Which vitamin is involved in metabolism of carbohydrates and some amino acids and is essential for nerve and muscle action, and is absorbed in the small intestine?

Which vitamin is involved in metabolism of carbohydrates and some amino acids and is essential for nerve and muscle action, and is absorbed in the small intestine?

• A. Thiamine
• B. Riboflavin
• C. Niacin
• D. Pantothenic acid

Answer: (A)

Thiamine acts as a coenzyme in energy metabolism and supports nerve and muscle function. In carbohydrate metabolism, its active form, thiamine pyrophosphate, is needed by enzymes like pyruvate dehydrogenase and α-ketoglutarate dehydrogenase to convert glycolysis products into acetyl-CoA and feed the TCA cycle, and by transketolase in the pentose phosphate pathway to help generate energy and biosynthetic inputs. It also participates in the breakdown of certain amino acids through these same enzyme systems, linking amino acid metabolism to energy production. The nervous system and muscles rely on steady energy supply, so thiamine is essential for proper nerve conduction and muscle action. It is absorbed in the small intestine, reflecting its status as a water-soluble vitamin with typical intestinal uptake and renal excretion when in excess. Other vitamins contribute to energy metabolism in different ways, but the described roles align most directly with thiamine.

Thiamine acts as a coenzyme in energy metabolism and supports nerve and muscle function. In carbohydrate metabolism, its active form, thiamine pyrophosphate, is needed by enzymes like pyruvate dehydrogenase and α-ketoglutarate dehydrogenase to convert glycolysis products into acetyl-CoA and feed the TCA cycle, and by transketolase in the pentose phosphate pathway to help generate energy and biosynthetic inputs. It also participates in the breakdown of certain amino acids through these same enzyme systems, linking amino acid metabolism to energy production. The nervous system and muscles rely on steady energy supply, so thiamine is essential for proper nerve conduction and muscle action. It is absorbed in the small intestine, reflecting its status as a water-soluble vitamin with typical intestinal uptake and renal excretion when in excess. Other vitamins contribute to energy metabolism in different ways, but the described roles align most directly with thiamine.