, a stable isotope of zinc was intravenously administered into a forearm vein over 1-2 minutes. The family then returned home. Morning spot urine samples were collected twice daily starting on day 5 and continuing through day 8. Once these collections were finished, the study for this child was complete. Dietary Zn was measured from laboratory assays of the duplicate test meals. Fractional absorption of Zn (FAZ) was measured by dual isotope tracer ratio methods in urine. Absorbed Zn was calculated by multiplying dietary Zn by FAZ.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Masking
QUADRUPLE
Enrollment
60
Participant in this arm were fed zinc biofortified maize (\~30 µg Zn/g).
Participants in this arm were fed zinc-oxide fortified maize (total level of \~60 µg Zn/g).
Participants in this arm were fed maize that was not fortified or biofortified (\~15 µg Zn/g maize).
University of Colorado Anschutz Medical Campus
Aurora, Colorado, United States
University Teaching Hospital
Lusaka, Zambia
Absorption of zinc
Absorption of zinc will be measured in young children fed a diet of control, Zn-biofortified, or Zn-fortified maize. Fractional absorption of zinc from all meals of the day will be measured by extrinsic labeling with stable isotopes of zinc. Fractional absorption of zinc will be measured by a dual isotope tracer ratio technique. Measurement of total zinc in duplicate diets on test day will allow determination of quantity of this micronutrient absorbed (mg/d).
Time frame: 1 day
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