Which vitamins are the precursors for the co-enzymes NAD+ and FAD?

The correct answer is the one that states B3 (niacin) and B2 (riboflavin) are the precursors for the co-enzymes NAD+ and FAD, respectively. Niacin, also known as vitamin B3, is essential for the synthesis of NAD+ (nicotinamide adenine dinucleotide), which plays a critical role in cellular metabolism and energy production. NAD+ is necessary for various dehydrogenation reactions, thus facilitating the metabolic processes that convert carbohydrates, fats, and proteins into usable energy.

Riboflavin, or vitamin B2, is crucial for the production of FAD (flavin adenine dinucleotide). FAD is another important co-enzyme involved in metabolic reactions, particularly in the Krebs cycle and fatty acid oxidation. It functions in redox reactions, helping to convert nutrients into energy.

These vitamins emphasize the interconnectedness of various micronutrients in metabolic pathways, highlighting the significance of a balanced diet to ensure adequate intake of these essential B vitamins.