Bile is also digestive juice, but there is no enzyme in bile to digest food. Therefore, bile is very important.

Bile plays an important role in the digestion and absorption of fat:

1. Bile salt, cholesterol and lecithin can be used as emulsifiers to reduce the surface tension of fat, emulsify fat into droplets and disperse them in intestinal cavity, thus increasing the action area of pancreatic lipase and accelerating its decomposition of fat.

2. Due to its molecular structure, bile salts can be polymerized to form micelles when reaching a certain concentration. The decomposition products of fat in intestinal cavity, such as fatty acids and monoglycerides, can be mixed into microgels to form water-soluble complexes (mixed microgels). Therefore, bile salts become a necessary carrier for insoluble fat hydrolysate to reach the surface of intestinal mucosa, which is of great significance for the absorption of fat hydrolysate.

3. Bile can promote the absorption of fat-soluble vitamins (vitamins A, D, E, K) by promoting the absorption of lipolysis products.

In addition, bile can also neutralize some gastric acid in duodenum; Bile salt is a humoral factor that promotes bile secretion after small intestine absorption.