In which part of the digestive system does most nutrient absorption occur?

Most nutrient absorption occurs in the small intestine due to its specialized structure and extensive surface area, which are critical for efficiently absorbing nutrients from digested food. The small intestine is lined with villi and microvilli that increase the surface area, allowing for a greater amount of nutrients to be absorbed into the bloodstream.

In addition to its anatomical adaptations, the small intestine has three distinct sections: the duodenum, jejunum, and ileum. Each section contributes to the digestion and absorption of different nutrients, such as carbohydrates, proteins, and fats. The chyme enters the small intestine partially digested, and by the time it moves through all three sections, most of the macronutrients and micronutrients have been absorbed.

This contrasts with the other parts of the digestive system: the stomach primarily functions in the breakdown of food and the initiation of protein digestion, the large intestine mainly absorbs water and electrolytes while forming waste products, and the esophagus serves solely as a passageway for food to move from the mouth to the stomach. These roles highlight why the small intestine is the primary site for nutrient absorption in the body.