Which part of the small intestine is primarily responsible for food absorption?

The ileum is the final and longest segment of the small intestine, and it plays a crucial role in the absorption of nutrients from digested food. After the chyme passes through the duodenum and jejunum, most of the essential nutrients and minerals have already been absorbed, but the ileum is specifically designed to absorb certain remaining nutrients, including vitamin B12 and bile acids, which are vital for digestion and metabolism. Additionally, the ileum contains specialized structures called Peyer's patches, part of the immune system, which help monitor intestinal bacteria and prevent the growth of pathogenic bacteria.

In contrast, while the duodenum and jejunum also contribute to absorption, their primary functions are more focused on the initial stages of digestion and the absorption of different nutrients, with the duodenum being responsible for processing the mixture of food and digestive juices and the jejunum handling a significant portion of carbohydrate and protein absorption. The colon, on the other hand, primarily handles the absorption of water and electrolyte, rather than nutrients from food.