Which nutrient is primarily absorbed in the duodenum?

The nutrient that is primarily absorbed in the duodenum is folic acid. The duodenum, which is the first portion of the small intestine, plays a crucial role in the absorption of several important nutrients, including certain vitamins and minerals. Folic acid, or vitamin B9, is absorbed in the proximal small intestine, particularly in the duodenum. This nutrient is vital for DNA synthesis and repair, as well as for cell division, making its absorption in this area particularly important for overall health, especially in populations such as pregnant women.

In contrast, while vitamin B12 absorption occurs primarily in the ileum (the last part of the small intestine) after it binds to intrinsic factor secreted by the stomach, sugar, such as glucose, is absorbed through the small intestine as a whole, but specific transport mechanisms are more concentrated in the jejunum, which follows the duodenum. Fiber, on the other hand, is not absorbed in the small intestine at all; instead, it passes through to the large intestine, where it can provide various health benefits, including promoting healthy digestion. Thus, folic acid is indeed the nutrient that is primarily absorbed in the duodenum.