Question

How are lipids digested in the body?

Answer 1

Hint: Lipids are mostly consumed in the form of triglycerides or neutral fat. Triglycerides are made up of free fatty acids and glycerol nucleus. Triglycerides are mainly present in animal source food. Apart from triglycerides, small quantities of cholesterol and cholesteryl esters are also present in food.
Dietary fats are classified into two types:
-Saturated fats
-Unsaturated fats.

Complete answer:
The lipolytic enzymes are responsible for the digestion of lipids. The digestion of lipids takes place at various places in the digestive system:
-Digestion in the mouth: the digestion of lipids itself does not happen in the mouth but saliva secretes an enzyme lingual lipase which is swallowed along with the food.
-Digestion in the stomach: by gastric lipase.
-Digestion in the intestine: most of the lipids and almost all lipids are digested in the small intestine because of the presence of bile salts, pancreatic lipolytic enzymes, and intestinal lipase. Intestinal lipase mainly acts on triglycerides and converts them into free fatty acids.

Role of bile salts in the lipids digestion

-Emulsification of fats: Lipolytic enzymes of the GI tract cannot digest the fats directly because the fats are insoluble in water due to the surface tension. Therefore, Emulsification is the process by which the large fat globules are broken down into minute droplets and made in the form of a milky fluid called
emulsion in the small intestine, by the action of bile salts. Bile salts reduce the surface tension and act as a surfactant which helps in the digestion. These small minute lipid droplets can now be digested by lipolytic enzymes.

-Absorption of fats: Bile salts help in the absorption of digested fats from the intestine into the blood. A mixture of Bile salts with fats and make complexes of fats called micelles. The fats in the form of micelles can be absorbed easily.

Note: The micelles containing monoglycerides, cholesterol, and fatty acids enter the cells of the intestinal mucosa by simple diffusion. Chylomicrons - Triglycerides and cholesterol esters are coated with a layer of protein, cholesterol, and phospholipids to form the particles called chylomicrons.