Objective: To study iron absorption from legume ferritin
Design: This study used a ‘randomized, crossover design’ in order to compare different forms of iron absorption. 16 non-anemic women, in a fasted state, received a standardized meal randomized to contain either 1 mg of iron from ferrous sulphate or from soybean ferritin. The meals were consumed with 60 mL of apple juice. After 4 weeks, blood was drawn to measure the degree of incorporation of the radiolabeled iron into red blood cells. They were then given another meal (with the alternate iron source to whichever one their first meal contained) containing 1 mg of iron from ferrous sulphate or from soybean ferritin. Another 4 weeks later, the subjects had their blood drawn and iron absorption was checked again by measuring the degree of radiolabeled iron incorporated into red blood cells.
Results: Whole body iron absorption was 29.9% for soybean ferritin and 34.3% for ferrous sulphate. Iron incorporation into red blood cells was 33% for soybean ferritin and 35.3% for ferrous sulphate.
Conclusions: These were not considered statistically significant differences so both forms of iron were considered equal. An inverse relationship between iron status and iron absorption was noted for both forms of iron, meaning that the physiological iron regulating sensors of the subjects worked for both forms of iron to allow for increased or decreased absorption depending on their individual iron status.