Library · Physiology
Fat digestion
Make it clearer
Digesting a fat means breaking it into pieces small enough to get into the body, and the work starts before you swallow: saliva contains an enzyme, lingual lipase, that already begins cutting triglycerides, which is the form fat takes in food.
The problem shows up in the intestine. Fat repels water and clumps into large droplets, and pancreatic lipase, the enzyme that has to cut it, is hydrophilic, that is, drawn to water. That is where bile comes in: it emulsifies the fat, breaking those large droplets into tiny ones. It is soap breaking up an oil stain into droplets so they can be washed away.
With the droplets now reachable, pancreatic lipase, along with colipase, cuts the bonds and leaves smaller pieces: diacylglycerols and monoacylglycerols.
Those pieces cluster into micelles, tiny packets, inside the intestine, and from there individual molecules diffuse across the membrane of the intestinal cell.
In brief
Fat digestion begins in the mouth: lingual lipase in saliva breaks bonds in triglycerides.
Bile emulsifies lipids, which repel water, so that pancreatic lipase, which is hydrophilic, can reach them.
Soap breaking an oil stain into droplets so it can be washed away.
That pancreatic lipase, with its coenzyme colipase, breaks the ester bonds and leaves diacylglycerols and monoacylglycerols.
The digested lipids cluster into micelles in the lumen, and individual molecules diffuse across the enterocyte membrane.
Sources (2)
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Digestion, StatPearlsPublished
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Nutrient Absorption, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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