Which part of the small intestine is involved in nutrient absorption?

The small intestine is crucial for digesting food and absorbing nutrients, and all three sections—duodenum, jejunum, and ileum—play a role in this process.

The duodenum, which is the first segment, receives partially digested food from the stomach and mixes it with bile and pancreatic enzymes, facilitating the chemical breakdown of nutrients. It is here that some vitamins and minerals start to be absorbed as digestion progresses.

Moving to the jejunum, this middle section is where the majority of nutrient absorption occurs. Its extensive surface area, due to folds, villi, and microvilli, maximizes contact with digested food, allowing for efficient absorption of carbohydrates, proteins, and fats into the bloodstream.

Finally, the ileum, the last part of the small intestine, continues the absorption process, particularly for vitamin B12 and bile acids. It also plays an essential role in absorbing any remaining nutrients that might not have been absorbed in the jejunum.

Since each section has a distinct yet collaborative function in nutrient absorption, it is accurate to state that all parts of the small intestine contribute to this vital process.