Download MBBS Biochemistry PPT 66 Lipid Ingestion And Digestion Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st year (First Year) Biochemistry ppt lectures Topic 66 Lipid Ingestion And Digestion Notes. - biochemistry notes pdf, biochemistry mbbs 1st year notes pdf, biochemistry mbbs notes pdf, biochemistry lecture notes, paramedical biochemistry notes, medical biochemistry pdf, biochemistry lecture notes 2022 ppt, biochemistry pdf.


LIPID METABOLISM

In Health and Diseases

7 Main Human Body Lipid (Forms)

1. Free Fatty acids
2. Cholesterol
3. Triacylglycerol
4. Phospholipid
5. Glycolipids
6. Lipoproteins
7. Eicosanoids
Metabolism of Lipid Forms

Generation, Operation, Destruction

? Sources/Biosynthetic Pathways (Anabolism)

? Functions/Associated Metabolic Pathways

? Breakdown/Degradation Pathways (Catabolism)

? Health= Biomolecules in body present in

regulated, balanced and in ordered

mechanisms.

? Disorders= Biomolecules of body get

dysregulated, imbalanced and interferences

in mechanisms.


Lipid Metabolism Derangement

Is Associated with

Obesity

Metabolic Syndrome

Non Communicable Diseases

Obesity And Metabolic Syndrome


SYNOPSIS

1. DIETARY LIPIDS

?INGESTION
?DIGESTION
?ABSORPTION
?TRANSPORTATION
?UPTAKE BY TISSUES
2. LIPOLYSIS: LIPID CATABOLISM /

Utilization Of Stored TAG

q FATTY ACID OXIDATION

q KETONE BODY METABOLISM

3. LIPOGENESIS:

q LIPID BIOSYNTHESIS

q DE NOVO BIOSYNTHESIS OF FATTY ACIDS

4. LIPOPROTEIN METABOLIM/

TRANSPORTATION OF LIPID FORMS

5. DISORDERS ASSOCIATED TO LIPID

METABOLISM

INGESTION OF DIETARY LIPIDS/

EATING OF DIETARY LIPIDS
?Lipids are chief

constituents of human

food.

Ingestion Of Dietary Lipids

? What quantity and quality of Lipid forms to be

ingested per day?

? Which forms of dietary Lipids ingested from rich

sources ?

? Why to eat dietary Lipids?
What quantity and

quality of Lipids to be

ingested per day?

In What

Amount (Quantity) Dietary Lipids to be

Eaten?
? Daily consumption of dietary Lipids

by human beings varies and

depends upon:

?Dietary habits of an individual
?Economic status of a family

RDA OF DIETARY LIPIDS

?Per day quantity of dietary

Lipids for an adult individual

is:

?20-35% of Calorie need

?50-80 grams/day of dietary

Lipids
In What Form (Quality) Dietary Lipids

are ingested?

FORMS AND SOURCES OF

INGESTED DIETARY LIPIDS



? Dietary ingested Lipids contain fol owing

forms of Lipids:

?Triacylglycerol (TAG):Principal dietary

Lipid form ingested - 98%.

?Phospholipid
?Cholesterol Ester
?Fat soluble Vitamins: are soluble in Fat

hence associated with fatty foods.




Quality Of Dietary Lipids To be ingested

? Natural

? PUFA of Cis Form

? Omega 3 and Omega 6

? PUFA:MUFA:SFA 1:1:1 ratio

Avoid Trans Fats

As they are detrimental to Health

? Sources of dietary Lipids

should be free from Trans

Fatty acids/less than 1%.

? Trans Fatty acids are not

readily metabolized by

human body.

? Trans Fats increases the

risk of Atherosclerosis.


Dietary Rich Sources Of Lipids

? Obtained from both foods of

Plant and Animal origin.
Forms Of Fat in Food Sources



Visible Fat

Butter, Margarine, Salad oils and

dressing, Shortening Fat Meat

Invisible Fat

Cheese, Cream portion of

homogenized milk, Egg yolk, Nuts,

Seeds, Olives.



Sources Of Plant Lipids

q Plant Oils: Peanut ,Safflower

,Sunflower, Olive, Mustard Oils,

Margarine etc.

qNuts: Peanuts , Walnuts , Cashew

,Almonds, Sesame ,Pine etc


Sources Of Animal Lipids

?Milk and Milk products

?Egg Yolk

?Sea foods ?Fish, Shell fish

?Animal-Fat ,Meat , Liver and

Brain


Rich Dietary Sources of PUFAs



Why To Eat Dietary Lipids?

OR

Importance Of Ingesting

Dietary Lipids
Importance Of Ingesting Dietary Lipids:

? TAG (predominantly ingested) - secondary source of

energy for body tissues.

? Source of Essential Fatty acids/PUFAs-structural

components of tissues.

? Source of Fat Soluble Vitamins- Vitamin A,D,E and K

associated with Fatty foods.

? Improve taste of recipes.

? Increase palatability and satiety value.

? Thus daily consumption of

dietary lipids is essential for


? Maintenance of normal

?Health

?Growth

?Reproduction



Digestion Of Dietary Lipids In GIT

Digestion of Dietary Lipids

Is

Cleavage Of Ester Bonds

Present In Various

Complex /Unabsorbable Lipid Forms

By

Lipases/Lipolytic Enzymes

In

Different Parts Of GIT


Prerequisites for Lipid Digestion

? GIT Hormones
? Optimum pH
? Emulsifiers
? Emulsification
? Lipid Digesting Enzymes- Lipases


Gastrin

Chyme stimulates

Cholecystokinin (CCK)

Secretin

to release bile from

gallbladder and

Pancreas for Pancreatic

juice.

Enterogastrone

?Cholecystokinin (CCK)

and Secretin

?Stimulates the:

Gal bladder to contract

and release bile.


Mechanism Of Lipid Digestion

in Different Parts of GIT


Insignificant Lipid Digestion

Occurs in Mouth and Stomach

? Though Salivary juice contains

Lingual Lipase and Gastric juice

contains Gastric Lipase .

? Digestion of dietary Lipids in

mouth is negligible and stomach

is~10% of TAGs are hydrolyzed
Insignificant Digestion Of Lipids In Mouth and

Stomach Due to:

?No optimal pH of salivary and gastric juices

?No optimal activity of Enzyme Lipases

(Optimal pH range 6-8)

?No Emulsification Process in Mouth and

Stomach

?Dietary Lipids (insoluble form) when not

emulsified

?Do not have contact with polar and soluble

forms of Lipases present in the aqueous

phase of salivary and gastric juices.

?There is no cleavage of Ester bonds of Lipid

structures in salivary and gastric juices

?Insignificant digestion of Lipids in mouth

and stomach.
Significant and Complete

Digestion

Of Dietary Lipids

Occurs In

Smal Intestine

In presence of Bile after

Emulsification

Requirements

for

Emulsification

To Form Emulsions


Essential y Requires

Presence Of Bile

In Smal Intestine

For Lipid Digestion and

Absorption

? Bile is a greenish

fluid produced in

Liver.


? Concentrated and

stored in Gal

bladder.

? Carried through bile

duct

? Later secreted in

Smal intestine via

Common Bile Duct

(CBD)


Composition Of Bile

? Bile is an

Alkaline solution

? Composed of:

?Bile Salts

(Surfactant)

?Bilirubin

(Bile Pigment)

?Bile acids

?Cholesterol

?Lecithin


Bile Acids Derived From Cholesterol


?Name Of Bile

salts :

?Sodium

Glycocholate

?Sodium

Taurocholate
Role Of Bile Salts In Formation of

Emulsions During Emulsification

? Emulsifying agents/Emulsifiers:

?Emulsifying Agents/Surfactants:

? Bile Salts
(Sodium Glycocholate, Sodium Taurocholate)

? Amphipathic Lipids
(Phospholipids)
?Bile salts have detergent

like action

?Bile salts serve as :

? Emulsifying agents

? Responsible for fat Emulsification

? Bile salts and dietary Amphipathic

Lipids by their detergent like

action:

?Reduces surface tension

?Increases surface area of Fats/Oil

and make them miscible with

aqueous phase.
? Emulsions bring non polar

dietary Lipids in close

contact with Lipid digesting

Enzymes present in aqueous

phase of intestinal juices.

What Is Emulsification?


Emulsification

Takes Place In Smal intestine

Which

Initiate and Completes

Significant Digestion of

Dietary Lipids


Emulsifiers brings out Emulsification

and forms Emulsions
?Emulsification is an Essential

Prerequisite Physicochemical

Process

?Which forms Emulsions from

dietary ingested Lipids.

? Emulsification takes place in the

lumen of smal intestine.

? Emulsification process occur

before digestion of dietary Lipids.
? During the process of

Emulsification there is

dispersion of large droplets

of Fats/Oils

? Into smal , miscible droplets

which are termed as

Emulsions.


?Emulsions have non polar

lipids (TAG) in center


?Covered with a peripheral

layer of Bile salts and

Amphipathic Lipids.

Emulsions formed by Bile salts, Triacylglycerols and pancreatic lipase.
Emulsification Forming Emulsions

Significance Of Emulsification
? Emulsification facilitate digestion of dietary

Lipids in smal intestine by:

?Reduces surface tension, increasing surface

area of Lipids

?Forms Emulsions
?Improves miscibility of non polar Lipids TAG

in aqueous phase.

?Brings contact of dietary Lipids with Lipid

digesting enzymes.

?Facilitates cleavage of Ester bonds of

dietary Lipids.

This post was last modified on 05 April 2022