FAT POWERPOINT FOR FIRST YEAR MEDICAL STUDENTS

1. Preeti shukla
Lecturer
RCN, Kanpur
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2. Fat
LIPIDS-
• Fats and oils belongs to a group called lipids. They
are characterized by greasy feel, insolubility in water.
They are mainly made up of carbon, hydrogen and
little oxygen. They are more concentrated source of
energy and provide 2.5 times more energy per gram
than carbohydrates and protein.
• Fats are solid at 20 degree. they are called oils if they
are liquid at that temperature.
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4. Fatty acids- the fatty acids may be saturated,
unsaturated and polyunsaturated. The flavor and
hardness of fat depend on the kinds and amounts of
fatty acids present in it. Simple fats and oils are of great
importance in food presentation. One, two or three fatty
acids may be esterified with glycerol to form
monoglycerides or triglycerides respectively. The most
common form of food fats are triglycerides.
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5. • Saturates fatty acids- the saturated fatty acids, each
carbon atom in the fatty acid carries all the hydrogen
atoms possible. They have single bond between
carbon atoms. Saturated fatty acids are found mainly
in animal fats but there are exceptions as, e.g-
coconut and palm oils, although vegetable oils have
an extremely high percentage of saturated fatty acids
and they are solid. Stearic acid, palmitic acid,
myristic acid and butyric acid are some of the
saturated acid.
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7. • Unsaturated fatty acid- the full complement
of hydrogen atoms is not received in
unsaturated fatty acids. This leads to the
formation of double bond between the atoms
so they have one or more double bonds
between the carbon atoms. Unsaturated fatty
acids are further divide in to two-
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8. 1- Monounsaturated- they have one double
bond between the carbon atoms. Oleic acid is an
example of monosaturated fatty acid and it is
found in groundnut oil, olive oil and corn
oil.they are mostly found in vegetable oils.
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9. • Polyunsaturated acids- fatty acids with two or more
double bonds are called polyunsaturated fatty acids.
These are mostly found in vegetable oils.
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10. Essential fatty acids- essential fatty acids are those
cannot synthesized by humans. They can derived
from food. The most essential fatty acid is lonoleic
acid which serves as the basis for the production
of other essential fatty acids. Linoleic acid is
abundantly found in vegetable oil.
• Deficiency of EFA in diet may result in growth
retardation, reproductive failure and skin
disorders. So at least 3% of energy requirement
should be derived from EFA.
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11. • Linoleic acid
• Alpha-linolenic acid
• Omega 3 fatty acids ( olive oil, fish oil,
mustard oil, soyabean and black gram)
• Omega 6 fatty acids (sunflower, cottonseed,
sesame and groundnut oil)
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12. Classification of lipids- on the basis of structure:
1- simple lipids
2-Compound lipids
3- Derived lipids
4- sterol
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13. 1- Simple lipids- the are made up of three fatty
acids attached to glycerol. They are mixed
triglycerides which means that more than one
type of fatty acids are present in fat.
• E.g- cooking oil and butter. Simple lipids
constitute more than 98% of food and body
fats.
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14. 2- Compound lipids- they are fats in which at
least one fatty acid is replaced by carbohydrate,
protein or phosphorus.
e.g- phospholipids, glycolipids and lipoprotein.
3-Derived lipids- they are the breakdown
products of fats and include diglycerides,
monoglycerides, glycerol and fatty acids.
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15. 4- Sterol- they are not made up of fatty acids and
glycerol but have benzene ring structure. These
fat like substance include cholesterol and fat
soluble vitamin A, D, E and K
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16. Classification of lipids on the bases of fatty
acids
1- Saturated
2- Unsaturated
3- Monounsaturated
4- Polyunsaturated
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17. FUNCTION OF FATS
1- ENERGY- Fats are a concentrated source of
energy. All tissues except those of central
nervous system and brain can utilize fat as a
source of energy. Fats are deposited in the
adipose tissue and this deposit serves as a reserve
source of energy during starvation.
2- Thermal insulation- subcutaneous fat acts as
an insulator against cold by retaining body heat.
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18. 3- Protein sparing action- an adequate intake of
fat in the diet allows proteins to perform their
main functions of growth and maintenance.
4- Protection of vital organs- fat provides a
protective padding to vital organs such as heart,
kidney and intestine from mechanical shock and
keeps them in place.
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19. 5- Absorption of fat soluble vitamins- fats are
essential fopr the absorption of fat soluble vitamins A,
D, E and K. So fats serves as vehicles for fat soluble
vitamins.
6- Essential fatty acids- fats contain essential fatty
acids linoleic, alpha-linolenic and arachidonic acids
which are essential for maintaining tissue in normal
health.
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20. 7- Satiety value- fats improve the palatability of the
diet and give satiety value. i.e- feeling of fullness in the
stomach.
8- Synthesis of hormones- the cholesterol is necessary
for the synthesis of some steroid hormones and bile
acids, e.g- sex hormone.
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FOOD SATISFACTION
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23. • SOURCES OF FATS-
1- Animal fats- ghee, butter, cheese, egg, yolk, meat
and fish.
2- Vegetable fats- groundnuts, mustard, soyabean,
coconut, almond and sunflower.
3- Other- small amount of fat are found in most other
food such as cereals, pulses and vegetables.
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25. • The minimum intake of visible fat for Indian
adult ranges from 20-40 g/day. The pregnant
and lactating mothers should contain at least
30g/day.
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27. • Digestion and absorption of fats- when a person takes
his food it enters the stomach where gastric lipase
produces slight hydrolysis of fat ( process of splitting
into smaller molecules by uniting with water)
• In the duodenum, bile secretion emulsifies fats.
Pancreatic lipase and intestinal lipase breakdown the
fats into a mixture of monoglycerides, diglycerides
and fatty acids.
• The products of digestion pass through the lacteals of
the small intestines to the thoracic duct, then to the
bloodstream and every cell of the body.
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30. • Fat metabolism is a biological metabolic
process that breaks down ingested fats into
fatty acids and glycerol after which into
simpler compounds that can be used with the
aid of cells of the body. These compounds
ultimately gets processed and broken down to
produce energy to the body cells.
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31. • Fat metabolism is controlled by hormones such
as insulin, growth hormone,
adrenocorticotropichormone, and
glucocorticoids. The rate of fat catabolism is
inversely related to the rate of carbohydrate
catabolism, and in some conditions, such as
diabetes mellitus, the secretion of these
hormones increases to counter a decrease in
carbohydrate catabolism.
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