The Effect of Ascorbic Acid on the Inhibition of Heme Iron Absorption in Caco-2 Cells
Open Access
- Author:
- Lindsay, Elizabeth
- Area of Honors:
- Nutritional Sciences
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Okhee Han, Thesis Supervisor
Rebecca L Corwin, Thesis Honors Advisor - Keywords:
- heme iron
ascorbic acid
Caco-2 cells
polyphenols
grape seed extract
EGCG - Abstract:
- Dietary polyphenolic compounds, such as those found in grape seed and green tea extracts, have a wide range of effects in vivo and vitro including chelation of metals such as iron. Because iron deficiency is the most common nutritional problem found throughout the world, it is wise to explore the effects of those compounds on the intestinal absorption of iron and to try to discover ways to reverse those effects. Previous research has shown that epigallocatechin-3-gallate (EGCG) and grape seed extract (GSE) both have an inhibitory effect on the absorption and transport of heme and non-heme iron across a cellular membrane. The objective of this study was to examine whether ascorbic acid (AA) counteracts the inhibitory effects of EGCG and GSE on heme iron absorption in Caco-2 cells. The fully differentiated intestinal Caco-2 cells grown on mircoporous membranes were incubated for 7 h with heme 55Fe in uptake buffer that contained EGCG, GSE, or a combination of each of the previous and AA in the apical compartment. GSE and EGCG significantly decreased (p < 0.05) heme iron transport at 5 and 7 h. AA increased (p < 0.05) apical heme iron uptake and reversed EGCG-mediated inhibition of heme iron uptake. AA also increased (p < 0.05) the transepithelial heme iron transport in the presence of both EGCG and GSE. This study shows that EGCG and GSE significantly decrease the transport of heme iron. GSE does so by working at the level of the basolateral, not the apical, membrane. EGCG works at the basolateral and apical membranes. In addition, AA reversed the inhibition of cellular iron uptake when added to EGCG but not when added to GSE.