In vitro and in vivo evaluation of iron bioavailability from microencapsulated ferrous sulfate

Objective To evaluate, by in vitro and in vivo methods, the bioavailability of a new microencapsulated ferrous sulfate (Ferlim) developed for food fortification, and compare it with electrolytic iron (Fe-0). Methods In vitro dialyzability assessment used reconstituted milk powder as matrix. In vivo assessment using the hemoglobin regeneration method in anemic piglets lasted for 13 days and the animals (n=23) were grouped according to the product of weight (kg) x hemoglobin (g/dL). FeSO4.7H(2)O was used as control. Results The percentages of dialyzed iron were 2.2 (standard deviation=0.1)%, 3.4 (standard deviation=0.1)% and 3.6 (standard deviation=0.0)% for FeSO4.7H(2)O, Ferlim and Fe-0 respectively (p < 0.05). Iron absorption was 16.0 (standard deviation=3.1)% for the control group, 15.1 (standard deviation=3.8)% for the Ferlim group and 12.8 (standard deviation=4.3)% for the Fe-0 group; the differences were not significant (p > 0.05). The absorption percentages of the relative biological value of FeSO4.7H(2)O were 94.2 (standard deviation=23.8)% for the Ferlim group and 79.7 (standard deviation=26.6)% for the Fe-0 group; the differences were not significant (p > 0.05). In numerical values (p > 0.05), the Fe-0 group presented the lowest mean relative biological value absorption (%) and concentration of total iron, heme iron and non-heme iron in the liver. Conclusion Microencapsulation of ferrous sulfate with alginate retains its bioavailability therefore it is a good alternative for the fortification of solid mixtures.