Complete Nutrition Practice Test 2026 – All You Need for Exam Prep

Vitamin C plays a crucial role in iron absorption by enhancing non-heme iron uptake in the gut. It does this by reducing ferric iron (Fe3+) to the more soluble ferrous form (Fe2+) and by forming a soluble complex that keeps iron available for absorption. This effect is especially important for non-heme iron, which is found in plant foods and fortified products; heme iron from animal sources is absorbed well on its own.

Several dietary components can inhibit iron absorption. Phytates in whole grains, legumes, and seeds bind iron and prevent its absorption. Calcium from dairy or supplements can interfere by competing for absorption. Polyphenols, such as tannins in tea and coffee, can also bind iron and reduce its uptake. Caffeine, when consumed with iron-rich meals, can further reduce absorption.

To maximize absorption, pair iron-rich plant foods with vitamin C–rich foods (like citrus, peppers, or tomatoes) and avoid consuming calcium-rich foods or tea/coffee during the same meal as iron-rich foods; if possible, separate these beverages by a couple of hours.