This PPT helps to simply understand the functions of carbohydrates in human health.

1. Mrs.P.Ramalakshmi, M.Sc., M.Phil.,
Assistant Professor of Food Processing and Quality Control,
V.V.Vanniaperumal College for Women,
Virudhunagar.

2.  Carbohydrates are sugars or polymers of
sugars such as starch, that can be hydrolysed
to simple sugars by the action of digestive
enzymes or by heating with dilute acids.
 Primary fuel source for body cells
 Made by carbon, hydrogen and oxygen in a
ratio 1:2:1
 General formula CnH2nOn

3. Source of Energy
Protein Sparing Action
Oxidation of Fats
Indispensability for Nervous System
Role in Muscle
Role in Liver

4. Source of Energy for Heart Muscle
Synthesis of Ribose from Glucose
Conversion to Fat
Promotes growth of desirable bacteria
Contribution of Dietary Fibre
Biosynthesis of Amino acids
Structural Component

5.  Carbohydrates are least expensive source of
energy to the body.
 Every gram of Carbohydrate, when oxidised
yields on an average 4 kilo calories.

6.  The body uses carbohydrates as a source of
energy, when they are adequately supplied in the
diet, sparing protein for tissue building.
 If diet does not adequate calories from
carbohydrate, the dietary protein is oxidised as a
source of energy.
 There is also breakdown of tissue proteins to a
greater extent.
 This function of carbohydrate of serving as a
source of energy and preventing dietary protein
from being oxidised is called Protein Sparing
Action.

7.  In oxidation of fats, the acetyl CoA formed from
the oxidation of fatty acids reacts with
oxaloacetic acid from carbohydrate and amino
acid metabolism to form citric acid which is
oxidised through the TCA cycle back to
oxaloacetic acid through a series of reactions.
 Hence, for β-oxidation of fats, carbohydrate is
essential.
 If adequate amount of carbohydrate is not
consumed, intermediary products of fat
oxidation are accumulated.
 Acetone, acetoacetic acid and β-hydroxy butyric
acid accumulate and produce ketosis.

8.  The main source of energy for central
nervous system is glucose.
 Prolonged hypoglycemia can lead to
irreversible damage to the brain tissue.

9.  Carbohydrates are the major source of energy
for muscular work.
 During muscular contraction, glycogen is
broken down to lactic acid through glycolysis.
 During the recovery period, lactic acid is first
oxidised to pyruvic acid and then to acetyl
CoA which is then oxidised to C02 and H2O,
thus producing energy for muscular work.

10.  These include detoxifying action and
regulating influence of protein and fat
metabolism.
 Liver is rich in glycogen and is more resistent
to certain poison such as carbon
tetrachloride, alcohol, arsenic and toxins of
bacteria.
 The rate of oxidation of amino acids in liver is
diminished if abundant supply of
carbohydrates are available.

11.  The heart muscle mainly uses glucose as
source of energy.
 In hypoglycemia, a definite adverse change in
the working of the heart has been observed.

12.  The pentose, ribose is present in RNA and in
many nucleotides.
 It is formed in the body from glucose by
Hexose Mono Phosphate pathway.

13.  Excess of calories fed in diet in the form of
carbohydrate is stored as fat in adipose
tissue.
 When the body is in need of energy, it can be
released from the adipose tissue.

14.  Lactose has several functions in the
gastrointestinal tract.
 It promotes the growth of desirable bacteria,
some of which are useful in the synthesis of
B-complex vitamins.
 Lactose also enhances the absorption of
calcium.

15.  A small amount of energy is produced from
the release of short chain fatty acids in the
large intestine.
 Fibre stimulates the peristalic movement.
 It helps in preventing many degenerative
diseases.

16.  The carbon skeleton for the synthesis of
alanine, aspartic acid and glutamic acid are
provided by glucose during its oxidation,
from pyruvic acid, oxalo acetic acid and β -
ketoglutaric acid respectively.

17.  Carbohydrates are precursors for many
organic compounds.
 As glycoproteins and glycolipids participate
in the structure of cell membrane and cellular
functions such as cell growth adhesion and
fertilisation.
 Carbohydrates are structural components of
many organisms.
 These include the fibre of plants, exoskeleton
of some insects and cell wall of
microorganisms.