Final answer:
B-vitamins primarily act as coenzymes, assisting enzymes in biochemical reactions related to energy metabolism, rather than directly providing energy to the body.
Step-by-step explanation:
The primary role of B-vitamins is not to provide the body directly with energy but rather to act as coenzymes. Coenzymes are vital for the function of enzymes, which in turn catalyze various biochemical reactions, including those involved in energy metabolism. B-vitamins are key components in numerous catabolic pathways that break down molecules for energy and anabolic pathways that build up molecules for cellular functions. Moreover, these vitamins are also crucial for healthy blood renewal and function. Although B-vitamins are intricately associated with energy metabolism, they do not supply direct energy like macronutrients do.