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Full-Text Articles in Nutrition
A Comparison Of Iron Absorption In Adults And Infants Consuming Identical Infant Formulas, Richard F. Hurrell, Lena Davidsson, Manju B. Reddy, Peter Kastenmayer, James D. Cook
A Comparison Of Iron Absorption In Adults And Infants Consuming Identical Infant Formulas, Richard F. Hurrell, Lena Davidsson, Manju B. Reddy, Peter Kastenmayer, James D. Cook
Manju B. Reddy
Fe absorption was estimated in adults and infants from the erythrocyte incorporation of Fe isotopes added to infant formula. Fe absorption was measured in adults using radioisotopes, and in infants with a stable-isotope technique. In adults, the geometric mean Fe absorption from a ready-to-feed soya formula with its native phytic acid content was 2.4%. This increased to 6.0 % (P < 0.05) after almost complete dephytinization. In infants, mean Fe absorption values were 3.9 and 8.7% respectively from the same products (P(O.05). In adults, mean Fe absorption from a spray-dried soya formula containing 110 mg ascorbic acid was 4.1 %, increasing to 5.3 % (P < 0.05) when ascorbic acid was doubled to 220 mgfl. In infants, mean Fe absorption values were 5.7 and 9.5 % (P < 0.05) from the same products. Mean Fe absorption from a milk-based formula was 6.5 % in adults compared with 6.7 % in infants. All meals in the adult and infant studies were fed using an identical meal size of 217 g. Increasing the meal size threefold in adults did not change fractional Fe absorption. Mean Fe absorption values for each meal were lower in adults than in infants, but the relative inhibitory effect of phytic acid and the enhancing effect of ascorbic acid were similar. We conclude that Fe absorption studies in adults can be used to assess the influence of enhancers and inhibitors of Fe absorption in infant formulas fed to infants. Further studies, however, are required to extend these findings to weaning foods and complete meals.
Soy Protein, Phytate, And Iron Absorption In Humans, Richard F. Hurrell, Marcel-A Juillerat, Manju B. Reddy, Sean R. Lynch, Sandra A. Dassenko, James D. Cook
Soy Protein, Phytate, And Iron Absorption In Humans, Richard F. Hurrell, Marcel-A Juillerat, Manju B. Reddy, Sean R. Lynch, Sandra A. Dassenko, James D. Cook
Manju B. Reddy
The effect of reducing the phytate in soy-protein isolates on nonheme-iron absorption was examined in 32 human subjects. Iron absorption was measured by using an extrinsic radioiron label in liquid-formula meals containing hydrolyzed corn starch, corn oil, and either egg white or one of a series ofsoy-protein isolates with different phytate contents. Iron absorption increased four- to fivefold when phytic acid was reduced from its native amount of 49-8.4 to < 0.01 mg/g of isolate. Even relatively small quantities of residual phytate were strongly inhibitory and phytic acid had to be reduced to < 0.3 mg/g of isolate (corresponding to < 10 mg phytic acid/meal) before a meaningful increase in iron absorption was observed. However, even after removal ofvirtually all the phytic acid, iron absorption from the soy-protein meal was still only half that of the egg white control. It is concluded that phytic acid is a major inhibitory factor of iron absorption in soy-protein isolates but that other factors contribute to the poor bioavailability of iron from these products.
Ferrous Fumarate Fortification Of A Chocolate Drink Powder, Richard F. Hurrell, Manju B. Reddy, Sandra A. Dassenko, James D. Cook, David Shepherd
Ferrous Fumarate Fortification Of A Chocolate Drink Powder, Richard F. Hurrell, Manju B. Reddy, Sandra A. Dassenko, James D. Cook, David Shepherd
Manju B. Reddy
An evaluation was made into the usefulness of ferrous fumarate as an iron fortificant for an experimental chocolate drink powder targetted to children and adolescents. Organoleptically ferrous fumarate was acceptable when the chocolate drink powder was reconstituted in milk or water that was heated to < 80". Unacceptable colour changes occurred, however, when boiling milk or water were used. In human Fe absorption studies when the Fe compounds were added to the chocolate drink immediately before consumption, ferrous fumarate was 3.31 % absorbed compared with 2.82% for ferrous sulphate and 2.11 % for ferric pyrophosphate. When the Fe compounds were processed during the manufacture of the chocolate drink powder, the absorption of ferrous fumarate was 5.27 %, ferrous sulphate 2.62 'YO and ferric pyrophosphate 0.55 %. Ascorbic acid had little or no effect on the absorption of ferrous fumarate. It is concluded that food processing can influence the relative absorption of fortification Fe and that, if not reconstituted with boiling milk or water, ferrous fumarate could be a useful compound for the fortification of chocolate drink powders.