TY - JOUR
T1 - The importance and bioavailability of phytoferritin-bound iron in cereals and legume foods
AU - Lönnerdal, Bo
PY - 2007/5
Y1 - 2007/5
N2 - Ferritin is present in several types of plants in low concentrations, but it is possible to enhance this content by plant breeding, or by inserting the gene for ferritin into staple foods. Since each ferritin molecule can bind thousands of iron atoms, this may be a sustainable means to increase the iron content of plants. Before launching such efforts it is important to determine whether ferritin-bound iron is bioavailable. We assessed this in vitro using Caco-2 cells and in vivo using radiolabeled ferritin and whole body counting in human subjects. In Caco-2 cells, we found that dietary factors affecting iron absorption, such as ascorbic acid, phytate, and calcium, had very limited effect on iron uptake from intact ferritin, suggesting that ferritin-bound iron is absorbed via a mechanism different from that of non-heme iron. Using in vitro digestion, we found that ferritin was relatively resistant against proteolytic enzymes. Binding of ferritin to Caco-2 cells was found to be saturable and the kinetics for binding characteristic for a receptor-mediated process. In human subjects, we found that iron absorption from animal ferritin was similar to that from ferrous sulfate, suggesting that iron is well absorbed from ferritin. We did not find any significant difference between iron absorption from ferritin reconstituted with high-phosphate (plant-type) and low-phosphate (animal-type) ferritin mineral, suggesting that plant ferritin-iron is bioavailable. In a subsequent human study we also found that iron from purified soybean ferritin given in a meal was as well absorbed as ferrous iron. In conclusion, iron is well absorbed from phytoferritin and may represent a means of biofortification of staple foods.
AB - Ferritin is present in several types of plants in low concentrations, but it is possible to enhance this content by plant breeding, or by inserting the gene for ferritin into staple foods. Since each ferritin molecule can bind thousands of iron atoms, this may be a sustainable means to increase the iron content of plants. Before launching such efforts it is important to determine whether ferritin-bound iron is bioavailable. We assessed this in vitro using Caco-2 cells and in vivo using radiolabeled ferritin and whole body counting in human subjects. In Caco-2 cells, we found that dietary factors affecting iron absorption, such as ascorbic acid, phytate, and calcium, had very limited effect on iron uptake from intact ferritin, suggesting that ferritin-bound iron is absorbed via a mechanism different from that of non-heme iron. Using in vitro digestion, we found that ferritin was relatively resistant against proteolytic enzymes. Binding of ferritin to Caco-2 cells was found to be saturable and the kinetics for binding characteristic for a receptor-mediated process. In human subjects, we found that iron absorption from animal ferritin was similar to that from ferrous sulfate, suggesting that iron is well absorbed from ferritin. We did not find any significant difference between iron absorption from ferritin reconstituted with high-phosphate (plant-type) and low-phosphate (animal-type) ferritin mineral, suggesting that plant ferritin-iron is bioavailable. In a subsequent human study we also found that iron from purified soybean ferritin given in a meal was as well absorbed as ferrous iron. In conclusion, iron is well absorbed from phytoferritin and may represent a means of biofortification of staple foods.
KW - Ferritin
KW - Iron
KW - Iron absorption
KW - Iron bioavailability
KW - Phytoferritin
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U2 - 10.1024/0300-9831.77.3.152
DO - 10.1024/0300-9831.77.3.152
M3 - Article
C2 - 18214015
AN - SCOPUS:35349025969
VL - 77
SP - 152
EP - 157
JO - Internationale Zeitschrift fur Vitaminforschung. International journal of vitamin research. Journal international de vitaminologie
JF - Internationale Zeitschrift fur Vitaminforschung. International journal of vitamin research. Journal international de vitaminologie
SN - 0300-9831
IS - 3
ER -