evaluation of iron bioavailability in caco-2 cell culture model: modification of the original method

background and objectives: in the original in vitro method for evaluation of iron bioavailability using caco-2 cell model, ferritin formation by cells is considered as a functional indicator of both absorption and utilization of iron. however, as iron is measured in the tested material and then ferritin concentration is measured in caco-2 cell lysate, it is almost impossible to have a concrete measure of iron bioavailability because the percent of absorbable iron cannot be calculated by the concentration of iron in caco-2 cell lysate. to overcome this problem, the original method was modified by using ferrous sulfate tablet as a standard and also including blank well in the cell culture plate to subtract the baseline ferritin concentration from the ferritin concentration of other wells. materials and methods: to evaluate iron bioavailability in this model, one kind of iranian traditional breads (sangak) was used. standard curve was plotted using iron concentration and ferritin/protein ratio in the x and y axes, respectively. results: the standard curve showed a linear equation: ferritin (ng)/protein (mg) = (5.96 × bread fe)+ 11.55, r2=0.989. using this equation, the bioavailability of iron from the tested bread was 79.76 ± 11.5% of ferrous sulfate. considering that the reported iron bioavailability from ferrous sulfate is about 10%, bioavailability of iron from the bread could be regarded 8%. conclusions: this data can be potentially usable to adjust the amount of absorbable iron in the target population for fortification programs. keywords: iron, bioavailability, caco-2 cell