Changing the zinc:iron ratio in a cereal-based nutritional supplement has no effect on percent absorption of iron and zinc in Sri Lankan children

The Thriposha programme is a community-level nutrition intervention in Sri Lanka that provides a combination of energy, protein and micronutrients as a 'ready-to-eat' cereal-based food. We measured the bioavailability of Fe and Zn from Thriposha formula at two different molar ratios of Zn:Fe in order to determine the effect on Fe and Zn absorption. Children 4-7 years (n 53) were given a meal prepared with 50 g Thriposha containing 1.5 mg Zn as zinc sulphate and either 9 mg (high Fe concentration (HiFe)) or 4.5 mg (low Fe concentration (LoFe)) Fe as ferrous fumarate. Zn and Fe percent absorption were measured using stable isotopes by tracer:tracee ratio and by incorporation of erythrocytes, respectively. Percent Fe absorption from the two meals was similar (6.6% (4.8) v. 48% (2.6); P=0.15), but total Fe absorption was significantly higher from the HiFe meal (0.59 (0.43) mg) than the LoFe meal (0.20 (0.12) mg; P=0.01). There was no significant difference between the two groups in Zn absorption (10.7% (0.9) v. 8.8% (1.4), P=0-13, respectively). Decreasing the amount of Fe in Thriposha did not cause a significant change in the percent absorption of Fe and Zn, but significantly lowered the total amount of absorbed Fe. These results demonstrate the utility of maintaining a higher Fe content in this supplement. Further studies to increase Zn content are warranted while maintaining a HiFe.