Table 3 Composition of extruded rice, administered study meals, human iron absorption, and in vitro iron solubility.

Each rice meal serving contained 49.5 g of unfortified rice and 0.5 g of fortified rice with 50 g of either bean or tomato sauce. Values are means ± SDs or geometric means (95% CI). Labeled means in a column without a common letter differ. P < 0.05, Bonferroni-corrected linear mixed model. Designated micronutrient composition of fortified kernels can be found in the Supplementary Materials. 54FeZnO, extruded rice containing 54FePP, ZnO, and a micronutrient mix (MN); 57FeZnSO4, extruded rice containing 57FePP, ZnSO4, and MN; 54FeZnOCT, extruded rice containing 54FePP, ZnO, MN, CA, and TSC; 57FeZnSO4CT, extruded rice containing 57FePP, ZnSO4, MN, CA, and TSC; 58FeZnOCE, extruded rice containing 58FePP, ZnO, MN, CA, and EDTA; Reference, extruded rice containing MN and 58FeSO4 solution added before consumption. N/A, not applicable.

Iron (mg/g)*Zinc (mg/g)*Fe/Zn/CA/TSC/
Fractional iron
absorption (%)§
RBV (%)§,||Relative iron
solubility (%)
54FeZnO3.5 ± 0. 504.2 ± 0.081:1.0:0:0:01:1.0:0.8:0.02.3 (1.9–2.8)a36a3.6 ± 0.5a
57FeZnSO43.2 ± 0.504.1 ± 0.191:1.1:0:0:01:1.1:1.0:0.03.5 (2.7–4.5)b54b4.7 ± 0.5a
54FeZnOCT3.2 ± 0. 504.2 ± 0.11:1.1:0.3:6.0:01:1.1:0.9:0.04.5 (3.6–5.5)b70.4b19.8 ± 2.7b
57FeZnSO4CT3.4 ± 0. 504.1 ± 0.191:1.1:0.3:5.5:01:1.1:0.9:0.06.3 (5.3–7.4)c98.3c27.1 ± 4.0b
58FeZnOCE3.3 ± 0. 504.1 ± 0. 191:1.1:0.3:0:0.61:1.1:0.9:0.06.4 (5.1–8.1)c101c24.1 ± 3.1b
Reference3.6 ± 0. 101.3 ± 0.01N/A1:0.3:0.8:0.06.4 (5.2–7.8)cN/AN/A

*Calculated iron and zinc contents in composite meals were based on the means from the analysis of single components [49.5 g of regular basmati rice, 0.5 g of extruded rice, and average mineral contents from the two different sauces (50 g of sauce); n = 3], and SDs for iron and zinc contents of composite meals were adapted by calculating the square root of the squared and summed SDs from each single component.

†Molar ratio in fortified rice.

‡Molar ratio per serving of rice—average mineral, PA, and AA contents from the two different sauces were calculated.

§n = 26.

||RBV calculation based on geometric mean fractional iron absorption (%) relative to fractional iron absorption from the reference meal for each subject.

¶Iron solubility was assessed in fortified rice kernels. For details on the calculation, please refer to the text, n = 3.