Which mineral is commonly used for bone health and can cause constipation at high doses?

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

Answer: (C)

Calcium is the mineral most directly tied to bone health. Our bones store the majority of the body's calcium, and this mineral is essential for bone formation and maintaining density. Because of its central role in bones, calcium supplementation is commonly used to support bone health and prevent osteoporosis. When taken in high doses, calcium can slow GI transit and lead to constipation, a known side effect of calcium supplements, especially in forms like calcium carbonate. The other minerals have different primary roles—iron supports oxygen transport, zinc is important for enzymes and immune function, and magnesium participates in many processes and can even have a laxative effect at high doses—so they don’t fit the combination of bone-health use and constipation as neatly as calcium does.