Which primary function best describes vitamin D in human nutrition?

• A. Is required for collagen synthesis through hydroxylation of proline and lysine
• B. Enhances intestinal absorption of calcium and phosphorus to support bone mineralization
• C. Acts as a coenzyme in carbohydrate metabolism by facilitating decarboxylation reactions
• D. Serves as the main antioxidant in plasma by directly neutralizing free radicals in aqueous environments

Answer: (B)

Verified step by step guidance

1. Identify the primary functions of vitamin D in human nutrition by reviewing its role in the body.
2. Recall that vitamin D is crucial for maintaining calcium and phosphorus balance, which are essential minerals for bone health.
3. Understand that vitamin D enhances the intestinal absorption of calcium and phosphorus, thereby supporting bone mineralization and overall skeletal integrity.
4. Compare this function with other options: collagen synthesis is primarily related to vitamin C, carbohydrate metabolism coenzyme roles are linked to B vitamins, and antioxidant functions in plasma are mainly attributed to vitamin E.
5. Conclude that the best description of vitamin D's primary function is its role in enhancing intestinal absorption of calcium and phosphorus to support bone mineralization.