Which vitamins are required to produce energy from carbohydrates, fats, and proteins?

• A. Vitamin A, D, E, K
• B. Vitamin B1, B2, B3
• C. Vitamin K, Biotin, Folic acid
• D. B1, B2, B3, Bs

Answer: (D)

B vitamins provide the essential coenzymes that drive the steps converting the three main fuels—carbohydrates, fats, and proteins—into usable energy. Thiamine (B1) helps decarboxylation steps in carbohydrate metabolism, feeding acetyl groups into the citric acid cycle. Riboflavin (B2) forms FAD/FADH2, key electron carriers in both the TCA cycle and fat oxidation. Niacin (B3) forms NAD+/NADP+, which carry electrons through glycolysis, the TCA cycle, and oxidative phosphorylation. Because energy production from all macronutrients relies on these coenzymes, a group of B vitamins supports the process, so listing B1, B2, B3 along with other B vitamins captures the vitamins required for energy production. The other options rely on vitamins that are not direct coenzymes for energy metabolism (for example, fat-soluble vitamins or vitamins not central to the energy-yielding pathways).