Non-heme iron absorption is enhanced by which factors?

• A. Calcium and phosphate.
• B. Vitamin C and acidic conditions.
• C. Vitamin A and zinc.
• D. Fat and fiber.

Answer: (B)

Non-heme iron absorption is improved when iron is kept soluble and in the ferrous form as it moves through the gut. The stomach’s acidic environment helps solubilize iron, and vitamin C is especially effective because it donates electrons to ferric iron (Fe3+) and converts it to ferrous iron (Fe2+). The ferrous form forms a soluble, easily absorbed complex with ascorbate, which protects iron from precipitation as the pH rises in the small intestine and aids uptake by intestinal transporters.

That’s why vitamin C together with an acidic environment best enhances non-heme iron absorption. In contrast, substances like calcium and phosphate can form insoluble complexes with iron and inhibit absorption; fat and fiber can slow or reduce iron uptake in some contexts; vitamin A and zinc do not act as enhancers for non-heme iron absorption. So pairing plant-based iron sources with vitamin C-rich foods (and ensuring enough gastric acidity) optimizes absorption.