BACKGROUND: Recent studies in humans suggest that ferritin iron in soybeans has high bioavailability. However, direct evidence for this is lacking because the soybeans were intrinsically labeled; thus, iron bound to other ligands, such as phytate, was also labeled. OBJECTIVE: The objectives of the study were to evaluate the absorption of iron from extrinsically labeled, purified ferritin (horse spleen) reconstituted with either high-phosphate iron mineral (plant-type) or low-phosphate iron mineral (animal-type) and to compare it with iron absorption from ferrous sulfate. DESIGN:Nonanemic, healthy young women were fed a standard breakfast meal supplemented with (59)Fe-labeled ferritin or ferrous sulfate, in randomized order. Fifteen subjects received ferritin with the low-phosphate iron mineral, and 15 subjects receivedferritin with the high-phosphate iron mineral. Iron absorption was measured in a whole-body counter after 14 and 28 d and by red blood cell incorporation after 28 d. RESULTS: There was no significant difference in iron absorption between ferritin and ferrous sulfate: low-phosphate iron mineral ferritin (x +/- SD: 21.4 +/- 14.7%) compared with ferrous sulfate (21.9 +/- 14.6%), or high-phosphate iron mineral ferritin (22.2 +/- 19.2%) compared with ferrous sulfate (16.7 +/- 7.1%). Results obtained by using whole-body retention of iron and red blood cell incorporation differed with the type of iron, which suggests that pathways for iron uptake and utilization differed for the 2 forms. CONCLUSIONS: Iron is equally well absorbed from ferritin and ferrous sulfate independent of the phosphate content of the ferritin iron mineral. Thus, dietary ferritin iron is likely to be a good source of iron.
RCT Entities:
BACKGROUND: Recent studies in humans suggest that ferritin iron in soybeans has high bioavailability. However, direct evidence for this is lacking because the soybeans were intrinsically labeled; thus, iron bound to other ligands, such as phytate, was also labeled. OBJECTIVE: The objectives of the study were to evaluate the absorption of iron from extrinsically labeled, purified ferritin (horse spleen) reconstituted with either high-phosphateiron mineral (plant-type) or low-phosphateiron mineral (animal-type) and to compare it with iron absorption from ferrous sulfate. DESIGN: Nonanemic, healthy young women were fed a standard breakfast meal supplemented with (59)Fe-labeled ferritin or ferrous sulfate, in randomized order. Fifteen subjects received ferritin with the low-phosphateiron mineral, and 15 subjects received ferritin with the high-phosphateiron mineral. Iron absorption was measured in a whole-body counter after 14 and 28 d and by red blood cell incorporation after 28 d. RESULTS: There was no significant difference in iron absorption between ferritin and ferrous sulfate: low-phosphateiron mineral ferritin (x +/- SD: 21.4 +/- 14.7%) compared with ferrous sulfate (21.9 +/- 14.6%), or high-phosphateiron mineral ferritin (22.2 +/- 19.2%) compared with ferrous sulfate (16.7 +/- 7.1%). Results obtained by using whole-body retention of iron and red blood cell incorporation differed with the type of iron, which suggests that pathways for iron uptake and utilization differed for the 2 forms. CONCLUSIONS:Iron is equally well absorbed from ferritin and ferrous sulfate independent of the phosphate content of the ferritin iron mineral. Thus, dietary ferritin iron is likely to be a good source of iron.
Authors: Elizabeth C Theil; Huijun Chen; Constanza Miranda; Heinz Janser; Bernd Elsenhans; Marco T Núñez; Fernando Pizarro; Klaus Schümann Journal: J Nutr Date: 2012-01-18 Impact factor: 4.798