Which of the following is a function of vitamins in the body?

Vitamins play a crucial role in the body by acting as catalysts in various metabolic processes. They are essential for the proper functioning of enzymes, which are proteins that speed up biochemical reactions. Without vitamins, many of these reactions would not occur efficiently or, in some cases, at all. For instance, B vitamins are integral to energy production, while vitamin C is important for the synthesis of collagen, showcasing the diverse roles vitamins play in facilitating numerous metabolic functions.

In contrast, while energy provision typically is associated with macronutrients like carbohydrates, fats, and proteins, vitamins themselves do not provide energy directly. They also do not give structural support, which is typically the role of proteins and carbohydrates, and they are not involved in long-term energy storage, as that is primarily the function of fat and glycogen in the body. Thus, the role of vitamins as catalysts in metabolic processes is their primary function.