Dietary fats provide about one third of our daily energy needs through fatty acid catabolism. Fatty acids are a major energy source for many organisms, providing up to 80% of the energy needs for the mammalian heart and liver. Hibernating animals also rely almost exclusively on fats for energy storage. Triacylglycerols are the main form for storing energy in the body, supplying 40% or more of daily energy intake on average. Cells can obtain fatty acid fuels from dietary fats, stored body fats, and fats synthesized in one organ for export to another. In vertebrates, ingested triacylglycerols are converted to micelles for absorption through the small intestine

1. Fatty acid catabolism
Kashaf Naz
Sp18-BSI-025
5/23/2019

2. Digestion, metabolism and transport
of fats
1. Dietary Fats Are Absorbed In the
Small Intestine

3. Oxidation of Fatty Acids is a Major Energy
Yielding Pathway in Many Organisms
 About one third of our energy needs comes from
dietary triacylglycerols
 About 80% of energy needs of mammalian heart
and liver are met by oxidation of fatty acids
 Many hibernating animals, such as grizzly bears
relay almost exclusively on fats as their source of
energy

4. Triacylglycerols
 Main function is energy storage
 On average, 40% or more of the daily energy
requirement of humans in highly industrialized
countries is supplied by dietary triacylglycerols
(although most nutritional guidelines recommend no
more than 30% of daily caloric intake from fats).

5. Digestion, Mobilization, and
Transport of Fats
 Cells can obtain fatty acid fuels from three sources
• Fats consumed in the diet.
• fats stored in cells as lipid droplets.
• fats synthesized in one organ for export to another
 provide more than half the energy requirements of
some organs, particularly the liver, heart, and resting
skeletal muscle.
 Stored triacylglycerols are virtually the sole source of
energy in hibernating animals and migrating birds.

6.  In vertebrates, before ingested triacylglycerols can be
absorbed through the intestinal wall they must be
converted from insoluble macroscopic fat particles to
finely dispersed microscopic micelles.
 This solubilization is carried out by bile salts, such as
taurocholic acid , which are synthesized from
cholesterol in the liver, stored in the gallbladder, and
released into the small intestine after ingestion of a
fatty meal
Dietary Fats Are Absorbed in the
Small Intestine

7. Fatty Acids Are Absorbed in the
Vertebrate Small Intestine