Which nutrient enhances non-heme iron absorption when consumed together?

• A. Calcium
• B. Vitamin C
• C. Phytates
• D. Fiber

Answer: (B)

When non-heme iron is eaten with another nutrient, absorption can go up or down depending on what that nutrient does in the gut. Vitamin C stands out because it directly enhances non-heme iron uptake. It acts as a reducing agent, converting iron from the ferric form to the more soluble ferrous form, and it forms a stable complex that stays soluble as it moves through the intestinal tract. This keeps iron available for absorption in the small intestine, which is especially helpful for plant-based iron sources that are otherwise less readily absorbed. A practical example is adding citrus juice to iron-rich foods or choosing vitamin C–rich fruits with meals to boost absorption.

The other options tend to hinder rather than help absorption. Calcium can compete with iron for shared absorption pathways, reducing iron uptake if consumed in large amounts with iron-rich meals. Phytates, found in whole grains and legumes, bind iron and prevent its absorption. Fiber can also bind minerals and slow their absorption. So vitamin C uniquely enhances non-heme iron absorption when eaten together with iron-containing foods.