Which mineral can affect iron absorption?

• A. Magnesium
• B. Calcium
• C. Zinc
• D. Potassium

Answer: (B)

Mineral interactions in the gut can influence how well iron is absorbed. Calcium is a well-established inhibitor of iron absorption. When calcium is present in the digestive tract, such as from dairy products or calcium supplements, it reduces the amount of iron that is taken up by intestinal cells. This effect is thought to involve competition for absorption-related processes in the enterocytes and possibly the formation of less soluble iron–calcium complexes, making iron uptake less efficient. Because of this, iron absorption from a meal can be noticeably lower when calcium is consumed at the same time. The other minerals listed don’t have as consistent or strong an impact on iron absorption in typical dietary contexts, so calcium is the best answer.