Caco-2 cells can be used to assess human iron bioavailability from a semipurified meal

A Caco-2 cell model with extrinsic radioiron was used to evaluate the effec t of dietary factors on nonheme iron bioavailability from a semipurified me al. Study 1 was conducted to evaluate the effect of enhancers (ascorbic aci d) and inhibitors (bran, phytate and tea) on iron bioavailability when adde d to semipurified meal containing egg albumen as a protein source. The effe ct of various proteins [bovine serum albumin (BSA), casein, beef and soy] o n iron bioavailability was evaluated in Study 2 by substituting the above p rotein sources for egg albumen. Protein solubilization following in vitro d igestion for individual test meals was not significantly different from the control. On the other hand, nonheme iron solubilization (0.8 +/- 0.0 to 5. 9 +/-. 0.3 vs. 4.9 +/- 0.8 mg/L) varied significantly. The total iron uptak e for each meal was calculated based on the percentage of radioiron taken u p and transported by Caco-2 cells and the amount of nonheme iron present in uptake solutions. Iron uptake ratios represent test/control values. With t he exception of BSA and ascorbic acid, the effect of dietary factors was si milar to that found in humans reported in the literature. A significant cor relation (r = 0.97; P < 0.0001) was found between the published human absor ption data and the iron uptake by the Caco-2 cells. The results of our stud y indicate the usefulness of Caco-2 cells in assessing human iron absorptio n and the feasibility of this cell model in studying iron bioavailability f rom various food combinations, otherwise not easily performed in humans.