Roles Of Tea Consumption & Co-Fortification In Iron Nutrition

Abstract

Objective I: Develop extruded rice capable of delivering iron, zinc, vitamin A and ascorbic acid, without developing unwanted sensory changes. Investigate if vitamin A increases iron dialyzability. Results: Multinutrient fortification with ferrous sulfate or micronized ferric pyrophosphate (mFPP) resulted in a totally unacceptable product with noticeable darkening of the extruded kernels. Fortification with mFPP alone, produced kernels similar to those produced with electrolytic iron (EF) which had very little darkening regardless of whether additional minerals were added. In vitro digestion of the mFPP and EF samples revealed an increase in iron dialyzability with the addition of ascorbic acid or ascorbic acid and vitamin A together. The addition of Vitamin A did not increase iron dialyzability from corn porridges. Objective II: Examine the effect of green or black tea on iron absorption in animal models. Methods: Rats: Thirty-six weanling rats were allocated into 3 groups. Control group was fed a semi-purified diet (20mg Fe/kg diet), Oral group was fed green tea extract mixed into the diet (28.6g tea/kg diet), and Gavage group was fed control diet with a twice daily gavage of tea solution (0.25g tea/ml). Saliva was collected on day 8 or day 31. Iron absorption was assessed using a 58Fe3+ tracer administered on day 1 or day 24. Pigs: Weanling piglets were allocated into 3 groups. Control group was fed an iron-deficient corn-soybean diet (46mg Fe/kg diet). The tea groups were fed the control diet with black or green tea extract mixed into the diet (10g tea/kg diet). Saliva was collected weekly. Iron absorption was assessed by hemoglobin repletion efficiency (HRE). Parotid glands were analyzed for proline-rich proteins (PRP) mRNA concentration. Results: Rats: There was no significant difference in iron absorption between the three groups on either day 1 or 24. Salivary PRPs increased to a greater extent in the oral group than in the gavage group, compared to the control. Pigs: There was no significant difference in iron absorption between the three groups. PRP mRNA concentration was not different among the three groups. Conclusions: Tea does not decrease iron absorption in rats or piglets, but does affect the saliva proteome. Our results indicate that either tea does not significantly inhibit iron absorption or that animals are able to quickly adapt to any inhibitory effects of tea.