Digestion of Lipids

Butter or meat are organic compounds consisting of carbon, hydrogen and, oxygen. These are highly concentrated and dietary fats in daily diet. These belong to lipids class and are insoluble in water and are not broken down by lipase i.e., fat digesting enzymes in the

gastrointestinal enzymes

. Hence lipid digestion takes long time.

Ebner’s gland

on the tongue secretes small amount of lipase. Real digestion of fat is done once it reaches the duodenum. Complex fat molecules should be broken down into smaller molecules. This takes place when the fat is mixed by the digestive enzyme lipase (enters into the duodenum from the pancreas). Lipase cuts down the lipid molecules into fatty acid and glycerol molecules. Fat enters the duodenum in the form of solid, which is impossible for pancreatic lipase enzymes to dissolve them.

To overcome this,


(produced by liver but stored in gallbladder) is used by the digestive system. Bile breaks down the fat into small droplets and are suspended into the digestive tract in the form of water. Fat molecules are easily accessible by the emulsification of lipase. This fastens the breaking of fat molecules and also their digestion.

Fat molecules are converted into fatty acids and glycerol by the lipase and some other digestive juices. Fat is absorbed by


(finger like projections in small intestine) in 10-15min. Each villus consists of series of lymph vessels or lacteal and blood vessels. Fatty acids and glycerol are absorbed by the lacteal which are drained into bloodstreams.

Blood stream transports fatty acids into the membranes of adipose or muscle cells. They are stored for energy or for oxidizing into energy. Glucose is the source of energy than fats. Only five percent of fat is converted into glucose and the rest is stored as a body fat in adipose cells. Glycerol is absorbed by the liver and is converted into glucose or broken down glucose into energy.

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