digestion and absorption of lipids

1. VIGNESWARAN G B.Sc. , M.Sc.
ASSISTANT PROFFESSOR,
DEPARTMENT OF BIOCHEMISTRY
NANDHA DENTAL COLLEGE AND HOSPITAL

2. Dietary lipids
 Lipids to be digested per day
- 60g (poorer sections of society)
- 160g (western countries)
 Cholesterol(1.2g)
 Phospholipids from bile (3-5g/day)
 Digestion of lipids
DIGESTION
INTESTI
NE
MOUTH
STOMAC
H
•Triacyl glycerol(90%)
•Cholesterol
•Cholesteryl esters
•Phospholipids
•Free fatty acids
Dietary
lipids

3. MOUTH
No digestion of
lipids in mouth
due to absence of
lipolytic enzymes
STOMACH
 Little digestion Lingual lipase (acid stable)
- Slightly digest
Gastric lipase
- Acidic environment is not suitable
- Acts in infants and breaks
short chain fatty acids in milk fat at a
neutral pH
- Formation of large fatty aggregate
in aqueous environment

4. INTESTINE Emulsification
 Conversion of large fatty aggregate
into smaller droplets
 Carried out by bile salts in the bile
 Increases the surface area to act
Emulsification
By Bile Salts
Bile action on
aggregates
Fatty
aggregate
Smaller
droplets
Hydrophilic
bile salts
Hydrophilic Hydrophobic

5.  Degradation of triacyl glycerol
Triacyl glycerol
Free
fatty
acids
Mono
acyl
glycerol

6.  Degradation of cholesteryl esters
Cholesteryl ester
Free
fatty
acids
Cholesterol

7.  Degradation of phospholipids
Phosphatidyl choline
Free
fatty
acids
Glyceryl
phosphoryl
choline