What is the primary role of vitamins in the body?

Vitamins play a crucial role in the body primarily by facilitating various metabolic processes and maintaining overall health. Each vitamin has specific functions that contribute to the body's biochemical functions, such as energy metabolism, immune function, and synthesis of hormones and collagen. They are essential for converting food into energy, aiding in the absorption of minerals, and supporting the functioning of enzymes that are key to metabolic pathways.

For example, B vitamins are important for energy production, while vitamin C plays a role in the synthesis of collagen and acts as a cofactor in various enzymatic reactions. The diverse roles of vitamins extend beyond a single function, highlighting their necessity for optimal health and bodily processes.

Other options do not accurately capture the comprehensive role of vitamins. They do not provide energy directly, nor are they a primary source of calories like macronutrients. While some vitamins do have antioxidant properties, reducing oxidative stress is just one aspect of their overall contributions to health. Hence, the answer reflecting their primary role in supporting metabolic processes and health is indeed correct.