Evaluation of Iron Bioavailability in Caco-2 cell Culture Model: Modification of the Original Method

Abstract

A B S T R A C T 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, R 2 =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.

Higher bioavailability of iron from whole wheat bread compared with iron‐fortified white breads in caco‐2 cell model: an experimental study

“…We employed the original method of in vitro evaluation of iron bioavailability, with some modifications . In this method, ferritin formation by caco‐2 cells is considered as a functional indicator of both absorption and utilization of iron in the tested material.…”

“…To overcome this problem, we modified the original method by making a standard curve of bioavailability using ferrous iron supplement and then comparing the results of the test lysate to the curve. The percentage of bioavailable iron in the tested material (bread) was then calculated …”

“…We employed the original method of in vitro evaluation of iron bioavailability, 12 with some modifications. 13 In this method, ferritin wileyonlinelibrary.com/jsfa ng ferritin∕mg protein = (5.96 × test material Fe) +11.55, R 2 = 0.989 Using this equation, the 'expected value' for ferritin/protein ratio of the test bread based on its iron content was calculated. The J Sci Food Agric 2017; 97: 2541-2546…”

Lemon Juice, Sesame Paste, and Autoclaving Influence Iron Bioavailability of Hummus: Assessment by an In Vitro Digestion/Caco-2 Cell Model

“…Other alternative techniques have been used to estimate iron bioaccessibility and bioavailability: the in vitro digestion preceding the iron dialysis, and the in vitro digestion coupled to the iron uptake by the Caco-2 cells [38]. The in vitro digestion/Caco-2 cell model was developed more than twenty years ago [39][40][41][42][43] and has gained much attention as a method for iron bioavailability prediction in the last decade [39,[44][45][46][47]. It was used to predict iron bioavailability from different food products, staple food crops, and forms of iron [48].…”