Iron absorption is enhanced by which of the following factors?

Iron absorption is enhanced by acidic chyme in the duodenum because the acidic environment helps to solubilize iron, particularly non-heme iron (the type found in plant sources). In this acidic condition, iron is in a more readily absorbable form, which facilitates its uptake in the intestines.

In contrast, an alkaline environment, such as that found in the upper part of the small intestine when the chyme is neutralized, can reduce iron solubility and subsequently impair absorption.

Factors such as oxalates and phytates are known to inhibit iron absorption. These compounds can bind to iron, making it less available for absorption. Additionally, the absence of ascorbic acid (vitamin C) would also negatively impact iron absorption, as ascorbic acid is known to enhance the absorption of non-heme iron by reducing it to a ferrous state and forming a complex that is more easily absorbed.

Thus, the presence of acidic chyme in the duodenum is crucial for optimal iron absorption.