Which vitamin plays a crucial role in carbohydrate metabolism?

Vitamin B1, also known as thiamine, plays a crucial role in carbohydrate metabolism. It serves as an essential coenzyme in the conversion of carbohydrates into energy. Specifically, thiamine is involved in the biochemical pathways that transform glucose into usable energy by facilitating the production of energy-rich molecules such as ATP (adenosine triphosphate).

In addition to its role in energy metabolism, thiamine is vital for the proper functioning of nerve cells, as it helps in the synthesis of neurotransmitters, which are crucial for communication between neurons. A deficiency in thiamine can lead to metabolic disorders such as beriberi, which is characterized by symptoms related to energy deficiency and nervous system dysfunction.

Other vitamins listed do not have the same critical role in carbohydrate metabolism. For instance, vitamin B12 is primarily involved in DNA synthesis and red blood cell formation, while vitamin C is an antioxidant that supports immune function and collagen synthesis. Vitamin E primarily serves as an antioxidant that protects cell membranes but does not play a significant role in carbohydrate metabolism. Thus, the importance of thiamine in converting carbohydrates into energy makes it the correct answer in the context of this question.