Which statement best describes the role of vitamin D in bone health?

• A. Vitamin D plays a key role in bone health by facilitating calcium absorption in the gut.
• B. Vitamin D decreases bone density.
• C. Vitamin D has no relation to bones.
• D. Vitamin D solely helps with vision.

Answer: (A)

Vitamin D is essential for bone health because it enables calcium absorption from the gut, which provides the minerals needed for bone formation and preservation. The active form of vitamin D, calcitriol, increases the production of calcium-binding proteins in intestinal cells, boosting how much calcium (and phosphate) is absorbed from the diet. When calcium absorption is adequate, bones mineralize properly, staying strong and dense; without enough vitamin D, calcium absorption drops, leading to softer bones and a higher risk of fractures (rickets in kids, osteomalacia in adults). The other statements aren’t correct because vitamin D does relate to bones, it doesn’t decrease bone density, and its role isn’t limited to vision.