Final answer:
Vitamin A2, among the listed options, is the vitamin that requires bile salts for emulsification and integration into the micelle for intestinal absorption. Fat-soluble vitamins A, D, E, and K use this mechanism for absorption, whereas vitamin B1 and B12 have different absorption pathways. The correct option is 3.
Step-by-step explanation:
The vitamins that require bile salts for emulsification and integration into the micelle for intestinal absorption are the fat-soluble vitamins, which include vitamins A, D, E, and K. Bile salts and lecithin play a crucial role in the digestion and absorption of dietary lipids by emulsifying them into smaller particles, known as micelles.
These micelles are then absorbed by the microvilli in the intestine. Fat-soluble vitamins are absorbed along with these dietary fats. Vitamin A2 (an alternative name for retinol, though not commonly used), as a fat-soluble vitamin, requires these mechanisms for absorption.
Vitamin B1 (thiamine) and vitamin B12 (cobalamin) have different absorption mechanisms, with B12 requiring intrinsic factor for absorption in the terminal ileum. Vitamin C (ascorbic acid) is water-soluble and does not require emulsification for absorption.
Vitamin B12 absorption is unique because it combines with intrinsic factor secreted in the stomach to form a complex that is absorbed in the terminal ileum via endocytosis. Therefore, the vitamin that requires bile salts for emulsification and integration into the micelle for intestinal absorption among the options provided is Vitamin A2. The correct option is 3.