Lactic acid decreases Fe (II) and Fe (III) retention but increases Fe (III) transepithelial transfer by Caco-2 cells

Journal article, 2005

Lactic acid (LA) has been proposed to be an enhancer for dietary iron absorption, but contradictory results have also been reported. In the present study, fully differentiated Caco-2 cell monolayers were used to evaluate the effects of LA (1-50 mmol/L) on the cellular retention and transepithelial transport of soluble non-heme iron (as ferric nitrilotriacetate). Our data revealed a linear decline in Fe(III) retention with respect to the concentration of LA added. In the presence of 50 mmol/L LA, retention of Fe(111) and Fe(II) decreased 57% and 58%, respectively. In contrast, transfer of Fe(111) across the cell monolayer was doubled, while Fe(II) transfer across the cell monolayer decreased 35%. We conclude that LA reduces cellular retention and transepithelial transport of Fe(l I) by Caco-2 cells in a dose-dependent manner. However, while LA also reduces retention of Fe(111) by Caco-2 cells, the transfer of Fe(III) across cell monolayers is enhanced, possibly due to effects on paracellular transport.